Relationship of Body Weight and body Condition Score with health and milk production in Holstein Friesian and Simmental cows

Dairy cattle have traditionally been selected for their ability to produce milk and milk components. The traditional singleminded approach to selection of dairy cattle has now changed and functional traits have been included in selection indices by decreasing the emphasis on production. Some of the functional traits of importance in dairy cattle are discussed in this thesis: Body Weight, Body Condition Score and Muscularity. The relationship of Body Weight and Body Weight Change with health disorders in early lactation in Holstein Freisian has been analyzed. Results of this study suggest that cows genetically inclined to have higher body weight and lower body weight loss in the early stages of lactation have less diseases. Daily body weights, therefore, should be the primary focus in early lactation because this is the period in which the majority of metabolic diseases occur. The relationship of Body Condition Score and Muscularity with production traits has been analyzed in Italian Simmental cattle. A growth function for body condition score was also estimated. Results of this study suggest that selection for body condition score and muscularity in dual purpose breeds may be possible, and body condition score may be indirectly improve muscularity. Moreover, cows that address more of the energy ingested to the adipose and muscular tissues, are incline to have lower milk production. The growth curve for body condition score may permit a comparison between expected and real body condition values and it may be useful both for the estimation of the Breeding Values of cows and in herd management.