| The global demand for milk is constantly growing and relies on intensive nutrition strategies not only for dairy cows, but, for calves, too. Consequently calves are weaned very early to stimulate an early intake of grain based concentrates for a fast rumen development. As cellulose digesters ruminants per se do not depend on starchy grains as energy source, thus, it appears fundamental to evaluate feeding strategies that aim at reducing the amount of concentrates in ruminant diets. A recently conducted study (DAFNE no. 100928 „Sugarhay“) demonstrated that concentrate feeding to dairy cows could be reduced by feeding high-quality hay with a high sugar content (~20% of dry matter).
To follow the idea of that project “Sugarhay”, the aim of this study is to evaluate the effects of hay feeding and hay quality on feed intake, daily gains, rumen development and rumen health of calves in comparison to a commercial grain based starter feed. Starter feeds for calves are largely composed of easily digestible grains, rich in starch, which help in meeting the nutrient requirements of the calf, however, can be problematic for the physiological development of a healthy rumen. In contrast to starter feed, high-quality hay contains more fiber, while still providing high energy and nutrients, and thus meets the physiological adaptation of ruminants to cellulose-rich feeds. Special interest is on early programming of the rumen development and microbial establishment.
Accordingly, we want to test the following hypotheses in a feeding trial with 40 calves of the breeds Simmental and Holstein Friesian:
1. Because of an elevated content of sugars, high-quality hay contains more energy and less fiber than typical hay used for calf nutrition, and thus will promote feed intake and body weight gain.
2. Replacing concentrate based starter feed by high-quality, energy rich hay primes rumen microbial ecology, reduces the risk for developing ruminal acidosis in calves, and a healthy rumen ecosystem can establish.
3. In comparison to concentrate based starter feed, feeding high-quality hay promotes the establishment of a healthy rumen microbial ecosystem and the development of a healthy efficient rumen wall in calves.
4. Replacing concentrate based starter feed by high-quality hay stimulates ruminating behaviour in calves, which in turn promotes rumen health and offers occupation to prevent stereotypies. |