Published online by Cambridge University Press: 02 September 2010
Since the productivity of farmed red deer is constrained by their inherent seasonal biology, the potential advantages of breeding out-of-season following melatonin administration were investigated. Calves born in February (F; no. = 8) were heavier at weaning in September of the same year than calves born with normal birth dates in June (}; no. = 8) (73·2 v. 441 (s.e.d. 3·59) kg; P < 0·001) and at the end of April of the next year (88·0 v. 67·6 (s.e.d. 6·44) kg; P < 0·02) although their suckled live-weight gain to 100 days of age was lower (304 v. 361 (s.e.d. 21·4) g/day; P < 0·05). After weaning, F calves had higher voluntary food intake than / calves (g dry matter per head per day) from September to November (1643 v. 2224 (s.e.d. 92·6); P < 0·002), November to February (1435 v. 926 (s.e.d. 67·9); P < 0·002), and February to April (1487 v. 2059 (s.e.d. 115·5); P < 0·02).
Unlike J calves, F calves showed puberty in their first autumn. F male calves (no. = 3) grew antlers which hardened in November, whereas J males (no. = 3) did not, and F males, aged 8 months, had significantly higher mean plasma concentrations of testosterone than J males, aged 4 months (1·35 v. 0·28 (s.e.d. 0·154) fj.g/1, P < 0·001). Oestrous cyclicity was observed in 3/5 group F females, aged 9 months, but in 0/5 group ] females, aged 5 months. Although the dams of F and ] calves had similar live weights at mating, birth and 100 days pos t partum, F dams were heavier (P < 0·05) at weaning. Following parturition, F dams had a mean voluntary food intake of 2700 (s.e. 110) g dry matter per head per day from February to April.
To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.
To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.