The aim of this experiment was to determine the age at puberty of both ram and ewe lambs of three genotypes: Awassi (A), Charollais x Awassi (CA), and Romanov x Awassi (RA) F 1 crosses. Twenty, six-month old lambs (10 from each sex) from each genotype were used. Ram and ewe lambs were kept in separate groups from the beginning until the end of the experiment. Birth weight and weaning weight were recorded for all animals. Body weights and body condition scores were recorded at monthly intervals between 6.5 and 12 months of age. Blood samples were collected weekly from ewe lambs and fortnightly from ram lambs to monitor progesterone and testosterone profiles, respectively. Semen characteristics and scrotal circumferences (SC) were evaluated fortnightly. Weight at puberty in ewe and ram lambs were not significantly different among the three genotypes and ranged around 35 kg and 42 kg, respectively. In ewe lambs, age at puberty was significantly higher (P< 0.01) in A (280±11.5 d) than in RA (232±11 d) and CA (255±11.5 d). Age at puberty of ram lambs was also significantly different (P < 0.01) among the three genotypes being higher in A (243±5 d) than in CA (223±5 d) and RA (226±5 d) ram lambs. Semen parameters improved with age in all genotypes. The RA ram lambs had greater semen concentration and lower abnormal spermatozoa than the other two genotypes (P< 0.05). Results of the present study indicate that crossing Awassi ewes with either Charollais or Romanov sires tends to improve reproductive characteristics of the F 1 crossbreds through advancing age at puberty in both ram and ewe lambs. (255 ± 11,5 d). Anche nei maschi l'età alla pubertà è risultata significativamente diversa (P < 0,01) tra i
Abstract— An experiment was conducted using three complete rations containing either 31.2, 45.0, or 58.6 °l° chopped wheat straw. Sixty Awassi ewes were divided into three experimental groups arranged in a randomized block design. Individual feed intake, milk yield from lambing to weaning of the lambs, and body weight of ewes and lambs were measured. The reduction in barley grain proportions with elevated levels of straw resulted in a reduction of the calculated metabolizable energy (ME) from 10.5 to 9.6 to 8.5 MJ.kg!1 in rations 1, 2, and 3, respectively. The crude protein (CP) contents were 14.2, 14.4 and 15.1 % DM for these rations, respectively. The voluntary feed intake decreased significantly and was lowest (P < 0.05) for group 3 until the seventh week, but leveled off thereafter until the end of the experiment at 13 weeks of lactation. Average body weights were 61.2, 60.1, and 51.6 kg at the end of eight weeks of the experiment for treatments I, 2, and 3, respectively. The body weights in the third group were significantly lower (P < 0.05) than those of the other groups during the first 8 weeks post-partum. The decreased body weight of the third group was then maintained throughout the experimental period. Thus, the average body weights were 66.2, 66.9, and 56.4 kg for rations I , 2, and 3, respectively, at the end of the experimental period. Total milk yields were not significantly different among the three groups, being 34.5, 37.9, and 39.0
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