A quantitative model of energy intake and partition in grazing sheep in various physiological states

Vera, Raül; Morris, James G.; Koong, L. J.

doi:10.1017/s0003356100039374

Cited by 15 publications

(3 citation statements)

References 50 publications

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“…A quadratic equation was fitted as being the most appropriate according to previous work (Vera, Morris and Koong, 1977). Intakes by the ewes had been recorded daily indoors for the first 7 to 17 days after lambing, with 12 out of the 16 ewes having values for 10 days or more; thereafter, recording was on a weekly basis, with the majority of ewes being recorded for days 33 to 44.…”

Section: Methodsmentioning

confidence: 99%

The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning

Newton

Orr

1981

Anim. Sci.

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Link to this article: http://journals.cambridge.org/abstract_S000335610004054XHow to cite this article: J. E. Newton and R. J. Orr (1981). The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning. ABSTRACTThe intake of silage, concentrates and grazed herbage, and the performance of 16 Masham ewes carrying and suckling either single or twin lambs, was measured during the last 7 weeks of pregnancy, during lactation and after weaning.There was no difference in intake between ewes with singles or twins in pregnancy, lactation or after weaning. The metabolizable energy intakes, from silage and concentrates, of the ewes with singles and twins were 101 and 100 MJ per head per day in weeks 7 and 6 pre partum, 21-4 and 19-9 MJ in weeks 3 and 2 pre partum, and 24-4 and 23-8MJ in the 1st week of lactation. The intakes from grass and concentrates were 32-3 and 338MJ in weeks 5 and 6 of lactation for the ewes with singles and twins respectively, and 13-8 and 15 2MJ from grass alone after weaning. There was no effect of ewe live weight on intake and, although the ewes with singles were producing less milk than those with twins, their intakes were similar.The same ewes consistently ate the most feed. The overall coefficient of concordance was 056 and the coefficients for mid-and late-pregnancy, late pregnancy and early lactation, and early-and mid-lactation were 0-57, 0-62 and 0-66 respectively. The ewes with twins that consistently ate the most lost less weight in pregnancy, produced similar litter weights and suckled lambs that grew faster. Their levels of intake and production were high: the growth rate from 0 to 6 weeks of age of the twin lambs suckling the large-eaters was 721 g/day compared with 631 g/day for those suckling the small-eaters. During lactation the ewes with singles appeared to consume more metabolizable energy than their maintenance, milk yield and live-weight gain requirements justified, whereas the group of smaller-eating ewes with twins put on more weight than expected from their intakes.

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Section: Methodsmentioning

confidence: 99%

The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning

Newton

Orr

1981

Anim. Sci.

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“…At high pasture mass the appetite (physiological condition and size) of the grazing animal sets maximum intake. In direct contrast to many models (e.g., Vera et al 1977), these empirical equations allow pasture mass to restrict animal intake and therefore animal performance. Their accurate use however, is dependent on knowing more precisely the pasture mass values for when A/ approaches maximum.…”

Section: Derivation Of General Intake Functionsmentioning

confidence: 99%

Pasture utilisation in hill country 2. A general model describing pasture mass and intake under sheep and cattle grazing

Bircham¹,

Sheath²

1986

New Zealand Journal of Agricultural Research

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A general model describing daily changes in pasture mass and apparent individual herbage intake under mob grazing was developed for future use as a component of feed budgeting within hill country farming systems. The basic concept of the model is that of a negative exponential. The exponent includes animal density, time, and a constant k -the relative rate of pasture disappearance. Where k is unknown, the model is useful in a historical sense for describing pasture mass and intake levels at intermediate stages of a grazing period. Current pasture growth and its consumption are included in the model. The model is restricted by the requirement that the combined herbage intake must exceed current pasture growth rate. In developing and understanding factors affecting k, general relationships between pasture residual mass and allowance were used. k is situation dependent, being influenced by maximum apparent intake per animal, pasture allowance, and green: dead herbage ratio. Established sets of relationships between k and allowance would allow the predictive use of the negative exponential model. General empirical relationships between individual herbage intake and pasture mass were also established for sheep and non-lactating beef cattle. These relationships are applicable for apparent intakes of less than maximum and serve as a simple guide when k is unknown or difficult to determine.

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“…In weeks 7 to 10 of lactation, pasture allowance varied from 3.7 to 15 kg DM/ewe/day, but there was no effect on intake, which averaged 1.94 kg DM/ewe/day. Peak feed intake for lactating ewes usually occurs by week 6 of lactation (Vera et al, 1977). It is therefore likely that intakes will fall for ewes in good body condition regardless of allowance, but for thin ewes the negative effect of stage of lactation on intake could be counteracted by an increased appetite to improve body condition.…”

Section: Pasture a Llowances And I Ntakesmentioning

confidence: 99%

Effect of Pasture Reserves and Stocking Rate on Ewe and Lamb Performance From Mid-Pregnancy to Weaning

Clark¹

1978

ProNZG

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The effect of two stocking rates (16 and 32 ewes/ha) and three initial levels of pasture reserves (1730, 2240 and 2720 kg DM/ha) on animal and pasture production was studied from June to December 1977. Total amount of pasture grown was unaffected by either stocking rate or pasture reserve. At 32 ewes/ha, 96.9% of net pasture production was eaten and no surplus conserved. At 16 ewes/ ha, 50.4% was eaten and 1120 kg DM/ha conserved. Increasing initial pasture reserves gave increased ewe liveweight at weaning at 32 ewes/ha, but no response at 16 ewes/ha. There were no treatment effects on single lamb birthweights or weaning weights. The relationship between ewe intake and pasture allowance at different physiological states is discussed.

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A quantitative model of energy intake and partition in grazing sheep in various physiological states

Cited by 15 publications

References 50 publications

The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning

The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning

Pasture utilisation in hill country 2. A general model describing pasture mass and intake under sheep and cattle grazing

Effect of Pasture Reserves and Stocking Rate on Ewe and Lamb Performance From Mid-Pregnancy to Weaning

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