The effects of variation in sward characteristics upon the ingestive behaviour and herbage intake of calves and lambs under a continuous stocking management

Abstract

that the lack of response under strip-grazing is a characteristic of the management imposed. AbstractGroups of calves and lambs grazed on plots of S23 perennial ryegrass, in successive periods of 2, 2 and 3 weeks, at stocking rates which resulted in a slow change in herbage mass on each plot and measurements were made of ingestive behaviour (biting rate, bite size and grazing time) and herbage intake.As the green herbage mass was progressively reduced from approx. 3000 to 1000 kg OM per ha between periods, biting rate and grazing time increased, but insufficiently to offset the rapid fall in bite size so that herbage intake declined by 24% and 39% for calves and lambs respectively. Patterns of response were similar in calves and lambs, though in all parameters except biting rate the lambs appeared to be more sensitive than the calves to changes in sward conditions and there was no evidence that lambs were better adapted to grazing on short swards than calves.Intake increased in both calves and lambs up to levels of 2500-3000 kg green OM per ha, though this response may have been attributable in part to the reinforcing effects of increasing herbage mass and diet digestibility. Lambs consistently selected a more digestible diet than calves.Both calves and lambs increased grazing time substantially in response to limiting sward conditions, in contrast to results in earlier strip-grazing trials with calves, thus supporting the suggestioti

Herbage intake, ingestive behaviour and diet selection, and effects of condensed tannins upon body and wool growth in lambs grazingLolium perenneandHolcus lanatusswards in summer

“…This explanation also fits the results for January, where herbage intakes from the two swards were similar, reflecting the similar OM digestibilities observed in both diets (Table 3), despite the higher intake per bite recorded in Yorkshire fog swards (Table 6). When expressed per unit of metabolic weight (Table 7), intakes were similar to those recorded previously by Jamieson & Hodgson (1979) for comparable lambs grazing ryegrass swards of similar digestibility, under continuous stocking management, and higher than those observed on ryegrass swards in summer with ewes by L 'Huillier etal. (1986).…”

Comportamento ingestivo de novilhas de corte em pastagem de gramíneas anuais de estação quente

“…10 minutos, durante o período diurno, sempre que o animal estivesse em atividade de pastejo, para calcular a taxa de bocado/minuto (Hodgson, 1982), cujo valor multiplicado pelo tempo de pastejo, resultou no número diário estimado de bocados. Para o cálculo da massa do bocado, dividiu-se o consumo de estimado de forragem pelo número diário de bocados (Jamieson & Hodgson, 1979).…”

“…As avaliações do comportamento ingestivo foram realizadas por meio de observação visual (Jamieson & Hodgson, 1979), com intervalos de dez minutos. Foram observadas quatro novilhas-teste, por piquete e suas atividades foram classificadas como pastejo, ruminação e ócio.…”

Comportamento ingestivo de novilhas de corte submetidas a estratégias de suplementação em pastagens de aveia e azevém

“…Para o cálculo da massa de bocado (MBOC), dividiu-se o consumo diário de forragem pelo total de bocados diários (taxa de bocado × tempo de pastejo; Jamieson & Hodgson, 1979b).…”