Metabolic changes in early lactation and impaired reproductive performance in dairy cowsRuurd Jorritsmaa, Theo Wensinga, Theo A.M. Kruipb, Peter L.A.M. Vosa and Jos P.T.M. Noordhuizena
a Department of Farm Animal Health, Ruminant Health Unit, Utrecht University, PO Box 80151, NL-3508 TD, Utrecht, The Netherlands
b Deparment of Genetics and Reproduction, Institute for Animal Health and Science, PO Box 65, NL-8200 AB, Lelystad, The Netherlands
(Received 17 January 2002; accepted 9 July 2002)
This review addresses the suggestion that the decline in dairy reproductive performance, as increasingly observed these days, may be due to a hampered process of metabolic adaptation in early lactating cows. In our opinion, adaptation to the negative energy balance is a gradual process. Because almost all cows do adapt in the long run, it is not possible to classify animals as adapted or non-adapted. The use of risk factors is more appropriate in this case and is discussed in this review. Among them are the body condition score and its derivatives, feed intake, the calculated negative energy balance, and metabolic parameters like the plasma concentration of insulin or the triacylglycerol content in the liver. Moreover, factors that play a role in the link between declined reproductive performance and the metabolic situation of the cow during the early lactating period are discussed. Among these are insulin, insulin-like growth factors, leptin, neuropeptide Y, non-esterified fatty acids, thyroïd hormones, urea, and ammonia.
Key words: fertility / dairy / periparturient metabolic adaptation / physiopathology / periparturition
Correspondence and reprints: Ruurd Jorritsma tel. (31) 30 253 1248; fax: (31) 30 252 1887;
© INRA, EDP Sciences 2003