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.

This study was carried out to generate information on village based indigenous chicken utilization, management practices, opportunities and challenges, to identify, characterize and describe the phenotypic variation of indigenous chicken populations. The study was also aimed to provide preliminary data on the genetic variation of indigenous chicken populations using microsatellite markers and to compare and evaluate the growth, egg production, reproductive performances, as well as the rate of survival of indigenous chickens under intensive and extensive management levels. Surveys using both purposive and random sampling methods were carried out in four zones of Northwest Ethiopia to describe the village-based poultry production systems and constraints in order to design future improvement and conservation strategies. The result of this study showed that the majority of the respondents were female (74.16 %). This indicated that most of the time the women, whether in male-headed or female-headed households are responsible for chicken rearing, while the men are responsible for crop cultivation and other off-farm activities. About 99% of the respondents gave supplementary feeds to their chickens. Night shelter was provided by almost all farmers in a part of the kitchen (1.36 %) or in the main house (39.07 %), in handwoven baskets (7.29 %), in bamboo cages (1.51 %) or in a separate shed purpose-made for chickens (50.77 %). The major causes of death of chickens during the study were seasonal outbreaks of Newcastle disease (locally known as âfengeleâ) and predation. It is important to collect and conserve local poultry breeds before they are fully replaced by the so-called improved exotic chicken breeds. As most of the poultry production is managed by women, focusing on training and education of women will aid not only the improvement of poultry production but also family management, family planning and the overall living standards of the family and the community. In the phenotypic characterization, a total of three hundred chickens were characterized under field conditions for qualitative and quantitative traits following standard chicken descriptors. Seven distinct indigenous chicken populations from four administrative zones were identified. Large phenotypic variability among chicken populations was observed for plumage colour. About 25.49 %, 22.30 %, and 16.40 % of the chickens have white, grayish and red plumage colours, respectively. The rest showed a considerable heterogeneity regarding plumage colours, like black, multicoloured, black with white tips, reddish brown and white with red stripes. The following characteristics were also displayed: plain heads (51.18 %), yellow shanks (64.42 %), and pea comb (50.72 %). About 97.52 % of the chickens did not have feathers on their legs. Variations were also observed in quantitative characteristics such as shank length, egg size and body weight and other reproductive traits exhibited in an intensive management system. In the genetic analysis, indigenous chicken populations representing seven different areas of Northwest Ethiopia were studied using microsatellite markers to determine genetic diversity and relatedness. Three South African chicken lines and two commercial chicken (RIR and WLH) breeds were included for control. A high genetic diversity was observed overall loci and populations with a heterozygosity value of 0.76. The largest heterozygosity (0.93) across all markers was observed in the Mecha chicken population, while the smallest heterozygosity across all loci (0.66) was observed in the White Leghorn breed. A higher genetic distance (lower genetic similarity) between the RIR commercial chicken breed and the Ethiopian indigenous chicken populations were observed compared to RIR and South African fowls. This indicates that the Ethiopian indigenous chicken populations have still not been highly diluted by the RIR commercial chicken breed either through the extension program or through the regional poultry breeding and multiplication institutes. The present result indicated that the clustering of the chicken populations is in accordance with their geographical origin and market places. Microsatellite markers used in this study were found suitable for the measurement of the genetic variation in Ethiopian chicken populations. These results can therefore serve as an initial step to plan the characterization and conservation of indigenous chickens in the Amhara region, Ethiopia. A study on the performance of indigenous chicken populations in terms of growth, carcass yield, egg production and egg quality was evaluated under intensive management conditions compared with the RIR commercial breed. Significant differences were observed among the indigenous chicken genotypes of Northwest Ethiopia for body weight, feed intake, FCR, mortality percentage at different phases of growth, indicating the phenotypic variations of the different chicken ecotypes. The Mecha chickens had the highest growth rate, followed by Guangua and Melo- Hamusit chickens, indicating that these lines are good for meat production. Analysis of carcass characteristics has shown that most of the male and female finisher grower chickens have a higher dressing percentage than the commercial RIR chicken breed managed under intensive management. Furthermore, data on age at point of lay (days) indicated that indigenous chickens reached the first egg production stage from 144 to 168 days, while the RIR breed started producing eggs at 150 days. In general, the current result indicates that the performance of the indigenous chickens is comparable with the RIR breed under intensive management systems. This indicates that there is a chance for better performance if proper selection and breeding plan are designed for indigenous chickens.

