N D Sargison1, D M West, R G Clark. 1. Department of Veterinary Clinical Sciences, Massey University, Palmerston North, New Zealand.
Abstract
AIMS: To substantiate a previous report of improved fertility and perinatal lamb mortality rate following iodine supplementation in a Manawatu Romney ewe flock. To contribute data which might be used to predict a response to iodine supplementation. METHODS: A controlled iodine supplementation trial was performed over 2 successive years. The possible confounding factor of different lambing paddocks on perinatal lamb mortality was removed by the reversal of the paddocks used by the supplemented and control ewes during the second year. RESULTS: During 2 successive years, iodine supplementation resulted in improved reproductive performance in a Manawatu Romney flock with 21% and 14% more lambs born to supplemented than to control mixed-age ewes in 1996 and 1997 respectively. Supplementation also resulted in improved perinatal lamb survival, although this effect was greater during the wetter 1996 Lambing season. Despite the production response during both years, a difference in lamb thyroid:bodyweight ratio was only noted following the drier 1997 winter. Ewe thyroid hormone concentrations before mating and during mid-pregnancy were poor indices of deficiency. CONCLUSIONS: Iodine deficiency should be included in the list of differential diagnoses for poor reproductive performance in ewes and in the investigation of high perinatal lamb mortality rates. CLINICAL SIGNIFICANCE: The annual cost associated with iodine deficiency in this Manawatu Romney flock is conservatively estimated at dollar 6.00 per ewe. This economic loss is considerably greater than the annual cost of iodine supplementation using iodised oil.
AIMS: To substantiate a previous report of improved fertility and perinatal lamb mortality rate following iodine supplementation in a Manawatu Romney ewe flock. To contribute data which might be used to predict a response to iodine supplementation. METHODS: A controlled iodine supplementation trial was performed over 2 successive years. The possible confounding factor of different lambing paddocks on perinatal lamb mortality was removed by the reversal of the paddocks used by the supplemented and control ewes during the second year. RESULTS: During 2 successive years, iodine supplementation resulted in improved reproductive performance in a Manawatu Romney flock with 21% and 14% more lambs born to supplemented than to control mixed-age ewes in 1996 and 1997 respectively. Supplementation also resulted in improved perinatal lamb survival, although this effect was greater during the wetter 1996 Lambing season. Despite the production response during both years, a difference in lamb thyroid:bodyweight ratio was only noted following the drier 1997 winter. Ewe thyroid hormone concentrations before mating and during mid-pregnancy were poor indices of deficiency. CONCLUSIONS:Iodine deficiency should be included in the list of differential diagnoses for poor reproductive performance in ewes and in the investigation of high perinatal lamb mortality rates. CLINICAL SIGNIFICANCE: The annual cost associated with iodine deficiency in this Manawatu Romney flock is conservatively estimated at dollar 6.00 per ewe. This economic loss is considerably greater than the annual cost of iodine supplementation using iodised oil.
Authors: Mushap Kuru; Buket Boga Kuru; Osman Sogukpinar; Cigdem Cebi Sen; Hasan Oral; Turgut Kirmizibayrak Journal: J Vet Res Date: 2020-11-06 Impact factor: 1.744