Guidelines for poultry production enterprises to increase the efficiency of broiler production and optimize the nutritional value of poultry litter and manure for use in ruminant nutrition is urgently needed. Therefore a study was conducted to investigate the effect of wood shaving (SA), wheat straw (WS), peanut hulls (PH) and sunflower hulls (SH) as bedding materials on the performance of broilers in conventional floor systems. In a second study the effect of different types of bedding materials and collecting periods on the feeding value of respectively broiler and layer hen manure for ruminants were investigated. Six hundred, day old Ross -1-broilers were randomly divided into 30 groups of 20 each. Six groups (replications) were then randomly allocated to one of the following five treatments: 1. Wood shavings and saw dust (Byproduct Development Services, 0.5 to 5 cm) 2. Peanut hulls 3. Sunflower hulls 4. Wheat straw (ground through a 30 mm sieve) 5. Control group (cement floor) Commercial broiler diets were fed ad lib. to all experimental groups. On the basis of weight of water absorbed per weight of bedding material, WS absorbed significantly more water than PH, SA or SH. No significant (P>0.05) differences in the percentage moisture release of different bedding materials occurred. Accordingly no significant differences in ammonia production, feed intake, weight gain, efficiency of feed conversion, carcass weight and dressing percentage of broilers were detected among the various treatments. The highest production number (weighted sum of average weight, percent livability, period and feed conversion) was calculated for broilers on peanut hulls, followed by no bedding material (control), wood shavings, sunflower hulls and lastly wheat straw. It was calculated that a broiler excreted approximately 878g dry matter in a 42 day period. The highest (P<0.05) crude protein content occurred in the manure of broilers raised on no bedding material followed by the peanut hulls treatment. No significant differences (P>0.05) occurred in the crude protein content of manure from the wood shavings and wheat straw treatments. Bedding materials in broiler litter did not influence effective degradability of crude protein statistically significant. The highest (P<0.05) acid detergent fibre content was recorded for wood shavings and the lowest for the control treatment, while the rest showed no significant differences. No significant differences occurred in the neutral detergent fibre (NDF) content of broiler litter gathered on the different bedding materials. The lowest (P<0.05) NDF content was again found where no bedding material was supplied. No significant differences occurred in the fat content of broiler litter originating from the different treatments. The highest (P<0.05) ash content and in vitro digestibility was in the pure excretion and the lowest in broiler litter containing wood shavings. There were no significant differences amongst the remaining treatments. Bedding material had no significant (P>0.05) influence on the mineral content of broiler litter. In an effort to investigate the effect of composting time (collecting period) on the feeding value of layer hen manure, ninety, 20 week old White Plymouth Rock layer hens were then randomly divided into 30 groups of 3 each. The 30 groups were then randomly allocated to 5 treatments. The manure of each treatment was respectively collected daily and after 14, 28, 42 and 56 days. All the layers received a commercial layer diet ad lib. The collection of layer manure after 56 days resulted in a significant (P<0.05) reduction in crude protein content, degradability and in vitro digestibility. No clear trend or influence of composting time on the ADF and NDF content of layer manure could be detected. Composting time had no influence on the fat content of layer manure. The ash content of layer manure increased significantly (P<0.05) with a delaying collecting period. Delaying of collecting time resulted in an increase in the percentage of Na, Ca, K, Mg, P and Cu of layer manure. No significant (P>0.05) influence of composting time on the concentrations of Fe, Zn and Mn was observed. It was concluded from the performance of the broilers on the different bedding materials and the nutritive value of the broiler litter that peanut hulls should be preferred as bedding material. SH should be the second choice followed by WS. Lastly it seems that layer manure should be collected on a regular basis and that the composting time should not exceed 42 days.

The study was conducted in the Somali region of eastern Ethiopia, with an arid to semiarid climate. The study aimed at the characterization of the rangeland resources, assessing the current condition of the rangeland, understanding pastoral perceptions on rangeland degradation and developing drought feeding strategies for livestock. Three experimental sites, representative of the three predominant vegetation types of eastern Ethiopia were selected. They were the arid Asbuli grassland (used as grazing area for large and small ruminants), the arid Aydora open savanna (bush-grassland: entirely used for grazing/browsing by all types of livestock), and the semi-arid Hurso closed savanna (bushland: selected for its importance as browsing for camels and goats). A degradation gradient was identified in each of the three vegetation types, where the botanical composition was surveyed and the rangeland condition assessed. The perceptions of the pastoralist on rangeland degradation were also quantified. The dry matter production of both the herbaceous and woody layer was determined, while the grazing and browsing capacity calculated. Key forage species were identified and the grazing pattern of various livestock species along the degradation gradient studied. The soil seed bank regeneration potential was assessed in a greenhouse experiment and the response of cattle, sheep and goats to a simulated drought, in terms of reduced fodder, was conducted under controlled conditions. The results of the study confirmed the existence of severe rangeland degradation that occurred since 1944 and which was aggravated after the 1974 drought. This contributed to an increase in the number of poor households. The average livestock holding per household declined from 809 Tropical Livestock Units (TLU) before 1974 to 483 TLU after 1974. Livestock holding shifted from a predominance of cattle to small ruminants, which are able to utilize the degraded rangeland more effectively. Camels are now the most important livestock species in terms of milk and meat production, mainly due to their ability to tolerate drought. The abundance of herbaceous plants, basal cover, dry matter production and grazing capacity was found to be higher in the benchmark sites compared to the other rangeland conditions. There was also a corresponding increase in percentage bare ground, soil compaction and soil erosion along the degradation gradients. Over-grazing and overutilization through continuous grazing of the herbaceous layer were identified as the main causes of these differences. Rangeland condition was observed to significantly influence the grazing behaviour of livestock in terms of plant species selection, grazing intensity and intake per animal. When forage sources were adequately available, animals selected fever plant species. As forage resources declined the animals spend more time grazing and more species selected, including less palatable species. The number of bites, intake per bite and intake as a percentage of the animalâs body mass also increased as the rangeland become more degraded. Acacia nubica and A. mellifera were identified as aggressive encroaching species in the Aydora open savanna and Hurso close savanna. The Aydora open savanna experienced extensive encroachment by woody plants with increasing plant densities across the degradation gradient. The Hurso closed savanna experienced an opposite trend where severe deforestation and a loss of valuable browse species occurred, mainly as a results of over cutting of the woody plants for firewood, charcoal making, construction and the clearing of the land for planted crops. The study on the soil seed bank of soil collected along the various degradation gradients showed a high abundance of plant seed present in the soil, confirming the potential of the area for rangeland restoration. As expected the body weight losses of all livestock species in the controlled feeding trial were highly correlated with the reduction in daily dry matter feed. More than 50% of the animals showed pronounced emaciation and physical weakness and 25% of the cattle and goats collapsed and died within ten weeks after the trial started. This explained the large scale mortalities of livestock during prolonged droughts. Drought must be accepted as part of the pastoral life and there should be an adequate early warning system regarding livestock feed availability and strategies of appropriate mitigation strategies. More realistic stocking rates is the obvious solution to the avoidance of stock losses during droughts, but in view of the well established culture of the pastoralists it is highly doubtful if they will be willing to reduce their animal numbers. In conclusion, the experimental results indicated the existence of genetic variability among the various Somali livestock breeds regarding the tolerance to feed shortages and in rates of compensatory growth. This demonstrates the opportunity for improving the genetic composition of the Somali herds through selection.

