Food intake, growth and mature size in Australian Merino and Dorset horn sheep

Thompson, J. M.; Parks, John Rabon

doi:10.1017/s0003356100010527

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…The effect of food on efficiency was expected from the food compositions (Table 1) and reflected both slower growth and higher food intake on L compared with H. Food efficiency was independent of sex in this trial in agreement with other studies (McClelland et al, 1973;Thonney et al, 1987a). The same authors and Thompson and Parks (1983) also found no overall breed effects on efficiency. There was evidence that the breeds used here differed in their response to the different foods: efficiency was reduced in all breeds on L compared with H but to a greater extent in the Suffolk (ratio L : H~0-463) than the Scottish Blackface (0·606).…”

Section: Lite Performancesupporting

confidence: 91%

Effects of food quality on growth and carcass composition in lambs of two breeds and their cross

Lewis

Macfarlane²,

Simm

et al. 2004

Anim. Sci.

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The effects offood quality, breed type and sex (ram and ewe) on Iamb growth and carcass composition, and their changes throughout growth, were measured. The three breed types wereScottish Blackface (B; no. = 24), Suffolk (5; no. = 28) and their reciprocal crosses (X; no. 33). The lambs had free access to a nutritionally non-limiting food, H, or a bulky food, L. Each lamb was scanned using X-ray computed tomography to measure the weights offat, lean and bone in the carcass at three degrees of maturity (0·30, 0·45 and 0·65) in live weight. Live weight and food intake data were recorded weekly. Average daily gains in live weight (ADG) and carcass tissues, intake (ADI) and efficiency (EFF = ADG/ADI) were calculated for each lamb between degrees of maturity. Gompertz and Spillman functions were used to investigate relationships between weight and both time and cumulative food intake.There wasa breed byfood interaction forfat and lean proportions (P < 0·05). Only on H was there a breed difference (P < 0·05) with S having less fat and more lean than either B or X, which did not differ from each other (P > 0·1). On food L there were no breed effects (P> 0·1). Across breeds, sexes and stages of maturity! food L caused lambs to have0·810as muchfat and 1·063as much lean compared with H (F < 0·00l!. There were breed byfood interactions for ADG IF < 0·05) and EFF (F < 0·01). ADG on L was O· 72 of that on H for S, as compared with 0·79for Band X. EFF on L was 0·463 of that on H for S, as compared with 0·586 for B and X. These were such that S was more sensitive to food effects on growth. The Gompertz and Spillman functions described growth well.

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Section: Lite Performancesupporting

confidence: 91%

Effects of food quality on growth and carcass composition in lambs of two breeds and their cross

Lewis

Macfarlane²,

Simm

et al. 2004

Anim. Sci.

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show abstract

“…Despite breed and sex having large effects on absolute, and scaled, gains and intakes, there were no breed or sex effects on food efficiency. 'This is in agreement with results of previous studies (McClelland et al, 1973;Butterfield et al, 1983;Thompson and Parks, 1983;Thonney et al, 1987;Lewis et al, 2004b).…”

Section: Live Performancesupporting

confidence: 94%

Effects of two dried forages, and a choice between them, on intake, growth and carcass composition in lambs of two breeds and their cross

2004

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The effects of forage type, breed type and sex on lamb growth and carcass composition, and their changes throughout growth, were measured. The three breed types were Scottish Blackface (no. =31), Suffolk (no. =28) and their reciprocal cross (no. =30). The lambs were given ad libitum a pelleted ryegrass alone, pelleted lucerne alone or a choice of both. Each lamb was scanned using X-ray computed tomography to measure the weights offat, lean and bone in the carcass at three proportions of mature body weight (0-30, 0·45 and 0·65). Live weights andfood intake data were recorded weekly. Average daily gains in live weight and carcass tissues, food intake and efficiency were calculated for each lamb between degrees of maturity. Relationships between weight and food intake were investigated using a Spillman function. Breed type had no effect on fat or lean proportion in the carcass but Scottish Blackface lambs had 1·04 times the carcass bone proportions of the Suffolk or crossbred lambs. Diet had no effect on carcass tissue proportions, The effect of sex on carcass composition changed with stage ofmaturity. Breed type and sex effects on intakes and gains in live weight and tissue weights were related to mature size differences. Scaling by (mature size)o·73 did not fully remove these differences. There were no effects of breed type, sex or diet on efficiency. Lambs on ryegrass had lower intakes (0·878 as great) and slower growth (0·851 as fast) than those on lucerne orthe choice treatment. The mean proportion of ryegrass in the choice diet was 0·366 (s.e. 0·0273); it increased slightly with time. There was no breed type by diet interaction for any of the variables examined. The Spillman function described growth well and showed that there were no effects of breed type, diet orsex onefficiency.

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“…However, ADG was similar in all groups showing that lthose weaned with less weight did not have a catching up growth. As post-weaning growth of lambs depends on solid food intake as well as on their genetically potential for growth (NAGPAL et al, 1994), weaning weight is an important factor for later growing because the increase of live weight is reduced in relation to food intake when animals approach to maturity (THOMPSON & PARKS, 1983).…”

Section: Ciência Rural V38 N3 Mai-jun 2008mentioning

confidence: 99%

Effects of weaning age and weight on lamb growth rate of Morada Nova breed raised in a tropical extensive production system

2008

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Food intake, growth and mature size in Australian Merino and Dorset horn sheep

Cited by 12 publications

References 14 publications

Effects of food quality on growth and carcass composition in lambs of two breeds and their cross

Effects of food quality on growth and carcass composition in lambs of two breeds and their cross

Effects of two dried forages, and a choice between them, on intake, growth and carcass composition in lambs of two breeds and their cross

Effects of weaning age and weight on lamb growth rate of Morada Nova breed raised in a tropical extensive production system

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