Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight. 1. Food intake, food efficiency and growth

1985 ◽  
Vol 40 (1) ◽  
pp. 55-70 ◽  
Author(s):  
J. M. Thompson ◽  
J. R. Parks ◽  
Diana Perry
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Growth Curves ◽  
Growth Efficiency ◽  
Food Conversion ◽  
Weaning Weight ◽  
Regular Oscillation ◽  
Selection For ◽  
Food Conversion Efficiency

ABSTRACTChanges in the pattern of food intake, food conversion efficiency and growth from weaning to maturity, were examined in 35 rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. The sheep were individually fed a pelleted ration ad libitum for at least 72 weeks and up to 90 weeks post weaning. Weekly food intake was described as an increasing exponential function of age with a linearly declining asymptote, about which a regular oscillation occurred, and weekly body-weight gain was described as an increasing exponential function of weekly food intake, about which a regular oscillation also occurred.The oscillations in weekly food intake had a period of about 52 weeks and appeared to be largely associated with seasonal variations in temperature, with an increased food intake during winter and a decreased food intake during summer. The oscillations in both the food-intake and body-weight functions were of similar phase and period and it was suggested that the body-weight oscillations were due to variation in gut-fill, a result of the seasonal oscillations in food intake.Selection for weaning weight changed the shape and magnitude of the food-intake curve, with the weight-plus having a greater rate of food intake (i.e. appetite) in the early stages of growth and a greater asymptote than the weight-minus animals. Selection for high and low weaning weight also resulted in an increase and a decrease in mature weight. Both strains had a similar growth efficiency, although when calculated as gross food conversion efficiency the weight-plus were higher than the weight-minus animals at the same body weight, whereas there was no difference between strains at the same age.The rams had both a higher asymptote and a slower rate of decline in food intake than the ewes. Rams had a higher mature weight than the ewes, although ewes had a slightly greater growth efficiency. However, when calculated as gross food conversion efficiency, ewes tended to be lower than rams, when compared either at the same age, or at the same body weight.When the food-intake curves were standardized for differences in mature size, strain differences in the magnitude of the food-intake curves were reduced, although differences in the shape were still apparent. Shape differences in the food-intake curves were reflected in the shape of the standardized growth curves, with the weight-plus maturing at a faster rate than the weight-minus animals. There was little difference between the sexes in the initial shape of the food-intake curve, although at later ages ewes had a lower food intake than rams. There was little difference between the sexes in the shape of the standardized growth curves.

Growth and carcass characteristics of desert goat kids and their temperate cross

1988 ◽  
Vol 46 (2) ◽  
pp. 231-235 ◽  
Author(s):  
A. Bello ◽  
S. A. Babiker
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Carcass Characteristics ◽  
Live Weight ◽  
Food Conversion ◽  
Internal Organs ◽  
Gut Fill ◽  
Food Conversion Efficiency

AbstractCrossbreeding of desert goat does with the temperate Saanen x Toggenburg buck was found to result in a significant increase in the daily live-weight gain and the empty body weight of their progeny slaughtered at about 30 kg live weight when compared with purebred desert goat kids (P < 0·001). Food intake did not differ between the two types of kids, but live-weight food conversion efficiency was significantly superior in crossbred kids (P < 0·05).Carcass weight and killing-out proportion tended to be greater in the crossbred kids reflecting lower weights of head, skin, internal organs and gut fill. Breed types did not differ in the weights of individual wholesale cuts. Carcass dissection revealed significantly higher muscle proportion (P < 0·05), significantly lower fat proportion (P < 0·01) and higher muscle: bone ratio in the crossbred kids.

Multibreed comparisons of British cattle. Variation in relative growth rate, relative food intake and food conversion efficiency

1985 ◽  
Vol 41 (2) ◽  
pp. 193-199 ◽  
Author(s):  
R. B. Thiessen ◽  
C. S. Taylor ◽  
J. Murray
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Genetic Variation ◽  
Food Intake ◽  
Relative Growth Rate ◽  
Conversion Efficiency ◽  
Food Conversion ◽  
Relative Growth ◽  
Breed Selection ◽  
Food Conversion Efficiency

ABSTRACTIn a multibreed experiment in which 292 heifers from 25 breeds were given a single complete pelleted diet ad libitum, body weight and food intake were recorded every 2 weeks. Relative growth rate, relative food intake and food conversion efficiency were calculated as the ratio of weight gain to body weight, food intake to body weight and weight gain to food intake respectively. The traits were measured over 12-week intervals from 12 to 72 weeks of age, and also over longer intervals of 24, 36, 48 and 60 weeks, each beginning at 12 weeks of age. Relative growth rate and food conversion efficiency declined continuously with increasing age, whereas relative food intake increased to a maximum in the 24- to 36-week period and then declined continuously.The between-breed genetic coefficient of variation (CVb) for relative food intake was very stable at about 0·04 whether measured over 12-week or longer intervals, whereas the CVVs for relative growth rate and food conversion efficiency were usually higher when measured over 12-week intervals compared with longer intervals. For the entire period from 12 to 72 weeks, the CVb was estimated as 0·029 for relative growth rate, 0·040 for relative food intake and 0·034 for food conversion efficiency. The corresponding intraclass correlations (t2) measuring the between-breed variation as a proportion of the total variation were estimated as 0·08, 0·18 and 0·15. Within-breed variation was thus much greater than between-breed variation for all three traits. Using published estimates of within-breed heritabilities, the parameters g21 measuring the between-breed genetic variation as a proportion of the total genetic variation, and g22, measuring the between-breed genetic variation as a proportion of the immediately selectable genetic variation, were estimated as 0·28 and 0·61 for food conversion efficiency and 0·25 and 0·57 for relative growth rate. Thus, for all three traits, despite their low CVb and t2 values, between-breed selection would be useful prior to within-breed selection.

