Studies with Laying Hens. 2. Energy Restriction
Layer and Breeder rations are still evaluated, as a rule, on the basis of their protein content, expressed as "percent protein". This is the easiest and most practical criterion, but unfortunately it is a relative measure, depending on general feed consumption. The latter hardly relates to the productive traits of the hen, being dependent primarily on the energy content of the feed and on the e...متن کامل
The factorial approach has been used to partition the energy requirements into maintenance, growth, and production. The coefficients determined for these purposes can be used to elaborate energy requirement models. These models consider the body weight, weight gain, egg production, and environmental temperature to determine the energy requirements for poultry. Predicting daily energy requiremen...متن کامل
The bacterium Erysipelothrix rhusiopathiae can infect a wide range of mammals (including humans) and birds. Disease outbreaks (erysipelas) have been considered unusual in chickens internationally, but outbreaks with high mortality and egg production losses have been diagnosed in Swedish laying hen flocks every year since 1998. Different aspects of E. rhusiopathiae infection in chickens were exa...متن کامل
Comparative gonadotrophic potency of anterior pituitaries from cocks, laying hens and non-laying hens in molt.
A bulk of studies on the assay of gonadotrophic hormone content of the anterior pituitary from the animals in various reproductive conditions has been done. Riley and Fraps(1942b) assayed pituitary glands from chickens in various reproductive stages, judging the gonadotrophic potency by the increment of uterine weights of immature mice, and concluded that glands from non-laying hens produced a ...متن کامل
During recent decades productivity of laying hens increased substantially (Elliot, 2008). Not only egg number, egg mass, and feed conversion has increased but also persistency of lay has improved. As such, this must have implications on the optimal amino acid nutrition of current laying hen strains. Simply stated, increasing egg mass output per hen means an increased amino acid output which has...متن کامل
عنوان ژورنال: Poultry Science