Relationships of ilumination and temperature with rumination, resting and grazing of merinos on supplemented dry pasture

A flock of 25 Merino adult, open ewes were kept dayand night on a 7.3 Ha paddock of tipical "dehesa" range during summer in Almadén, Spain (38° 45"N longitude and 4° 42"W latitude). The paddock had a watering point and sufficient oaks to provide shade. It was possible the observation of sheep activities without disturbing them. The available pasture was estimated by weighing the clipped dry pasture inside I x 2 m hazard determined frames every 30 days. The ewes received daily a balanced diet formulated to contain 14% crude protein between 10,00 and 10,20 hours in an adjacent corral. On july 15 a ram was introduced to the ewes; there were matings, not recorded. Sheep were numbered and weights recorded on july 2 and september 30. The sheep behaviour was recorded each 10 days, from july 2, to September, 30. Records of shade temperatures and sheep activities were made on observation days with binocular glasses each two hours. The grouping of sheep activities included the following classification: I. Grazing. 2. Idling. 2A. Standing. 213a. Ruminating.2Bb. Sleeping. Two nights of full moon the actvities of ewes were also recorded each two hours but rumination could not be observed because insufficient light. The available pasture provided an average daily ingestion of 1.59; 0.82 and 0.42 kg by head, on July, august and september months, respectively. The concentrate provided an additional daily ingestion of 0.38 kg by head. The ratio of daytime grazing to idling was 6/3 on July and august and 514 on september. The distribution of idling day time on july and august showed that rumination was diminishing from 50¬60% of animals on the first observation time after grazing end until almost no rumination recorded 6¬8 hours thereafter. As far as rumination decreases sleeping increases. Two to six animals were just standing on central idling time, but at the last idling time observation about 80% of animals were standing. On september a different pattern of time distribution during central day was observed. It seems to appear more time devoted to graze standing and to sleeping and less to rumination. The pattern of behaviour recorded on september, 2, was affected by a rain and clouds three days period with decreasing temperature. The grazing time cessation in the morning and that of reassuming such activity in the afternoon seems to be independent of temperature. The animals stop grazing about 18-20° C in the morningand reassume grazing at 36-40° C in the afternoon on july and august. On september the pattern in the central period of day was rather different, with less time spent to rumination and more to standing and to grazing. First period of night grazing was a simple continuation of evening grazing. Sheep had alternate succesive periods of rest and grazing about two hours long on the night. Un rebaño de 25 ovejas Merinas vacías fue mantenido durante un verano día y noche, en una superficie de 7.3 Ha de dehesa arbolada, con agua (38" 45"N,4°42"W). Las ovejas recibieron diariamente, aparte el pastoreo, 10 kg de un concentrado de 14% de proteína bruta. Fueron pesadas el 217 y el 3019. El pasto disponible se estimó por pesada diferencial de áreas de I x2 m cada 30 días. Se llevaron registros de la temperatura ambiente y las actividades de cada oveja mediante observación directa cada 10 días. También se observaron las ovejas cada dos horas dos noches de plenilunio. Las observaciones de las actividades del ganado se agruparon en: 1. Pastando, 2. En reposo, 2A. Descansando, 2Ba. Rumiando, 2Bb. Durmiendo. El pasto disponible proporcionó por cabeza una ingesta media diaria estimada de 1,59; 0,82 y 0,45 kg en los meses de julio, agosto y septiembre. . El cociente del tiempo diario dedicado a pastar acarradas fue de 613 en julio y agosto y de 514 en eptiembre. El tiempo de rumia iba disminuyendo desde un 50-60% de los animales en la primera observación en descanso hasta extinguirse 6-8 horas después. Por el contrario, a medida que disminuye el número de animales rumiando aumenta el número de animales durmiendo. En septiembre los animales dedicaron más tiempo a pastar y a dormir y menos a rumiar. El cese del pastoreo en la mañana con 18-20"C y su reanudación en la tarde con 36-40"C parece ser independiente de la temperatura en julio y agosto. Durante la noche los animales tenían periodos alternantes de descanso y pastoreo. El pastoreo de tarde se prolongaba en la noche y el de mañana era continuación del de alba.