Study on the 305-day milk yield of Jersey cows under small scale family conditions raised in Albania. II. adjustment factors for 305-day milk yield

Yetersiz girdili üretim sistemleri koşullarında, küçük ölçekli aile işletmelerinde yetiştirilen 1476 Jersey ineğinden elde edilen 935 birinci ,607 ikinci,432 üçüncü laktasyon sırasındaki verim kayıtlarında buzağılama yaşı ve mevsiminin 305 günlük süt verimi ve düzeltme etki faktörleri değişkenliğindeki rolü incelenmiştir. Düzeltme faktörlerinin sapmasız tahminlerini elde etmek konusunda yanlızca “inekler arası “farklılığı değilde fakat ayni zamanda “ inekler içi” farlılığıda dikkate aldığından Maksimim olabilirlik meteodu kullanılmıştır. Karışık Doğrusal Regresyon metoduna göre yürütülen varyans analizi; modele dahil edilen tüm tüm faktörlerin 305 günlük süt verimi değişkenliği üzerine etkilerinin istatistik olarak önemli olduğunu göstermiştir(P

Anahtar Kelimeler:

Jersey, buzağılama, inek, süt verimi, Arnavutluk, süt sığırı, laktasyon, en büyük benzerlik, küçük işletmeler

Arnavutluk'ta küçük ölçekli Aile işletmesi koşullarındaki jersey ineklerinde 305 günlük süt verim özellikleri üzerine bir araştırma-II.305 günlük süt verimi için düzeltme faktörleri

Data of 935 first lactations, 607 second lactations and 432 third lactations obtained by 1476 Jersey cows that are managed in small scale family farms, under conditions of low input production system, were analyzed in order to study effects of factors: calving age and season on variance of 305-day milk yield and their effect adjustment. ML (Maximum Likelihood) Method was used to obtain unbiased prediction for adjustment factors, as it is able to take into account and estimate not only differences “between cows” but also “within cow”. Analysis of variance carried out according to mixed linear regression model indicates that all factors included in this model show statistically significant effects (P<0,001) on the variance of 305 day milk yield. Mixed linear model with “age of calving x month of calving” increased significance (P<0.05) of this model in explanation of total phenotypic variance of milk yield for first three lactations only by 0,72 %. This situation doesn‟t justify the use of joint multiplicative factors for calving age and month.

Keywords:

Jersey, calving, cows, milk yield, Albania, dairy cattle, lactation, maximum likelihood, small farms,

PDF

___

Aleandri,R. Nardone, A. Pilla, M.A (1983).Un metodo di calcolo dei coeficienti di correcione per l`eta e per il mese di parto della produzione lattea nelle bovine di razza Frizona Italiana, Bruna e Pazzata Rossa Friulana. Prod. Anim. 2. No.23
Cassell G. B. (2004). Adjusting Holstein records for age and month of calving Genetics and management, Virginia Tech. USA J. of Dairy Sci.
Fimland,E.A Bar-Anam, R Harvey W.R. (1972). Studies on dairy records from Israili Friesian Cattle. I.Influence of some environmental effects. ActaAgric.Scandin.,22,3 4.
Hanset, R. (1978). Influence de certains facteurs non genetiques sur la production laitiere. Methodologies. Ann.Med.Vet., 122
Kume K, Llukani M, Tafaj R&Dervishi V (1989). Influence of non genetic factors on milk yield of dairy cattle. Bulletin of zoo technical and veterinary sciences.
Kume K, Llukani M Tafaj R ( 1990 ). Adjustment of 305-day milk yield for effects of calving age and month in first three lactations of Black and White cows” Bulletin of zoo technical and veterinary sciences, No.1, p. 25-32, y. 1990
Leroy,P. Hanset, R. (1980) L`influence de certains facteurs non genetiques sur la Francois,A. production laitiere. VII. Correction pour l`age au velage, independement du numero de lactation en race Pie-Noire de Hevre. Ann.Med. Vet. 124, 379-388
Miller P. D. (1970 )Joint influence of month and age of calving on milk of Holstein cows in the Northeastern U.S. J. of Dairy Sci.vol. 53, p 359: y.1970
Moster B. E, Theron H.E.& Kanfer F.H. J (2001). The effect of calving season and age at calving on production traits of South African dairy cattle. ARC- Animal Improvement Institute Department of Statistics, University of Pretoria The African J. of Anim.Sci.
Wood P. D. P (1972). The relationship between the month of calving and milk production. Anim. Prod. 12; p. 253-259.
Wunder,W.W. McGilliard,L.D. (1967).Season of calving and their interactions with age for lactation milk yield“ J.Dairy Sci. 50: 386