Estimates of the energy required for maintenance by adult sheep 2. Grazing sheep

Langlands, JP; Corbett, J. L.; McDonald, I.; Reid, Gavin

doi:10.1017/s0003356100021462

Cited by 33 publications

(18 citation statements)

References 6 publications

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“…Equations 20, 25, 30 and 36 (Table 7) were the most effective models obtained in this study for predicting DOMI, for groups of 30 cows in weeks 1 to 4, 5 to 8, 9 to 12 and 13 to 16 of lactation, respectively; the population tolerance limits for groups of 30 cows in these equations were ±0-47, +0-56, +0-51 and ±0-39, respectively. If 1 lb DOM supplies 1-65 Meal of metabolizable energy (ME) (Langlands, Corbett, McDonald and Pullar, 1963), the tolerance limits on the least effective of these equations (no. 25) are equivalent to ±0-92 Meal in a total intake of about 36-6 Meal ME; the latter value (Agricultural Research Council, 1965) is for a 500-kg Ayrshire cow giving 20 kg of milk on a diet containing 2-6 Meal ME/kg DM.…”

Section: Resultsmentioning

confidence: 99%

Prediction of the voluntary intake of food by dairy cows: 1. Stall-fed cows in late pregnancy and early lactation

1970

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SUMMARYData from 22, 28, 36 and 41 pregnant cows in weeks 4, 3, 2 and 1 before calving respectively and 51, 65, 56 and 36 cows in weeks 1 to 4, 5 to 8, 9 to 12 and 13 to 16 of lactation respectively were used in multiple regression analyses to study the feasibility of predicting the daily total and the roughage organic matter and digestible organic matter intakes of cows given known weights of concentrates plus roughage ad libitum. The digestibility of the total intake and of the roughage component, the weight of concentrates eaten per day, the proportion of roughage in the total intake, age, milk yield, fat-corrected milk yield, live-weight gain and the 1·0, 0·73 and 0·66 exponents of live weight were used as independent variables.The accuracy of the models was assessed from the significance of the partial regression coefficients, the size of the residual standard errors, and the population tolerance limits about predicted values, and by applying selected models to a set of data not included in the study. The results indicated that the precision likely to be achieved in the prediction of intake for individual cows was of limited practical application, but the mean intakes of groups of 30 similar cows could be predicted with an acceptable level of accuracy for practical application. In general, weight of concentrates offered and the digestibility of the roughage were the most effective independent variables in all cows, together with milk yield in lactating cows. The application of the results to conventional feeding systems and to complete diets offered ad libitum is discussed.

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Section: Resultsmentioning

confidence: 99%

Prediction of the voluntary intake of food by dairy cows: 1. Stall-fed cows in late pregnancy and early lactation

1970

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“…The other exponents of live-weight calculated (equations 6 and 7) were also nearer to 1-0 than to 0-73-an observation also noted with sheep by Langlands et al (1963). The other exponents of live-weight calculated (equations 6 and 7) were also nearer to 1-0 than to 0-73-an observation also noted with sheep by Langlands et al (1963).…”

Section: Discussionmentioning

confidence: 49%

“…For the same sheep in periods 1 and 2, after deducting 3-0 g. DOM per g. gain in live-weight (Langlands, Corbett, McDonald and Reid (1963)) for group 2 and 2-5 g. DOM per g. gain for the less mature sheep in group 3, the calculated equation was:…”

Section: Resultsmentioning

confidence: 99%

The effect of age and live-weight on the feed intake of grazing wether sheep

1965

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SUMMARY1. Estimates of the voluntary feed intake of three age groups of wether sheep on ryegrass and white clover pasture from July to October, 1962, were made by total collection of faeces and the use of local faecal nitrogen-digestibility regressions.2. Average faecal output and intake of digestible organic matter (DOM) increased with age of the sheep. However, relative to body weight (W) or to W073, the aged sheep (5 years old), which did not change much in weight over the period, consumed only about two-thirds of the DOM consumed by the younger (sixteen- and four-month-old) growing sheep.3. For the growing sheep intake was directly related to weight. Intake was calculated to be 24 W (kg.)–28 ±108 g. DOM per day.4. The results are discussed in relation to the errors in estimation of digestibility. Comparison of the intake estimates with other published data suggests there was a high apparent maintenance requirement. The voluntary feed intakes observed, when expressed as g. dry matter per kg. W0–73, were somewhat higher for young sheep but lower for aged sheep than estimates of previous authors.

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“…J. F. Russel, personal communication). An automatic device for withdrawing blood samples at frequent intervals has also been developed (Farrell, Corbett & Leng, 1970) and lightweight infusion pumps which can be carried by sheep or cattle have been described by Leng, Corbett & Brett (1968) and Treacher (1973).…”

Section: Symposium Proceedings I974mentioning

confidence: 99%

Measurement of energy expenditure in the grazing ruminant

Whitelaw¹

1974

Proc. Nutr. Soc.

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Although our knowledge of the energy metabolism of farm livestock has advanced substantially during the last 20 years, we still know remarkably little about the energy expenditure or energy requirements of the grazing animal. Attempts to estimate these requirements have in the past relied upon two indirect approaches, the first based on the extrapolation of values obtained indoors by conventional calorimetric procedures and the second based on regression analyses of data relating to food intake, live weight and live-weight change of animals at pasture. Estimates obtained by the calorimetric approach have indicated that the energy expenditure of the grazing sheep may be from 10% to as much as 70% greater than that of the housed sheep (Blaxter, 1967; Graham, 1964 a, b

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Estimates of the energy required for maintenance by adult sheep 2. Grazing sheep

Cited by 33 publications

References 6 publications

Prediction of the voluntary intake of food by dairy cows: 1. Stall-fed cows in late pregnancy and early lactation

Prediction of the voluntary intake of food by dairy cows: 1. Stall-fed cows in late pregnancy and early lactation

The effect of age and live-weight on the feed intake of grazing wether sheep

Measurement of energy expenditure in the grazing ruminant

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