The act of rumination

Abstract

1. A detailed analysis was made of the rumination behaviour of one caged sheep on four combinations of diet, ranging from 100% hay to 100% concentrate meal.2. When hay was fed there was no relationship between the quantity of it ingested and the amount of rumination, which averaged 8 hr. daily. When concentrates were fed alone rumination time fell to 2½ hr. per day and much of this was ‘pseudorumination’.3. Evidence is produced to show that the number of chews and not the time chewing is the accurate way of measuring rumination quantitatively. This particular sheep made an average of 39,000 rumination chews per day when hay was fed.4. The duration of the intervals between boli was constant at 15% of total rumination time, but the rate of chewing varied from 83–99 chews per minute, being slower during the midnight to noon half of the 24 hr., when most rumination occurred.5. Rumination periods last from under 1 min. up to about 2 hr.6. Tiring during a rumination period was reflected by an increase in the intervals between boli but the number of chews per bolus remained unchanged.7. The first bolus of each period of rumination was chewed less than those following. This sheep averaged fifteen periods of rumination per day, a daily total of 500 boli were regurgitated. There were 2500 chews per period and seventy-eight chews per bolus.

Comparisons of some factors affecting digestibility in sheep and cows

“…chewing frequency) changed without total rumination time changing. This factor was discussed by Gordon (1958) who observed (Gordon, 1965) in sheep a closer relationship between time spent actually chewing during rumination and feed intake than between intake and total rumination time. Further work should compare in sheep and cattle chewing frequency during rumination and the actual time spent chewing during rumination.…”

Post Parturient Oestrus in Merino and Dorset Horn Sheep

“…Hafez (1952) reported that lactation seemed to defer post parturient oestrus. The percentage of both Merino and Dorset Horn ewes which were lactating when post parturient oestrus occurred was considerably greater and post parturient oestrus occurred sooner after parturition than in the studies recorded by Gordon (1958) involving other breeds and crosses. More Merino than Dorset Horn ewes were lactating when post parturient oestrus occurred after both a winter and summer lambing.…”

Padrões da distribuição nictemeral do comportamento ingestivo de vacas leiteiras, ao início e ao final da lactação, alimentadas com dieta à base de silagem de milho

“…As diferenças entre os estádios de lactação, quanto ao padrão de dispersão da atividade de rumi- A importância do componente de ritmo 1 em relação aos outros componentes de ritmo, para descrever o padrão de distribuição circadiano da ruminação, no início e no final da lactação, está de acordo com observações anteriores sobre consistência da ruminação durante o período noturno (Gordon, 1958;Gordon & Mc Allister, 1970;Deswysen et al, 1989Deswysen et al, , 1993. A importância dos componentes de ritmo 2 e 3 foi associada, respectivamente, à atividade de ruminação no início da tarde, também descrita por Pearce (1965) e Deswysen et al (1989Deswysen et al ( , 1993) e à existência de um pequeno pico da atividade entre 7 e 8h.…”