This study made use of the opportunity provided by fenceline contrasts in Namibia to measure differences in rangeland and learn from farmers about the inputs and outputs of management on each side of the fence. The 34 measured contrasts were mostly clustered within the Camelthorn and Thornbush Savannas, with three in the Highland and Dwarf shrub Savannas of Namibia. Mean annual rainfall ranges from 235 to 475 mm. Rangeland measurements focussed on well established perennial vegetation to avoid the fluctuating effect of ephemerals. Eight characteristics were measured and significant (P<0.05) differences occurred in at least one of these at each contrast. Two characteristics (distance from sample point to the nearest perennial grass and the species) were combined to determine a rangeland condition index. At 22 of the 34 contrasts the condition index was significantly (P<0.05) higher on one side of the fence. There was no clear method to distinguish between the influences of different management inputs that may have caused the fenceline contrasts. Therefore, subjective judgment was relied upon to identify bush control as the most likely single causative factor at ten contrasts, stocking rate and period of rest at five contrasts each, and stocking density at two contrasts. Management contributed to both causes and consequences of fenceline contrasts. The negative correlation between stocking rate and rangeland condition index was weak (r = â0.2575, P = 0.04, n = 64), suggesting that there may have been more farms where a higher stocking rate was the cause of poorer rangeland than farms where the higher stocking rate was the consequence of better rangeland raising the carrying capacity. The stronger correlation between profit and income (r = 0.9288, P < 0.001, n = 25) than between profit and expenditure (r = 0.0267, P = 0.899, n = 25), suggests that farmers should focus on reducing non-essential expenditure to increase profitability. Game farming can earn high income, but continuous selective grazing by gregarious game animals may lead to poorer rangeland condition. Useful lessons were learnt from the case study of an innovative farmer who adapted his management based upon his keen observations of rangeland dynamics. Many of his interventions were strategically timed in relation to rainfall events. There is much that can be learnt by both scientists and other farmers from the management strategies applied by successful farmers who earn a good profit while sustaining the rangeland.

A trial was conducted to determine the total rumen degradable protein intake (RDPI) required to maximise the digestible organic matter intake (DOMI) of beef cows consuming low quality grass hay from the Northern variation of Cymbopogon-Themeda pasture type (pure grassveld). Thirty five pregnant Afrikaner x Simmentaler crossbred cows (±517.08kg, SD 53.06) were randomly allocated to 5 treatments. Treatments provided the following RDP levels/cow/day 0g, 180g, 360g, 540g and 720g. A RDP source, calcium caseinate (90% crude protein (CP) on dry matter basis and 100% rumen degradable) was used and mixed with molasses based concentrate. The cows had ad lib access to low quality grass hay (2.26% CP, 73.94% neutral detergent fibre). The trial period consisted of 14 days adaptation, 21 days intake study and 7 days digestibility study. No statistical significant (P > 0.05) influence of RDP level on the apparent digestibility of dry matter (DM), organic matter (OM) and neutral detergent fibre (NDF) was detected. The grass DM intake (DMI), DOMI and metabolisable energy intake (MEI) increased in a linear and quadratic manner (P < 0.05) with increasing levels of supplemental RDP. The single broken-line model predicted DOMI/kg BW0.75 with higher accuracy (R2 = 0.45) than the quadratic regression procedure (R2 = 0.07). According to this model 4.03g daily RDPI/kg BW0.75 or 8.07% RDP of DOM was required to maximise DOMI of pregnant beef cows consuming winter grassveld hay. In a second trial the potential to substitute true protein with urea was investigated. Urea replaced 0%, 25%, 50%, 75% and 100% of the natural supplemental RDP. The same procedure as described in the first trial was followed. The increasing proportion of urea did not significantly (P > 0.05) influence the apparent digestibility of DM, OM and NDF. There was a linear increase in grass DMI (P = 0.0355) at increasing levels of urea, with the highest intake observed when urea was used as a sole source of nitrogen (N). DOMI and MEI increased in both linear and a quadratic manner (P < 0.05) with increasing levels of urea. The molar proportions of acetic, propionic and butyric acid were not affected (P < 0.05) by the substitution of urea, while the molar percentages of iso-butyric and iso-valeric acid were significantly decreased (P < 0.0001) with increasing urea levels. Ammonia N increased linearly (P = 0.0426) while the ruminal pH was not affected (P > 0.05) by increasing the proportion of urea. It seems that urea can be the sole RDP source in supplements for pregnant beef cows consuming the low quality grass hay. In the third trial, the influence of replacing natural protein with urea on the performance of beef cows grazing natural winter grassveld was investigated. Pregnant Afrikaner x Simmentaler crossbred cows were randomly allocated to the two treatments. The number of cows per treatment varied between 18 and 28 each year. The trial was executed over four consecutive winter periods from 2003 to 2006. The treatment licks comprised of: 1) 100% supplemental RDP from urea and 2) 50% supplemental RDP from urea and 50% from cottonseed oilcake. Lick provision was controlled to ensure the total RDPI as recommended in the first trial. Increasing the proportion of supplemental RDP from urea did not have a significant (P = 0.9938) effect on the end live mass of the cows. The urea levels did not significantly influence (P > 0.05) weaning mass, corrected weaning mass and average daily gain of the calves. The lack of significant lick treatment effect on live mass, body condition score and performance of the calves suggests that urea can be used as a sole source of RDP.

The goal of this study was to generate a database of laboratory results for African lion (Panthera leo) blood to obtain reliable reference ranges to augment what is currently available in literature. Also to investigate the possibility of age and sex having an influence on these reference ranges. The specific objectives of this study were: o to determine reference values for haematological and biochemical blood variables for lions bred in captivity, as a function of age and sex; o to evaluate the Beckman Coulter Acâ¢T 5diff Haematology Analyzer for lion differential white blood cell analyses; o to determine morphometric measurements and establish reference growth curves (and range reference values) for lions bred and reared in captivity as a function of age and sex; o to determine reference values for some practical and meaningful body measurements and their correlations. This study was conducted on three lion ranches in the Free State province and at the Bloemfontein Zoological Gardens (Bloemfontein Zoo) with captive lions (Panthera leo) of both sexes and ages ranging from three months to nine years. Lions were divided into four age groups according to published literature. Animals were chemically immobilized (darted) with Zoletil® 100 at 4 to 5mg/kg in their holding camps and moved to a shaded place as soon as the drug had taken its full effect. Blood was collected into three different types of blood collection tubes and body measurements were taken. This was all done as fast as possible before the effect of the immobilizing drug could wear off. In some cases it was necessary to give an animal a top-up dose to prevent it from waking up too quickly. Animals were moved back to their holding camps to fully recover from the immobilization. Blood analyses done with the Acâ¢T 5diff Haematology Analyzer from Beckman Coulter® for haematological parameters was conducted within 30 minutes after blood collection. Blood for biochemistry parameters was centrifuged, serum collected and cryo preserved at -20°C until it could be taken to the laboratory for analyses. Blood smears were made on the lion ranches and Bloemfontein zoo immediately after the analysis with the Acâ¢T 5diff Haematology Analyzer, fixed and packed for transport to the laboratory. At the laboratory the serum was used for biochemistry analyses, using standard laboratory techniques. Blood smears were stained and examined under a light microscope for the differential white blood cell count by means of the manual-visual method. Results were statistically analyzed to determine reference ranges and the influence of age and sex on these reference range values for the different parameters, were considered. Body measurement were also statistically analyzed to determine correlations between body weight and different other measurements. These correlations were then used to determine if it will be possible in a field situation to use the age and sex of an animal together with a certain body measurement to estimate body weight accurately, if actual weighing was not possible. From these analyses it was concluded that age and sex do have an influence on blood analysis and blood reference ranges for the African lion (Panthera leo). Unfortunately, it differs between parameters and there is not one rule to apply. The conclusion could also be made that body weight could be determined by measuring the head length of an animal. More research is warranted to obtain more data set and establish range reference values that can be validated and used with a high degree of confidence in the lion breeding industry.