Genetic evaluation systems require accurate estimates of genetic parameters. The genetic, phenotypic and environmental parameters for objectively measured wool, subjectively assessed wool and conformation traits as well as 16-month live weight were estimated for South African Merino sheep. Records of the Tygerhoek Merino resource flock were used to estimate these parameters. The database consisted of records of 4 495 animals, the progeny of 449 sires and 1 831 dams born in the period 1989 to 2004. The pedigree records used have been collected between 1969 and 2004. In this data, four lines were represented, namely a line selected on clean fleece weight, a line selected against rearing failure, a fine wool line, as well as an unselected control line. Single trait linear mixed models were used. Fixed effects that were assessed included birth status (single/multiple), sex (male/female), age of the dam in years (2-6+years), year of birth (1989-2004) selection line (1-4) and the sex*birth year interaction. Preliminary analysis showed that all the fixed effects had significant (P<0.05) effects on all the traits studied. The random effects included a combination of direct additive, maternal additive and maternal permanent environmental effects as well as the covariance between direct and maternal additive effects. The direct heritability estimates (h²a) for objectively measured traits were 0.38 for 16- month live weight (LW), 0.36 for greasy fleece weight (GFW), 0.40 for clean fleece weight (CFW), 0.65 for clean yield (CY), 0.37 for staple length (SL), 0.20 for staple strength (SS), 0.68 for fibre diameter (FD), 0.61 for coefficient of variation of fibre diameter (CVFD) and 0.61 for standard deviation of fibre diameter (SDFD). The maternal heritability estimates were 0.05 for LW, 0.09 for GFW, 0.10 for CFW and 0.05 for FD. The proportion of the total phenotypic variance due to the maternal permanent environment (c²pe) amounted to 5% for fleece weights. The correlation between direct and maternal genetic effects for LW, GFW and CFW were -0.28, -0.65 and -0.70 respectively. These results suggested that worthwhile responses to selection for objectively measured traits would result from directed selection. Estimates of h²a for subjectively assessed wool traits were 0.49 for wool quality (QUAL), 0.28 for regularity of crimp (ROC), 0.33 for wool colour (COL), 0.23 for wool oil (OIL), 0.21 staple formation (STAPL), 0.22 belly and points (BANDP), 0.50 for woolly face score (WFS), 0.15 for face cover score (FCS), and 0.45 for pigmentation (PIGM). Maternal genetic effects were significant for QUAL, ROC and COL amounting to 0.06, 0.03 and 0.07 respectively. The correlation between direct and maternal genetic effects for QUAL, ROC and COL were -0.62, -0.70 and -0.45 respectively. The h²a estimates for subjectively assessed conformation traits were 0.13 for topline (TOPL), 0.39 for total fold score (TOT), 0.15 for front quarters (FQ), 0.16 for pastern score (PS), 0.32 for hocks (HOCKS) and 0.37 for the general conformation score of the head (GEN). Among the subjectively assessed conformation traits the maternal genetic effects were significant only for PS at 0.05 while GEN was affected by c²pe at 5%. The correlation between direct and maternal genetic effects was -0.71 for PS. The improvement of subjectively assessed wool and conformation traits by selection seems possible from the results of present study. Genetic correlations (rg) among objectively assessed traits general agreed with literature values. Among the subjectively assessed traits favourable rg estimates were estimated between ROC and COL (0.31), for QUAL with ROC (0.49) and COL (0.26) and between STAPL and BANDP (0.58). The relationships between ROC and STAPL (-0.49) and for QUAL with STAPL (-0.45) and BANDP (-0.20) were unfavourable. Estimates of rg among subjective conformation traits were generally low, variable in sign and not significant. The only exceptions were rgâs between HOCKS and FQ (0.71) and of GEN and TOPL with TOT (-0.31 and -0.47 respectively). Phenotypic and environmental correlations among objective, subjective wool and conformation traits were low to moderate. Maternal relationships of respectively 0.86 and 0.19 were found between GFW and CFW and between CFW and FD. The rg of LW with subjective wool traits were not significant, with the exception of moderate and favourable rg for LW with ROC (0.20) and for LW with WFS (0.20). These results suggested that heavier sheep are likely to have more even fleeces and higher scores for WFS. The rg were favourable with COL (-0.19), STAPL (0.35) and BANDP (0.42). CFW and CY were also favourably related to COL, STAPL, BANDP and QUAL where sheep with higher fleece weights and yield had wool with higher quality and better scores for COL, STAPL as well as BANDP. SL was favourably related to COL, BANDP and WFS and negatively related to OIL. These results indicated that sheep with longer staples had better scores for COL, BANDP and WFS as well as lower scores for OIL. Among the subjective wool traits only ROC was significantly related to SS at 0.33. Moderate and unfavourable genetic correlations were estimated for FD with QUAL, ROC and FCS, where sheep with a good quality wool that have more even fleeces and softer wool covering the face had reduced FD. The corresponding relationship with STAPL and BAND were unfavourable. Genetic correlations of CVFD and SDFD with QUAL and ROC were favourable and while these traits were unfavourably related to a number with STAPL. Phenotypic and environmental relationships between objectively measured traits and subjectively assessed wool traits were low to high and variable in sign. On the genetic level LW was favourably related to all the subjectively assessed conformation traits studied. Heavier sheep were generally plainer, had better scores for GEN, HOCKS, and FQ as well as for TOPL. Estimates of rg were favourable for CY with GEN (0.25), HOCKS (0.19), TOT (-0.26) and FQ (0.18), for FD with PS (-0.16) and TOPL (-0.18), for CVFD with HOCKS (-0.17), FQ (-0.33) and TOPL (-0.25), between CFW and GEN (0.23), and between SS and FQ (0.39). The relationships of SDFD with FQ and TOPL were negative. Unfavourable correlations occurred between SS and TOT (0.25), between FD and HOCKS and FD and TOT at 0.13, for fleece weights with TOT (GFW 0.48 and CFW 0.28) and TOPL (GFW 0.34 and CFW 0.29) and between CY and TOT at -0.26. Phenotypic and environmental relationships between objectively measured traits and subjectively assessed wool traits were low to high in magnitude and variable in sign. The results showed that selection for LW and objective wool traits will thus not seriously compromise subjective wool and conformation traits. The exception is FD, CVFD and SDFD, where unfavourable genetic relationships with STAPL and BANDP were found. Furthermore, from these results, it was clear that unrestrained discrimination against wrinkles in Merino sheep would adversely affect economically important objectively measured wool traits such as SS, FD and wool weight. Selection against wrinkles should be carefully monitored to minimise the risk of animals producing reduced fleece weights with broader fibres. It is therefore, proposed that animals with excessive wrinkles be culled from the breeding stock.

