Thesis (MSc. Agriculture (Animal Production)) -- University of Limpopo, 2015 / A series of experiments were carried out to investigate the effect of replacing calf starter feed with lucerne leaf-meal (LLM) on diet intake, rumen degradation and growth of Holstein heifer calves. The treatments were calf starter pellets (PEL), a mixture of 65% calf starter concentrate pellets and 35% LLM (P65L35), and a mixture of 50% calf starter concentrate pellets and 50% LLM (P50L50). The first part of the study determined nutrient composition of lucerne leaf-meal (LLM), calf starter pellets and lucerne leaf-meal substituted diets. The experimental design was a completely randomised design (CRD). Lucerne leaf-meal had high protein (25% DM) and gross energy (GE) (16.2 MJ/kg DM) levels; low starch (0.2% DM) and fibre fractions. All diets had similar (P>0.05) crude protein (CP) and GE values. The concentrate diet was higher (P<0.05) in starch, ether extracts and fibre bound CP (neutral detergent insoluble crude protein). The second part of the study estimated the supply of energy and protein fractions and carbohydrate composition from LLM and the diets. A CRD was used. Lucerne leaf-meal had high energy density and protein supply with low unavailable fibre and protein contents. All the treatments had TDN above 80%. Non-fibre carbohydrate levels differed (P<0.05) across treatments. The energy fractions were similar (P>0.05) across all dietary treatments. However, Diets P65L35 and P50L50 had higher (P<0.05) soluble and non-fibre carbohydrates than PEL diet. The third part of the study determined in vitro degradation of LLM and the three dietary treatments using the ANKOM DaisyII incubator system. Lucerne leaf-meal had high in vitro dry matter (IVDMD), organic matter (IVOMD), crude protein (IVCPD) and neutral detergent fibre (IVNDFD) degradation. All diets had similar (P>0.05) IVDMD and IVOMD at 0, 4, 10 and 48 hours of incubation. Higher (P<0.05) IVNDFD, IVCPD and effective degradation (ED) were observed in Diets P65L35 and P50L50 than in Diet PEL. No differences (P>0.05) in IVNDFD and IVCPD were observed at 24 and 48 hours of incubation. The rate of degradation (‘c’) was similar (P>0.05) across all the diets. The data demonstrated that LLM diets had higher (P<0.05) degradation values than Diet PEL. vi The fourth part of the study determined the effects of replacing calf starter pellets with lucerne leaf-meal on diet intake, feed conversion ratio and growth of pre-weaned (21 to 42 days old calves) and transition (43 to 56 days old calves) Holstein heifer calves. The experimental design was a completely randomised design, with a total of 24 calves housed in individual pens. This study was divided into two experimental phases, namely, pre-weaning (Experiment 1) and transition (Experiment 2) phases. In each experiment, different calves were used. Body weights were taken weekly. The balance of ruminal nitrogen (% RNB) was predicted using Large Ruminant Nutrition System (LRNS) model. In Experiment 1 calves had free access to clean water and fed 4 litres/calf/day of unpasteurised milk. During the pre-weaning phase, differences (P<0.05) were observed in solid feed dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and starch intakes with Diet P50L50 having higher (P<0.05) intakes than Diets PEL and P65L35. Similarly, higher (P<0.05) % RNB and daily weight gains (ADG) were observed with calves on Diet P50L50. However, calves had similar (P>0.05) initial and final weights and feed conversion ratio (FCR). Calves in Experiment 2 were fed 2 litres/calf/day of unpasteurised milk. Calves were weaned at the age of 56 days. During the transition phase, calves on Diet HP50L50 had higher (P<0.05) CP intake and % RNB than those on HPEL and HP65L35 diets. However, higher (P<0.05) solid feed starch intake was observed with calves on Diet HPEL. All dietary treatments had similar (P>0.05) DM intake, initial and final live weights, ADG and FCR. The fifth part of the study predicted diet concentrations of Holstein heifer calves under specific conditions using the level 1 solution of Large Ruminant Nutrition System (LRNS) model. During the pre-weaning phase, P65L35 and P50L50 diets indicated higher (P<0.05) energy density values than Diet PEL. However, all diets had similar (P>0.05) metabolisable energy levels. No differences (P>0.05) in net energy for maintenance (NEm) and gain (NEg) during the transition phase were observed. However, Diet HPEL had higher (P<0.05) apparent TDN and ME levels compared to other dietary treatments. Diets P65L35 and P50L50 had higher (P<0.05) protein, energy density and degradation values than Diet PEL. It is concluded LLM inclusions in the calf diet improved Holstein heifer calves’ performance. / Agricultural Research Council (ARC)

