Factors related to dairy herds with a high and low incidence of ketosis

Effect of ethanol in feed on milk flavor and chemical composition

A crossover study was performed using 24 dairy cows to investigate whether pure ethanol in concentrations that could be found in well-fermented silages influenced milk composition or flavor. Cows were fed a standard ration of well-fermented grass silage for ad libitum intake and high moisture barley and a protein concentrate in restricted amounts. A daily dose of ethanol (600 g) was divided into three meals/d and fed with grass silage. When cows received ethanol, milk yields decreased slightly, but milk fat and protein concentrations increased so that energy-corrected milk yield increased by 0.9 kg/d. Milk concentrations of lactose and urea decreased, concentrations of ethanol and acetone increased, concentrations of free fatty acids increased slightly, and alpha-tocopherol concentrations were unaffected. The proportion of palmitic acid in milk fat increased, and the proportion of unsaturated acids decreased. Organoleptic milk quality was reduced because of an increase in milk tainted by feed flavors. The off-flavor could not be attributed solely to the ethanol transmitted to the milk. Precautions should be taken to avoid extensive production of ethanol during fermentation of grass silage and other feeds that are to be fed to dairy cows.

Evaluation of additional acetone and urea analyses, and of the fat-lactose-quotient in cow milk samples in the herd recording system in Norway

The purpose of this study was to evaluate the use of additional acetone and urea analyses to the established herd recording system (protein, fat, lactose, and somatic cell count) in cow milk samples every second month. Samples were obtained from 43/82 herds (800/1368 cows) in a lowland/highland area. Acetone concentration (mmol/l) were classified into acetone classes 1 (<0.7); 2 (0.7-1.4); and 3 (>1.4). There was an association between increasing acetone class and increasing ketosis incidence in herd (Kendall's Tau-b = 0.13). The highest percentage frequencies of acetone classes 2 and 3 were in weeks 4-6 postpartum. Milk yield, urea, and lactose were significantly lower; milk protein not different, and milk fat was significantly higher in herds with high ketosis incidence and in cows in acetone classes 2 and 3. General linear models, obtained by backward elimination of non-significant variables, showed that milk protein was negatively associated to milk yield and positively associated to milk fat. Milk yield decreased, and milk fat concentration increased with increasing acetone level. Milk fat and milk lactose were negatively associated, and a fat-lactose-quotient might be promising in a model to rule out subclinical ketosis cows.

Ketosis treatment and milk yield in dairy cows related to milk acetoacetate levels

Milk yield and milk acetoacetate (M-acac) were measured weekly for the first 6 weeks of lactation in 5 herds with a ketosis problem. Ketosis treatments and the corresponding ketotest score, were also recorded. The treatment rate was highest 7-16 days after calving. Most of these early cases were associated with low ketone levels in milk, whereas the treatment rate for cows with high ketone levels was highest 17-31 days after calving. Nearly half of the treated cows were low-ketone animals. They were classified as ketosis cases in the cow health card records, although probably suffering from other post partum disturbances in many instances. About 40% of the cows with high ketone levels recovered spontaneously. Reduction in milk yield associated with peak M-acac levels was transient and moderate. It was concluded that health card statistics overestimates the severity of the ketosis problem in Norway.

Ketosis treatment and milk yield in dairy cows related to milk acetoacetate levels

Milk yield and milk acetoacetate (M-acac) were measured weekly for the first 6 weeks of lactation in 5 herds with a ketosis problem. Ketosis treatments and the corresponding ketotest score, were also recorded. The treatment rate was highest 7-16 days after calving. Most of these early cases were associated with low ketone levels in milk, whereas the treatment rate for cows with high ketone levels was highest 17-31 days after calving. Nearly half of the treated cows were low-ketone animals. They were classified as ketosis cases in the cow health card records, although probably suffering from other post partum disturbances in many instances. About 40% of the cows with high ketone levels recovered spontaneously. Reduction in milk yield associated with peak M-acac levels was transient and moderate. It was concluded that health card statistics overestimates the severity of the ketosis problem in Norway.