FOUR TRIALS WERE CONDUCTED AT THE UFSâS EXPERIMENTAL FARM TO EVALUATE, AND DEVELOP A MORE EFFICIENT PROTOCOL FOR SUPEROVULATION AND EMBRYO CRYOPRESERVATION AND TRANSFER METHODS IN BOER GOATS. EACH TRIAL WAS CONDUCTED WITH SPECIFIC OBJECTIVES. THE FIRST TWO TRIALS WERE CONDUCTED DURING THE AUTUMN AND SPRING SEASONS OF 2005, TO EVALUATE THE OVARIAN RESPONSE OF BOER GOAT DOES TO SUPEROVULATION AND EMBRYO RECOVERY PROCEDURES FOLLOWING A PRE-TREATMENT WITH A GNRH AGONIST. FURTHER ALSO TO EVALUATE THE EFFECT OF SEASON ON THE OVARIAN RESPONSE TO SUPEROVULATION. TWENTY-ONE MULTIPAROUS MATURE BOER GOAT DOES WERE USED AS DONORS DURING THE NATURAL BREEDING SEASON (AUTUMN). IN ALL DOES, THE ONSET OF THE OESTRUS WAS SYNCHRONISED WITH CIDRâS INSERTED INTRAVAGINALLY FOR A PERIOD OF 17 DAYS. DOES WERE ALL SUPEROVULATED WITH 200 MG PFSH/DOE ADMINISTERED I.M. IN 7 DOSAGES, AT 12H INTERVALS, STARTING 48H PRIOR TO CIDR REMOVAL. THE TREATMENT GROUP RECEIVED A GNRH AGONIST (GNRHA) (40μG/DAY/DOE) TREATMENT, ADMINISTERED AS 2 INJECTIONS PER DAY FOR 7 DAYS, STARTING ON DAY 8 OF CIDR INSERTION. THE CONTROL DOES WERE SYNCHRONISED AND SUPEROVULATED, BUT RECEIVED NO GNRHA. OESTROUS DETECTION WAS PERFORMED TWICE DAILY PRIOR TO PROGESTAGEN TREATMENT (CIDR APPLICATION) AND AT 8H INTERVALS FOLLOWING CIDR REMOVAL FOR A PERIOD OF 72H. FIXED-TIME LAPAROSCOPIC AI WITH DILUTED BOER GOAT SEMEN WAS PERFORMED 36 AND 48H FOLLOWING CIDR REMOVAL. BLOOD SAMPLES WERE ALSO COLLECTED FROM 5 ANIMALS IN EACH GROUP AT 4 DAY INTERVALS DURING PROGESTAGEN TREATMENT AND AT DAY 14 OF PROGESTAGEN TREATMENT TO EVALUATE THE HORMONAL EFFECT OF GNRHA TREATMENT. FROM SUPEROVULATION TREATMENT UNTIL CIDR REMOVAL, BLOOD SAMPLES WERE COLLECTED TWICE DAILY AND THEN AT 8H INTERVALS FROM CIDR REMOVAL FOR A PERIOD OF 3 DAYS. THE BLOOD SAMPLES WERE ALSO TAKEN AT 24 H INTERVALS FOLLOWING THE SECOND AI UNTIL EMBRYO FLUSHING (DAY 6 FOLLOWING AI). SERUM PROGESTERONE AND OESTROGEN CONCENTRATIONS WERE DETERMINED VIA RADIOIMMUNOASSAY. EMBRYOS WERE THEN FINALLY SURGICALLY RECOVERED (DAY 6) UNDER GENERAL ANAESTHESIA. THE OESTROUS SYNCHRONISATION RESPONSE WAS EVALUATED BASED ON THE OCCURRENCE OF OESTRUS, TIME TO ONSET OF OESTROUS AND DURATION OF THE INDUCED OESTROUS PERIOD. THE EMBRYO YIELD AND QUALITY WAS ALSO EVALUATED. ONLY 81% OF THE DOES EXHIBITED OVERT SIGNS OF OESTRUS PRIOR TO SYNCHRONISATION TREATMENT APPLICATION (INDICATION OF CYCLIC ACTIVITY). THE MEAN DURATION OF THESE NATURAL OESTROUS CYCLES WAS RECORDED AS 20.1±3.5D, WHILE THE NATURAL OESTROUS PERIOD LASTED FOR 37.7±11.9H. FOLLOWING SYNCHRONISATION AND SUPEROVULATION TREATMENT, 100% AND 80% OF THE DOES IN THE FSH/GNRHA AND FSH-TREATED DOES SHOWED SIGNS OF OESTRUS, RESPECTIVELY. THE TIME INTERVAL FROM CIDR REMOVAL TO ONSET OF OESTRUS AND DURATION OF THE INDUCED OESTROUS PERIOD DID NOT DIFFER SIGNIFICANTLY, ALTHOUGH THE DURATION OF THE INDUCED OESTROUS PERIOD IN THE FSH/GNRHA GROUP (19.6±5.5H) TENDED TO BE SHORTER, COMPARED TO THE FSH-TREATED DOES (25.0±7.4H). THE OCCURRENCE OF ABNORMAL CLâS WAS 38.1% IN TOTAL, WHILE 23.8% OF THE DOES DID NOT HAVE ANY CLâS. THERE WERE NO SIGNIFICANT DIFFERENCES IN EMBRYO YIELD AND QUALITY PARAMETERS MEASURED. IN DOES PRE-TREATED WITH GNRHA HOWEVER, THE NUMBER OF DEGENERATE EMBRYOS TENDED TO BE HIGHER, WHILE THE NUMBER OF TRANSFERABLE EMBRYOS TENDED TO BE LOWER, COMPARED TO THE CONTROL (FSH) DOES (6.6±4.2 VS. 1.7±1.5 AND 3.4±2.7 VS. 9.3±6.1, RESPECTIVELY). THE SECOND TRIAL REPEATING ALL THE PROCEDURES PERFORMED IN THE FIRST TRIAL WAS CONDUCTED IN THE SPRING OF 2005 (OUTSIDE THE BREEDING SEASON), USING 22 MULTIPAROUS BOER GOAT DOES AS RECIPIENTS. ONLY 45.5% OF THE DOES SHOWED OVERT SIGNS OF OESTRUS PRIOR TO THE APPLICATION OF OESTROUS SYNCHRONISATION AND SUPEROVULATION TREATMENT. GNRHA TREATMENT HAD NO BENEFICIAL EFFECT IN RESPONSE TO OESTROUS SYNCHRONISATION AND OVULATION RATE. THE TOTAL MEAN STRUCTURES FLUSHED WAS SIGNIFICANTLY (P<0.05) LOWER IN THE DOES PRETREATED WITH GNRHA (12.6±6.0 PER DOE, COMPARED TO THE CONTROL DOES (17.6±4.9 PER DOE). THE MEAN TOTAL NUMBER OF EMBRYOS COLLECTED PER DONOR AND THE FERTILISATION RATE WERE SIGNIFICANTLY (P<0.05) LOWER IN DOES PRETREATED WITH GNRHA THAN IN THE FSH-TREATED DOES (11.5.±5.3 VS. 16.5±6.1 AND 81.6±32.2% VS. 92.6±19.5%, RESPECTIVELY). GNRHA TREATMENT HAD NO EFFECT ON THE MEAN NUMBER OF UNFERTILISED OVA PER DONOR. PRE-TREATMENT OF DOES WITH GNRHA HOWEVER RESULTED IN A SIGNIFICANTLY (P<0.01) HIGHER MEAN NUMBER OF DEGENERATIVE EMBRYOS WHEN COMPARED TO THE CONTROL DOES (6.9±4.5 VS. 3.2±4.2 PER DOE). SUBSEQUENTLY, THE NUMBER OF TRANSFERABLE EMBRYOS AND TRANSFERABLE RATE (4.3±4.0 AND 32.7±26.9%) WAS LOWER IN DOES PRE-TREATED WITH GNRHA, COMPARED TO THE CONTROL DOES (13.1±5.3 AND 75.2±26.8%). THE MEAN TIME TO ONSET OF OESTRUS WAS SIGNIFICANTLY (P<0.05) EARLIER DURING THE NATURAL BREEDING SEASON (24.9±4.8H), COMPARED TO OUTSIDE THE BREEDING SEASON IN DOES (30.5±9.1H). SIMILARLY, THE MEAN DURATION OF THE INDUCED OESTRUS WAS SIGNIFICANTLY (P<0.05) LONGER DURING THE NATURAL BREEDING SEASON (24.0±5.7H) - THAN OUTSIDE THE BREEDING SEASON (18.2±3.7H). SEASON DID NOT HAVE ANY SIGNIFICANT EFFECT ON THE TOTAL NUMBER OF CLâS INDUCED, ALTHOUGH THE NUMBER OF CLâS ON THE RIGHT OVARY WAS SIGNIFICANTLY (P<0.05) LOWER DURING THE NATURAL BREEDING SEASON. SEASON DID NOT HAVE EFFECT ON THE NUMBER OF STRUCTURES RECOVERED, EMBRYOS, DEGENERATIVE AND TRANSFERABLE EMBRYOS PER DONOR. THE MEAN NUMBER OF UNFERTILISED OVA PER DONOR (3.3±2.8) WAS SIGNIFICANTLY (P<0.05) HIGHER IN GOATS