Subclinical ketosis: prevalence and associations with production and disease.

摘要: Cows in 32 southern Ontario Holstein herds were monitored for subclinical ketosis a period of two and one half years. Milk samples routinely collected the level milk ketone bodies determined by use commercial nitroprusside based test powder (reactions scored as negative, +1 or +2). Approximately 92% positive reactions observed first 65 days lactation that time prevalence was 12.1%. Based on this prevalence, minimum possible duration would be 7.9 lactational incidence rate The during individual ranged from 0 to 33.9%. Subclinical more likely found cows experiencing metritis than unaffected cows. Detection elevated levels ketones also indicated cow had significantly higher risk having clinical ketosis, cystic ovaries diagnosed within following four days. scores +2 associated with reduction daily production 1.0 1.4 kg respectively.