Reproductive and lactation management for year-round ewe milk production with non-traditional dairy breeds

The ability of Finnsheep x Dorset meat ewes to achieve high milk yields in short and frequent 73-day lactation periods on the STAR accelerated lambing system in a year-round dairy system was tested together with ewe reproductive success. Ewes (n = 53) were managed in 3 groups and enrolled in a triply replicated (for management group) 3'3 Latin square design (3 pens, 3 lactations, 3 diets). Diets (L-SH, M-SH, H-SH) contained 31.6, 36.3, 40.0% aNDFom and 41.3, 37.2, 31.9% NFC. Milk was recorded at each 2X milking, ewes and lambs weighed weekly. Ewes were bred to lamb with 219-day lambing intervals. To facilitate breeding, progesterone CIDRs were employed for 7 days prior to breeding during increasing day-light period breeding months. Individual lactation curves were fitted to 127 evaluated lactations. Lactation parameters were analyzed with a model including Square Number, Pen and Lactation within Square Number, and Diet, with 3 to 6 ewes in each cell of each Latin Square. Ewes offered the M-SH diet produced more (P = 0.03) milk/d (1.40, 1.58, and 1.37 ± 0.07 kg) and higher (P = 0.02) lactation yields (95.8, 109.6, and 93.0 ± 5.29 kg), compared with ewes offered the L-HS or H-SH diets, respectively. Investigating the effect of breeding season (January, March, June, August, and October) on reproductive success, conception rates ranged between 83.3 and 94.1% and were not affected by breeding season. Litter sizes were lower for matings in March and June (P < 0.05) compared to June, August, and October. Average daily gains of lambs raised artificially ranged between 283 and 328 g ± 11.2 g per day and were significantly higher for January-born lambs than for March born lambs (P < 0.001). Both milk production and reproductive success were high for ewes milked year-round in short and frequent lactations.