Growth and Development

摘要

Maternal nutrition has a key role on fetal growth can program the longtermphysiology of the offspring. We investigated effects of feeding 72multiparous Holstein cows during late-pregnancy with an experimentalsource of Folic acid (FOA; Zinpro Corp.), 2 Co sources [Co glucoheptonate(Copro) or Co pectin (CoPectin), Zinpro Corp.] and rumen-protectedMet (RPM) on calf developmental parameters at birth and through 9-wkof age. Cows were fed a basal diet [1.37 Mcal/kg of dry matter (DM),14.5% crude protein] and randomly assigned (17–21 per treatment) toCopro, FOA+Copro, FOA+CoPectin, or FOA+CoPectin+RPM. In eachFOA group cows received 50 g FOA. Co treatments delivered 1 ppm Co/kg DM. The RPM was fed at 0.09% of DMI to achieve a ratio of 2.8:1Lys:Met in the MP. Calves received 3.8 L of first-milking colostrum fromtheir dam within 6 h, and were housed in individual outdoor hutches beddedwith straw, fed twice daily with a milk replacer, and had ad libitumaccess to a starter grain mix from birth to weaning at 42 d of age. Bodyweight, hip and wither height, hip width and body length were measuredat birth and weekly through weaning (42 d of age) and until 9 wk of age.The statistical model in SAS 9.4 included treatment, age and their interactionsas fixed effects. Preplanned contrasts were FOA vs. no FOA,CoPectin vs. Copro, and RPM vs. no RPM. Metabolite concentrations inplasma indicated no differences over time due to maternal diet in energymetabolism, liver function, or oxidant status. However, blood neutrophilphagocytosis capacity was greater (P = 0.03) in calves born to cows supplementedCoPectin. Although maternal diet did not alter developmentalparameters at birth, during the first 9 wk of age calves born to cowssupplemented CoPectin had greater (P < 0.05) starter intake and weeklyaverage daily gain. Overall, data indicated that CoPectin supplementationduring late-gestation had a positive effect on neonatal calf performance.Whether effects arose from greater availability in utero of vitaminB12 synthesized from Co by rumen microbes remains to be determined.