LOCATION:

North Mississippi Branch Experiment Station, Holly Springs

Coastal Plain Branch Experiment Station, Newton

College of Veterinary Medicine, MSU

 

Quarter samples taken from 148 bred pre-partum heifers and cultured for bacterial organisms indicated 58.5% of the animals were infected in an average of 1.36 quarters/animal. Infected animals averaged 2.30 infected quarters/animal. Sixty-one percent of the infected quarters resulted from environmental Staphylococcus; 19.2% from Staphlococcus Aureus; 12.5% from environmental Streptococcus; and approximately 7% from Norcardia, Corynebacterium, Pseudomonas and yeast.

Seventy-two bred heifers at the North Mississippi Branch and 32 at the Coastal Plain Branch of MAFES were assigned to a treatment group receiving 10 cc/qtr of an antibiotic dry cow medication 60 days pre-partum or to a control group receiving no antibiotic udder infusion. Somatic cell counts and linear scores taken from first DHIA test day post-partum for the North Mississippi heifers averaged 325,389; 3.26 and 618,889; 4.08 respectively for the treated and control groups. Linear and actual count scores for the Coastal Plain Branch averaged 2.51; 176,750 and 4.08; 415.611, respectively for the treatment and control groups. Actual first lactation production for the North Mississippi treated heifers averaged 16,490 milk, 534.8 fat, 539.3 protein compared to 16,060 milk, 542.6 fat, 534.7 protein for the control group.

Similar studies in other states have confirmed the results of this study. Pre-partum treatment of heifers has become a standard practice in herds experiencing mastitis in freshening heifers. Predisposing factors causing heifer mastitis are thought to be fly bites on teat ends, suckling among calves and transfer from dry cows to pregnant heifers. Measures taken to control these situations should help in preventing heifer mastitis. Cure rates from pre-partum antibiotic udder infusions in heifers have approached 90%. The small volume of the heifer's udder and the advance of scar tissue usually found in the mature infected udder likely accounts for this high cure rate.

As in dry cows, the non-lactating period is the most effective and economical time to eradicate mastitis causing pathogens in heifers. The results from the preceding trial support this recommendation. Proper treatment techniques and recommendations such as those used in this trial should always be followed.

¹College of Veterinary Medicine, Mississippi State University