ANSC 2120 Lecture Notes - Lecture 33: Dairy Cattle, Rumen, Lactation
29 Feb 2016
School
Department
Course
Professor
Document Summary
Lecture 33: lactation ii meeting nutrient requirements (cid:1) (cid:1) (cid:1) (cid:1) Maximize energy intake (dm intake x energy density) without compromising rate of fiber fermentation in the rumen or any other health aspect. Optimize intake of rumen degradable protein and undegradable protein to meet requirements of absorbed amino acids: meet protein and meet energy reqs. Energy is the pacesetter (limiter: crude protein (cp) Rdp feeds microbes; if too much, lose n as nh3. Rup feeds cow; increases milk yield. Assumed to solely be a function of bw^3/4 (metabolic body size) This assumption is not true physiologically because high- yielding cows have higher maintenance costs than low yielding cows, but it usually works in practice. Net energy requirement for milk production (ne-l) = milk yield x milk energy concentration. Milk yield: yield varies per day with stage of lactation, genotype, management factors (incl. nutrition) Lecture 33: lactation ii meeting nutrient requirements: yield per lactation is determined by.
