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Does shearing lambs improve performance?

Factsheet name: Does shearing lambs improve performance?

Need / Issue: Lamb management

Introduction:

In Ireland approximately 20% of the annual sheep kill occurs between January and March. Some of these sheep (March born) are housed for a finishing period and offered either concentrate or concentrate and forage based diets. Previous studies have shown that shearing ewes that are housed during late pregnancy increases the body weight of their lambs at birth. The increased body weight of the lambs at birth from ewes shorn at housing was due to increased silage dry matter intake which was partly a reflection of cold stress immediately post shearing, and more importantly, a reflection of reduced heat stress in late pregnancy and an extended gestation period.

 

To shear or not to shear? This is a question often asked by producers who house lambs during the finishing period. There is an opinion that shearing prior to finishing increases food intake and lamb performance. A study was completed at Athenry to evaluate the effects of shearing on the performance of lambs housed during the finishing period

    Athenry study

    In October, March born lambs, which had been purchased from 33 farms were housed in slatted floor pens. The lambs were offered one of 11 different diets. Half of the lambs on each diet (2 pens) were shorn 2 days post housing and the remainder remained unshorn (2 pens). All lambs were slaughtered 54 days after initiation of the study.   

     

    The effects of shearing on the performance of store lambs during finishing is presented in Table 1. Lambs that were shorn had a higher daily food intake than lambs which had not been shorn but there was no difference in carcass weight. Therefore, shearing lambs prior to finishing reduced the efficiency of conversion of metabolizable energy to carcass gain by approximately 10%.

     

    Table 1. Effect of shearing on the performance of store lambs during finishing.

     

    Treatment

     

    Unshorn

    Shorn

    Food intake (kg DM/day)

    1.29

    1.39

    Carcass weight (kg)

    22.4

    22.4

    Carcass gain (g/day)

    90

    89

    Efficiency (g carcass/ MJ ME intake)

    5.3

    4.9

    (Keady and Hanrahan 2015)

     

    Conclusion

    Shearing lambs increases food intake, has no effect on carcass gain, and reduces the efficiency of conversion of energy intake to carcass weight.

      Topic: management

      Production: Meat

      Animal Category: Lamb

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