RESUMEN
Growth and voluntary feed intake (VFI) in grazing temperate farmed deer species are influenced by the feeding value of the forage and the stage of the deer's seasonal cycle. Liveweight gain (LWG) of growing red deer was greater when perennial ryegrass (0.80)/white clover (0.20) pasture was grazed at 10 cm than 5 cm surface height, but venison production by one year of age was still low. Chicory and red clover were of superior feeding value for deer than perennial ryegrass-based pastures, increasing LWG of young red and hybrid (0.25 elk; 0.75 red deer) deer during summer and autumn, due to higher VFI and to higher organic matter digestibility. Relative to perennial ryegrass, chicory disintegrated faster in the rumen, with very low rumination time and faster rumen outflow rates of liquid and particulate matter. Inputs of red clover and chicory substantially increased venison carcass weights at one year of age from grazing red and hybrid stags. In indoor pen feeding studies, red deer were shown to have a seasonal cycle of digestive function, with greater rumen mean retention time (MRT) and greater rates of rumen ammonia production in summer than in winter. It was deduced that the purpose of the digestive cycle was to maintain apparent digestibility constant as VFI increased during summer. Tropical sambar deer were also shown to have seasonal cycles in growth and VFI that were of reduced amplitude compared with red deer. Peak VFI and growth occurred in autumn and minimum VFI and growth occurred in spring. Feed conversion (kg DM eaten/kg LWG) was more efficient for sambar than for red deer, due to lower VFI and lower heat production, but there was no difference between species in digestive efficiency.
Asunto(s)
Crianza de Animales Domésticos , Fenómenos Fisiológicos Nutricionales de los Animales , Ciervos/crecimiento & desarrollo , Digestión/fisiología , Conducta Alimentaria , Animales , Animales Domésticos/crecimiento & desarrollo , Animales Domésticos/fisiología , Peso Corporal , Ciervos/fisiología , Masculino , Carne , Rumen/metabolismo , Rumen/fisiología , Estaciones del Año , Clima TropicalRESUMEN
The artificial insemination of 400 red deer hinds with sambar deer semen resulted in 31 pregnancies at day 40 (24 at day 100) and the birth of four calves. Only one female calf was born alive. The artificial insemination of 10 sambar deer hinds with red deer semen resulted in five pregnancies at day 40, of which none went to term. Gel electrophoresis of three blood proteins confirmed the live calf as the first documented sambar deer x red deer hydrid. G-banded karyotypes were consistent with the calf (2n = 62; six unpaired and one paired metacentric autosomes) being the offspring of a red deer dam (2n = 68; single pair of metacentric autosomes) and a sambar deer sire (2n = 56; seven pairs of metacentric autosomes).
Asunto(s)
Cruzamientos Genéticos , Ciervos/genética , Hibridación Genética , Animales , Proteínas Sanguíneas/genética , Aberraciones Cromosómicas , Bandeo Cromosómico , Femenino , Muerte Fetal , Inseminación Artificial/métodos , Inseminación Artificial/veterinaria , Cariotipificación , Masculino , Embarazo , Pruebas de Embarazo/veterinaria , SemenRESUMEN
Seasonal onset of pubertal ovulation and incidence of luteal cyclicity was assessed from plasma progesterone profiles over 15 months for tame red deer (n = 7) and sambar deer (n = 7) hinds. Seasonal responses to photoperiod were determined from plasma prolactin profiles. All red deer attained puberty at 17-18 months of age in May-June and expressed 3-6 luteal cycles of length 20.0+/-10.4 days (mean+/-s.e.m.) over 52-102 days. Six sambar deer attained puberty at 7-19 months of age, between August and December. Duration of luteal cyclicity was variable. While one animal remained continuously cyclic for 13 months, most entered anoestrus between November and February. The mean length of the luteal cycle was 17.2+/-0.3 days. While red deer exhibited strongly seasonal patterns of prolactin secretion, sambar deer showed no such seasonal trends. The data collectively indicate that young sambar hinds at temperate latitudes exhibit loosely defined patterns of reproductive seasonality that are 4-6 months out of phase with those of red deer, although some individuals may be non-seasonal. Failure to express seasonal patterns of prolactin secretion indicates that sambar deer may not perceive photoperiodic cues to the same extent as do red deer.