Interrelationships of growth hormone AluI polymorphism, insulin resistance, milk production and reproductive performance in Holstein-Friesian cows
2008
Balogh, O.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science | Szepes, O.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science | Kovacs, K.,Research Inst. for Animal Breeding and Nutrition, Herceghalom (Hungary) | Kulcsar, M.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science | Reiczigel, J.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science | Alcazar, J.A.,Cornell Univ., Ithaca (USA). Coll. of Engineering | Keresztes, M.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science | Febel, H.,Research Inst. for Animal Breeding and Nutrition, Herceghalom (Hungary) | Bartyik, J.,Enying Agricultural Co., Polgardi-Kiscseripuszta (Hungary) | Fekete, S.Gy.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science | Fesus, L.,Research Inst. for Animal Breeding and Nutrition, Herceghalom (Hungary) | Huszenicza, Gy.,Szent Istvan Univ., Budapest (Hungary). Faculty of Veterinary Science
Healthy Holstein-Friesian cows (n=22, parity: 2-4) were subjected to an intravenous glucose tolerance test 10-15 days after calving. AluI genotype of growth hormone, several plasma metabolites and metabolic hormones were determined, and current and previous lactation yields were recorded. We also used the Revised Quantitative Insulin Sensitivity Check Index (RQUICKI) and its modified version (RQUICKIBHB) for the estimation of peripheral insulin sensitivity. Eighteen cows were leucine homozygous (LL), four were heterozygous (LV). AluI polymorphism was not associated with any of the calculated glucose and leptin indicators of the intravenous glucose tolerance test. LV cows were prone to higher basal insulin levels, longer time to reach half of the maximal and basal insulin concentrations and larger insulin area under the curve. Both RQUICKI and RQUICKIBHB estimated decreased insulin sensitivity in LV compared to LL cows. Higher plasma NEFA and BHB levels accounted for slower glucose disappearance and lower insulin release and insulin clearance rate. Average yield was inversely related to glucose area under the curve and time to reach baseline concentration. Plasma cortisol lowered glucose clearance rate and prolonged time to reach basal levels. More weight loss was associated with higher glucose peak and prolonged glucose disappearance time. All cows became cyclic and showed signs of estrus. There were no differences between LL and LV animals in the onset of ovarian activity and in the time of first observed estrus. We conclude that Holstein-Friesian cows heterozygous for AluI polymorphism of the growth hormone gene may be more likely to develop insulin resistance during early lactation than leucine homozygous cows.
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