Please use this identifier to cite or link to this item:
Full metadata record
DC FieldValueLanguage
dc.contributor.authorHassan, Faiz-ul--
dc.description.abstractThe performance of crossbred cattle at military and other institutional dairy farms in Punjab was evaluated. The studies were conducted at three military dairy farms, one government farm of Livestock and Dairy Development Department and the experimental farm at University of Agriculture Faisalabad. Data on first and later lactations of crossbred dairy cattle (n=8375) from three Military dairy herds from 1984 to 2007 were used to study the effect of genetic group, herd, year and season of calving and parity on productive and reproductive traits using a general linear model. The overall 305-d milk yield, total milk yield, lactation length and dry period were 1944±36.7 kg, 1874±36.8 kg, 255±3.2 days and 224±11.8 days, respectively. The service period, calving interval, and gestation period averaged 196±10.6 days, 469±10.9 days, and 274±0.28 days, respectively. The phenotypic trend was positive for most of the productive traits. However, productive life and herd life decreased over the years. Deterioration in service period and calving interval was also obvious. Wide variation in performance traits of crossbred dairy cattle of three Military herds showed significant effects of management and feeding at these farms. At Livestock Experiment Station Qadirabad, overall 305-d milk yield, total milk yield, lactation length, dry period, service period and calving interval were 2453.1±63.26 kg, 2601.8±72.12 kg, 291.3±5.24 days, 170±13.34 days, 181±12.94 days and 465±12.98 days, respectively. The generations, season and year of calving and parity were the significant factors influencing performance traits. The phenotypic trends was negative for total milk yield (-24kg/year), lactation length (-0.3 days/year), productive life (-13 days/year) and herd life (-24 days/year). Significant deterioration in productive traits was found after F 1 generation. Pattern of calving was compared between Sahiwal crossbreds (Friesian or Jersey) and Nili-Ravi buffaloes and purebred Sahiwal cattle. Lactation records of 9,174, 22,499 and 656 of Nili-Ravi buffaloes, Sahiwal and crossbred cattle were used for this purpose. Seasonality of calving is more pronounced in buffaloes than Sahiwal and crossbred cattle in Pakistan. The relationship between days open and seasonality of calving in the Nili-Ravi buffaloes, Sahiwal and Crossbred cattle was also established using the same dataset. Nili-Ravi buffaloes and crossbred cows calving in winter had fewer days open than those calving in summer. Nili- Ravi and Sahiwal herds showed deterioration in days open over the years. There was an average increase (per year) of 1.5 days in days open for Nili-Ravis and 0.6 days for Sahiwals. Increase in days open over the years was also observed for Sahiwal crossbreds. Individual and maternal effects both for additive and heterotic gene actions in milk yield and reproductive traits were estimated using data of 178 cows (740 lactations) at University herd. Individual heterosis was statistically significant for traits like age at first calving, 305-day milk yield, total milk yield and productive life. Performance of animals however, improved as the Bos taurus inheritance increased but going beyond 75% deteriorated performance especially traits such as productive life.en_US
dc.description.sponsorshipHigher Education Commission, Pakistanen_US
dc.subjectNatural Sciencesen_US
dc.subjectGenetics & evolutionen_US
dc.subjectAnimals (Zoology)en_US
dc.subjectCold-blooded vertebratesen_US
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

Files in This Item:
File Description SizeFormat 
1700S.pdfComplete Thesis3.14 MBAdobe PDFView/Open
1700S-0.pdfTable of Contents19.35 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.