TREATED OUTSIDE THE NATURAL BREEDING SEASON THAN DURING THE NATURAL BREEDING SEASON (0.9±2.4). IT COULD BE CONCLUDED THAT PRE-TREATMENT WITH GNRHA DOES NOT HAVE ANY BENEFICIAL EFFECT ON OESTROUS RESPONSE, TIME TO ONSET AND DURATION OF THE INDUCED OESTROUS PERIOD. THE ADDITION OF THE GNRHA INTO THE FSH GOAT SUPEROVULATION PROTOCOL REDUCED THE NUMBER OF STRUCTURES RECOVERED, EMBRYO YIELD, AND THE FERTILISATION RATE (THE NUMBER OF EMBRYOS PER STRUCTURES ON OVARIES). THE PRE-TREATMENT WITH GNRHA ALSO INCREASED THE NUMBER OF DEGENERATE EMBRYOS - WHICH ULTIMATELY REDUCED THE TOTAL NUMBER OF TRANSFERABLE EMBRYOS. IT COULD THUS BE RECOMMENDED THAT A PRE-TREATMENT WITH A GNRH AGONIST IN A BOER GOAT MOET PROGRAMME IS NOT WARRANTED. THE SERUM PROGESTERONE CONCENTRATIONS DID NOT DIFFER BETWEEN THE TREATMENT GROUPS, THROUGHOUT THE OESTROUS SYNCHRONISATION PERIOD. AT 48H FOLLOWING THE SECOND AI (96H AFTER CIDR REMOVAL), THE CONTROL DOES RECORDED A SIGNIFICANTLY (P<0.05) HIGHER MEAN SERUM PROGESTERONE CONCENTRATION (11.3±4.9 NG/ML), THAN IN THE FSH/GNRHA-TREATED DOES (4.3±2.1 NG/ML). THE SERUM PROGESTERONE CONCENTRATIONS INCREASED FOLLOWING THE SECOND AI AND WERE HIGHEST ON THE DAY OF EMBRYO FLUSHING IN BOTH GROUPS â WITHOUT ANY SIGNIFICANT DIFFERENCES. THE MEAN SERUM OESTROGEN CONCENTRATION WAS SIGNIFICANTLY (P<0.05) HIGHER ON DAY 12 OF SYNCHRONISATION (5TH DAY OF GNRHA TREATMENT) AND AT THE 4TH PFSH (SUPEROVULATION) INJECTION IN THE FSH/GNRHA TREATED GROUP COMPARED TO THE CONTROL DOES. AT THE TIME OF THE FIRST AI (36H FOLLOWING CIDR REMOVAL) THE MEAN SERUM OESTROGEN CONCENTRATION WAS SIGNIFICANTLY (P<0.05) HIGHER (58.3±26.9 PG/ML) IN THE CONTROL (FSHSTIMULATED) DOES, COMPARED TO THE FSH/GNRHATREATED DOES (15.7±17.4 PG/ML). THE BLOOD HORMONAL LEVELS INDUCED DURING SUPEROVULATION WERE DEPENDENT ON VARIOUS OVARIAN FACTORS WHICH ULTIMATELY DETERMINE THE COMPETENCE OF THE OOCYTES AND EVENTUALLY VIABILITY OF THE EMBRYOS. A THIRD TRIAL WAS CONDUCTED DURING THE NATURAL BREEDING SEASON (AUTUMN, 2006). SEVENTEEN MULTIPAROUS MATURE BOER GOAT DOES WERE USED AS DONORS IN THIS TRIAL TO EVALUATE AND REFINE THE FSH SUPEROVULATORY TREATMENT BY COMPARING TWO ROUTES OF GONADOTROPHIN (PFSH) ADMINISTRATION. HERE 27 RECIPIENTS WERE USED TO EVALUATE THE SURVIVAL RATE OF THE GOAT EMBRYOS FOLLOWING CRYOPRESERVATION USING THE CONVENTIONAL SLOW FREEZING OR VITRIFICATION METHOD. DOES RECEIVED A PFSH SUPEROVULATION TREATMENT INTRAMUSCULAR OR SUBCUTANEOUS, WHILE RECIPIENTS RECEIVED FRESH, SLOW FROZENTHAWED OR VITRIFIED-THAWED EMBRYOS. THE ROUTE OF ADMINISTERING GONADOTROPHIN TREATMENT DID NOT AFFECT THE OESTROUS RESPONSE, THE TIME FROM CIDR REMOVAL TO THE ONSET OF OESTRUS AND DURATION OF THE INDUCED OESTROUS PERIOD. THE ROUTE OF GONADOTROPHIN ADMINISTRATION DID NOT AFFECT THE OVULATION RATE, THE TOTAL NUMBER OF STRUCTURES, NUMBER OF EMBRYOS AND TRANSFERABLE EMBRYOS COLLECTED PER DONOR. THE MEAN NUMBER OF UNFERTILISED OVA IN THE I.M. GROUP (3.3±4.8) WAS SIGNIFICANTLY (P<0.05) HIGHER, THAN IN THE S.C. GROUP (0.3±0.8). SIMILARLY, THE MEAN NUMBER OF DEGENERATED EMBRYOS PER DONOR IN THE DOES ADMINISTERED THE FSH SUBCUTANEOUSLY (5.9±4.5) WAS SIGNIFICANTLY (P<0.05) HIGHER, WHEN COMPARED TO THE INTRAMUSCULAR GROUP (2.6±2.3). A TOTAL OF 88.9% RECIPIENTS DEMONSTRATED SIGNS OF OESTRUS FOLLOWING CIDR REMOVAL. A PREGNANCY RATE OF 85.7%, 50.0% AND 37.5% WAS RECORDED FOLLOWING THE TRANSFER OF FRESH, SLOW-FROZEN AND VITRIFIED EMBRYOS, RESPECTIVELY. EMBRYO SURVIVAL RATES OF 35.7%, 25.0% AND 31.3% WERE THEN EVENTUALLY RECORDED FOLLOWING FRESH, SLOW-FROZEN AND VITRIFIED EMBRYO TRANSFER. IT COULD THUS BE CONCLUDED THAT AN ADVANTAGE OF THE SUBCUTANEOUS ROUTE OF ADMINISTRATION RESULTED IN A LOWER NUMBER OF UNFERTILISED OVA RECOVERED, WHICH WAS HOWEVER NEGATED BY A HIGHER NUMBER OF DEGENERATE EMBRYOS RECORDED. THEREFORE BOTH ROUTES CAN BE USED FOR THE ADMINISTRATION OF PFSH SUPEROVULATION TREATMENT IN BOER GOAT DOES DURING THE BREEDING SEASON. A RELATIVELY HIGH PREGNANCY RATE WAS OBTAINED FOLLOWING THE TRANSFER OF FRESH EMBRYOS. HOWEVER, THE SURVIVAL RATE OF EMBRYOS FOLLOWING EITHER FRESH, SLOW FROZEN-THAWED OR VITRIFIEDTHAWED EMBRYOS WAS UNSATISFACTORY. MORE RESEARCH IS THUS WARRANTED, WITH A HIGHER NUMBER OF ANIMALS, DIRECTED AT IMPROVING THE SURVIVABILITY OF EMBRYOS FOLLOWING FRESH AND CRYOPRESERVED GOAT EMBRYO TRANSFER. THE FOURTH TRIAL WAS CONDUCTED DURING THE NATURAL BREEDING (AUTUMN, 2007). DONOR DOES WERE SUPEROVULATED FOLLOWING A LONG (17 DAY) PROGESTAGEN SYNCHRONISATION PROTOCOL, WITH OR WITHOUT PROSTAGLANDIN-F2Î OR SUPEROVULATED FOLLOWING A PREDETERMINED TIME OF OVULATION (DAY 0 PROTOCOL). RECIPIENT DOES RECEIVED FROZEN-THAWED OR FRESH BOER GOAT EMBRYOS FOLLOWING OESTROUS SYNCHRONISATION USING DIFFERENT PROTOCOLS. DURING THE SYNCHRONISATION TREATMENT PRIOR TO SUPEROVULATION ONLY 71.4% OF THE DOES IN THE DAY 0 PROTOCOL EXHIBITED SIGNS OF OESTRUS, WHILE ONLY ONE DOE EXHIBITED SIGNS OF OESTRUS FOLLOWING SUPEROVULATION. ALL DOES SHOWED OVERT SIGNS OF OESTRUS FOLLOWING LONG PROGESTAGEN TREATMENT WITH OR WITHOUT ADMINISTRATION OF PROSTAGLANDIN-F2Î. ALL DOES ALSO DEMONSTRATED A SIMILAR RESPONSE TIME FROM CIDR REMOVAL TO THE ONSET OF OESTRUS AND THE DURATION OF THE INDUCED OESTROUS PERIOD. THE DAY 0 PROTOCOL RESULTED INTO A SIGNIFICANTLY (P<0.01) LOWER TOTAL NUMBER OF CLâS (4.0±3.5) PER DOE - COMPARED TO GROUP 2 (17-DAY PROGESTAGEN TREATMENT PLUS PGF2Î) (14.5±4.6) AND GROUP 3 (17-DAY PROGESTAGEN TREATMENT) (16.5±5.9). THE MEAN NUMBER OF STRUCTURES RECOVERED FROM GROUP 1 (1.4±0.5) WAS