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    The effect of solid feed diet on the oral and cross-sucking behaviour of pre-weaned dairy calves : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2013) Hansen, Chelsie
    In the dairy industry calves are most frequently artificially reared in groups, which create a greater opportunity for solid feed consumption and non-nutritive oral behaviour. This study aimed to compare the effect of differing solid feed diets on the pre- and post- weaning feed intake, growth rate and oral behaviour of calves reared artificially in groups. This experiment was a randomised block design with the treatments diets allocated at random, in blocks. The research was completed at Massey University’s dairy calf unit #4 and involved 108 Friesian and Jersey x Friesian dairy calves that were allocated to one of three treatment diets: lower forage (LF) alfalfa total mixed ration (TMR); a higher forage alfalfa (HF) TMR; and perennial ryegrass hay along with a pelleted starter (HPS). Calves were reared in 36 groups of three calves per group and monitored until 12 weeks of age. Calves fed HPS had the greatest dry matter intake (LF: 0.80 (0.012), HF: 0.95 (0.012), HPS: 1.70 (0.011) kg/DM/d), live weight at 40 d of age (LF: 60.3 (1.41), HF: 63.8 (1.41), HPS: 67.1 (1.38) kg) compared with TMRs. These calves also spent the most time eating (LF: 129.1 (0.14), HF: 163.7 (0.14), HPS: 154.1 (0.14) mins/d), and spent the least amount of time engaged in non-nutritive pen sucking (LF: 13.4 (0.16), HF: 11.2 (0.17), HPS: 10.3 (0.16) mins/d). It was concluded that, while cross-sucking was not entirely eliminated, providing perennial ryegrass hay along with a pelleted starter resulted in the least non-nutritive sucking behaviour, along with the greatest feed intake and growth rates compared with low and high forage alfalfa based total mixed rations.
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    The effect of milk feeding levels on growth rates of high and low BI Friesian bull calves before and after weaning : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University, New Zealand
    (Massey University, 1984) Wang, Xinjun
    Eight Friesian bull calves from high breeding index parents (HBI, BI of parents = 134) and eight from low breeding index parents (LBI, BI of parents = 103) were used to estimate the effects of milk intake and BI on calf growth performance, voluntary herbage intake, digestion and nitrogen metabolism. 1. The calves were allocated to one of two levels of milk intake from 3 weeks of age until weaning at about 7.5 weeks of age. The milk was fed twice daily at either 4.5 (LM) or 6.0 (HM) litres/calf/d. 2. Daily intakes of freshly harvested herbage (perennial ryegrass and white clover pasture) offered ad libitum throughout the pre-weaning period and for a further 3 weeks period following weaning, were measured. 3. The calves were then grazed on pasture together in a mob and the liveweight at 21-25 weeks of age was measured. 4. Calf growth rates at various stages were recorded. The HM calves grew significantly (p<0.05) faster than LM calves (0.55 v 0.44 Kg/d) in the pre-weaning period. Their growth rate was slower in the 3 weeks following weaning (0.21 v 0.31 Kg/d) but the difference in this period was not significant. 5. The overall growth rate from 3 to 21-25 weeks of age was not significantly different between HM and LM calves (0.52 v 0.53 Kg/d), nor was the calf LW at 21-25 weeks of age (124 v 130 Kg for HM and LM calves respectively). 6. LM calves consumed significantly (p<0.01) more herbage organic matter (OM) both before and after weaning (0.18 and 0.33 Kg OM/d pre-weaning and 1.13 and 1.28 Kg OM/d post-weaning for HM and LM calves respectively). Reducing daily milk intake by 1 Kg increased daily herbage OM intake by 0.11 Kg before weaning and by 0.12 Kg after weaning. The difference in herbage intake caused by milk intake level persisted for two weeks following weaning. It was not significantly different in the third week after weaning. 7. It was demonstrated that the LW at the commencement of the experiment (3 weeks of age) was positively correlated with the mean overall growth rate (from 3 to 21-25 weeks). LW at 3 weeks of age was also positively correlated with the voluntary herbage intake in the third week following weaning, and also digestibility of herbage organic matter in the post-weaning period. 8. By extrapolating the linear relationship between nitrogen retention (NR) and nitrogen intake (NI) per metabolic weight (Kg0°75 ), the estimated nitrogen requirement for maintenance (Nm) was 0.418 g N/Kg0°75/d. 9. There were no significant differences in growth rate, herbage voluntary intake, digestibility or nitrogen metabolism between the BI groups, nor any interactions between the BI and levels of milk intake.
