Study Of The Effects Of Different Types Of The Cowshed On Development Of Chinese Holstein Replacement Heifers In Cold Area

This study was to explore the effects of different types of cowshed on the development of replacement heifers and to provide a scientific basis for pro-duction management through measuring and analysing the chest girth, body height, body length of replacement heifers rearing under different types of cowshed in Hohhot area. Raising management, diet composition, epidemic prevention and standard of first breeding of test heifers were consistent, ex-cept the type of cowshed.Test 1:Totally 152 healthy replacement heifers from 4 to 5 months old under two different types of cowshed, including 61 heifers raised in simple outdoor shelter (group L) and 91 heifers raised in fully enclosed barn (group F), were selected and tracked measurement of body height, body length and chest girth to the age at first breeding (about 14 months old). The results showed that the body height, chest girth and body length of group L and F at the beginning were 98.78 and 99.32 cm,120.55 and 117.47 cm,117.47 and 102.00cm, respectively, no significant difference (p>0.05). At the end of test, the corresponding index were 126.26 and 128.53 cm (p< 0.01),173.24 and 175.50 cm (0.1> p> 0.05),142.63 and 144.34 cm (p< 0.01), respectively. The cumulative growth during the whole test of corresponding index of group F were 1.72cm (p<0.05),5.34cm (p< 0.01) and 2.10 cm (0.1>p> 0.05) higher than group L, respectively. In summary, different types of cowshed have sig-nificant negative effects on replacement heifers before the age at first breed-ing.Test 2:the date set consisted of chest girth, body height, body length of 3163 healthy replacement heifers before 18 months old, including 1098 heif-ers raised in simple outdoor shelter (group L) and 2065 heifers raised in fully enclosed barn (group F).The results showed that the chest girth, body height, body length of group L at birth were 78.94 and 80.09cm,77.08 and 77.35cm, 71.55 and 70.68cm, respectively, no significant difference (p>0.05). The cor- responding index at 3 months old were 109.49 and 106.98cm (p<0.01),93.01 and 93.97cm (0.1>p>0.05),91.88 and 94.63cm (p<0.01), respectively. At 6 months old, the chest girth of group F was 2.03cm higher than group L (p<0.05), the body height was 3.68cm higher than group L (p<0.01), the body length of group F was 0.55cm higher than group L (p>0.05). The body size of group F were 2.45cm,0.33cm and 0.29cm higher than group L, respectively, no significant difference (p>0.05). In summary, the development of replace-ment heifers before 3 months old under simple outdoor shelter was better than heifers under fully enclosed barn. From the birth to 18 months old, no signif-icant difference between the two types of cowshed.Conclusion:(1)The developments of chest girth, body height, body length of re-placement heifers raised in simple outdoor shelter and fully enclosed barn are in the normal growth rule.(2)The development of replacement heifers raised under the fully en-closed barn is better than replacement heifers raised under simple outdoor shelter.(3)The value of corrected body sizes is better to represent the develop-ment of replacement heifers than the value of average body sizes in different months does.(4)The value of chest girth, body height, body length in different stand-ard day age from this test can be used to evaluate the development of re-placement heifers.