In the first study performance data from 465 Boer goat rams tested in a central performance test in the Northern Cape Veld-Ram Club from 1989 to 2007 were analysed to determine the relationship between performance and sale price. Rams were subjected to extensive management conditions on natural pastures for 160 days and finished-off in a feedlot for 50 days. Upon the conclusion of the entire test period, the rams were auctioned. Performance information was available for buyers for decision making. Traits analysed included final weight (FW), final weight index (FWI), average daily gain (ADG), average daily gain index (ADGI), growth per day of age index (ADOI), Kleiber ratio (KR), auction weight (AW), scrotal circumference (SC), selection index (SI) and sale price (SP). Stepwise regression analyses, using proc GLM of SAS were performed to identify variables that significantly influenced sale prices. Final weight was significant in eight out of eighteen years, auction weight was significant in six of the seven years measured and selection index influenced prices in seven out of ten years. Scrotal circumference, average daily gain, final weight index, average daily gain index and Kleiber ratio had little influence on sale price. Growth per day of age index did not show any influence on sale price. Price was positively correlated (P<0.05) with many of the performance traits. All significant correlations were moderate to high and ranged from 0.37 to 0.80. The amount of variation in sale price accounted for by the performance traits ranged from 15% in year 1991 to 65% in 1998. The most important traits influencing sale price (SP) were final weight, auction weight, and selection index. The results indicated that buyers of stud rams put more emphasis on production traits such as body weight and that they recognize the importance of performance data as shown by their preference for animals with high selection indices. In the second study data consisting of 3855 records and collected from 1998 to 2008 were analysed to estimate genetic parameters for economic traits in two Boer goat flocks. The traits investigated were weaning weight and post-weaning weight. Least square analysis was used for estimation of environmental effects. Genetic parameters were estimated from single and bivariate trait analyses using ASREML software fitting animal models. By ignoring or including maternal additive genetic effects and their covariance and maternal permanent environmental effects seven different models were fitted for each trait. The fixed effects of sex, type of birth, age of dam, year of birth, herd, season and age of lamb, were all significant (P<0.05) for both traits. The direct heritability estimates varied from 0.24 for weaning weight to 0.31 for post-weaning weight. The corresponding maternal permanent environment due to the dam was 0.10 and 0.44 respectively. The maternal heritability (0.03) for weaning weight was lower than its corresponding direct heritability. Estimates of genetic parameters in this study confirmed that selection for weaning weight would result in genetic improvement of Boer goats.

