CHARACTERISTICS OF LACTATION CURVE IN DAMASCUS GOATS IN JORDAN | ||||
| Journal of Animal and Poultry Production | ||||
| Article 2, Volume 4, Issue 8, August 2013, Page 479-491 PDF (872.56 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2013.71508 | ||||
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| Authors | ||||
| E. M. Ayasrah; S. Abou-Bakr; M. A. M. Ibrahim | ||||
| Animal Production Department, Faculty of Agriculture, Cairo Univ. | ||||
| Abstract | ||||
| Test day milk yield data on Damascus goats maintained at Walla station belonging to ministry of agriculture in Jordan were collected over the period from 2002 to 2010 and included 7700 test days (1540 records). Wood model parameters were estimated using non-linear regression and individual curves were fitted. The characteristics of lactation curve were computed. The initial yield (a), rate of increase (b) and rate of decline (c) parameters in Wood’s model for Damascus goats were 1.12±0.002, 0.35±0.0003 and 0.08±0.00, respectively. The values of peak milk yield (PMY), peak week (PW) and persistency (PS) were 1.29±0.007 kg, 3.93±0.008 and 0.86±0.07, respectively. Heritability estimates were found to be low, being 0.09 ±0.01, 0.07 ±0.01, 0.08±0.01, 0.04 ±0.001 and 0.07±0.01 for a, b, c, PMY and PS, respectively. Repeatability estimates were 0.30, 0.21, 0.25, 0.13 and 0.21 for a, b, c, PMY and PS, respectively. Positive genetic correlation between the parameter a and parameter b and c were 0.99 and 0.99, respectively. The genetic and phenotypic correlations between b and c were high significant (0.99 and 0.91, respectively). Negative genetic and phenotypic correlation between the parameter a and PS were -0.99 and -0.81, respectively. It is concluded that incomplete gamma function of Wood to Damascus goats milk yields was sufficient in describing lactation curve in Damascus goats. | ||||
| Keywords | ||||
| Lactation curve; peak milk yield; persistency; Damascus goats | ||||
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