Distribution of Clinical Mastitis Among Quarters of the Bovine Udder

Abstract

Clinical mastitis episodes occurring from 1962 through 1991 in the Louisiana State University Dairy Research Herd were studied to determine the distribution of clinical mastitis among quarters of the udder. Data were detailed records of all mastitis episodes that occurred during 1630 Holstein lactations. Incidence of episodes, categorized according to which quarters within a cow were clinical for a given case, were compared with mathematical expectations based upon the assumption that quarters were independent. Results indicated that quarters within a cow were more alike with respect to clinical mastitis than would be expected if quarters were independent. More episodes occurred in which either no quarters or all four quarters were clinical. Deviation of observed frequencies from expectation could have resulted from generalized cow differences, such as cow milk yield, immune competency, mammary type characteristics, and general health. Front quarters had less clinical mastitis than rear quarters when all episodes were considered. No difference was observed in incidence between front and rear quarters when only first episodes in first lactations were considered. No difference was observed between incidence in left and right quarters. Diagonal pairs occurred less often than expected and at about half the frequency of other pairs. Dependence between quarters should be taken into consideration when experiments are designed and analyzed.

The influence of laterality on mastitis incidence in dairy cattle - preliminary study

“…Although several studies did not show different incidences of clinical mastitis episodes between left and right quarters (Batra et al, 1977;Adkinson et al, 1993), Walsh (1985) reported a different incidence of clinical mastitis between left and right quarters in a herd with a one-sided milking parlour. The higher frequency of right-quarter mastitis episodes was caused by teat impaction.…”

“…Several authors found the incidence of clinical mastitis to be higher in rear quarters than in front quarters (Rendel and Sundberg, 1962;Flock and Zeidler, 1969;Grootenhuis, 1975;Batra et al, 1977;Adkinson et al, 1993;Miltenburg et al, 1996;Barkema et al, 1997). Deviation from expectation of observed mastitis incidence on quarter level could be attributed to differences in risk factors with bacterial infections around the teat opening between the quarters of the bovine udder in developing clinical mastitis (Barkema et al, 1997).…”

“…Research on the distribution of clinical mastitis revealed that the incidence of clinical mastitis on udder-quarter level often differs from a random distribution (Flock and Zeidler, 1969;Grootenhuis, 1975;Adkinson et al, 1993;Barkema et al, 1997). Several authors found the incidence of clinical mastitis to be higher in rear quarters than in front quarters (Rendel and Sundberg, 1962;Flock and Zeidler, 1969;Grootenhuis, 1975;Batra et al, 1977;Adkinson et al, 1993;Miltenburg et al, 1996;Barkema et al, 1997).…”

An individual modelling tool for consecutive clinical mastitis during the same lactation in dairy cows: a method based on a survival model

“…This model describes, for example, a situation where the treatment carried out during acute clinical mastitis obliterates mastitis symptoms without resulting in total eradication of the germs from the udder [46], in a proportion p of cases. It was also adapted to the case of clinical mastitis affecting a quarter; other quarters then run a much greater risk of suffering mastitis later than they would have, had no quarter of the udder ever been infected [1]. It was adapted in fact in all cases where there was a possible state change in the udder after clinical mastitis.…”

An individual modelling tool for within and between lactation consecutive cases of clinical mastitis in the dairy cow: an approach based on a survival model

“…These risk factors were for the most part demonstrated by adjusting the number of cows observed as having clinical mastitis to a Poisson distribution within the framework of a Generalised Linear Model (GLM) type model [28] including fixed effects or even individual random effects. During these analyses, the authors retained only the clinical cases of mastitis arising a certain number of days after a previous episode of clinical mastitis; this time-lapse varies from 8 [22], 10 [24], 14 [1,4,12], 30 [13,40] to 90 [25] days depending on the author. This selection carried out between the mastitis cases observed is aimed at eluding a possible dependence between consecutive events.…”