The effect of progesterone supplementation post mating and shearing of ewes in early pregnancy on the reproductive performance of ewes and birthweight of lambs

References

• Ashworth , CJ . 1995 . Maternal and conceptus factors affecting histotrophic nutrition and survival of embryos . Livestock Production Science , 44 : 99 – 105 .
   Google Scholar
• Clarke , JN , Roberts , EM , Carter , AH and Kirton , AH . 1966 . Hormonal synchronization of oestrus in Romney ewes during the breeding season . Proceedings of the New Zealand Society of Animal Production , 26 : 107 – 21 .
   Google Scholar
• Doney , JM , Smith , WF and Gunn , GR . 1976 . Effects of post-mating environmental stress or administration of ACTH on early embryonic loss in sheep . Journal of Agricultural Science, Cambridge , 87 : 133 – 6 .
   Web of Science ®Google Scholar
• Kelly , RW . 1982 . Reproductive performance of commercial sheep flocks in South Island districts. 1. Flock performance and sources of wastage between joining and tailing . New Zealand Journal of Agricultural Research , 25 : 175 – 83 .
   Web of Science ®Google Scholar
• Kenyon , PR , Morris , ST and McCutcheon , SN . 2002 . Does an increase in lamb birthweight through mid-pregnancy shearing necessarily mean an increase in lamb survival rates to weaning? . Proceedings of the New Zealand Society of Animal Production , 62 : 53 – 6 .
   Google Scholar
• Kenyon , PR , Morris , ST , Revell , DK and McCutcheon , SN . 2003 . Shearing during pregnancy — review of a policy to increase birthweight and survival of lambs in New Zealand pastoral farming systems . New Zealand Veterinary Journal , 51 : 200 – 7 .
   PubMed Web of Science ®Google Scholar
• Kleemann , DO , Walker , SK , Grimson , RJ , Smith , DH , Grosser , TI and Seamark , RF . 1991 . Exogenous progesterone and embryo survival in Booroola-cross ewes . Reproduction, Fertility and Development , 3 : 71 – 7 .
   PubMedGoogle Scholar
• Kleemann , DO , Walker , SK and Seamark , RF . 1994 . Enhanced fetal growth in sheep administered progesterone during the first three days of pregnancy . Journal of Reproduction and Fertility , 102 : 441 – 7 .
   Google Scholar
• Kleemann , DO , Walker , SK , Hartwich , KM , Fong , L , Seamark , RF , Robinson , JS and Owens , JA . 2001 . Fetoplacental growth in sheep administered progesterone during the first three days of pregnancy . Placenta , 22 : 14 – 23 .
   PubMed Web of Science ®Google Scholar
• Knight , TW and Lynch , PR . 1983 . “ Effect of Shearing on Embryo Mortality ” . In Annual Report. , 115 – 115 . Wellington, , New Zealand : New Zealand Ministry of Agriculture and Fisheries Agricultural Research Division .
   Google Scholar
• Knight , TW , Moore , R and McMillan , W . 1982 . “ Reproduction ” . In The Whatawhata Way , Edited by: Shimmins , M . 41 – 52 . Wellington, , New Zealand : Agricultural Promotion Associates Ltd .
   Google Scholar
• Knight , TW , Hall , DRH and Lynch , PR . 1988 . Effects of pre-joining shearing, stress, pasture allowance and haemoglobin type on reproductive performance of Romney and Marshall Romney ewes . New Zealand Journal of Agricultural Research , 31 : 249 – 58 .
   Web of Science ®Google Scholar
• McLeod , BJ and Phillips , DJ . 1998 . “ Hormonal control of the reproductive processes ” . In Reproductive Management of Grazing Ruminants in New Zealand , Edited by: Fielden , ED and Smith , JF . 3 – 42 . Hamilton, , New Zealand : Occasional Publication No. 12. New Zealand Society of Animal Production .
   Google Scholar
• McMillan , WH . 1987 . Post-mating progesterone supplementation in ewes and hoggets . Proceedings of the New Zealand Society of Animal Production , 47 : 151 – 3 .
   Google Scholar
• McMillan , WH and Knight , TW . 1982 . Shearing and time of joining effects on reproduction in two-tooth ewes . Proceedings of the New Zealand Society of Animal Production , 42 : 45 – 6 .
   Web of Science ®Google Scholar
• Morris , ST and McCutcheon , SN . 1997 . Selective enhancement of growth in twin foetuses by shearing ewes in early gestation . Animal Science , 65 : 105 – 10 .
   Google Scholar
• Morris , ST , Kenyon , PR , Burnham , DL and McCutcheon , SN . 1999 . The influence of prelamb shearing on lamb birthweight and survival . Proceedings of the New Zealand Grassland Association , 61 : 95 – 8 .
   Google Scholar
• Morris , ST , McCutcheon , SN and Revell , DR . 2000 . Birth weight responses to shearing ewes in early to mid gestation . Animal Science , 70 : 363 – 9 .
   Google Scholar
• Parr , RA , Davis , IF , Fairclough , RJ and Miles , MA . 1987 . Overfeeding during early pregnancy reduces peripheral progesterone concentrations and pregnancy rate in sheep . Journal of Reproduction and Fertility , 80 : 317 – 20 .
   PubMedGoogle Scholar
• Rattray , PV , Garrett , WN , East , NE and Hinman , N . 1974 . Growth, development and composition of the ovine conceptus and mammary gland during pregnancy . Journal of Animal Science , 38 : 613 – 26 .
   PubMed Web of Science ®Google Scholar
• Revell , DK , Morris , ST , Cottam , YH , Hanna , JE , Thomas , DG , Brown , S and McCutcheon , SN . 2002 . Shearing ewes at mid-pregnancy is associated with changes in fetal growth . Australian Journal of Agricultural Research , 53 : 697 – 705 .
   Google Scholar
• Rutter , W , Laird , TR and Broadbent , PJ . 1971 . The effects of clipping pregnant ewes at housing and of feeding different basal roughages . Animal Production , 13 : 329 – 36 .
   Google Scholar
• Rutter , W , Laird , TR and Broadbent , PJ . 1972 . A note on the effects of clipping pregnant ewes at housing . Animal Production , 14 : 127 – 30 .
   Google Scholar
• Smeaton , DC , Webby , RW , Tarbotton , IS and Clayton , JB . 2000 . The effects of shearing Finnish Landrace x Romney ewes in mid-pregnancy on lamb survival, birth weight and other weights . Proceedings of the New Zealand Society of Animal Production , 60 : 58 – 60 .
   Google Scholar
• Smith , JF , Cruickshank , GF , McGowan , LT , Parr , J and Mortimer , BJ . 1988 . Seasonal changes in oestrus, ovulation and conception of Coopworth ewes treated with CIDRs and PMSG . Proceedings of the New Zealand Society of Animal Production , 48 : 99 – 102 .
   Google Scholar
• Smith , JF , Konlechner , JA and Parr , J . 1991 . The efficacy of used CIDR devices for synchronisation of oestrous and post-mating treatment . Proceedings of the New Zealand Society of Animal Production , 51 : 111 – 5 .
   Google Scholar
• Smith , ME , Bigham , ML , Knight , TW and Sumner , RMW . 1980 . A review of effects of shearing on sheep production . Proceedings of the New Zealand Society of Animal Production , 40 : 215 – 20 .
   Google Scholar
• Welch , RAS , Kilgour , R , Robson , GA , Smith , ME and Williams , ET . 1979 . The effect of shearing ewes during the mating period on subsequent lambing pattern . Proceedings of the New Zealand Society of Animal Production , 39 : 100 – 2 .
   Google Scholar