Browsing by Author "Anderson, Warren James"
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- ItemInfluence of plane of nutrition on the productivity of Angus heifers : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University(Massey University, 1977) Anderson, Warren JamesThis experiment was designed to study the influence of autumn live weight and nutritionally-enforced live weight change on calf birth weight and the subsequent productivity of three-year-old, primiparous Angus heifers, calving in the spring of 1975. All heifers were pasture fed on "Tuapaka", No. 3 sheep farm, Massey University, and the treatments imposed followed those normally experienced by cattle on hill country. This was achieved by altering pasture intake by the manipulation of stocking rate during first pregnancy. The research herd of 54 heifers was comprised of animals reared to two-and-a-half-years-of-age at three different origins, namely Massey (Tuapaka), Hawke's Bay and Wairarapa, which consequently gave the three autumn live weight groups. On 1 May, 1975, a switchover design for pre-calving nutritional plane was initiated by allocating heifers within origin to one of three treatment groups. The first group of 19 heifers was fed at a high plane continuously to calving. A second group of 18 heifers was fed at a high plane of nutrition for 70 days (to 10 July, 1975) until three weeks before the start of calving (30 July, 1975). The third group of 17 heifers was fed on a low plane of nutrition from 1 May to 10 July, 1975, when it was switched to a high plane. The three groups were identified as HP-HP, HP-LP and LP-HP, respectively. The least squares means for the live weight of the groups at the start of the experiment, at switchover 70 days later, and at the last weighing date before calving were: 1 May, 1975: HP-HP, 382.4kg; HP-LP, 382.0kg; LP-HP, 380.1kg (NS). 10 July, 1975: HP-HP, 381.3kg; HP-LP, 382.1kg; LP-HP, 362.2kg (p<0.01). 25 July, 1975: HP-HP, 395.7kg; HP-LP, 376.0kg; LP-HP, 375.0kg (p<0.01). The live weight of the heifers, as classified by origin at the last weighing date before calving (25 July, 1975), did not differ from that at the start of the experiment (1 May, 1975) by more than 1.7kg. The least squares means for the weight of the heifers of the origin groups at 25 July was: Massey, 367.8kg; Hawke's Bay, 407.4kg; Wairarapa, 371.7kg, The Hawke's Bay heifers were significantly (p<0.01) heavier than those from the other two origins. The first order interaction between winter nutritional regime and autumn live weight was not significant. The birth weight of the calf was not significantly influenced by the plane of nutrition of the dam or her autumn starting weight. Within treatments, the least squares means for birth weight were: HP-HP, 27.8kg; HP-LP, 25.7kg; LP-HP, 25.9kg. The maximum difference was 2.1 kg. (0.05