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    Prediction of milk yield of 3-year-old Angus cows and the influence of maternal milk production on the postnatal growth of beef steers : a thesis presented in fulfilment of the requirements for the degree, Master of Sicnece (Animal Science), Massey University, Palmerston North, New Zealand
    (Massey University, 2013) Roca Fraga, Fernando Javier
    Maternal milk production influences calf weaning weight which is the major driver for economic return in a cow-calf operation. The objective of this study was to use measures of calf milk intake to estimate milk production of Angus (AA; n=43), Angus×Friesian (AF; n=32), Angus×Jersey (AJ; n=40) and Angus×Kiwi-Cross (AK; n=21) cows, and to determine how milk yield was related to calf growth rate (n=64) from birth to one year of age. Milk production was estimated by the weigh-suckle-weigh (WSW) technique at an average 32, 49, 80, 120 and 160 days (D) post-partum. Third-order Legendre polynomials were fitted to milk data using random regression to estimate the lactation curve for each cow. Live weight of all steers was recorded at birth and thereafter accompanying every WSW measurement. Postweaning live weight was recorded at an average D240, D330 and D350 of age. Growth curves for each steer were estimated by fitting third-order Legendre polynomials to live weight data using random regression. The average total milk production from D32 to D160 was 1337 ± 22 kg for AF cows, 1245 ± 20 kg for AJ cows, 1301 ± 32 kg for AK cows and 1017 ± 20 kg for Angus cows. The AF, AJ and AK cows produced more (P<0.05) milk from D32 to D160 than the AA cows. The AF cows produced more (P<0.05) milk than AJ cows, with AK cows being intermediate and not differing (P>0.05) from either AF or AJ cows. Crossbred cows produced more milk (P<0.05) at all stages of lactation when compared with straightbred AA cows. In the present study, as the proportion of Friesian or Jersey in the crossbreds increased from 0 to 50%, an extra 325 kg and 240 kg of milk, respectively, was expected compared to the AA cows. Total energy intake from milk was higher (P<0.05) for the AF-, AJ- and AK-reared steers compared to those reared by AA dams. This resulted in higher liveweight gains so that steers reared by crossbred cows were heavier (P<0.05) from D60 to D270 than those reared by AA cows. Results also revealed that the higher live weight at D60 in AJ-reared steers compared to AA-reared steers was due to differences in milk consumption from D32 to D60. The higher live weight of AF- and AK-reared steers at D60 compared to AA-reared steers was attributed to a maternal effect on steer size; however, from D90 until weaning at D160, any differences in live weight were due to differences in milk consumption. Estimation of the theoretical pasture consumption revealed that AA- reared steers compensated for the lower milk intake by eating more grass, however, this was not enough to support high daily gains during the pre-weaning period. The differences in live weight seen at weaning between steers were maintained post-weaning until D270 and were attributed to differences in milk consumption during the pre-weaning period. Under nonlimiting nutrient availability, AF, AJ and AK cows were able to pr
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    Assistance at parturition of primiparous, two-year-old, Angus heifers and the effect of liveweight gain of heifers in early pregnancy on birth weight of the calf : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2009) Hickson, Rebecca Edith
    A simulation showed that calving heifers for the first time at two compared with three years of age increased profitability of a beef breeding herd; however, profitability of calving two-year-old heifers was dependent on the incidence of assistance at parturition. The predominant cause of dystocia (and hence assistance at parturition) in beef breeding heifers is feto-maternal disproportion. This condition could be alleviated by reducing birth weight of calves relative to live weight of heifers. In a survey of farmers, 20% of those currently calving heifers at three years of age indicated that if the need for assistance at parturition was eliminated, they would calve their heifers at two years of age. In two surveys conducted of the same farmers in consecutive years, mean incidence of assistance at parturition in primiparous, two-year-old heifers was 7.0% and 9.5%, and reached 100% in some herds. Mortality rate by four weeks postpartum was 30% for assisted calves and 11% for assisted heifers. Methods of reducing the need for assistance at parturition in primiparous, two-year-old, beef breeding heifers would be of value to the beef cattle industry in New Zealand. The objective of this research was to identify whether manipulation of liveweight gain of primiparous, two-year-old, Angus heifers in the first trimester of pregnancy could be used to regulate birth weight of calves, and to identify factors contributing to the need for assistance at parturition. Three experiments were conducted in which heifers were fed for various rates of liveweight gain: 1. moderate versus low for the first trimester of pregnancy; 2. a 2 x 2 factorial experiment in which liveweight gain was 1220 high versus moderate for ten days prior to insemination, and moderate versus a loss for the first trimester of pregnancy; 3. high and moderate, moderate and a loss, or moderate and moderate for days 0-42 and 42-90 of pregnancy, respectively. Birth weight of calves was not affected by treatment in experiments 1 and 3. In experiment 2, birth weight of the calf relative to live weight of the heifer was least in the high-then-low treatment, but subsequent live weight of those calves was also less, partially negating any potential benefits to production. An additional experiment revealed similar fetal weight at the end of the first trimester for heifers that had moderate or low liveweight gain from 21 days prior to conception. Probability of assistance at parturition increased with birth weight of the calf and decreased with increased live weight of the heifer. Body dimensions of calves did not affect the likelihood of assistance. Assistance had no effect on subsequent performance of surviving animals. Manipulation of liveweight gain of heifers in the first trimester of pregnancy did not offer a means of reliably regulating birth weight of calves; however, the impact of assistance at calving did not justify delaying first calving until three years of age. Birth weight and assistance at calving can currently be best managed through selection of appropriate service sires for primiparous heifers.