Difference in Body Weight at Breeding Affects Reproductive Performance in Replacement Beef Heifers and Carries Consequences to Next Generation Heifers.

Ramanathan K Kasimanickam,Vanmathy R Kasimanickam,Madison L Mccann

doi:10.3390/ani11102800

Abstract

Simple SummaryThe effect of prebreeding feeding to attain 55% vs. 65% of mature cow body weight (MBW; 545 kg) at breeding on the reproductive performance of beef heifers and its offspring was investigated. Angus-cross dam heifers from weaning were randomly fed to attain 55% (n = 1622) vs. 65% (n = 1578) of MBW and off-spring (F1) heifers born to dam heifers in both 55% (n = 1285) vs. 65% (n = 1324) groups were fed to attain 65% of MBW. Results showed that restricted feeding negatively affected puberty, breeding season pregnancy and 21-day calving rates. F1 generation heifers that were fed normal diets but were born to dams that were fed restricted diets also had reduced puberty, breeding season pregnancy and 21-day calving rates. In conclusion, restricted feeding during the prebreeding period of dam heifers reduced post-pubertal fertility and fertility of their heifer offspring that were fed normal prebreeding diets.Nutrition imprinting carries consequences across generations. The effect of 55% vs. 65% of mature cow body weight (MBW; 545 kg) at breeding on the reproductive performance of heifers and their offspring was investigated. Angus-cross dam heifers were randomly fed to attain 55% (n = 1622) vs. 65% (n = 1578) of MBW, and offspring (F1) heifers born to dam heifers [55% (n = 1285) vs. 65% (n = 1324)] were fed to attain 65% of MBW. Bodyweight and reproductive indices were recorded throughout the study. In dam heifers, puberty (44% vs. 53%), breeding season pregnancy (86.4% vs. 90.6%) and 21-day calving rates (55.2% vs. 65.4%) did vary, but dystocia rate (8.7% vs. 9.0%) did not differ between 55% and 65% MBW groups. Puberty (49.2% vs. 58.2%), breeding season pregnancy (87.2% vs. 92.8%) and 21-day calving rates (53.8% vs. 64.1%) did differ (p < 0.05), but dystocia rate (8.4 vs. 9.2%) did not differ between F1 heifer groups. In conclusion, 55% of MBW at breeding negatively affected the reproductive performance of heifers and its offspring heifers. The recommendation is to feed heifers a balanced diet to reach 65% of MBW at breeding with consideration of production traits.

Highlights

Mean body weight at weaning and at breeding and average daily gain for dam heifers across locations and years are given in Supplementary Tables S3 and S4, respectively
The weaning weight did not differ between dam heifers in the 55% and 65% mature cow body weight (MBW)
Target mature Body weight (BW) at breeding differed between dam heifers in the 55% and 65% BW groups, i.e., 305 and 349 kg and 56% and 64%

Summary

Introduction

Production performance of replacement beef heifers born earlier in the calving season was greater than those that were born later in the calving season [1,2,3]. Many key factors play a vital role, including heifers that were born to genetically superior parents, were born early in the calving season and attained puberty early. Greater lifetime productivity of beef replacement heifers can be expected if they have first calving by 2 years of age. Heifers need to be bred and conceived at 15 months of age to calve at 24 months of age [1,3]

Methods

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Conclusion