caa a22 4500 388061383 CHVBK 20180307125121.0 cr unu---uuuuu 161130e199802 xx s 000 0 eng 10.1017/S1357729800008912 doi S1357729800008912 pii (NATIONALLICENCE)cambridge-10.1017/S1357729800008912 Predicting changes in food energy requirements due to genetic changes in growth and body composition of growing ruminants [Elektronische Daten] Incorporation of food intake into breeding objectives for ruminants is often difficult because the relevant genetic parameters are unavailable. A non-statistical approach to estimating the genetic relationships between food costs and genetic changes in growth and body composition traits was therefore developed. Equations which predict additional food requirements associated with genetic changes in growth and body composition traits are derived from an interspecies growth model. In the growth model, a genotype is mainly described according to its expected mature weights of protein, lipid and a composition trait of interest in the empty body under non-limiting conditions. Other model parameters describe the expected growth of the animal in a specific environment. An example is shown for beef cattle in the United Kingdom, where increases in carcass weight by 1 kg and carcass subcutaneous fat proportion by 0·01 result in increases in food costs by £0·97 and £7·34 respectively for a production system where animals are given an intensive silage/concentrate diet, are slaughtered at 305 kg and have a commercial fat grade 4L. A strong dependence of the results on the type of production system, especially the degree of maturity in protein at slaughter, is demonstrated. The model is easily adapted to other breeds and ruminant species. The approach is recommended for incorporating food intake into breeding objectives for ruminants in situations where reliable estimates of the necessary genetic parameters for a more conventional specification of the breeding objective are unavailable. Copyright © British Society of Animal Science 1998 breeding programmes nationallicence food intake nationallicence ruminants nationallicence Amer P. Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG Emmans G. C. Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG Animal Science Cambridge University Press 66/1(1998-02), 143-153 1357-7298 66:1<143 1998 66 ASC https://doi.org/10.1017/S1357729800008912 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1357729800008912 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Amer P. Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG NATIONALLICENCE 700 1- Emmans G. C. Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG NATIONALLICENCE 773 0- Animal Science Cambridge University Press 66/1(1998-02), 143-153 1357-7298 66:1<143 1998 66 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge