S. U. REHMAN, M. AHMAD AND M. SHAFIQ¹

Livestock Production Research Institute, Bahadurnagar, Okara;¹Research Centre for Conservation of Sahiwal Cattle, Jhang, Pakistan

Abstract 

    The data on 3434 records for lactation milk yield and lactation length and 2314 records for dry period of Sahiwal cows maintained at the Livestock Experiment Station (LES), Bahadurnagar, Okara, Pakistan and its Patadars during 1986-2000 were analyzed by least square analysis of variance techniques, using the LSMLMW computer programme. The population means for lactation milk yield, lactation length and dry period were 1547 ± 36.69 kg, 268 ± 4.53 days and 214 ± 16.64 days, respectively. The milk yield averaged 1617 ± 35.09 kg at LES and 1477 ± 43.54 kg at Patadar’s herds of Bahadurnagar. The effects of herd and year of calving on milk yield were highly significant (p<0.01), while season of calving had only significant (P<0.05) effect on the said trait. Lactation number had no effect on lactation milk yield. The least squares means of lactation length were 265 ± 4.33 and 271 ± 5.37 days, at herds of LES and Patadars, respectively. The variation in lactation length due to herd and lactation number was non-significant but year and season of calving had significant (P<0.01 and P<0.05, respectively) effect on the said trait. The least squares means for dry period were 155 ± 16.41 days at LES and 273 ± 17.84 days for the cows kept by Patadars of Bahadurnagar. The dry period differed significantly (P<0.01) by herd, year of calving and lactation number, while season of calving had no effect on this trait. The lactation milk yield was significantly less in Sahiwal herd kept by Patadars as compared to the herd maintained at LES, Bahadurnagar, Okara.

Key words: Sahiwal cows, lactation milk yield, lactation length, dry period.