SIGNIFICANTLY (P<0.05) LOWER, COMPARED TO GROUP 3 (11.4±7.3). THIS MEAN IN THE DAY 0 GROUP HOWEVER DID NOT DIFFER SIGNIFICANTLY, WHEN COMPARED TO GROUP 2 (8.4±7.7). THE VARIATION RECORDED BETWEEN ANIMALS IN THE GROUP 2 WAS VERY HIGH. THE DAY 0 PROTOCOL RESULTED IN A SIGNIFICANTLY (P<0.01) LOWER MEAN NUMBER OF EMBRYOS BEING RECORDED. HOWEVER, THE MEAN NUMBER OF UNFERTILISED OVA AND DEGENERATING EMBRYOS WAS SIMILAR FOR ALL THE TREATMENT GROUPS. THE DAY 0 (GROUP 1) GROUP RESULTED IN THE COLLECTION OF ONLY ONE EMBRYO, WHICH WAS ALSO TRANSFERABLE, BUT DUE TO THE SINGLE VALUE THIS DATA WAS NOT ANALYSED. THE ADDITION OF PROSTAGLANDIN-F2Î HAD NO EFFECT ON THE FERTILISATION RATE AND THE MEAN NUMBER OF TRANSFERABLE EMBRYOS RECORDED BETWEEN GROUP 2 AND 3. THE TIME INTERVAL FROM CIDR REMOVAL TO THE ONSET OF OESTRUS IN THE ADULT DOES WAS SIGNIFICANTLY (P<0.01) SHORTER THAN THAT RECORDED IN THE YOUNG DOES. HOWEVER, AGE DID NOT HAVE ANY SIGNIFICANT EFFECT ON THE DURATION OF THE INDUCED OESTROUS PERIOD. THE MEAN NUMBER OF CLâS, STRUCTURES AND EMBRYOS RECOVERED WERE HOWEVER SIGNIFICANTLY (P<0.01) HIGHER IN THE ADULT DOES. NO RECOVERY OF UNFERTILISED OVA WAS RECORDED IN THE YOUNG DOES AND THE FERTILISATION RATE AND MEAN NUMBER OF UNFERTILISED OVA DID NOT DIFFER BETWEEN THE YOUNG AND ADULT DOES. SIMILARLY THE AGE OF THE DOE HAD NO EFFECT ON THE MEAN NUMBER OF DEGENERATE EMBRYOS PER DONOR RECORDED. THE MEAN NUMBER OF TRANSFERABLE EMBRYOS PRODUCED IN THE ADULT DOES (15.8±6.4) WAS SIGNIFICANTLY (P<0.01) HIGHER, THAN IN THE YOUNG DOES (9.5±3.7). THE TIME FROM CIDR REMOVAL TO THE ONSET OF OESTRUS WAS NOT AFFECTED BY REPEATED SUPEROVULATION TREATMENT. DOES SUPEROVULATED FOR THE FIRST TIME SHOWED A SIGNIFICANTLY (P<0.05) SHORTER MEAN DURATION OF OESTRUS (20.8±10.1H), WHEN COMPARED TO THOSE REPEATEDLY SUPEROVULATED (30.4±6.7 H). REPEATED SUPEROVULATION DID NOT SHOW AN EFFECT ON THE TOTAL NUMBER OF CLâS PRODUCED PER DOE. HOWEVER, THE MEAN NUMBER OF STRUCTURES RECOVERED WAS SIGNIFICANTLY (P<0.05) LOWER IN THE REPEAT-TREATED DOES (6.0±8.7), COMPARED TO DOES SUPEROVULATED FOR THE FIRST TIME (11.7±5.0). SIMILARLY, THE MEAN NUMBER OF EMBRYOS RECOVERED PER DOE WAS SIGNIFICANTLY (P<0.05) HIGHER IN DOES SUPEROVULATED FOR THE FIRST TIME. THE MEAN NUMBER OF UNFERTILISED OVA PER DONOR WAS ALSO SIGNIFICANTLY (P<0.05) HIGHER IN THE REPEATEDLY-TREATED DOES (5.5±7.8), COMPARED TO THE 0.1±0.3 FOR DOES SUPEROVULATED FOR THE FIRST TIME. THIS RESULTED IN A SIGNIFICANTLY (P<0.05) LOWER FERTILISATION RATE BEING OBTAINED IN THE REPEATEDLY-TREATED DOES (50.0±70.7%), COMPARED TO DOES SUPEROVULATED FOR THE FIRST TIME (99.4±1.9%). THE MEAN NUMBER OF DEGENERATE EMBRYOS DID NOT DIFFER SIGNIFICANTLY BETWEEN THESE GROUPS. THE NUMBER OF TRANSFERABLE EMBRYOS RECORDED WAS SIGNIFICANTLY (P<0.05) LOWER IN THE REPEATEDLY TREATED DOES (3.8±8.5), COMPARED TO THEIR COUNTERPARTS (10.7±4.0). IN GROUP A (CIDR + PGF2Î + ECG; CHRONOGEST) 88.9% OF THE DOES RESPONDED TO OESTROUS SYNCHRONISATION. ALL DOES IN GROUP B (CIDR +ECG; FOLLIGON) AND GROUP C (CIDR + ECG; CHRONOGEST) EXHIBITED SIGNS OF OESTRUS FOLLOWING OESTROUS SYNCHRONISATION. DOES FROM GROUP A (42.0±3.7 H) EXHIBITED A LONGER (P<0.05) TIME INTERVAL FROM CIDR WITHDRAWAL TO THE ONSET OF OESTRUS, COMPARED TO GROUP C DOES (32.0±8.6H). THERE WAS HOWEVER, NO SIGNIFICANT DIFFERENCE WITH RESPECT TO THE TIME INTERVAL FROM CIDR REMOVAL TO THE ONSET OF OESTRUS BETWEEN GROUP A AND B. GROUP B AND C DOES ALSO RECORDED A SIMILAR RESPONSE TIME FROM CIDR WITHDRAWAL TO THE ONSET OF OESTRUS. THE DURATION OF THE INDUCED OESTROUS PERIOD BEING SIGNIFICANTLY (P<0.05) SHORTER IN GROUP B (19.0±13.5H), WHEN COMPARED TO GROUP A (39.0±15.1H). NO SIGNIFICANT DIFFERENCE WAS RECORDED BETWEEN GROUP B AND C REGARDING THE DURATION OF THE INDUCED OESTROUS PERIOD. IT COULD THUS BE CONCLUDED THAT THE POOR OVARIAN RESPONSE TO THE SUPEROVULATORY TREATMENT IN THE GROUP 1 (DAY 0 PROTOCOL) WARRANTS FURTHER RESEARCH WHICH WILL HAVE TO FOCUS ON THE SYNCHRONISATION OF OVULATION AND AN APPROPRIATE TIME FOR INITIATING A SUPEROVULATORY TREATMENT IN THIS PROTOCOL. THE ADDITION OF A PROSTAGLANDIN-F2Î TREATMENT IN THE SUPEROVULATORY PROTOCOL FOLLOWING A LONG PROGESTAGEN SYNCHRONISATION TREATMENT IN BOER GOAT DOES ALSO HAS NO REAL ADVANTAGE. THE TIME OF PROSTAGLANDIN ADMINISTRATION AND THE DOSAGE USED COULD HAVE CONTRIBUTED TO THE OBSERVED RESULTS. THE AGE OF THE DONOR DOE HAS BEEN SHOWN TO HAVE A MAJOR EFFECT ON THE OVARIAN ACTIVITY FOLLOWING SUPEROVULATION TREATMENT. ALTHOUGH THE YOUNG DOES RECORDED AN ACCEPTABLE FERTILISATION RATE, THE NUMBER OF TRANSFERABLE EMBRYOS WAS HOWEVER LOWER. THEREFORE, IF A LARGE NUMBER OF ACCEPTABLE EMBRYOS (THE MAXIMUM) ARE REQUIRED IN A MOET PROGRAMME, IT IS MORE APPROPRIATE TO SUPEROVULATE MULTIPAROUS MATURE GOATS. THIS WILL LEAD TO THE PRODUCTION OF MORE TRANSFERABLE EMBRYOS. THE NUMBER OF TIMES THAT A DONOR CAN BE UTILISED IN A BOER GOAT MOET PROGRAMME SEEM IS TO BE LIMITED TO THREE TIMES DUE TO REDUCTION IN THE NUMBER OF STRUCTURES AND EMBRYOS BEING RECOVERED FROM THE 4TH TIME REPEATEDLY TREATED DOES. MOREOVER, THE NUMBER OF UNFERTILISED OVA INCREASED FOLLOWING REPEATED SUPEROVULATION, HENCE REDUCING THE FERTILISATION RATE AND EVENTUALLY THE NUMBER OF TRANSFERABLE EMBRYOS. THE THREE PROTOCOLS USED FOR OESTROUS SYNCHRONISATION IN RECIPIENTS WERE EFFICIENT IN SYNCHRONISING OESTRUS. THE PREGNANCY RATE OBTAINED WAS GENERALLY LOW IN ALL THE TREATMENT GROUPS AND POSSIBLE INTERACTIONS THUS COMPLICATE THE MAKING OF ANY DEFINITE RECOMMENDATIONS.

The fencing of small areas and stocking them with game species is becoming a common tendency in South Africa. The main objective of this study, conducted during the 2003/04 and 2004/05 seasons in a small fenced in game enclosure (78 ha) in the Bloemfontein district, Free State Province, was to determine the small-scale habitat and feeding preferences of springbok (Antidorcas marsupialis), blesbok (Damaliscus pygargus phillipsi) and black wildebeest (Connochaetes gnou) within the same vegetation type. The associations between soil, vegetation and grazing time by these herbivore game species were also determined, as well as whether the simulated influence of Type I herbivores on the sward structure will affect the small-scale habitat preferences of these herbivore species, which are all regarded as Type III species. A relatively homogeneous area of 250 x 200 m (5 ha) in the middle of an open grassland area was selected for intensive study. The selected area was subdivided into twenty experimental plots of 50 x 50 m (0.25 ha), which were permanently marked and allocated an identification code. Analysis of the soil was done to assess the physical properties, ionic content and electrical resistance of the soil in each experimental plot. Plots varied considerably in terms of the chemical content of the soil, which was largely influenced by soil texture. This may account for the heterogeneity of the vegetation of the demarcated area. Prior land use and small-scale variation could also have influenced the soil quality and vegetation. The botanical composition of the herbaceous layer was determined using a wheel point apparatus according to the nearest plant method, based on occurrence. Surveys were done at the end of each growing season (2003/04 & 2004/05). Above-ground dry matter production was determined by harvesting all plants in 20 randomly-selected 0.25 m² quadrates within each experimental plot, and weighing them. Plots on the northern side had a lower number of grass species with a lower grazing value (predominantly Increaser species), while plots on the southern side had a higher number of grass species with a higher grazing value (predominantly Decreaser species). Changes in the botanical composition between the two seasons (an increase in Increaser species) and the decrease in veld condition scores suggest that the veld is over-utilised and in a poor condition, and that stocking rates are currently too high. However, veld in this condition is the preferred habitat of short grass grazers. Therefore, a compromise between short grazing (habitat suitability) and veld in a good ecological condition seems to be the proper approach. The small-scale spatial preferences of the three herbivore game species were studied by making observations, using binoculars, from a parked vehicle during the morning and afternoon. Both springbok and blesbok preferred habitat patches with a high abundance of Increaser species, relatively high species diversity and moderate to low veld condition score. Black wildebeest tended to favour patches with a higher occurrence of Decreaser species, although Increaser species were also relatively abundant in these plots. The preferred experimental plots generally had a low above-ground DM production. The number of habitat patches utilised was highest during the dry season. A modification of the grazed-class method was used to determine the favoured grass species and percentage utilisation during the different seasons. Marked plants were inspected weekly from June 2004 to May 2005, and subjective estimates were given for utilisation using a developed field reference guide. Themeda triandra, Eragrostis obtusa, Panicum stapfianum, E. plana and Digitaria eriantha were the favoured grass species of springbok, blesbok and black wildebeest. Less-favoured species included Brachiaria eruciformis, Cynodon dactylon, E. chloromelas and Setaria incrassata, while non-favoured species included Tragus berteronianus, Aristida bipartita and Cymbopogon pospischilii. Seasonal variation in utilisation was demonstrated, with a larger number of species that were utilised during the rainy season. Associations between soils, the herbaceous layer and time spent grazing indicated that soil texture, and degradation due to over utilisation, were the most important factors that caused spatial variation in the botanical composition of the grassland area. Less-favoured and nonfavoured grass species mainly occurred on heavy clay soil and were closely associated with soil Na, Ca, Mg and K. In contrast, favoured grass species mostly occurred on soil with higher sand and silt content and were closely associated with soil N, C and Zn. Time spent grazing by springbok, blesbok and black wildebeest were closely associated with the favoured grass species (as listed above). To determine the influence of the simulated effect of Type I species on the small-scale habitat preferences, the grass was mown in two plots with a lawnmower at a height of 5 cm, and in another two plots at a height of 15 cm. Each cutting treatment consisted of a plot containing palatable and unpalatable grass species. Observations were conducted as described previously. The simulated influence of Type I species on the sward structure (grass mown at 5cm) of underutilised grassland may facilitate the occupation of such grassland by short grass grazers, particularly blesbok, which previously avoided these areas. Generally, no distinctive changes in the activity of springbok and black wildebeest could be found. It is recommended that stocking rates in the game enclosure be reduced and maintained at sustainable levels to allow the vegetation to recover and reduce further degradation. Continual assessment of the vegetation is essential to monitor further changes in the herbaceous layer and evaluate long-term sustainability of the game enclosure. Similar monitoring is recommended for all small fenced game ranches.

1. The purpose of the first chapter was to give a short introduction to the study. Although there were exponential increases in knowledge, there are still fields of study where there is little understanding and enormous gaps relating to information. A short history of the development of cattle was presented, with special reference to the Simmentaler breed. The objectives of this study were then stated. These objectives were: the definition of breeding objectives, derivation of economic values and development of economic selection indices for the Simmentaler breed in South Africa. 2. In Chapter 2 the development of breeding objectives and the derivation of economic values were reviewed. There seems to be general consensus that definition of breeding objectives should be the primary step in the design of structured breeding programs. Development of the breeding objective can be described in terms of the following phases: specific ation of the breeding, production and marketing system, identification of sources of income and expense in commercial herds, determination of biological traits that influence income and expense, derivation of economic values, choice of selection criteria, and estimation of phenotypic and genetic parameters. The modeling methods to derive economic values can be divided into simulation, dynamic programming and profit functions. 3. In Chapter 3 the important traits, which should be considered for the development of breeding objectives, as well as the criteria to be included in the selection index were reviewed. Traits were classified as fitness-, production-, product-, input-, type- and behavioural traits. The decision whether or not to include a trait in the breeding objective depends on the relative economic value of the trait, the potential for genetic improvement and the possibility of accurate and cheap measurement. Several traits determine economic efficiency, and the required balance of these traits is likely to differ between different production systems. 4. The purpose of Chapter 4 was the development of a general breeding objective for the Simmentaler breed in Southern Africa as well as the derivation of economic values for beef production traits. Income was partitioned between weaners (steers), surplus heifers and cull cows. Expenses were calculated for all classes and included feed cost, husbandry cost and marketing cost. Economic values for weaning weight (direct), weaning weight (maternal), yearling weight (400 days), final weight (600 days) and mature cow weight were derived as partial derivatives of the profit equation. These values, expressed per genetic standard deviation, in South African Rand per cow, corrected with the discounted gene flow and diffusion coefficient methods (in brackets) are, 25.57 (75.01), 15.21 (47.97), 28.49(83.63), -13.95 (-40.79) and -69.29 (-63.39) respectively. 5. The objectives of Chapter 5 were to expand the Simmentaler breeding objective by inclusion of functional traits and to derive economic values for the functional traits calving rate, days -to-calving, calving-ease (direct) and calving-ease (maternal). It was assumed, for these categorical traits, that there is an unobserved underlying normal distribution of the sum of genetic and environmental values, and that the phenotypic category is defined by threshold values on this distribution. The consequences of a change in fitness included changes in costs, changes in culling rate, number of barren cows and the number of surplus offspring available for sale. Results emphasised the relative importance of fertility. Economic values, expressed per genetic standard deviation in South African Rand per cow, corrected with the discounted gene flow and diffusion coeffic ient methods (in brackets) are, 18.98 (15.27), - 93.82 (- 75.51), 1.08 (1.31) and 1.15 (1.08) for calving rate, days-to-calving, calving-ease (direct) and calving-ease (maternal), respectively. 6. The objectives of Chapter 6 were to expand the Simmentaler breeding objective by the inclusion of product quality traits and to derive economic values for dressing percentage, backfat thickness, tenderness and marbling. A method to derive economic values for these optimum traits was described. It was as sumed, for the categorical traits, that there is an unobserved underlying normal distribution of the sum of genetic and environmental values, and that the phenotypic category is defined by threshold values on this distribution. The consequences of a change in the mean performance of a trait include changes in the number of animals in different quality classes and as a result thereof, changes in the expected value of a carcass. Economic values, expressed per genetic standard deviation in South African Rand per cow, corrected with the discounted gene flow and diffusion coefficient methods (in brackets) are, 20.96 (61.50), 0.39 (1.14), -3.52 (-10.33) and 0.18 ( 0.52) for dressing percentage, backfat thickness, tenderness and marbling respectively. 7. The development of economic selection indices for an integrated Simmentaler production system was described in Chapter 7. The breeding objective was defined in terms of production-, functional- and product quality traits. Criteria included in the total index are birth- and weaning weight (direct and maternal), yearling weight, final weight, mature cow weight, days -to-calving, backfat thickness, tenderness and marbling. The total merit index (IT) for an integrated Simmentaler production system is IT = â 1.65 BWD â 1.99 BWM + 2.28 WWD + 1.76 WWM + 1.48YW â 0.50 FW â 2.02 MCW â 13.21 CD + 4.92 BF â 2.34 T + 12.77 M. The correlation between this index and the breeding objective is 0.987. The economic superiority, over the average progeny, of the progeny from the top 40% of animals selected on their ranking in the total index, is expected to be R116.49.

