Estimation of Adjustment Factors for Standardizing Lactations to Mature Age and 305 Day of Milk Yield of Holstein Cattle Reared at Polatli State Farm in Turkey
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Tarih
2008
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Medwell Online
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
In this study, adjustment factors of lactation milk yield to mature age and 305 day of milk yield were estimated for Holstein cattle reared in Polatli State Farm. A total of 3184 lactation records of Holstein cattle reared in Polatli State Farm between 1993 and 2006 were used. The factors for standardizing incomplete lactations to 305 day were estimated by taking into consideration nine calving age groups (2, 3, 4, 5, 6, 7, 8, 9, 10 and older years of age). The factors for standardizing to mature equivalent estimated by polynomial regression method are between the 20th month and 145th and older. For lactations less than 305 days, average of adjustment factors for 30, 60, 90, 120, 150, 180, 210, 240, 270, 300 and 305th days, were 8.70, 4.32, 2.82, 2.14, 1.69, 1.48, 1.31, 1.18, 1.09, 1.01 and 1.00, respectively. For lactations more than 305 days, the average of adjustment factors for 310,340, 370,400,430,460,490, 520, 550, 580 and 600th days were 0.99,0.93,0.88,0.84, 0.90, 0.77,0.74,0.72, 0.69, 0.67 and 0.65, respectively. Adjustment factors were estimated as 1.14 and 1.51 for the youngest cows (calving in 24th month) and for oldest cows (calving in 145th month), respectively.
Açıklama
Anahtar Kelimeler
Cattle, holstein, milk yield, adjustment factors, 305 day, mature age
Kaynak
Journal Of Animal And Veterinary Advances
WoS Q Değeri
N/A
Scopus Q Değeri
N/A
Cilt
7
Sayı
9
Künye
closedAccess
