M.A. Kristula

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.

Diagnosis and treatment of four stallions, carriers of the contagious metritis organism—case report

Contagious Equine Metritis (CEM), a venereal disease of horses caused by the bacterium Taylorella equigenitalis, was first diagnosed in 1977 and subsequently spread to many nations [Proc 24th AM Assoc Equine Pract (1979) 287]. The disease was confirmed in the United States in 1978 [Proc Am Assoc Equine Pract (1983) 295]. Specific regulatory procedures for this disease have been established in the United States and 37 other countries. From 1999 through 2001, four of 120 imported European stallions tested positive for CEM at a quarantine facility in Darlington, MD, USA. Two stallions were identified by positive bacterial cultures for T. equigenitalis on arrival. The other two positive stallions were negative on initial bacterial cultures, but were identified as CEM carriers when test mares (that they had mated) were culture-positive for T. equigenitalis. Since T. equigenitalis, is a fastidious slow-growing coccobacillus, additional sets of samples taken over a interval might be required to ensure positive stallions are detected before mating test mares. Likewise, additional sets of samples taken over a long interval after treatment of a stallion for CEM might be required to ensure that positive stallions treated for CEM are detected before mating test mares. Aggressive systemic antibiotic therapy accompanied by routine topical therapy might be required to treat some CEM-positive stallions.

Drinking water temperature affects consumption of water during cold weather in ponies

Two within-subjects cross-over trials were conducted to compare ad libitum consumption of warm drinking water with ambient near-freezing drinking water during cold weather. In Trial 1, eight ponies consumed a mean of 41% more water when provided continuously heated water than when provided ambient near-freezing water (P< 0.01). Similarly, in Trial 2, six ponies consumed a mean of 38% more water when provided buckets filled with hot water twice daily than when provided ambient near-freezing water (P< 0.05). Overall for both trials, 14 ponies drank a mean of 40% more warm than ambient near-freezing water. This difference was highly significant (P< 0.0005 ). Videotape procedures were used to evaluate drinking behaviour. During both trials, most drinking occurred within 3 h after feeding. There were no qualitative differences in drinking behaviour observed in either trial.

Use of a repeated-measures logistic regression model to predict chronic mastitis in dairy cows

Abstract The use of a repeated-measures logistic regression model is shown by evaluating the use of somatic cell counts to identify cows with chronic mastitis as determined by bacteriologic culture. The most important variable to predict wether a cow had chronic mastitis was the average linear score of all of the previous Dairy Herd Improvement Association (DHIA) test dates. The model did not accurately classify cows with chronic mastitis. Results from this study suggest that DHIA centers should be cautious using algorithms of the somatic cell count type to report cows with chronic mastitis to dairy farmers.

A preliminary investigation of the association between the first postpartum milk fat test and first insemination pregnancy rates

Abstract We studied the association between milk fat percentage, as measured by the first Dairy Herd Improvement Association test, and pregnancy rates from first insemination in 1640 cows from 22 herds. A multivariable Cox proportional hazards model was used to analyze the data. There was a significant inverse relationship between milk fat percentage and first insemination pregnancy rates.

No effect of drinking water temperature (ambient vs. chilled) on consumption of water during hot summer weather in ponies

Abstract Consumption of ambient warm (17°–31°C) vs. ice-chilled (0°–1°C) drinking water was compared in a within-subjects cross-over trial using nine mature pony stallions housed in tie-stalls during hot summer weather (15°–29°C). Ponies drank similar quantities whether provided warm water or chilled water. This is in contrast to earlier reported findings that during cold winter ponies drank more if provided warm water than if provided cold water. There were no qualitative differences in drinking behaviour owing to water temperature.

Relationship of declines in grain consumption and milk yield to estrus in dairy cattle

A retrospective study was done to determine if a reduction in daily grain consumption or decline in daily milk yield were accurate indicators of estrus in 25 Holstein cows. A computer automatically identified all cows that left more than 10% of their daily grain allocation in the feed stall or that gave less than 85% of their most current 7-d daily average milk yeild. By retrospectively analyzing breeding records, grain refusal and milk declines were identified as either occurring in conjunction with estrus or nonestrus. Declines in grain consumption and milk yield were frequently associated with estrus, but many cows in estrus did not exhibit such declines. While such declines hold promise as estrous detection aids, it was concluded that refusals of daily grain allocation or declines in daily milk yield were not sufficiently accurate to supplant other methods of estrous detection in dairy cattle.

Evaluation of a Dairy Herd Improvement Association test to report chronic intramammary infections in dairy cattle

Abstract This study evaluated the accuracy of a Dairy Herd Improvement Association test compared with bacterial culture to report the prevalence of chronic intramammary infections in dairy cattle. The Association classification considers a cow to have a chronic intramammary infection when her linear score is 4 or greater for more than one test in a lactation. The threshold level of linear score 6 minimized the sum of the misclassification errors. The Association test was not sensitive or specific enough compared with bacterial culture to classify individual cows accurately.