ANIMAL BREEDING IN RELATION TO NUTRITION AND ENVIRONMENTAL CONDITIONS

• DOI: 10.1111/j.1469-185x.1947.tb00330.x
• Publication Date: 2008-01-22T08:02:14Z
• Authors: JOHN HAMMOND
• Keywords: Daylight; Animal Breeding

Summary 1. The action of the gene on characters an animal is limited to those manifestations which are physiologically possible if survive. Environmental conditions affecting physiology will therefore have a selective genes give rise in harmony with environment concerned. main problem breeding be able direct course evolution and select giving increased development certain characters. 2. Where character by environmental it not for capacity manifesting themselves excess these limitations. If, therefore, physiological factor limiting this manifestation removed placing under optimal question, then higher level production. 3. Owing survival rate at birth, genetic control reproduction has, natural conditions, often become linked variation daylight hours. Egg production hens depends increasing hours sheep decreasing hours, varying degree according latitude origin breed. Before progress can made selection concerned this, birth has regulated conditions. 4. Most commercially valuable animals quantitative rather than qualitative, so that manifest important. In high milk yield various factors (letting down milk, food intake before after parturition, pressure, etc.) turn further increase yields, yields been until appropriate taken eliminate factors. 5. A disadvantage method within specially controlled limit scope selected effectively. Thus temperate climates directly applicable tropical climates, regulating body temperature air temperatures for, combination latter must effective. 6. meat growth plane nutrition during different phases important, means proportions obtained. nutritive specialized breeds pork, bacon, lard native pigs produced, when repeated experimental inbred lines, same types individuals as before. Genetic would appear most effective carried out nutritional favourable question. Nutritional affect post‐natal greater extent pre‐natal development; other hand, importance ones because uterine more stable external environment. 7. It suggested controlling next generation reared, i.e. uterus, man could future only his domestic but also himself