GENOMIC SELECTION AND CROSSBREEDING FOR DISEASE RESISTANCE IN ORGANIC DAIRY COWS

Organic dairy production creates unique challenges that higher innate levels of disease resistance will alleviate. The influences of genotype and breed composition on behavior and fly infestation are also minimally known and could have important implications for both the health of cows and pasture use recommendations. Our goals are to enhance disease resistance in organic dairy cattle through the adoption of optimal genomic selection and crossbreeding strategies and to understand the relationship of genotype to grazing behavior. To do this, we will genotype approximately 2200 Holsteins and 1500 crossbred cattle. Genomic predictions for resistance to calfhood pneumonia, mastitis and other cow disease will be determined for Holsteins. For Holsteins and crossbreds, we will determine A2 beta casein genotype, and obtain genomic predictions for yield traits, productive life, and conformation. Health events and disease will be recorded and associated with genomic predictions. Cows will be visually assessed for measures such as body condition score, we will evaluate behaviors such as bite rate and time until shade is sought, and we will determine fly counts on individual cows. Optimal genetic selection and crossbreeding strategies to enhance herd profitability levels will be established. We will disseminate results to organic dairy producers through workshops, webinars, field days, popular press, and electronic resources. We will also support student training in organic dairy production through the development of new undergraduate curriculum. This project will enhance the appeal of organic dairy production by promoting greater profitability, improving animal welfare, and reduce frustrations associated with managing diseased animals.