Results from an on-farm study at Table Rock Farm in
At the start of the study, dry cows with a somatic cell count (SCC) of less than 200,000 were randomly assigned to one of three treatment groups: teat sealant only, intramammary antibiotic therapy, or a combination of intramammary antibiotic therapy and teat sealant. The 149 cows enrolled in the trial had no history of clinical mastitis during the previous lactation or upon testing with a California Mastitis Test (CMT) at dry-off. To ensure that no bacteria were introduced into the udder during infusion, strict disinfection and treatment protocols were used.
At calving, study participants were again tested with a CMT. Within 35 days of calving, a DHIA technician obtained a milk sample from each animal for SCC testing. SCC testing also was repeated at the next official DHIA monthly herd test.
The findings revealed no difference in SCC levels or in the occurrence of clinical mastitis between the three study groups.
The following table shows the percentage of cows that developed clinical mastitis after calving, as well as the percentage of cows with SCC greater than 200,000:
Treatment Animals % clinical % elevated per group mastitis SCC Teat sealant alone 47 29.8% 17% Dry-cow antibiotic therapy 50 30% 14% Dry-cow therapy and teat sealant 52 30.8% 15.4%
During the course of the study, the farm maintained a linear somatic cell score between 3.1 and 3.9. The authors caution that operations with a higher linear score may need to use both a teat sealant and traditional dry-off antibiotic therapy to see a reduction in mastitis-infection rates.
The authors also note that farms with a low SCC can significantly reduce dry-treatment expenses by using a teat sealant alone. Cost of the teat sealant was $7.60 per animal in this study. In contrast, cost of using both a dry-cow antibiotic treatment and teat sealant was $13.15 per animal. The use of a teat sealant alone also can decrease the risk of antibiotic residues in milk.
Currently, Table Rock Farm uses on on-farm cell counter to check each cow's somatic cell count at dry off. Those with a SCC less than 200,000 and no history of mastitis in their most recent lactation receive a teat sealant only. Cows with an SCC greater than 200,000 receive dry-cow antibiotic treatment and teal sealant, says Meghan Hauser, co-owner of the 1,000-cow dairy
The study was funded in part by the Northeast Sustainable Agriculture Research and Education organization.
Table Rock Farm