The goal of beef cow/calf production is to wean one heavy, healthy calf with the greatest genetic potential to perform per cow, every year, according to Jesse Fulton. The director of Beef Quality Assurance for the University of Nebraska’s Extension program, Fulton spelled out the best way to go about it in a Cattleman’s College seminar.
“How do we do that?” he asked. “We do it by focusing on reproductive efficiency. We need to get cows pregnant.”
Fulton defined reproductive efficiency (RE) as the optimization of the pregnancy rate early in the breeding season and the development and selection of replacement heifers that are highly fertile at the lowest cost possible.
Dr. Vitor Mercadante, a veterinarian and professor of animal sciences with a specialization in bovine reproductive physiology for Virginia Tech, outlined how to achieve the best RE outcomes.
“It’s best to think of it as an equation,” said Mercadante. “Reproductive efficiency equals nutrition and animal health plus selection pressure plus reproductive technologies.”
He defined selection pressures as forces that drive evolution via natural selection and specified that the technologies he referred to in his equation have to be “well established, supported by research and field tested.”
Mercadante then gave a quick rundown on what herdsmen should be focusing on to find their optimum RE.
Breeding Season Management – When choosing which cows to breed, farmers should select cows that have managed to get pregnant “earlier,” which Mercadante defined as the first 21 days of the breeding season. These cows tend to live longer, and cows that get pregnant earlier experience earlier calving and birth heavier calves.
He said that the breeding season should be kept to 90 days or less, something that only 45% of current domestic operations adhere to.
Breeding Soundness Exam (BSE) – While 95% of dairy operations use AI during their breeding season, 93% of beef cattle farms use natural service for breeding. When using natural service breeding methods, farmers need to utilize BSE in order to ensure that bulls are physically capable to mate and have full capacity to produce functionally normal spermatozoa.
AI – The advantages of using AI are disease prevention, a widespread selection of bulls, the benefit of proven genetics, reduction of overall costs due to eliminating the need for bull maintenance, uniformity of gene selection and the opportunity for more selective crossbreeding.
Estrus Synchronization – Estrus synchronization is the process of manipulating the estrous cycle that results in standing estrus (heat) in the majority of animals in a short time. Breeding a large number of cows on the same day optimizes labor, results in more females pregnant and earlier calving.
Transgenic Technologies – Transgenics introduce modified genes and DNA sequences into livestock without crossbreeding or hybridizing. Practical applications of transgenics in livestock production include improved reproductive performance, increased feed utilization and growth rate, improved milk production and increased disease resistance. It is a more precise technique, but not radically different from genetic selection or crossbreeding in the results it produces.
As the labor market continues to shift, focusing on RE will be critical for all beef operations.
by Enrico Villamaino