Relation between Holstein bulls’ proofs for milk in USA and the survival and body weights up to 18 months of their F₁ zebu progeny in Venezuela

Abstract

Summary The purpose of the study was to determine the relation between Holstein bulls’ proofs for milk in USA, and the survival and body weights of their F1 progeny under lowland grazing conditions in Venezuela. Semen was selected from sires with the highest proofs available locally (class H, n = 23) or with proofs close to the breed average (class A, n = 18). Mean proofs were 934 kg (H) and 237 kg (A), respectively, when semen was purchased (1989–93), falling to 204 and −386 kg when updated in 2001. Dams were Brahman‐type zebus on seven farms, raising the F1 progeny (n = 866) on native or cultivated pasture with only mineral supplements. Records of survival to 8 and 18 months and weights at birth, 8 and 18 months of age were analysed using linear models. Sire class had no effect on survival or weight at birth, but H progeny were slightly heavier than A progeny at 8 (4.0%, p = 0.06) and 18 months (2.6%, p < 0.05). The interaction class × farm was only significant for survival, with H progeny equal or superior to A groups on six farms. The effect of sire within class was highly significant for survival to 8 months and weight at 18 months. Rank correlations using sires’ milk proofs and F1 progeny weights and survival were not significant. It was concluded that the use of Holstein bulls with high milk proofs may lead to slightly higher 18‐month weights in their F1 progeny in tropical grazing systems, covering the additional cost of H semen, but that sire evaluation for weight gain and progeny survival rates may be justified under these conditions.

Relation between Holstein bulls’ proofs for milk in USA and the milk yield, age at first calving, calving interval and survival to third calving of their F1 zebu progeny in Venezuela

“…The difference in 18‐month weight of males was sufficient to cover the additional cost of the H semen used to produce progeny of both sexes. The highly significant differences between sires in age at first calving found in the present case are to be expected, given similar results obtained for weights at 18 months of age (P acheco et al. 2003).…”

“…The difference in the present case was associated with heavier culling of the A progeny after first calving, as there was no evidence of any difference between the two classes till then. Neither was any effect of sire class detected on calf survival to 8 or 18 months of age, using records from the same farms and four additional herds (P acheco et al. 2003), but there was a significant class × farm interaction, with H calves surviving as well or better than the A progeny on six of the seven farms.…”

“…While recognizing the problem of progeny group size, the difference between extreme adjusted mean for sires with ≥ 10 daughters was striking, varying by between 24 and 55 percentage points, depending on calving number. At the same time, highly significant differences in F 1 calf survival due to sires were found in a much larger sample from these and neighbouring herds (P acheco et al. 2003).…”

“…The results were affected by a difference of 6 months in favour of A progeny on farm 5 but the groups were small and, in contrast with the other farms, the timing of first service was not determined by weighing the heifers. This aspect requires further study, as evidence from a larger sample showed that H progeny weighed slightly more than A progeny at 18 months of age (P acheco et al. 2003), which suggests that they might also calve younger, provided weight is used as the criterion for first service.…”

“…The purpose of the present paper is to describe the productive performance of the female F 1 progeny of Holstein sires, classified according to genetic merit for milk in the USA and used in dual purpose herds in the Venezuelan lowlands. The body weights and survival rates of young stock are described in a companion paper (P acheco et al. 2003).…”