Housing conditions of dry cows: effects on teat contamination and somatic cells at the beginning of the subsequent lactation

The study investigated the effects of housing conditions and temperature-humidity index (THI) during the dry period on total bacteria counts of bedding material, animal cleanliness, and teat bacterial contamination on 212 cows from three farms. Additionally, milk yield, quality, total somatic cells, and leucocyte fractions were evaluated in the subsequent lactation on a subgroup of 119 cows. The results showed a relationship between persistent high THI, teat bacterial contamination, and pathogens on teat skin. Somatic cell count (SCC) in milk at the beginning of the next lactation was not affected by THI during the dry period. Multiple correlation analysis revealed a relationship among high milk SCC, high percentage of neutrophils, high bacterial count of bedding during the dry period, and high milk production at dry-off. The study confirms that critical environmental conditions, such as high THI and poor bedding hygiene, during the dry period, can affect teat bacterial contamination and increase the risks for high SCC in the next lactation. High milk production at dry-off may be another risk factor.