The fasting metabolism of Brahman, Africander and Hereford×Shorthorn cattle

Abstract

I. The fasting metabolism of twenty-seven animals, nine Brahmans, nine Africanders and nine Hereford x Shorthorns was measured after fasts of 96 h duration. Urine was collected over successive 24 h intervals and gas exchange was determined 96-103 h after the last meal.2. Urinary urea decreased and creatinine increased throughout the fasting period. There was no difference between breeds in the urinary excretion of nitrogen, urea and creatinine on the 4th day of fasting (72-96 h). Excretion of nitrogen, urea and creatinine increased by 259, 197 and 45 mg/kg increase in fasted weight and by 8.9,7'6 and 0.91 mg/kcal increase in fasting metabolism respectively. Protein oxidation accounted for 25.6, 21.7 and 22.7% of the fasting heat production of Brahman, Africander and Hereford x Shorthorn cattle respectively, values which were not significantly different. 13'7%.

Energy Utilization by the Lacombe and Yorkshire Breeds of Pig

“…(Marston, 1968). The reason for the lower fasting HP for the Lacombe pigs may be that this trait is specific to breeds, as has been reported by Blaxter and Wainrnan (1966) and by Vercoe (1970) in cattle.…”

Brahman and Brahman crossbred cattle grown on pasture and in feedlots in subtropical and temperate Australia. 3. Feed efficiency and feeding behaviour of feedlot-finished animals

“…Frisch and Vercoe (1969) reported that lower feed intakes in Brahmans relative to Africanders and Shorthorn · Herefords (weight adjusted) fed ad libitum lucerne was likely due to lower maintenance requirements in the Brahmans. Another study by Vercoe (1970) suggested the lower fasting metabolism of Brahmans relative to Africander and HS bulls aged 13-22 months (P < 0.05) may have been due to a lower requirement for energy to carry out functions of basal metabolism, or if they had similar requirements, Brahmans may have been able to use the energy released by biochemical processes occurring at basal conditions more efficiently. Therefore, it appears that B. indicus cattle require lower feed intake relative to B. taurus genotypes in order to meet maintenance requirements.…”

“…Efficiency of feed utilisation has several variable components including feed intake, digestion of feed, metabolism (including variation in body composition), activity and thermoregulation (reviews by Archer et al 1999;Herd et al 2004). Early research on tropically adapted genotypes (Vercoe 1967(Vercoe , 1970Vercoe 1969, 1977;Vercoe et al 1972) shows there are differences in feed intake, eating rate, weight gain, metabolic rate and efficiency of feed utilisation between breeds and across different environments. However, those early studies were based on low numbers of animals and did not include representatives of the large Continental breeds that have since been imported to Australia.…”

Effects of Crossbreeding and Sex on Energy Requirements and Utilization by Young Pigs

“…(Blaxter and Wainman 1966;Vercoe 1970;Garret 1910) and in sheep (Blaxter 1962;Bull et al 1970 A collection pcriod of 6 days was used during which the daily feed allowance remained unchanged. The total duration of the feeding period was 40 days, after which the pigs were killed and their bodies treated similarly to those of the initial slaughtcr group.…”