HEJA LODGE – Heifers are the future of the beef herd, consist of the most recent genetics and for these reasons investments made in management and selection of heifers are likely to bring significant benefit to the herd in future, says Dr Dietmar Holm of the University of Pretoria.
Dr Holm captivated the audience last week at the second Meat Production School hosted by the Namibian Stock Breeders Association when he explained how increased management for fertility fits into a beef production system.
At the hand of some results of recent heifer studies, he stressed the importance of inputs in management regarding structured breeding, vaccination, health and nutrition to ensure proper development of heifers for them to perform up to their genetic potential. “It is important that the heifer development plan should be based on scientific evidence, and of particular importance is nutrition during critical times of reproductive development. A stable system with only minimal changes from year to year is also important consideration to ensure that a herd of cattle is developed over time that performs optimally within the system. Investments in the efforts of selection of the best heifers include selection based on the performance of the dam, functional conformation for adaptability in the particular environment, but most importantly selection based on reproductive ability. Producers should take care in the selection process to prevent accidental selection for unwanted traits by selecting for genetically correlated traits,” he stressed.
He summed up three recent South African trials investigation management and selection of beef heifers, saying in the first trial, the potentially negative effect of high levels of dietary nitrogen intake in developing heifers during the two to three months preceding the breeding season was investigated, in the second trial the effects of two different oestrus synchronisation programmes were tested against control groups of heifers at similar stages of pubertal development, and interactions between pubertal development stage and synchronisation programme were investigated. In the third trial, the effects that selection based on different applications of pelvis area data might have on surviving heifers compared to those that were culled were critically evaluated.
He went on to explain how nitrogen supplementation can affect fertility of pubertal beef heifers and also how beef heifers at different stages of pubertal development respond to synchronisation programmes.
Holm concluded the session with a discussion on how pelvimetry should be used to select against dystocia in beef heifers.