EFFECT OF SOME NON-GENETIC FACTORS ON SOME PRODUCTIVE AND REPRODUCTIVE TRAITS OF HOLSTEIN COWS BRED IN IRAQ

Jabbar Jadoh Al-Kanaan, Adnan

doi:10.33762/bagrs.2010.56631

	EFFECT OF SOME NON-GENETIC FACTORS ON SOME PRODUCTIVE AND REPRODUCTIVE TRAITS OF HOLSTEIN COWS BRED IN IRAQ
Basrah Journal of Agricultural Sciences
Article 5, Volume 23, Issue 1, 2010, Pages 49-63 PDF (0 K)
DOI: 10.33762/bagrs.2010.56631
Author
Adnan Jabbar Jadoh Al-Kanaan
Abstract
A total of 4753 records were analyzed in this study. Data belonged to Holstein cows bred at Al-Naser Dairy Cow Station (60 km south of Baghdad), The aim was to study the effect of birth year, birth season, calving year, calving season, parity, lactation period and age at first calving in total milk yield (305 days) (TMY 305 days), lactation period (LP), dry period (DP), calving interval (CI) and age at first calving (age1st). The result indicated that birth year affected all studied traits, there was an increase in (TMY 305days) and decrease in the other traits in preceding to birth year. Calving season had a significant effect on (age1st),as autumn calving caused earlier age while spring calving gave late ages, All traits increased with preceding of calving year except (LP).Cow calving in Autumn producing more (TMY 305days), (LP), less (CI) and older at (age1st) in comparison with others. Parity had significant effect on a gradual decrease in (LP) till 10th parity, a highest (TMY 305days) was given by fourth and third parity, and the lowest yield was in the 10th parity. An increase in (LP) caused increase in (TMY 305days) and (CI) and decrease in (DP).

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