Weight at conception and gestational gains in the efficiency of beef cows and progeny performance.

Ricardo Z Vaz,João Luiz B Costa,José Fernando P Lobato,João Restle,Lidiane Eloy,Pablo T Costa

doi:10.1590/0001-3765202220191280

Abstract

The aim of this study was to evaluate the effects of conception weight and gestational weight gain on performance and productive efficiency in beef cows and their calves. Eighty-eight primiparous, three-year old Braford females were used, divided according to weight at conception and gestational performance (High and Low): cows with a low conception weight and low gestational weight gain (LL), cows with low conception weight and high gestational weight gain (LH), cows with high conception weight and low gestational weight gain (HL), and cows with high conception weight and high gestational weight gain (HH). At calving, HH cows were heavier than LH and HL and these were heavier than LL cows. Male calves born to HH cows were superior in body weight to those born to LL cows at 150, 210 and 365 days. Female calves born to HH, HL or LH cows were superior to those born to LL cows in pregnancy at 14 months of age. The LL and HL cows were more efficient in calf production. Actual fertility was influenced by the nutritional level of the herd, where HH cows were superior than LL cows. Better cow herd nutrition increases the development and performance of the progeny.

Highlights

Due to their lower efficiency, breeding herds are largely kept in natural pastures
The weights of the groups differed at calving (P
LL - cows which were light at conception with low gestational weight gains; LH - cows which were light at conception with high gestational weight gains; HL - cows which were heavy at conception with low gestational weight gains; HH - cows heavy at conception with high gestational weight gains

Summary

Introduction

Natural pastures do not have the necessary nutritional quantity or quality for the increased demands for breeding, or later during pregnancy or during lactation after calving (Vaz & Lobato 2010) In certain situations, this restriction can cause a loss in weight and in the body condition of the cows (Colazo et al 2009). A surplus or deficit of nutrients consumed by the cow can influence prenatal foetal development (Tsuneda et al 2017), since maternal nutrition can modify the uterine environment during gestation or during the growth phase (Du et al 2010), which, in the event of malnutrition, may impair development in the offspring Such inadequate nutrition delays development of the reproductive tract, retarding puberty in the young heifers and resulting in lower reproductive performance

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Discussion

Conclusion