Influence of prepartum nutrition on cow performance and subsequent calf performance, glucose tolerance, carcass characteristics, efficiency, and gene expression

The objective of this dissertation was to evaluate potential fetal programming effects of beef cow nutrition within beef production systems.;Fall-calving cows grazing endophyte-fescue experience a decline in forage quality during late gestation, when fetal growth occurs at a high rate. Fall-calving, mature cows and their progeny were used to evaluate the effects of late gestation dried distillers grains plus solubles (DDGS) supplementation on cow performance, and progeny growth and carcass characteristics. Cows were offered daily DDGS supplementation or offered no supplement 69 +/- 9 d prepartum through calving. Cow BW and BCS change during late gestation were greater for cows offered supplement. Supplementation had no effect on calving date, calf birth or weaning BW, or pre-weaning ADG, milk production, AI conception, or overall pregnancy rate. For steer progeny, dam DDGS supplementation had no effect on feedlot performance or carcass characteristics.;In one experiment, spring-calving, mature cows and their progeny were used to evaluate the effects of prepartum dietary energy on cow performance as well as performance and carcass characteristics of subsequent progeny. Cows were limit-fed isonitrogenous rations that provided 100% or 125% of TDN requirements, respectively, from 83 +/- 10 d prepartum to calving. Cow BW change through breeding was greater and BCS change tended to be greater for cows 125% of TDN requirement. Birth BW was greater for calves born to cows fed excessive dietary energy with no increase in percentage of unassisted births. There were no effects of dietary energy on calving date, milk production, or subsequent pregnancy rate. Calf feedlot performance was not affected by prepartum energy. Although progeny born to dams fed excessive dietary energy tended to have greater marbling scores at weaning, prepartum dietary energy had no effect on carcass marbling score or other carcass characteristics.;Two experiments were conducted to investigate the effects of prepartum dietary CP intake on cow performance as well as subsequent progeny growth, carcass characteristics, and plasma glucose and insulin concentrations. Spring-calving, mature cows in both experiments were limit-fed rations formulated to be isocaloric, and provide 100% or 129% of CP requirement, respectively, from 92 +/- 10 or 78 +/- 12 d prepartum to calving in Exp. 1 and 2, respectively. Prepartum CP intake had no effect on cow BW, BCS, milk production, and subsequent reproduction or progeny pre-weaning growth in either experiment. In Exp. 1, postweaning ADG, final BW, and HCW were decreased in progeny born to dams fed excessive dietary CP. In Exp. 2, progeny post-weaning growth was not affected by treatment; yet, 12th rib fat thickness, KPH, and yield grade were greater for progeny born to dams fed excessive dietary CP. Progeny born to dams fed excessive dietary CP had decreased glucose and insulin concentrations, and insulin to glucose ratios, indicating greater insulin sensitivity.;Mid-gestation is a critical time for the development of skeletal muscle and adipogenesis. Much of the work that has demonstrated promising fetal programming effects, was done in nutrient restricted or overfed dams, 50% or 150% or energy and protein requirements, respectively. One experiment was conducted to investigate the effects of divergent plane of nutrition during mid-gestation on cow performance and progeny growth, feed efficiency, methane production, glucose tolerance, carcass characteristics, and gene expression in LM. Mature cows were limit-fed 3 planes of nutrition from 196 +/- 14 to 114 +/- 14 d prepartum: 100% energy and protein requirement (REQ), 70% requirement ( 70%REQ), or 130% requirement (130%REQ). Cow ADG during mid-gestation was greatest for 130%REQ, least for 70%REQ, with REQ intermediate. Transition period (30 d post-weaning) ADG was greatest for 70%REQ progeny, least for REQ progeny, with 130%REQ progeny intermediate. Treatment had no effect on progeny RFI or 24 h methane emissions; but, REQ progeny tended to have decreased RG relative to 70%REQ and 130%REQ progeny. Treatment had no effect on progeny glucose and insulin concentrations, AUC, glucose clearance rate, or insulin to glucose ratio during glucose tolerance test. Progeny of REQ dams had greater HCW than 70%REQ progeny, with 130%REQ intermediate and not different from either. Treatment had no effect on other carcass characteristics. Treatment had no effect on expression of 13 selected genes in LM, with the exception of MYH1. Expression of all target genes, except MYH7, changed as progeny d of age increased. There was a treatment by d of age interaction for expression of MYH1, in which expression of MYH1 was least in progeny born to 70%REQ dams at 392 +/- 14 d of age relative to REQ and 130% progeny. There were treatment by progeny sex by d of age interactions for expression of SLC2A4, YY1, and MYH7. (Abstract shortened by UMI.).