Herd characteristics and management practices associated with bulk-tank somatic cell counts in herds in official Dairy Herd Improvement Association programs in Ohio
Ml. Khaitsa et al., Herd characteristics and management practices associated with bulk-tank somatic cell counts in herds in official Dairy Herd Improvement Association programs in Ohio, AM J VET RE, 61(9), 2000, pp. 1092-1098
Objective-To identify herd characteristics and management practices associa
ted with bulk-tank somatic cell counts (BTSCC) in dairy herds in Ohio enrol
led in official Dairy Herd Improvement Association (DHIA) programs.
Sample Population-186 dairies in Ohio.
Procedure-All herds in official DHIA programs in 9 counties were asked to p
articipate. Extensive information regarding herd characteristics and manage
ment practices was obtained, using a standardized questionnaire. Bulk-tank
milk samples were requested from all participating herds for bacterial cult
ure. Official DHIA test-day records for January 1997 were obtained from all
herds enrolled in official DHIA programs in the 9 counties. Potential asso
ciations were identified, using multivariable ANOVA.
Results-Participation was 186 of 479 (39%) herds. Streptococcus agalactiae
and Mycoplasma spp were not isolated from bulk-tank milk samples. Staphyloc
occus aureus was isolated from 64 of 172 (37%) of the herds. The BTSCC were
inversely associated with peak daily milk production, postmilking teat dis
infection, percentage of eligible cows in the herd detected in estrus, and
directly related to the extent to which BTSCC was perceived as a herd probl
em during the preceding 2 years. Type of housing for nonlactating cows and
product used for treatment of nonlactating cows also were significantly ass
ociated with BTSCC.
Conclusions and Clinical Relevance-Consideration of herd characteristics an
d implementation of management practices associated with BTSCC could result
in increased milk yield and production of milk with lower BTSCC.