A study was conducted using commercial broiler breeders with the males fed a diet containing, either 120/0 or 140/0 protein and body weight maintained at either 900/0 or 1000/0 of that recommended by the primary breeder (fed separately), or allowed to eat from the female feeders (controls). Female feeders in the separately fed pens were equipped with especially designed grills, which denied access to the males. The male feeder in these pens was elevated so that females were denied access. Males fed separately (body weight 90% or 1000/0, and dietary protein 120/0 or 140/0) had a significantly higher percentage fertility (4.20/0) than males allowed to eat with the females. No differences in percentage fertility were found among the four separately fed groups. No differences were noted in percentage hatch of fertile eggs among any of the treatment groups. Males eating from the female feeders had significantly heavier body weights and testes weights at 65 weeks of age than breeder males in the separately fed, groups. Mean body weights were 3819g and 4773g at 35 weeks of age, and 4192g and 5443g at 65 weeks of age for males eating separately and eating with the females, respectively. Furthermore, males in the control group had significantly larger breast angle measurements when compared with the separately fed males. No differences were observed in foot scores and semen concentration among males in the various treatment groups. / Master of Science

<p dir="ltr">The development of feeding skills is essential for infant health, growth, and family well-being. Despite the importance of this skill, relatively little is known about the development of independent solid feeding skills relative to other body systems – like vocalizations – or external factors including caregivers or the feeding environment. The purpose of this preliminary study was to examine the relationship between feeding skills, vocalizations, and caregiver feeding responsiveness at the same point in 6-8-month-old infants. We conducted this study remotely in order to obtain the most accurate assessment of infant skills and include diverse infant feeding experiences within their own home environments. Twenty-five typically developing – low-risk – infants and a pilot group of ten infants at increased risk for feeding and communication disorders completed the study, along with their caregivers. Infants were categorized as “at-risk” if they spent time in the Neonatal Intensive Care Unit. We collected feeding data through caregiver-recorded videos of typical mealtimes, vocalization measures from daylong audio recordings, and responsiveness assessments from video-conferencing interviews with caregivers and the mealtime feeding videos. In our sample, it was feasible to use these remote data collection methods, and we obtained high inter- and intra-rater reliability for all measures (> 90%). In our preliminary study, we found that infants in the low- and at-risk groups demonstrated different oral motor feeding skills. In hierarchical regression models, the interaction between risk group and utterance duration was the most significant predictor of oral motor feeding skills, while neither vocalization measure was strongly related to eating efficiency. In the opposite direction, feeding skills were not predictive of either normalized child vocalization count or utterance duration. Relative to caregiver feeding responsiveness, we found that caregiver feeding responsivity alone did not predict feeding or vocalization measures. Responsivity in combination with weeks of feeding experience and medical risk group was related to oral motor feeding skill but not related to vocalization measures. Overall, this study provided initial evidence that feeding skills develop as a dynamic system, influenced by multiple within-child and external factors, and future research is warranted on the influence of these factors on feeding and communication skill development.</p>

Kikuyu pasture (Pennisetum clandestinum) is potentially the most important source of roughage used to feed dairy heifers in summer in KwaZulu-Natal. It is commonly believed that on kikuyu pasture beef breed females grow at a faster rate than those from dairy breeds when no supplementation is given. Little conclusive evidence is, however, available to support this. Explanations as to why such differences may exist are also limited. Eight Hereford and eight Holstein heifers of similar age and maturity stage were used in a trial. The trial was run over a twenty week period. For the first ten weeks all the animals in the trial grazed ad libitum kikuyu pasture with no supplementation except for a mineral lick. Over this (grass only) period the two breed groups formed the two treatments. During the second ten week period of the trial all of the Holsteins and four of the Herefords were fed a restricted but equivalent amount (1 .7 kg) of a maize meal based concentrate. The use of a computerized, mobile feeding system allowed concentrate intake of individual animals to be measured. Animal height, weight and condition score readings were taken weekly over the grass only and the concentrate (final seven weeks) periods of the trial. Herbage intake and digestibility were estimated using n-alkanes as indigestible markers in two experiments conducted during the grass only and concentrate periods. The Herefords had a significantly higher ADG than the Holsteins (0.82 vs. 0.04 kg/day; P < 0.01) over the grass only period. During the concentrate period the rate of mass gain of the Holstein treatment did not differ significantly (P >0.05) from the Hereford treatment receiving concentrate. The Herefords receiving concentrate were also not significantly different (P > 0.05) in rate of mass gain from the Herefords not receiving concentrate. Rate of height gain was not significantly different (P> 0.05) between treatments over either the concentrate or the grass only periods. During the grass only period the Holsteins lost condition (0.07 condition score units per week) whilst the Herefords gained condition at an equivalent rate. The voluntary intake of concentrates was not significantly different (P > 0.05) between the Herefords and Holsteins (19.19 vs. 16.40 g/kg/L.W(liveweight) (0.75)). Regression coefficients relating level of concentrate intake to rate of mass gain were also not significant (P > 0.05) for either of the treatments receiving concentrate. The use of n-alkanes as indigestible markers showed the intake of the Holstein treatment to have an intake 55% (P < 0.0 1) higher than the Herefords (185.4 vs. 120.5 g/kg L.W(0.75)) over the first experiment where both treatments were grazing ad lib. kikuyu alone (grass only period). During the concentrate period intake of the Herefords receiving concentrate exceeded that of the Holsteins (P < 0.01) by 23% (139.1 vs. 113.1 g/kg L.W(0.75)). Review of the literature, suggests that the double alkanes technique greatly over-estimated intake. Errors in herbage sampling (accentuated by pasture rotation in the first experiment), a low daily dose of the synthetic alkane (C(32)) and incorrect estimation of the C(32) content in the daily doses are identified as possible causes of the over-estimation of intake. Faecal recoveries of the herbage n-alkanes were demonstrated to increase with increasing chain length and hence C(35) was proposed as the most reliable herbage alkane for dry matter digestibility determination. Digestibility differences between treatments estimated using the C(35) alkane were not significantly different (P > 0.05) in either the first or second experiments. The mean digestibility estimates (using the C(35) alkane) for the first and second experiments were 64.9 and 56.61 %, respectively. In conclusion, higher growth rates of Herefords on kikuyu pasture would seem to be primarily due to differences in the dry matter intake of the grazed herbage. Further work using other breeds of dairy and beef animals is required. The underlying cause of differences in dry matter intake between breeds also requires investigation. / Thesis (M.Sc.Agric.)-University of Natal, Pietermaritzburg, 1995.

The involvement of dopamine in anticipatory and consummatory aspects of feeding behaviors was investigated in the present thesis. All measurements of dopaminergic activity were taken by in vivo electrochemical techniques. In Experiment 1, dopamine efflux in the nucleus accumbens and caudate of male rats was monitored during sessions in which a small, unsignalled liquid meal was consumed. Increases in the electrochemical measure of dopamine activity, which were of similar temporal pattern and magnitude, were observed in both the nucleus accumbens and striatum following meal consumption. These data suggest a possible postingestional role of dopamine in these two brain structures. In Experiment 2, a conditioned feeding paradigm was utilized to study the role of dopamine during a discrete anticipatory phase of feeding. Rats were conditioned to discriminate between a positive conditioned stimulus (CS+) predictive of meal delivery, and a negative conditioned stimulus (CS-) that was not associated with food. Increases in dopamine activity, as determined by changes in electrochemical oxidation currents, were found to be greater during the CS+ than during the CS- in both the nucleus accumbens and caudate. In addition, the magnitude of increase was greater in the nucleus accumbens than the caudate, suggesting that the accumbens may be preferentially involved in the processing of external incentive stimuli. The results support a role for dopamine in both the nucleus accumbens and caudate during appetitive or anticipatory responding for food in the male rat. / Medicine, Faculty of / Graduate

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