Breeding objectives of Brangus cattle in Brazil

Abstract

Our goal was to define a breeding objective for Brangus beef cattle in Brazil. Bioeconomic models were produced and used to estimate economic values (EVs). The scenarios simulated were typical full‐cycle beef production systems that are used in tropical and subtropical regions. The breeding objective contained pregnancy rate (PR), warm carcass weight (WCW), mature cow weight (MCW), number of nematode eggs per gram of faeces (EPG) and tick count (TICK). Two models were used in series to estimate the EV. A deterministic model was used to simulate effects of PR, WCW and MCW on profitability with a constant parasite load. Subsequently, stochastic models were used to estimate economic values for TICK and EPG as consequences of their environmental effects on weight gains, mortality and health costs. The EV of PR, WCW, MCW, EPG and TICK, was US$1.59, US$2.11, −US$0.24, −US$5.35 and −US$20.88, respectively. Results indicate positive emphasis should be placed on PR (12.49%) and WCW (65.07%) with negative emphasis on MCW (13.92%), EPG (2.77%) and TICK (5.75%). In comparison with the indexes usually used, these results suggest a reformulation in the selection indexes of the beef production system in tropical and subtropical regions in order to obtain greater profitability.

BrangusSelection: um algoritmo para seleção ótima de acasalamentos com índice de seleção customizável

“…A base de dados contém dados referentes a 1366 bovinos da rac ¸a Brangus, sendo 511 machos e 855 fêmeas. Os dados correspondem aos valores de DEP aprimorada pela Genômica (DEPG) das características dos animais que compõem o índice de selec ¸ão bioeconômico construído em [Simões et al 2020], acrescido da variável de temperamento. O algoritmo pode, contudo, ser executado para qualquer índice, visto que trabalha somente sobre a matriz de contribuic ¸ão.…”

“…Um objetivo de selec ¸ão é uma característica desejável que se quer obter no futuro rebanho, que pode compreender características genéticas ou econômicas [Simões et al 2020]. Os critérios de selec ¸ão são as características pelas quais os animais são avaliados para que os objetivos de selec ¸ão sejam atingidos [Abreu et al 2013].…”

“…Neste texto, é apresentado o algoritmo BrangusSelection, que usa uma estratégia que combina programac ¸ão linear e o método branch and bound para encontrar a soluc ¸ão ótima do problema e estabelecer diferentes cenários para investigar a eficiência com a qual o problema é resolvido. O índice bioeconômico desenvolvido em [Simões et al 2020], com adic ¸ão de variáveis correspondentes ao temperamento, será usado para apresentac ¸ão dos resultados. No entanto, o algoritmo proposto é genérico e pode ser executado com qualquer índice.…”

Selection indexes for Nellore production system in the Brazilian Pantanal

“…Most EV for the CW is negative, according to several studies (Wolfová et al, 2005;Ochsner et al, 2017;Simões et al, 2020). Larger animals are not always the most suitable and profitable to production systems, due to the high energy required for their maintenance and the consequent increased feeding costs.…”

On the problem of compensatory mating in animal breeding

“…A selection process intends to elect the animals to become the next generation parents [Yokoo et al 2019, Simões et al 2020, Weigel et al 2017, Dunne et al 2021]. The selection process analyses the herd's genetic/economic values and phenotypes of genetic/economic interest.…”