Evaluation of free-stall mattress bedding treatments to reduce mastitis bacterial growth.

Bacterial counts were compared in free-stall mattresses and teat ends exposed to 5 treatments in a factorial study design on 1 dairy farm. Mattresses in five 30-cow groups were subjected to 1 of 5 bedding treatments every other day: 0.5 kg of hydrated limestone, 120 mL of commercial acidic conditioner, 1 kg of coal fly ash, 1 kg of kiln-dried wood shavings, and control (no bedding). Counts of coliforms, Klebsiella spp., Escherichia coli, and Streptococcus spp. were lowest on mattresses bedded with lime. Mattresses bedded with the commercial acidic conditioner had the next lowest counts for coliforms, Klebsiella spp., and Streptococcus spp. Wood shavings and the no-bedding control had the highest counts for coliform and Klebsiella spp. Compared with wood shavings or control, fly ash reduced the counts of coliforms, whereas for the other 3 bacterial groups, the reduction was not always significant. Streptococcus spp. counts were greatest in the control group and did not differ among the shavings and fly ash groups. Teat swab results indicated that hydrated lime was the only bedding treatment that significantly decreased the counts of both coliforms and Klebsiella spp. There were no differences in Streptococcus spp. numbers on the teats between any of the bedding treatments. Bacterial populations grew steadily on mattresses and were generally higher at 36 to 48 h than at 12 to 24 h, whereas bacterial populations on teats grew rapidly by 12 h and then remained constant. Hydrated lime was the only treatment that significantly reduced bacterial counts on both mattresses and teat ends, but it caused some skin irritation.

Comparison of bacteria populations in clean and recycled sand used for bedding in dairy facilities.

Bedding samples were collected twice from commercial dairy free-stall facilities that used recycled sand and clean sand in both the summer and winter. Collection began on the day sand was taken from the pile (d 0) and placed in the free stalls, and continued for 5 to 7 additional days. The number of colonies per gram of bedding of gram-negative bacteria, coliforms, Streptococcus spp., and Klebsiella spp. were estimated for each sand sample as well as amounts of dry and organic matter. Clean sand (CS) and recycled sand (RS) had the same bacterial counts when compared at any sampling time. The mean counts of bacterial populations did vary over the course of the study in both CS and RS. There was a significant increase in bacterial counts from d 0 to d 1 for gram-negative bacteria, coliforms, and Streptococcus spp. in both winter and summer. Counts of gram-negative bacteria, coliforms, Klebsiella spp., and Streptococcus spp. did not differ from d 1 to 7 in the winter. Total counts of gram-negative bacteria did not differ from d 1 to 7 in the summer. On d 1 in the summer, coliform counts were lower than at d 5 to 7, and Klebsiella spp. counts were lower than on d 3 to 7. Streptococcus spp. counts were high on d 1 and were constant through d 7 in both winter and summer trials. The number of coliform and Klebsiella spp. in both CS and RS was below the threshold thought to cause mastitis during the sampling times. The number of Streptococcus spp. was high in both CS and RS during the sampling periods. Other management factors need to be identified to decrease the number of Streptococcus spp. in bedding. Recycled sand had a higher organic matter and lower dry matter compared with CS in winter and summer. The results for this study were obtained from multiple herd comparisons, and herd was a significant effect suggesting that different management systems influence the number and types of bacteria in both CS and RS.

Evaluation of prostaglandin F2 alpha treatment in dairy cows at risk for low fertility after parturition.

OBJECTIVE: To evaluate the effect of 2 postpartum prostaglandin F2 alpha (PGF 2 alpha) treatment protocols on reproductive performance of dairy cows at risk for low fertility. In addition, various medical conditions in cows that are recognized as having adverse effects on fertility were evaluated as criteria for fertility treatment. DESIGN: Prospective study. ANIMALS: 291 cows with, and 271 cows without, risk factors for low fertility. PROCEDURE: Cows at risk for low fertility were randomly assigned to 2 treatment groups. Group-1 cows received 3 i.m. injections of PGF2 alpha at weekly intervals after parturition, and group-2 cows received 1 i.m. injection of PGF2 alpha 17 to 24 days after parturition. RESULTS: Compared with a single PGF2 alpha treatment 17 to 24 days after parturition, there was no added benefit of 3 treatments with PGF2 alpha 3 to 10, 10 to 17, and 17 to 24 days after parturition in cows at risk for low fertility. Cows without risk factors for low fertility had 20% higher pregnancy rates, compared with cows with risk factors for low fertility. Twinning had a negative effect on future fertility. CLINICAL IMPLICATIONS: Results of this study indicate that further consideration should be given to the timing and intervals of PGF2 alpha administration after parturition. Risk factors for low fertility, such as retained placenta, twins, and assisted calvings, are valid criteria to evaluate different treatment options to improve fertility in dairy cows.