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1252
Shearing during milking increases milk yield in dairy ewes
The effect of shearing during lactation was investigated in 48 dairy ewes of 2 breeds (Manchega, MN; Lacaune, LC); 32 were multiparous (MN, n = 16, 69.5 ± 1.7 kg BW; LC, n = 16, 69.1 ± 1.9 kg BW) and 16 were primiparous (MN, n = 8, 59.4 ± 2.0 kg BW; LC, n = 8, 57.4 ± 2.4 kg BW). Ewes were permanently sheltered indoors and allocated in 4 groups by breed to which treatments were randomly applied in duplicate. Treatments were: US (unshorn) and SH (shorn) during mid lactation at mild winter conditions. Diets consisted of alfalfa hay ad-libitum and concentrate rationed individually at milking according to breed and requirements (MN, 0.45 kg/d; LC, 0.65 kg/d). Ewes were in straw-wood chips bedded pens and the ambient temperatures were mild before (12.6 ± 0.9ºC) and after (13.0 ± 0.3ºC) shearing. Fleece weight was greater in shorn MN than LC (1.04 ± 0.10 vs. 0.75 ± 0.09 kg/ewe). As a result of shearing, rectal temperature decreased in the MN-SH ewes, when compared to the MN-US (38.51± 0.11 vs. 38.88 ± 0.12ºC, respectively), but did no vary in the LC ewes (38.57 ± 0.08ºC). No differences were detected in the fill value of the alfalfa hay, expressed as French sheep fill units (SFU), between sheep breeds (0.97 ± 0.03 SFU/kg DM). Lactational responses to shearing during milking varied according to breed, the results in LC being more marked than in MN ewes. Feed intake increased 5% in the LC-SH, when compared to LC-US, but did not vary in the MN ewes. Moreover, the LC-SH ewes yielded 10% more milk than LC-US ewes, but no differences were detected in the MN ewes. There were no differences in milk composition between US and SH ewes in both breeds. The milk protein and lactose yields were higher for LC-SH than LC-US ewes (20% and 17%, respectively) agreeing with the milk yield increase. No effects of shearing were detected on metabolic (glucose, NEFA) and hormonal (cortisol, insulin) plasma values, as well as on BW and BCS changes. In conclusion, shearing lactating ewes during winter, under moderate cold conditions, is a suitable management option for improving feed intake and milk production of high-yielding dairy ewes, without deleterious effects neither on physiological indicators nor milk composition regardless their production level.
Keywords:
Dairy sheep, shearing, lactation, milk yield, milk composition