Factors affecting intervals between date of calving and incidence of health disorders in diseased dairy cows

Abstract

The effects of herd and cow were analysed for their influence on the interval between date of calving and date of disease occurrence during lactation for each of 4 disorders: mastitis; sterility; metabolic disorders; claw disorders. The studies were performed exclusively on diseased cows of 3 breeds: German Black and White; German Red and White; Angler. Analysis of variance indicated that herd effect claimed more than half of determined variance for mastitis and sterility, metabolic and claw disorders were predominantly influenced by cow factors. However, only up to 27% of total variance could be determined by the whole set of factors. Breed significantly affects the time interval between date of calving and occurrence of mastitis. Lactation number influenced intervals for sterility: time spans increased, when age of cow was rising. Calving month had an effect on mastitis and sterility intervals. The milk yield parameters 100-days lactation yield and maximum daily milk yield were shown to cause significant changes in length of intervals for metabolic disorders and sterility. Increases in both traits were related to generally rising time intervals. The effect of disorders recorded previously was shown in a separate analysis to be of great importance on all disorders and determined additionally up to 9% of total variance. Mastitis, claw and metabolic disorders occurred 8–12 days earlier in lactation, when no health disorder had been recorded before. The interval calculated for sterility decreased for 6 days, when any disorder preceded. Incidence of claw disorders was delayed for about 22 days, when mastitis was previously recorded. The cow effects considered were supposed to give information about the temporal risk of predisposed cows to disease during lactation.