Effect of growth rate on mineral retention and body composition of growing lambs

Abstract

1989). Effect of growth rate on mineral retention and body composition of growing lambs. ABSTRACT Groups of wether lambs were grown at different rates from about 24 kg live weight to 50 kg, by feeding them different amounts of the same concentrate diet. The slow growing lambs had higher contents of protein, ash, calcium (Ca), and phosphorus (P), and less fat and magnesium (Mg) than other groups. Differences in composition were significant between slow (120 g/day) and fast growth (230 g/day; P < 0-05) but not always between intermediate (160 g/day) and other growth rates. The differences became small and insignificant when data were expressed on a fat-free basis except for Mg which decreased with slow growth. Ash, for example, increased from 47 g/kg fat-free gain with fast growing animals to 54 g/kg with slow growth. Mg decreased from 0-44 g/kg fat-free gain with fast growth to 0-24 g/kg with slow growth. The data support the view that the ratio of ash to fat-free empty-body increases only slightly with age.The basic diet contained 3-9 g Ca per kg dry matter and the effect of a substantial supplement of calcium carbonate on lambs growing at the fast rate was to increase their retentions of ash, Ca and P by a factor greater than 1-25. There are alternative explanations for this finding. One possibility is that the availability of Ca in the basic diet had been reduced by unknown factors. It is also possible that the supplementary carbonate altered the acid/base status of the animals and resulted in conditions which favoured skeletal mineralization.

The effect of a change in blood acid-base status on body composition and mineral retention in growing lambs

“…Other carbonates might also be effective and Wan Zahari et al (1989b) and Rajaratne et al (1990) have reported significant increases in mineral retentions in lambs given relatively high concentrations of calcium carbonate. It would seem that substantially greater skeletal mineralization could be induced in growing lambs by the use of alkalogenic diets, such as cereal diets treated with NaHCO 3 , or by grass-legume based diets.…”

İvesi erkek kuzularının besi performansı ve karkas özelliklerine süt emme döneminde farklı büyütme sistemlerinin etkisi

“…Kuzuların soğuk ve sıcak karkas ağırlıkları bakımından G-I ve G-III grupları arasındaki fark önemli bulunurken (P<0.05), karkas randımanı, iç yağ ve kuyruk ağırlıkları bakımından fark bulunmamıştır. Kuzuların doğumdan sonra erken dönemde yeterli miktarda kaba ve kesif yem tüketmeleri ile gerçekleşen yüksek büyüme hızı, adipos dokunun daha hızlı gelişmesine neden olmaktadır (Okeudo et al 1994;Vergara & Gallego 1999;Wan Zahari et al 1989). Ad libitum yem tüketimi de kuzu karkaslarının yağlanmasına neden olabilmektedir (Rattray et al 1973).…”