The main aim of this study was to evaluate the effectiveness of repeated inoculations of a Corynebacterium cutis lysate (Ultra-Corn®) - a non-specific immune-stimulant, to reduce the milk SCC in commercial dairy cows. An additional aim was to evaluate if these inoculations had any detrimental effects on milk quality. This study was performed in two separate trials, using Holstein cows with SCCâs over 250 000 cells/ml of milk at different stages of lactation from two commercial dairy farms in the Free State Province. On each farm, cows were paired according days in milk and SCC, in order to obtain two homogeneous groups of experimental animals. The two groups of cows in each farm were randomly allocated to a treatment or a control group. Both groups in the same farm were managed under the same conditions for the entire trial periods. The only difference was that cows from the treatment group received 3 weekly inoculations of Corynebacterium cutis lysate(Ultra-Corn® ), while those from the control group received distilled water for injection (the same volume as the cows in the treatment group). Two similar trials were conducted, using the same basic experimental design. Differences were only in the dose of the Corynebacterium cutis lysate inoculated per cow treated, number of experimental animals and duration of the observation periods. In Trial 1, cows from the treated group received 3 weekly vaccinations of Ultra-Corn® (4 ml per cow, thus 80mg of Corynebacterium cutis lysate per cow) injected subcutaneously (sc), while those from the control group received 3 weekly sc injections of 4 ml distilled water. This was followed by 8 weeks of observation of the effect of treatment on milk SCC and composition. In Trial 2, the three doses of Corynebacterium cutis lysate administered weekly per cow for the treated group was 2ml/100kg, thus 40mg Corynebacterium cutis lysate/100 kg per cow. This was followed by 8 weeks of observation of the effect of treatment on milk SCC and composition. Individual quarter milk samples were collected weekly from all cows and analysed for SCC and a combined milk sample (from the measuring bottle in the milk parlour) from each cow was also taken for butterfat, protein, lactose and urea content. The results were compared between the two groups per farm, using ANOVA procedures for repeated measures analysis, using the 95% confidence level (SAS, 2004). The two farms were evaluated separately, due to the possible differences between general management conditions, which could introduce serious confounding factors if the results from the two farms were combined. However, it can be considered that both dairy farms used an acceptable level of commercial dairy management practices and produced an acceptable yield per cow under South African commercial conditions. In general no significant differences were recorded between the treated and control groups of cows in both farms in both trials in terms of milk SCC, butterfat, protein, lactose and urea content of the milk. In this study, the immuno-stimulant effect of Ultra-Corn®, a Corynebacterium cutis lysate could not be confirmed in lactating cows. Although this inoculant does not seem to have any detrimental effects on the main solids of the milk, its use cannot be justified as it did not significantly reduce somatic cell counts in lactating cows. Further research is warranted to develop and evaluate the effectiveness of vaccines against mastitis causing organisms, in order to control SCC and mastitis in dairy cows. However, when such studies are conducted it is advisable to use very high number of experimental units and proper control trials should be conducted. All efforts should be done to ensure minimum environmental changes during these trials, which can introduce serious confounding effects in the experimental design.

The aim of the study was to characterize and evaluate the quality of fresh semen of 4 breeds of chicken and the susceptibility of cockerel semen to a cryopreservation protocol, assessed microscopically for sperm motility and morphology and ultimately fertilizing ability following AI. The differences between breeds were determined by comparing the fertilizing ability and hatchability of fresh and frozen-thawed semen. The study was carried out at Glen Agricultural Development Institute and at the University of the Free State. Four chicken breeds, namely the Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn, were used. Qualitative characterization of the semen was performed in 28 cockerels (7 per breed). Semen was collected using the massage technique twice a week in the first trial. The eosin-nigrosin staining technique was used to microscopically evaluate the morphology of the sperm from the different breeds. The fresh semen parameters evaluated were ejaculate volume, semen colour, semen pH, sperm concentration, the