Increased dietary protein in the second trimester of gestation increases live weight gain and carcass composition in weaner calves to 6 months of age

Abstract

Genetically similar nulliparous Polled Hereford heifers from a closed pedigree herd were used to evaluate the effects of dietary protein during the first and second trimester of gestation upon foetal, placental and postnatal growth. Heifers were randomly allocated into two groups at 35 days after artificial insemination (35 days post conception (dpc)) to a single bull and fed high (15.7% CP) or low (5.9% CP) protein in the first trimester (T1). At 90 dpc, half of each nutritional treatment group changed to a high- or low-protein diet for the second trimester until 180 dpc (T2). High protein intake in the second trimester increased birth weight in females (P=0.05), but there was no effect of treatment upon birth weight when taken over both sexes. Biparietal diameter was significantly increased by high protein in the second trimester with the effect being greater in the female (P=0.02), but also significant overall (P=0.05). Placental weight was positively correlated with birth weight, fibroblast volume and relative blood vessel volume (P<0.05). Placental fibroblast density was increased and trophoblast volume decreased in the high-protein first trimester treatment group (P<0.05). There was a trend for placental weight to be increased by high protein in the second trimester (P=0.06). Calves from heifers fed the high-protein treatment in the second trimester weighed significantly more on all occasions preweaning (at 1 month (P=0.0004), 2 months (P=0.006), 3 months (P=0.002), 4 months (P=0.01), 5 months (P=0.03), 6 months (P=0.001)), and grew at a faster rate over the 6-month period. By 6 months of age, the calves from heifers fed high nutrition in the second trimester weighed 33 kg heavier than those fed the low diet in the second trimester. These results suggest that dietary protein in early pregnancy alters the development of the bovine placenta and calf growth to weaning.

Maternal periconceptional and first trimester protein restriction in beef heifers: effects on placental parameters and fetal and neonatal calf development

“…This finding is consistent with previous reports of sex-specific effects of dietary perturbation in early gestation on bovine fetal development (Micke et al 2015;Taylor et al 2018). In contrast, studies investigating perturbations occurring during the second trimester in the bovine (Miguel-Pacheco et al 2017) and in the second and third trimesters in humans (Clifton 2010) report that the female is more responsive. The expected sex-differences in calf birth BW were disrupted at term (Copping et al 2014), even though birth BW was normalised following maternal protein restriction ceasing on 98 dpc.…”

“…Similar fetal growth restriction in both sheep (McMillen et al 2001) and cattle (Long et al 2009;Sullivan et al 2009b) has been linked to changes in placental development. The present study reported a similar average placental weight (4.9 kg) to that of dairy cattle (5 kg; Laven and Peters 2001) but higher than the 4.1 and 3.9 kg reported in 2- (Miguel-Pacheco et al 2017) and 3year-old calving beef heifers (Sullivan et al 2009b). Placental efficiency in the present study, a measure of the capacity of the placenta to support growth of the fetus (Fowden et al 2009), was lower (7.0 : 1) than the 8.5 : 1 reported by Sullivan et al (2009b).…”

“…Following realimentation in these heifers, only cotyledon weight remained affected at 250 dpc; however, changes in placental vascularity became apparent by 250 dpc (Vonnahme et al 2007). Interestingly, trophectoderm volume in heifers that experienced protein restriction during the first trimester was increased at birth (Miguel-Pacheco et al 2017). This adaptation may alter the functional potential of the placenta and thereby enable enhanced nutrient supply to the fetus during later gestation if maternal nutrition increases (Perry et al 1999).…”

Low protein intake during the preconception period in beef heifers affects offspring and maternal behaviour

“…The observed effects upon maternal behaviour and offspring weight and behavioural changes associated with the PreL diet suggests that uterine environment may be modified by maternal intake before the implantation period as previously reported in sheep and rodents (Stevens et al, 2010;Kleemann et al, 2015). Previous findings, however, suggest that compensatory mechanisms exist within this progeny, as weight differences apparent at birth may not be apparent at 6 months of age (Micke et al, 2010a;Miguel-Pacheco et al, 2017). This does not however infer that differences in physiology and importantly production traits do not persist (Micke et al, 2010a).…”

Feeding corn distillers grains as an energy source to gestating and lactating beef heifers: Impact of excess protein on feedlot performance, glucose tolerance, carcass characteristics and Longissimus muscle fatty acid profile of steer progeny

“…Increased uterine blood flow and nutrient transfer to the fetus as well as elevated IGF-1, in turn, may increase progeny performance. Miguel-Pacheco et al (2016) observed that providing heifers with a high-protein (15.6%) diet in the second trimester resulted in a faster growth rate and a significant increase in body weight (~33 kg) in their calves at 6 months of age when compared with calves born to heifers fed low protein (6.1%) in the second trimester. Furthermore, calves born to cows supplemented with adequate protein had carcasses with higher marbling scores, a greater percentage of carcasses grading US Department of Agriculture (USDA) Choice, and heavier hot carcass weights compared to cows fed protein below their requirements (Stalker et al 2006(Stalker et al , 2007Larson et al 2009).…”