Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Janet L. Henderson x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To determine herd characteristics and management practices associated with milk production in dairy herds enrolled in official Dairy Herd Improvement Association (DHIA) programs in Ohio. Sample Population—186 dairy farms in Ohio.

Procedure—All herds in official DHIA programs in 9 counties were invited to participate. Information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were obtained for bacteriologic culture. Official DHIA test-day records were obtained, and associations were identified, using multivariable ANOVA procedures.

Results—Of 479 eligible producers, 186 (39%) participated, and consecutive bulk-tank milk samples were available for culture from 172 (36%). Streptococcus agalactiae and Mycoplasma spp were not recovered from bulk-tank milk samples, but Staphylococcus aureuswas recovered from 64 (37%) herds. Mean (± SD) number of lactating cows in participating herds was 97 ± 66, with 123 (66%) herds milking < 100 cows. The RHA was significantly associated with number of cows in milk, estimated percentage of herd detected in estrus, reported annual percentage of heifer calves born alive that died before 8 weeks old, percentage days in milk, use of bovine somatotropin during the preceding 2 years, and sex of the person completing the questionnaire.

Conclusions and Clinical Relevance—In this study, the strongest indicator of milk production was number of cows in milk. However, merely adding cows to a herd should not be considered to guarantee increased milk production, because other management traits could be confounded with increased number of cows in a herd. (Am J Vet Res 2001;62:1262–1266)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To identify herd characteristics and management practices associated with bulk-tank somatic cell counts (BTSCC) in dairy herds in Ohio enrolled 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 participate. Extensive information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were requested from all participating herds for bacterial culture. Official DHIA test-day records for January 1997 were obtained from all herds enrolled in official DHIA programs in the 9 counties. Potential associations 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. Staphylococcus aureus was isolated from 64 of 172 (37%) of the herds. The BTSCC were inversely associated with peak daily milk production, postmilking teat disinfection, percentage of eligible cows in the herd detected in estrus, and directly related to the extent to which BTSCC was perceived as a herd problem during the preceding 2 years. Type of housing for nonlactating cows and product used for treatment of nonlactating cows also were significantly associated with BTSCC.

Conclusions and Clinical Relevance—Consideration of herd characteristics and implementation of management practices associated with BTSCC could result in increased milk yield and production of milk with lower BTSCC. (Am J Vet Res 2000;61:1092–1098)

Full access
in American Journal of Veterinary Research