| dc.contributor.author |
Bizelis, JA |
en |
| dc.contributor.author |
Deligeorgis, SG |
en |
| dc.contributor.author |
Rogdakis, E |
en |
| dc.date.accessioned |
2014-06-06T06:41:55Z |
|
| dc.date.available |
2014-06-06T06:41:55Z |
|
| dc.date.issued |
1990 |
en |
| dc.identifier.issn |
03784320 |
en |
| dc.identifier.uri |
http://dx.doi.org/10.1016/0378-4320(90)90003-X |
en |
| dc.identifier.uri |
http://62.217.125.90/xmlui/handle/123456789/338 |
|
| dc.title |
Puberty attainment and reproductive characteristics in ewe lambs of Chios and Karagouniki breeds raised on two planes of nutrition |
en |
| heal.type |
journalArticle |
en |
| heal.identifier.primary |
10.1016/0378-4320(90)90003-X |
en |
| heal.publicationDate |
1990 |
en |
| heal.abstract |
Twenty ewe lambs from each of the two Greek breeds Chios (C) and Karagouniki (K) were assigned at random to high (H) and low (L) planes of nutrition. The level of feeding was adjusted weekly according to live weight so that at the time of expected puberty the animals of the H and L groups would reach 70 and 50%, respectively, of the mature ewe body weight estimated for the flock. The occurrence of oestrus was detected by ram presentation, and the ovarian activity was monitored by progesterone concentrations in blood samples collected twice weekly. Progesterone and oestradiol profiles around the second pubertal ovulation were also determined by blood sampling in twenty animals. Ovulation rate was assessed by laparoscopy at four defined oestrous cycles. Ewe lambs in the H group grew faster (P<0.01) and were heavier (P<0.01) at the beginning of the first breeding season than those on the L plane of nutrition. The Chios started to ovulate 12 days earlier (P<0.05) and showed oestrus 9 days earlier than the Karagouniki ewe lambs. Chios showed breeding activity for 26 days (P<0.01) longer than the Karagouniki ewe lambs, and animals in the H group 25 days (P<0.01) longer than those in the L group. The duration of the breeding season and the number of oestrous cycles per ewe lamb were correlated with age at first (r= -0.71 and r= -0.66. P<0.001) and last ovulation (r=0.80 and r=0.82, P<0.001). Ewe lambs in the H feeding group showed a significantly higher ovulation rate than those in the L group. Ovulation rates during the second breeding season were affected by carry-over effects of the nutritional regime. The level of progesterone was higher while oestradiol was lower in Chios than in Karagouniki ewe lambs during the luteal phase of the first pubertal cycle. Ewes in the H group had a higher (P<0.05) oestradiol concentration during the oestrous cycle than ewes in the L group, while the preovulatory peak was of the same magnitude for both feeding groups. The results indicate that the two breeds are different in terms of reproductive characteristics and that differences in growth rate and body weight, imposed by feed intake manipulation in early life, have significant effects on most pubertal reproductive characteristics of the ewes and carry-over effects in their second breeding season. |
en |
| heal.journalName |
Animal Reproduction Science |
en |
| dc.identifier.issue |
3 |
en |
| dc.identifier.volume |
23 |
en |
| dc.identifier.doi |
10.1016/0378-4320(90)90003-X |
en |
| dc.identifier.spage |
197 |
en |
| dc.identifier.epage |
212 |
en |