percentage live and dead sperm, sperm motility and the abnormalities of the sperm. The percentage live and dead sperm, sperm motility and abnormalities were also evaluated for the frozen-thawed cockerel semen. During the second phase of the study, semen was collected 3 times per week from the same cockerels. Semen was frozen using a fastâfreezing procedure on dry ice, with 10% DMSO as the cryoprotectant. AI was performed on 4 different breeds of hens (20 hens per breed) (Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn), using fresh semen (control) and frozen-thawed semen. During AI of each breed, 10 hens were inseminated with fresh and the remaining 10 hens with frozen-thawed semen. The sperm characteristics of the semen samples of the 4 breeds recorded were ejaculate volume, ranging from 0.3±0.1 to 0.4±0.1ml, semen pH of 7.6±0.4 to 7.7±0.3, sperm motility (scale of 0-5) 2.8±0.8 to 3.1±0.9, estimated sperm motility 58.8±12.5 to 63.8±13.6%, ejaculate concentration (x109 sperm/ml) of 320.4±286.5 to 748.5±475.3, percentage live sperm 75.6±29.1 to 81.5±26.8%, and the percentage dead sperm 18.6±26.8 to 24.4±29.1% respectively, with the percentage normal sperm ranging between 77.3±17.1 and 84.8±9.0%. Head, mid-piece, tail and other sperm abnormalities of the fresh semen of the 4 breeds ranged from 2.9±3.3 to 7.7±9.6%, 7.9±5.2 to 11.0±7.0%, 0.4±0.8 to 1.9±3.0% and 0.6±0.9 to 1.5±1.9%, respectively. Semen samples were frozen in pellet form on a block of dry ice, by pipetting into the indentations on the surface of the ice. The frozen cockerel pellets were thawed following cryopreservation, by being placed into a test tube in a water bath (60°C), and the tube shaken continuously until complete thawing of the pellet. During the time of semen cryopreservation, a decrease in the number of live, morphologically normal sperm, and increase in the percentage dead sperm and sperm with abnormalities were recorded. The freeze-thawing process caused a significant (P<0.05) decrease in the percentage live sperm and the sperm motility, ranging between 37.4±10.4 and 42.3±12.1% and 3.6±0.5 and 3.9±0.3 respectively. A consequent increase in the percentage of dead sperm (between 57.7±12.1 and 62.4±10.8%) was also recorded. The sperm abnormalities regarding sperm head abnormalities ranged between 17.3±3.8 to 22.5±10.3%, the mid-piece abnormalities 7.9±3.8 to 10.4±2.0% and the tail abnormalities between 0.5±0.9 to 2.0±2.4% respectively for the thawed semen. Frozen-thawed semen was thawed in a water-bath 60°C and hens were inseminated twice per week using the frozen-thawed semen, and once a week with fresh semen for a total period of two weeks. Data for the two trials were analyzed using the ANOVA and the Tukeyâs Studentized Range (HSD) test for repeated measures (SAS system General Linear Models Procedure). A total of 973 eggs, from all breeds of chicken namely the Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn were collected following AI with fresh and frozen semen from individually caged hens. Eggs were collected, incubated and hatched to check if fertile and normal chicks could be produced from frozen-thawed cockerel semen. The difference in fertility and hatchability of the hens of the different breeds were compared and found to be highest in Rhode Island Red, White Leghorn, and Potchefstroom Koekoek respectively and lowest in New Hampshire using fresh semen. When using frozen-thawed semen, the sequence of fertility performance was the White Leghorn, Rhode Island Red, Potchefstroom Koekoek and New Hampshire, respectively. The effect of the numbers of sperm per AI dose on fertility, age at embryonic death, and hatchability of fertile eggs were also evaluated. Low numbers of sperm per AI in the hens resulted in a decrease in the total number of chicks hatched. The lowest fertility rate recorded was in the New Hampshire (2.7%), when using frozen-thawed semen to inseminate the hens. This may be attributed to the low numbers of sperm inseminated per AI dose. Egg hatchability of the fertile eggs was high in the White Leghorn (13.6%), Rhode Island Red (12.8 %), Potchefstroom Koekoek (9.7 %) and low in New Hampshire (2.7%) respectively, which could possibly be attributed to the egg size. Medium sized eggs were preferable for setting, in order to obtain an acceptable hatch, as they generally hatch better than the larger eggs. The results recorded for fertility and hatchability in the control group (fresh semen), was similar to the results recorded by other researchers, showing that the AI method used was acceptable. There still exists a necessity to develop an ideal cryopreservation method (diluent and freezing procedure), which would allow for acceptable long term storage of cockerel semen in liquid nitrogen (-196°C) for future use and export with minimum loss regarding sperm viability and fertilizing capacity.