Abstract
Nulliparous yearling beef heifers (n=360) were used to evaluate the effects of maternal dietary protein during the periconception and first trimester periods of gestation on postnatal growth, feedlot performance, carcass characteristics, and the expression of genes associated with appetite in the arcuate nucleus of their male progeny. Heifers were individually fed a diet of 1.18g crude protein (CP)/day High protein (HPeri) or 0.62g CP/day Low protein (LPeri) beginning 60days before conception. From 24 to 98days post-conception (dpc), half of each treatment group changed to the alternative post-conception diet and were fed 1.49g CP/day (HPost) or 0.88g CP/day (LPost) yielding four treatment groups in a 2×2 factorial design. From day 98 of gestation, heifers received a common diet until parturition. Calves were weaned at 183days and developed on pasture before feedlot entry. Bulls underwent a 70-day Residual Feed Intake (RFI) feedlot test commencing at 528days of age. Feedlot entry and final body weight (BW), feedlot average daily gain (ADG) and RFI were not different (p>0.05). Progeny of dams that had a change in diet (LPeri/HPost and HPeri/LPost) had 9% higher daily dry matter intake (DMI) during the RFI test (p<0.05) than progeny of dams that received low diet throughout both the peri-conception period and first trimester (LPeri/LPost). Further, mRNA expression of the appetite-stimulating agouti-related protein (AGRP) was increased in the arcuate nucleus of High Peri/LPost bulls (p<0.05). Longissimus dorsi muscle cross sectional area, carcass dressing percentage, and estimated retail beef yield (RBY) were all higher (p<0.05), and rump (P8) fat tended to be lower (p=0.07), for bulls from HPost dams despite no difference in carcass weight (p<0.05). This study is of commercial importance to the livestock industry as specific periods of maternal dietary supplementation may increase feed intake, enhance progeny muscling, and alter fat deposition leading to improvement in efficiency of meat production in beef cattle.
Highlights
Protein is the most common limiting factor to production under Australian extensive pasture beef production systems (Bortolussi et al, 2005)
Ethics Committee (Australia), The University of Adelaide (Australia), and The University of New England (Australia) Animal Ethics Committees (Approval numbers: 18/11, S2012249, and AEC14-037, respectively). The purpose of this experiment was to determine the impact of maternal dietary protein during the peri-conception [PERI; −60–23 days post-conception; conception being the day of artificial insemination (AI) and implantation being 18–22 dpc; Wathes and Wooding, 1980; Spencer and Hansen, 2015] and first trimester (POST; 24–98 dpc) periods in nulliparous heifers upon postnatal growth, appetite [as measured by Dry Matter Intake (DMI)], and carcass characteristics in the male progeny
Post-natal progeny body weight (BW), average daily gain (ADG), and height at weaning tended to vary with an interaction between PERI and POST diet (p < 0.10), but there were no differences between diet groups (p > 0.10)
Summary
Protein is the most common limiting factor to production under Australian extensive pasture beef production systems (Bortolussi et al, 2005). Maternal dietary protein intake during pregnancy in heifers impacts fetal, as well as post-natal and adult growth, physiology, metabolism, and carcass traits of the offspring (Larson et al, 2009; Sullivan et al, 2009a; Micke et al, 2010a,b; Long et al, 2012; Copping et al, 2020) These bovine studies, and others in the ovine (Muhlhausler et al, 2006), illustrate that early gestation is an important period of development. Report on the impact of protein intake in cattle during the periconception period and early gestation on the subsequent progeny growth, appetite, or carcass characteristics (Micke et al, 2010a)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
