|ROSENKRANS, JR, C|
Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/29/2004
Publication Date: 2/5/2005
Citation: Flores, R., Looper, M.L., Coffey, K.P., Coblentz, W.K., Rosenkrans, Jr, C.F. 2005. Relationship of prepartum concentrations of insulin-like growth factor-i (igf-i) in cows with birth weight, concentrations of igf-i, and weaning weights of calves. American Society of Animal Science Southern Section Meeting. Journal of Animal Science 83(Suppl. 2):31.
Technical Abstract: Objectives were to determine relationships between maternal concentrations of insulin-like growth factor-I (IGF-I) during gestation in grazing beef cows and subsequent calf birth weight, concentrations of calf IGF-I at birth, weaning weights of calves, and resumption of luteal activity (LA) in cows. Further, the effects of supplementation on maternal concentrations of IGF-I during gestation, and calf birth weight and weaning weight were investigated. Crossbred multiparous beef cows (n = 82) were assigned to paddocks of stockpiled fescue and fed diets of either soyhulls (SH), corn:soybean meal (CSB), or not supplemented (C) at 0.91 kg/d from d 179 of gestation until approximately 60 d after parturition. Blood serum samples were collected from cows at 179 ± 2 d and 207 ± 2 d of gestation. Calf weight and a blood serum sample were obtained at birth. Concentrations of IGF-I were quantified in serum samples. Maternal concentrations of IGF-I at d 179 of gestation were not correlated (P > 0.10) with any calf parameters; however, maternal IGF-I at d 207 was positively correlated (r = 0.24; P < 0.05) with calf IGF-I at birth. Calf IGF-I at birth was negatively correlated (r = -0.27; P < 0.05) with adjusted weaning weight. Concentrations of IGF-I at d 179 or 207 of gestation was not correlated (P > 0.10) with resumption of LA in cows. Prepartum supplementation tended (P = 0.10) to decrease maternal concentrations of IGF-I at d 207 compared with C cows. Prepartum supplementation did not influence (P > 0.10) the percentage of cows with LA at breeding, concentrations of calf IGF-I at birth, calf birth weight, or calf weaning weights. Reduced concentrations of IGF-I at birth in calves may help identify calves with increased weaning weights.