Développement de rations alimentaires protéiques adaptées aux vaches laitières de la race Ayrshire

Quebec is one of the biggest contingents of Ayrshire cows with about 400 breeders. Some of these breeders have already expressed a suspicion about the differences in feeding behavior of Ayrshire cows and Holstein cows. It is known that each breed of dairy cow has characteristics specific to both behavior and milk production. The Jersey breed, despite its small size, is known to produce milk rich in protein and lipids, while the slightly larger Ayrshire breed produces significant quantities of milk with high levels of protein. A study in Finland has demonstrated differences in the milk transformation of Ayrshire vs Holstein. These differences are due to the coagulation of milk, dependent on protein quality. So the transfer of nitrogen to the milk is done differently in these two races. The Holstein breed is the most common breed in Canada, so diet programs are created based on the characteristics of this breed, despite the fact that small breeds are still very present. Therefore, dairy rations are less adjusted to the needs of smaller breeds of due to the lack of research on physiology and nutrition with these breeds. A project initiated by Agrinova in 2016 aimed to study an increase in crude protein in rations of Ayrshire cows relative to the ususal ration on 2 dairy farms. A trend has been observed towards higher milk production and better components for the more protein-concentrated diet. These productivity gains have allowed more farm income. It would be relevant to carry out a larger project from a serious collaboration between several players in the Quebec milk sector (Ayrshire Farms, Ayrshire Associations, Agriculture and Agri-Food Canada, Valacta and Agrinova). To address this issue, this project proposes to change the quality and quantity of protein in rations served in Ayrshire herds in Quebec. In a subsequent step, based on field results, an experiment will be conducted in Agriculture and Agri-Food Canada's Research Center to determine the difference in the efficiency of utilization of nitrogen and energy between Ayrshire and Holstein. Therefore, the overall objective of this project is to study the impact of changes in dietary intake of nitrogen on the performance, reproduction, health and milk quality of dairy cows of the Ayrshire breed. This study will help establishing corrective factors for adjusting the software used to balance rations, used in consulting services, according to protein recommendations adjusted to the specific requirement of the Ayrshire breed.