title: Nutrient restriction and realimentation in beef cows during early and mid-gestation and maternal and fetal hepatic and small intestinal in vitro oxygen consumption.
abstract: Objectives were to determine the effects of advancing gestation, maternal nutrient restriction during early and mid-gestation, and realimentation on fetal liver and jejunal mass and energy use in both dams and fetuses. On day 30 of pregnancy, multiparous, non-lactating beef cows (initial BW=621±11.3 kg and body condition score=5.1±0.1) were assigned to one of the two dietary treatments: control (CON; 100% requirements; n=18) and restricted (R; 60% requirements; n=28). On day 85, cows were slaughtered (CON, n=6; R, n=6), and remaining cows continued on control (CC; n=12) and restricted (RR; n=12) diets, or were realimented to the control diet (RC; n=11). On day 140, cows were slaughtered (CC, n=6; RR, n=6; RC, n=5), remaining cows continued on the control diet (CCC, n=6; RCC, n=5), or were realimented to the control diet (RRC, n=6). On day 254, all remaining cows were slaughtered. Maternal liver O2 consumption linearly increased (P⩽0.04) and jejunal weight (g/kg) linearly decreased (P=0.04) as gestation advanced in CON groups. Fetal BW, and hepatic and small intestinal absolute mass, protein content and O2 consumption linearly increased (P⩽0.04) as pregnancy advanced in CON groups. However, mass and O2 consumption relative to BW linearly decreased (P⩽0.001) in the fetal liver in CON groups. When analyzing the effects of dietary treatment, at day 85, fetal jejunal O2 consumption (mol/min per kg BW) was lower (P=0.02) in the R group when compared with the CON group. At day 140, maternal hepatic weight (g) was lower (P=0.02) in RC and RR cows when compared with CC, and fetal jejunual O2 consumption (mmol/min per mg tissue and mmol/min per g protein) was greater (P⩽0.02) in RC when compared with RR. At day 254, maternal hepatic O2 consumption (absolute and relative to BW) was lower (P⩽0.04) in the RCC cows when compared with RRC. Fetal hepatic weight was lower (P=0.05) in the CCC group when compared with RCC and RRC. The changes in response to nutrient restriction and realimentation in both the dam and fetus may indicate an adaptation to a lower amount of available nutrients by altering tissue mass and metabolism.
authors.affiliation: 1Department of Animal Science,North Dakota State University,Fargo,ND 58108,USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Prezotto
authors.affiliation: 1Department of Animal Science,North Dakota State University,Fargo,ND 58108,USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Camacho
authors.affiliation: 2Department of Animal & Dairy Sciences,Mississippi State University,Mississippi State,MS 39762,USA.
authors.forename: C O
authors.initials: CO
authors.lastname: Lemley
authors.affiliation: 1Department of Animal Science,North Dakota State University,Fargo,ND 58108,USA.
authors.forename: F E
authors.initials: FE
authors.lastname: Keomanivong
authors.affiliation: 1Department of Animal Science,North Dakota State University,Fargo,ND 58108,USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Caton
authors.affiliation: 1Department of Animal Science,North Dakota State University,Fargo,ND 58108,USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Vonnahme
authors.affiliation: 1Department of Animal Science,North Dakota State University,Fargo,ND 58108,USA.
authors.forename: K C
authors.initials: KC
authors.lastname: Swanson
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004032:Diet / Q000662:veterinary*; D005260:Female; D007421:Intestine, Small / Q000033:anatomy & histology / Q000378:metabolism*; D008099:Liver / Q000033:anatomy & histology / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption; D011247:Pregnancy; D011897:Random Allocation
keywords: bovine; energy use; fetal; maternal; viscera