Studies were made on growth, carcass and egg performance as well as mortality of the Lesotho native chickens compared to the South African native (Potchefstroom Koekoek, Ovambo, Lebowa-Venda and Naked Neck) and two exotic lines, namely the New Hampshire a nd Rhode Island Red from 3-days old to 70 weeks old (moulting). Chickens were raised in two batches with an interval of four weeks between the two batches: from 3-day old to ten and six in Batches 1 and 2, respectively. Chickens were reared in Bloemfontein (UFS) under confinement, fed ad libitum with broiler starter mash for the first four weeks where after grower mash was fed to the chickens up to the age of ten weeks old. From this stage until the end of the laying phase, they were all fed yellow maize and managed semi-intensively in Lesotho at the NULFOA. The study was done in two phases, namely the pre-laying and laying phases. With the exception of feed conversion ratio (FCR), which was conducted in the first 35 days of the study, all measurements of growth and egg performance traits were recorded weekly while mortality was recorded daily. Carcass yield analysis was done at 70 weeks of age. Presentation of the growth data was done in three stages, namely 3-day, 26-week and 70-week weights, which are considered crucial in a chickenâs life span. The means of the Lesotho line were significantly different (p<0.05) from other lines in all growth traits, namely 3-day weight, 26-week weight, average daily gain (ADG) and average weekly gain (AWG) except for the FCR and hen weight at 70 weeks old. With the exception of the New Hampshire and Potchefstroom Koekoek, no significant differences (p>0.05) were observed between the Lesotho hen weight and other lines. The Ovambo had the highest body weight and avera ge daily gain of all the native populations at 26-weeks old, while the Potchefstroom Koekoek had the highest 70-week weight. Feed conversion ratios ranged between 3.2±1.9 for the New Hampshire to 3.9±1.2 for Naked Necks in Batch 1, and 3.3±1.2 for New Hampshire to 4.2±0.9 for the Lesotho line in Batch 2. All differences between the lines for FCR were highly significant (p<0.01). All the lines commenced their egg production between the 25th to 26th weeks of age and there were no significant differences (p> 0.05) between the ages at first lay among all the lines. Egg production was found to differ significantly (p<0.05) among the different lines. The average number of eggs laid per week per hen and egg weight of the Lesotho hens was 1.2 and 48.5g, respectively. The New Hampshire had a significantly (p<0.05) higher dressed weight than other lines (1903.0±190.8g) while the Naked Neck had the lowest (1297.7±133.0g). Bone and head weight were not significantly different (p>0.05) among the different lines. The Lesotho line had the highest overall mortality (89%) of all the lines. The lowest mortality (27%) was found in the Potchefstroom Koekoek. A probable reason for high mortalities in the Lesotho could be ascribed to the result of inbreeding within the line. Although the Lesotho hens exhibited the lowest growth at the onset of laying (1113.8±71.6g), they eventually compensated and ended being large (2047.5±65.6g) at 70-weeks old. The Lesotho hen, like the New Hampshire and Potchefstroom Koekoek showed potential for being a good dual-purpose breed, since it was able to maintain a high body weight at the end of laying. Therefore the breed has an advantage of fetching a higher market price at the end of laying. The constraint is that of their low growth in the earlier part of their life span. This can be improved through the implementation of planned breeding programs.

The present study was carried out to estimate genetic, phenotypic and environmental parameters for growth traits, genetic trends as well as the level of inbreeding in the South African Brahman breed. The data used were obtained from the South African Brahman Breedersâ Society and consisted of pedigree information of 181 508 animals and 221 015 performance records, ranging from birth to 18-months weight /final weight collected between 1955 and 2002. Performance records available before editing as classified according to age ranges were birth weight (BWT) = 67 336, weaning weight (WWT) (80â300 days) = 62 159, yearling weight (YWT) (301-500 days) = 41 313 and final weight (FWT) (501-900 days) = 32 602. The linear animal model used included the fixed effects of contemporary group (herd-year-season), sex, management group, age of the calf, age of the dam. Direct genetic, maternal genetic and permanent maternal environmental as random effects as well as sire x herd-year-season interaction as an additional random effect. Preliminary analyses showed that all fixed effects had a significant (P<0.0001) effect on all traits studied. Genetic parameters for growth traits were estimated using ASREML software by fitting univariate and bivariate animal models. Production traits considered after editing were BWT = 41 509, WWT = 37 705, YWT = 22 682 and FWT = 13 055 records collected between 1985 and 2002. The reason for using the data only from 1985 is that only a small number of records were recorded up to 1984. The direct heritability estimates of BWT, WWT, YWT and FWT were 0.28, 0.14, 0.14 and 0.18 respectively. The corresponding maternal heritability estimates were 0.11, 0.06, 0.05 and 0.03 respectively. The maternal permanent environmental component due to the dam contributed 3 - 7 % of the total phenotypic variance of the traits under consideration. The corresponding contribution of sire x herd-year-season interaction ranges from 5 - 6%. The genetic correlation between animal effects was -0.36 for BWT, other traits studied did not show an antagonism between animal effects. The prospects of improvements of these traits by selection seem possible and the contributions of permanent maternal environmental effect are not equally important as maternal effects though the effects are small. Estimates of phenotypic correlations were low to moderate (0.22 to 0.64), whereas genetic correlations were moderate to high (0.47 to 0.91). Genetic correlations between BWT and WWT, YWT and FWT were 0.62, 0.47, and 0.52 respectively. The corresponding genetic correlations between direct and maternal effects of the same trait (ram, rma) were (-0.4204, -0.014), (-0.4241, 0.0567) and (0.05170, 0.0879) respectively. Genetic correlations between WWT and postweaning weights were 0.88 and 0.91 for YWT and FWT respectively. The corresponding maternal correlation was at unity. Lastly, the genetic and maternal correlation between YWT and FWT were 0.83 and unity, respectively. Positive genetic trends were observed for all traits except for the maternal genetic trend for BWT, which had a slightly negative slope. Direct genetic progress for BWT was 0.0207 kg/year (1987-2002), whereas progress for WWT was 0.1kg/year (1985-1995) and 0.4 kg /year (1996-2001). Progression in direct genetic effect for YWT was 0.1kg/year (1985- 1995) and 0.3 kg/year (1996-2001) whereas progress for FWT was 0.13 kg/year (1985-2001). The maternal genetic trends were -0.003, 0.04, 0.008 and 0.003 kg/year for BWT, WWT, YWT and FWT, respectively. Genetic progress was in general low over the years for all traits. Therefore, estimation based on BLUP of breeding values may be more important in the future and should be considered to maximise opportunities for genetic change. Inbreeding level and its possible influence on growth traits of the South African Brahman cattle were investigated. Inbreeding coefficients were calculated by inverting the diagonal of the inverse relationship matrix using the MTDFNRM program of the MTDFREML package. Inbreeding depression was estimated as the regression of performance on individual and dam inbreeding coefficients using an animal model. The mean inbreeding of the population was very low (0.01) with an average of (0.03) for inbred animals. Although regression coefficients of BWT, WWT, YWT and FWT on inbreeding of animal and dam were significant for all traits, the results showed that inbreeding at present is not a serious problem in the South African Brahman breed.

