Effect of calf suckling on oxytocin, prolactin, growth hormone and milk yield in crossbred Gir x Holstein cows during milking.
This study evaluated the effect of different milking managements on oxytocin, prolactin and growth hormone release in Gir x Holstein cows. Six cows were suckled by their calves, before and after milking (SM group); another six cows were submitted to exclusive milking (M group). High OT levels were observed during suckling of the SM group, however both groups had similar levels of OT during milking. The SM group presented PRL levels significantly higher than the M group, however only during suckling. For GH levels, the SM group showed higher levels than the M group, however this difference was significant only during the first suckling, cleaning of the teats and at the beginning of machine milking. Despite these results, SM cows produced more milk (milking plus suckling) than M cows, however milk obtained by milking was similar for both groups.
Negrão
João Alberto
JA
USP/FZEA, FAPESP, Cx. Postal 23, 13630-970, Pirassununga/SP, Brazil. jnegrao@usp.br
Marnet
Pierr-Guy
PG
D000818:Animals; D000833:Animals, Suckling / Q000502:physiology; D002417:Cattle / Q000097:blood / Q000502:physiology*; D003612:Dairying / Q000379:methods; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000378:metabolism*; D010121:Oxytocin / Q000097:blood*; D011388:Prolactin / Q000097:blood*; D013997:Time Factors
D010121:Oxytocin; D011388:Prolactin; D013006:Growth Hormone