Components of weight loss in pregnant hill ewes during winter

Abstract

Live weight of 180 free-grazing Blackface ewes was measured approxim-ately every two weeks throughout a 12-month period. Mean live weight was at a maximum (47 kg) in late autumn prior to mating and declined progressively to 39 kg at about the time of parturition.Six ewes were slaughtered in November before mating, six at about the 16th week of pregnancy, and a further 11 in April during the final week of pregnancy. The loss of weight of maternal tissues (i.e. live weight less the weight of fleece and contents of the gastrointestinal tract and gravid uterus) during this period was more than 20% (7·5 kg) and comprised 51% of the fat, 14% of the water, and 20% of the protein plus ash present at maximum live weight. During the earlier stages of pregnancy there was an appreciable loss of water from the maternal tissues, but in late pregnancy the rate of water loss decreased and that of fat increased considerably.The distribution of fat throughout the maternal tissues at different levels of total fat content and the pattern of fat mobilization from various depots are described. The largest single contribution to fat loss during the pregnancy period was that of the subcutaneous reserves, which were depleted by 86%, most of this being lost during the first four months. At the other end of the scale bone fat reserves were reduced by only 25%, almost all of this occurring during the final month.

Breed and sex differences in muscle distribution in equally mature sheep

“…The procedures adopted at slaughter were essentially those of Russel, Gunn and Doney (1968). Carcasses were prepared according to standard commercial practice and stored at -20°C until dissection took place.…”

Energy Cost of Pregnancy in Single- And Twin-Bearing Ewes

“…$Assuming that dietary ME substitutes for energy from body tissues with an efficiency of 83To (BlaxLer 1962). (Field and Suttle 1968;Russel et al 1968) or imposed experimentally by undernutrition (Sykes and Field 1972 Foot and Greenhalgh (1970) employing the same technique. However, (Blaxter 1962) Sykes and Field ( 1972), and is intermediate between those of Russel et al (1967) (Romanoff 1967 …”

Variations du volume des adipocytes et de la note d'état corporel chez la brebis Rasa aragonesa pendant la lactation et après le tarissement

“…Les dépôts adipeux sous-cutanés des brebis contribuent de façon importante à cette mobilisation des lipides corporels au cours du cycle productif (Russel et al, 1968). Les variations du gras sous-cutané peuvent être estimées in vivo à partir de la note d'état corporel (Russel et al, 1969), ou par les modifications de la taille des adipocytes sous-cutanés (Thornton et aL, 1983 (Vernon et al, 1981(Vernon et al, , 1987Vernon & Taylor, 1986 …”