کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2458417 1110755 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The effect of ram replacement and sex ratio on the sexual response of anoestrous ewes
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم دامی و جانورشناسی
پیش نمایش صفحه اول مقاله
The effect of ram replacement and sex ratio on the sexual response of anoestrous ewes
چکیده انگلیسی

It is accepted that an important source of variation in the response of anoestrous ewes, to the introduction of rams, is the intensity of male stimulation. The aim of this study was to investigate strategies capable of increasing the impact and transmission of the ram stimuli. In Experiment 1, two groups of seven ewes (Bluefaced Leicester♂ × Swaledale♀) were individually penned with one ram and for the next 6 h the rams either remained in the pen or were replaced hourly. Blood samples revealed no difference in the pattern of plasma LH secretion. In Experiment 2, three groups of 16 ewes were either introduced to one ram, individually (H) or in groups of 8 (L), or remained isolated. Ram introduction increased the plasma LH pulsatility (P < 0.001). H ewes displayed more (nine versus six) male-induced LH pulses (pulses occurring within the first 45 min) and more pulses per 8 h intervals than the L group of ewes (1.9 ± 0.3 versus 1.3 ± 0.3), but these differences were not significant. It was concluded that (i) frequent replacement of rams within a few hours following ram introduction to ewes does not further improve the response of ewes, especially if the ram:ewe ratio is high; (ii) the characterization of the plasma LH secretion parameters during a period of 6–8 h does not seem to be an effective method to detect small differences in the intensity of stimulation received by the ewes when exposed to rams; (iii) North Country Mule ewes (Bluefaced Leicester♂ × Swaledale♀) in the UK respond to the presence of rams in spring (late oestrous/early anoestrous season) with an elevation in plasma LH secretion.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Small Ruminant Research - Volume 65, Issue 3, October 2006, Pages 223–229
نویسندگان
, , ,