Inter-age correlations of food conversion efficiency with body weight, growth rate and food intake within and between British breeds of cattle

1986 ◽  
Vol 43 (1) ◽  
pp. 91-100 ◽  
Author(s):  
R. B. Thiessen ◽  
St C. S. Taylor
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Strong Association ◽  
Unit Weight ◽  
Food Conversion ◽  
Unit Body Weight ◽  
Pelleted Diet ◽  
Food Conversion Efficiency

ABSTRACTIn a multibreed experiment 306 females from 25 British breeds of cattle were given a standard pelleted diet ad libitum. Correlations of food conversion efficiency (FCE) with body weight, weight gain, and food intake were studied over 12-week and longer periods from 12 to 72 weeks of age. Inter-age correlations of FCE with itself and the other traits were also studied over age intervals separated by 12, 24, 36 and 48 weeks. The between-breed correlations were genetic while the within-breed correlations were phenotypic.Between breeds, FCE measured over the full age range from 12 to 72 weeks appeared to be very highly correlated with FCE measured over the 12-week period between 24 and 36 weeks of age. Correlations of 12 to 72 week FCE with traits not requiring measurement of food intake were much lower, being at most 0·77 for weight gain, 0·73 for weight gain per unit body weight and 0·57 for body weight. The pattern of correlations implied that over constant age ranges the larger faster-growing breeds with high intakes tended to be more efficient; however, these correlations were generated primarily at early ages between 12 and 36 weeks and FCE at later ages could not be predicted from other traits measured at earlier ages. Nevertheless, between-breed selection to improve FCE by indirect selection on body weight and weight gain could be effective but there would appear to be no advantage in waiting beyond 1 year of age.Within breeds, correlations of 12 to 72 week FCE with FCE measured over 12-week periods increased with age from 0·24 to 0·61. Correlations of FCE with weight gain in the same 12-week periods were quite high (0·49 to 0·89) and those with weight gain per unit weight were invaribly higher (0·68 to 0·90). However, as a predictor of FCE in any subsequent period, weight gain per unit body weight was poor and weight gain of no value whatsoever. There was no strong association of FCE with body weight.

Breed and sex differences in equally mature sheep and goats 1. Growth and food intake

1987 ◽  
Vol 45 (2) ◽  
pp. 239-260 ◽  
Author(s):  
M. L. Thonney ◽  
St C. S. Taylor ◽  
T. H. McClelland
Keyword(s):  
Food Intake ◽  
Conversion Efficiency ◽  
Mammalian Species ◽  
The Body ◽  
Food Conversion ◽  
Size Scaling ◽  
Daily Food ◽  
Fleece Weight ◽  
Mature Size ◽  
Food Conversion Efficiency

ABSTRACTGenetic size-scaling accounts for most of the variation found among mammalian species in food intake and growth rate, with food conversion efficiency independent of the body size of the species. Is the same true of breeds and strains within species?Animals from Soay, Welsh Mountain, Southdown, Finish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and from a breed of feral goats were grown to 0·40, 0·52, 0·64 or 0·76 of the mean mature weight of their breed and sex. Food was offered ad libitum and individually recorded.Allometric growth coefficients were obtained for fleece weight, femur weight and femur length. Fleece was late maturing and femur early.Breed and sex size-scaling coefficients, obtained by regression of breed and sex means on mature size, were similar to those found at the species level for age from conception to slaughter, time taken to mature and food conversion efficiency. Coefficients were higher than expected for total and daily food consumption, especially at early stages of maturity. Most breed coefficients were close to expectation while sex coefficients were somewhat higher than expected.There were significant breed deviations: Welsh Mountain, Oxford Down and probably Soay sheep required less time and Jacob sheep and feral goats required more time to mature than expected from differences in mature size. Soay and Welsh Mountain sheep appeared to be more efficient and feral goats and Jacob sheep less efficient food converters over the same maturity interval.

Phenotypic variation in residual food intake of mice at different ages and its relationship with efficiency of growth, maintenance and body composition

1996 ◽  
Vol 63 (1) ◽  
pp. 149-157 ◽  
Author(s):  
J. A. Archer ◽  
W. S. Pitchford
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Phenotypic Variation ◽  
Growth Efficiency ◽  
Maintenance Requirement ◽  
Different Ages ◽  
Selection For ◽  
Young Mice

AbstractFood intake and body weight of 119 mice was measured from 3 to 18 weeks of age. Residual food intake was calculated for each week as the variation in food intake independent of variation in weight gain, weight maintained and sex. Growth efficiency and maintenance requirement were calculated by fitting curves to data from 3 to 18 weeks. The repeatability of residual food intake was low in young mice, but increased as they matured. Growth efficiency was correlated with residual food intake in very young mice. Residual food intake was not correlated with maintenance requirement in young mice, but as mice matured the correlation of residual food intake with maintenance requirement increased to 0·6. Body composition at maturity was correlated with residual food intake and maintenance requirement of mature mice, but a large proportion of the variation in residual food intake and maintenance requirement was independent of body composition. The results suggest that the age at which residual food intake is measured is important if it is to be used as a criterion for selection for efficiency.

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