Comparative analyses of foregut and hindgut bacterial communities in Slick Holsteins and Wild type Holsteins when fed totally mixed rations (TMR) diets in a tropical climate.

One of the greatest challenges to dairy production in subtropical and tropical regions of the world is heat stress. In the future, climate change may also expose the temperate regions of the world to hotter and longer hot seasons which might increasingly expose dairy cows to chronic heat stress, negatively affecting dairy productivity. To minimize the effects of heat stress, three management strategies have been identified: 1) physical modification of the environment, 2) improved nutritional management practices, 3) genetic development of heat-tolerant breeds. Unfortunately, heat tolerance is negatively correlated with production In Puerto Rico US Holstein crossings with Criollo cattle produced PR Holsteins (slick-hair Holsteins) with higher milk production and shorter calving interval than their wild-type. PR Holsteins “rabifinas” exhibit a very short, sleek, and mostly glossy coat very similar to the phenotype described by Olson et al. in 2003, after introducing the Slick gene from the Senepol into Holstein cows. As “wild type” and Slick Holstein dairy cows experience heat stress differently, we hypothesize that under heat stress conditions “wild type” and Slick Holstein dairy cows will have a different rumen and hindgut microbiomes, and these differences could help explain putative variance in feed efficiency between these types of cattle. We sequenced 16S rRNA genes from wt and slick cows in both the foregut and hindgut samples to relate to feed efficiency and milk production.