A study was conducted to investigate the influence of different particle sizes of a specific amorphous limestone source (calcium carbonate) in a layer diet on egg production and egg quality at peak production (week 24). Ninety nine layer pullets, 17 weeks old, were obtained from a commercial layer breeder. The pullets were randomly allocated to three groups. All the pullets received the same layer diet. The only differences among the treatment groups were that the pullets in each group received one of the three different particle sizes in the diet namely:- (a) Less than 1.0 millimetre (b) 1.0 and 2.0 millimetre (c) 2.0 and 3.8 millimetre The influence of the three particle sizes on the feed intake, body weight and egg production as well as egg characteristics was recorded. The average weekly feed intake, body weight and egg production of layers from week 18 up to 28 were not (P> 0.05) different among the layer diets with the different particle sizes. The particle size of limestone in the layer diets did not influence egg weight (P= 0.2159) and egg output (P=0.2388) significantly at peak production. Average egg weight tended (P= 0.2159) to be heavier when coarse particles were fed. No statistic al significant (P> 0.05) differences in egg volume, egg contents, egg surface area, shell weight per unit surface area, shell percentage and shell thickness occurred. According to these results limestone particle size in layer diets has no influence on eggshell quality. In the second study the effect of particle size distribution of a specific limestone source in layer diet on egg production and egg quality at peak production (week 24) was investigated. One hundred and sixty seven layer pullets , 17 weeks old, were obtained from a commercial layer breeder. The pullets were randomly allocated to five groups. All the pullets received the same layer diet. The only differences among the treatment groups were that the pullets in each group received one of five different ratios of fine (less than 1.0 mm) and coarse (between 2.0 and 3.8 mm) limestone particle size namely 100, 75, 50, 25 and 0 % fine or coarse. The influence of the five dietary limestone particle size distributions on the feed intake, body weight, and egg production of layers as well as egg characteristics mentioned in the first study were investigated. No significant (P> 0.05) influence of dietary limestone particle size distribution was found on feed intake, body weight and egg production of layers. Accordingly no significant differences occurred in egg volume, (P= 0.1310) and egg surface area (P= 0.1393). The highest (P< 0.001) egg contents were recorded where 100 and 75% fine limestone particles were included in the diet. Although significant differences for shell weight (P<0.0017) and shell percentage (P<0.0001) occurred, no clear influence of particle size distribution on these characteristics could be detected. In accordance wit h shell weight per unit surface area no significant differences (P> 0.05) in eggshell thickness occurred. It was concluded that different dietary limestone particle sizes and distributions have no influence on eggshell quality at peak production (week 24). The influence of dietary limestone particle size and distribution during the later stages of the laying period on bone formation and egg quality needs further investigation.

1. A study was conducted to investigate the effects of dietary Ca levels and feed restriction on the bone development of broiler breeder pullets up to 18 weeks of age. Six hundred and forty one-day-old Ross breeder pullets were randomly assigned to 4 treatment groups; namely 1.0% Ca (0.45% Pi), 1.5% Ca (0.7% Pi), 2.0% Ca (0.9% Pi) and 1.0% Ca (0.45% Pi). The first three treatments were feed restricted while the last treatment was fed ad lib. At 6, 12 and 18 weeks of age 20 pullets were randomly selected from each treatment and killed. Treatment effects on bone dimensions (length, width and weight), bone ash, Ca and P contents of tibia, mechanical properties (bone strength and stress) were investigated. Increasing dieta ry Ca levels had no significant (P>0.05) effect on bone measurements. As expected, all the bone measurements significantly (P<0.05) increased with age. Feed restriction significantly (P<0.05) reduced all the bone characteristics. The results suggested that 1.0% Ca (average 0.7 g/hen/day) is sufficient to support bone development and growth for feed restricted broiler breeder pullets up to 18 weeks of age. 2. One hundred and ninety eight Ross broiler breeder pullets were reared on restricted diets with 1.0, 1.5 and 2.0% Ca up to 22 weeks of age. The pullets in each experimental diet were further randomly divided into three treatments with 1.5, 2.5 and 3.5% dietary Ca (66 birds per treatment) fed from 23 to 60 weeks. At 35 and 60 weeks of age, 12 pullets per treatment were randomly selected and killed to obtain tibiae and humeri. Treatment effects on bone dimensions, bone ash, Ca and P content of tibia, mechanical properties, true cortical area (TCA) and percent bone were investigated. The 1.5% Ca diet resulte d in lower (P<.05) feed intake and body weight. Calcium level had no effect on bone dimensions, bone stress, ash content, Ca content of ash, TCA and percent bone. These results suggest that the 2.5% dietary Ca (4 g/hen/day) may be adequate to support bone development and growth of feed restricted broiler breeder pullets. 3. The broiler breeder pullets described in paragraph 2 were used to investigate the effects of three levels of dietary Ca (1.5, 2.5 and 3.5%) during the early lay period (23 to 35 weeks) on egg production and eggshell quality. Increasing dietary Ca level from 1.5 to 3.5% had no significant effect (P>.05) on egg production, egg weight, egg mass, egg surface area and egg contents. Increasing the level of Ca from 1.5 to 2.5% increased shell weight, shell weight per unit surface area, shell percentage and shell thickness. As anticipated, egg weight increased with age. The converse was true for egg production and eggshell parameters. It was concluded that a dietary Ca level of 2.5% and Ca intakes of 3.8, 3.9, and 3.5 g at weeks 27, 30 and 33, respectively were sufficient to sustain good eggshell quality of feed restricted broiler breeder hens. 4. The mentioned broiler breeder hens in paragraph 3 were fed three dietary Ca levels, 1.5, 2.5 and 3.5% from week 36 to 60. Regression analysis suggested that Ca level during the rearing period could positively influence eggshell quality during the later stages of lay (36 to 60 weeks). Increasing dietary Ca level from 1.5 to 2.5% during the laying period significantly (P<.05) increased egg production, egg weight, egg mass, shell weight, egg contents, egg surface area, shell percentage, shell weight per unit surface area and shell thickness. As anticipated, egg weight, shell weight, egg contents and egg surface area increased with age while egg production, egg mass, shell percentage and shell thickness declined. These results suggest that the 2.5% Ca (3.8 g/hen/day) is adequate to support egg production and to improve eggshell quality in feed restricted broiler breeder hens. 5. The effect of dietary Ca intake (1.5, 2.5 and 3.5% dietary Ca) on Ca retention of broiler breeder hens (30 per treatment) and the relationship between Ca retention and egg characteristics was investigated. Shell (r=0.27) and faecal (r=0.50) Ca excretions were significantly (P<.05) positively related to Ca intake of broiler breeders. Proportionally less of the Ca intake was used for eggshell formation as the intake of broiler breeders increased. It seems that a higher Ca intake was mainly accompanied by a higher Ca excretion through the faeces. The net effect of Ca intake and total Ca excretion was that the 2.5% Ca level (3.8 g Ca /hen/day) exhibit a significant (P<.05) higher Ca retention compared to 1.5% Ca. It was concluded from the results that 1.0% dietary Ca (0.7 g /pullet/day) is needed during the rearing period up to 22 weeks. Thereafter 2.5% Ca (3.5 to 4.0 g /hen/day) should be included in broiler breeder diets up to 60 weeks. The possible effect of Ca levels during the rearing period on eggshell quality needs further investigation.