Abstract
Data on 218 lantationa of 127 Tharparkar cowe atr thn Govarnment Livestock Farm, Rakh District Bliakkar wore analyRed, for variation in milk yield. due to season of calving end Como physiologioal factorEi. Milk yield averaged 11A8.5 26-S ltg mild was. aignificantly affected by the aeaao.n f calving,. The. erYW'S calving. during autumn were the pooreot in Prink yield but the Fraductfon di'd not differ mignificutntly in cows oalving daring the other three 44u.at3ovis, Pon* yield and initial milk yield were 2215P5 -h 4.8 and 431,6 -L 9_1 kg, reepeotively. Mean lacta-tion period was 220,4 + .1 2 days and the. peraistenoy fivr.aged 6E53 .± 11.11,a per cent. TES p) correlation 9 betwetn llactiti-un milk yield 19. nd the other variables, viz.„ peak yield, lactation period snd. persi9teney were 0,61, 0,78, 038 and. 0,47. respeatively. Multiple correlation for th.ri effeot& of pc!alt yield, initial yield and persieteney of lactation milk yield was .0.806. Tlio test {If 9ignificahe indivated that each independent variable contributed riigniticaritly laatatior) 1eld, Tho multiple regrewlion eduction to prodiot lactation yield (Y) from peak yield initial yield (X2) and pinsimteney (X3) was = _6.67,39 + 3.2444 Xi 0..5928 X2 + 11.8568 X3 The standard part:ial regression iridicated relative iniplartarice of 56:17.133 for peak yield, initial yield and persistency in influenciog the milk yield.
INT RODUOTION
Tharparkar breed of cattle is a dairy-cum-draught type and mainly
*Department of Animal. Breeding & Ganetiesp University of Agrileniturer Faisslabad,.
19
Zaheer Ahmad, M D. Ahmad A Ghaffar. (1984) Studies on the factors affecting milk yield in Tharparkar cows, Pakistan Journal of Agricultural Sciences, Volume 21, Issue 3,4.
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