Breeding objectives for a Nellore cattle rearing system

Abstract

-The objective of this work was to define the traits that should be included as breeding objectives for Nellore cattle, according to simulations with a bio-economic model for rearing systems. The economic values (EVs) of the traits were calculated as the differences between the profits due to an increased performance of 1% in each trait, with the others traits remaining constant. To determine the impact of each selection on the revenue system, two scenarios were simulated based on the traits being selected. In the first scenario, the adopted selection criteria were: weaning weight (WW), weaning rate (WR), yearling weight (YW), and mature cow weight (MCW). In the second scenario, the cumulative productivity (CP) of dams was used as an indirect evaluation of the performance of calves, with all the other traits included, except WW. In the first scenario, an EV of R$ 1.44 kg -1 was obtained for WW. In the second scenario, an EV of R$ 2.91 kg -1 was obtained for CP. The trait with the highest EV in both scenarios was WR, which enhanced the profits by R$ 3.21 for each 1% increased performance. The meat price paid to the producer is the factor with the greatest impact on the EVs of all examined traits.

Evaluation of slaughter cattle grades and standards of cull cows

“…Research on this issue has been of great importance in recent decades, as evidenced by publications by scientists in advanced dairy farming. The share of this trait in the overall assessment of breeding value is: in Germany -6%, in France -13%, in the Netherlands -12%, in the United States -13%, in Canada -8%, in New Zealand -10% (Damasceno & Calmon, 2015;Effa et al, 2013). The practice of using cattle has convincingly demonstrated that the economic efficiency of milk production is largely driven by factors such as the genetic potential of cows and the duration of their productive use (Palii et al, 2019b;Pidpala & Zaitsev, 2018).…”

Factors Affecting Weight Gain in Nelore Calves from Birth to Weaning in the Bolivian Tropic

“…An objective to be met by any livestock system is that it generates efficient productive results that allow maximizing economic returns (Damasceno Carvalho et al, 2015).…”

Relationship of Longevity with Productive and Reproductive Variables in Nelore Cows of the Bolivian Tropic

“…Age at first calving, survival and longevity are economically important characteristics in beef cattle (Dakay et al, 2006;Carvalho et al, 2015;Damiran et al, 2018). Longevity, includes from the first to the last calving, being an economically important trait.…”