부산대학교 도서관

The seasonality of lamb production affects lamb markets and prices. Whereas, an out-of-season breeding and organic fall lamb production scheme may enhance product availability and competitiveness. Six rams and 100 Katahdin ewes were selected for an out-of-season breeding during April and May. Ewes were synchronized for estrus using CIDR® device (EaziBreed™) before breeding and fed ‘flushing’ feed for four weeks. Ewes were bred in mixed sire groups for two estrus cycles (35d). Animals were rotationally grazed and maintained good body condition score (3.0) throughout the seasons at certified organic farm in Missouri. Mean live weight measured monthly from breeding to lambing were 57.8, 60.1, 62.1, 64.7 and 59.3 kg, and July’s weight was (<0.05) heavier reflecting the pregnancy. Ninety three ewes were diagnosed as for pregnancy, and 89 ewes lambed in fall giving birth to 121 lambs (136% lambing rate). Lambs were weaned at 120 d old and grass fed and supplemented with 260 g organic corn/hd/d (113g/d/1st week, 227g/d/2ndweek, 340g/d/3rdweek) for 30 days before marketing. Ninety seven percent of weaned lambs were maintained as an organic production status for marketing. Lamb birth weight, average daily gain weight, weaning weight, and 30 d post weaning weight, post weaning average daily gain weight were 3.74 ± 0.03 kg, 21.00 ± 0.24 kg, 24.78 ± 0.28 kg, 176 ± 2 g/d respectively. These measures were recorded significantly (P < 0.05) higher for males than for females, which was further exemplified as post weaning average daily gains for ram lambs at 208 g/d vs. 145 g/d for ewe lambs. Eighty two lambs were sold at a livestock auction, which showed that the organic lamb lots were more competitive for price premium over non-organic peer groups, and received 5 to 15% higher values. An out-of-season breeding and organic fall lamb production regimen may enhance lamb product competitiveness and market demands.