THE EFFECT OF SOME ENVIRONMENTAL FIXED IN FACTORS OF MILK PRODUCTION WITH HOLESTAIN CATTLE IN IRAQ | ||
| IRAQ JOURNAL OF AGRICULTURE | ||
| Article 1, Volume 19, Issue 1, March 2014, Pages 1-10 | ||
| Authors | ||
| W.J. Al-khazraje; H.N. Hermiz | ||
| Abstract | ||
| A total of 5464 milk yield records of 2704 Holstein cows at Al-Nasser station of the United Company for Animal Resources in Al-Soueira (50 km south of Baghdad) were used to derive factors to adjust total milk yield (TMY), daily milk yield (DMY) and lactation period (LP) for some fixed effects including parity, year and month of calving as well as, genetic parameters of the studied traits were estimated. The General Linear Model (GLM) within the SAS program was used to estimate the effects of fixed factors, and Restricted Maximum Likelihood method (REML) used to evaluate variance components of random effects. Overall means of TMY, DMY and LP were 3849.6 ± 24.55 Kg, 14.35 ± 0.06 Kg and 315.98 ± 0.99 day. respectively. The effect of parity, year and month of calving on all studied traits were significant (P<0.01). Age at first calving affect TMY significantly (P < 0.01), an,d regression of TMY on Age at first calving was -25.44 Kg/month, whereas, its effect on DMY and LP lacked significance. The regression of TMY on LP was 8.24 Kg/day (P< 0.01), The heritability of TMY, DMY and LP were 0.15, 0.20 and 0.27, respectively. All Genetic correlations sigificant (P<0.01) and positive between all traits, The links genetic significantly (p <0.01) and positive among all traits reaching 0.26 and 0.20 and 0.58 between the production of total milk and all of the production of milk daily and lactation length and the production of milk daily and lactation length, respectively, while the estimate of the correlation coefficient phenotypic between milk production and all of the total daily production of milk and lactation length is positive and significantly (p <0.01) and amounted to 0.54 and 0.39 respectively, while the value of daily milk production and lactation length was (0.03) and non-significant. | ||
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