Obyda Al-Masr(1) Majed AL-Dakkak(1) Mansour Ahmad*(1) Mohammed Amin(1) and Kahtan dayyop(2)
(1). Animal Wealth Research Administration, General Commission for Scientific Agricultural Research (GCSAR). Damascus, Syria.
(2). Fedio Diary Station, General Organization for Cattle, Lattakia, Syria.
(*Corresponding author: Dr. Mansour Ahmad, Animal Wealth Research Administration, (GCSAR). Damascus, Syria. E-mail: email@example.com).
Received: 14/04/2015 Accepted: 16/05/2015
This study was conducted at Fedio Dairy Station, General Organization for Cattle, Lattakia, Syria. Calving records of Holstein cows from 1989 to 2013 comprising 396 herds with 1646 calving events were used to evaluate the effect of the dry period length on the next daily milk production of Holstein cows. Dry period length (DP) of cows was grouped into 13 groups (group 1: 0-10, group 2: 11-20, group 3: 21-30, group 4: 31-40, group 5: 41-50, group 6: 51-60, group 7: 61-70, group 8: 71-80, group 9: 81-90, group 10: 91-100, group 11: 101-110, group 12: 111-120, and group 13: > 120 days). Average of DP was 85.13±1.64 days and 16.13±0.17 kg was the daily milk production in Holstein cows. The results clarified that the effect of dry period length (DP) was significant (P<0.05) on daily milk production. Also the cows within the DP groups of 41-60 had the greatest daily milk production in the next productive parity, while reduction or prolonging the dry period length led to cut down in the daily milk production. The conclusion was that the optimum length of the dry period length was (41-60 days), and the necessity of non-negligence or prolonging this period greatly (more than 100 days) because it increases the risks of culling in the cattle and shortens the length of milk production parity later, which decreases the economic earnings.
Keywords: Subsequent daily milk production, Dry period length, Holstein cows, Syria.