ABSTRACT.
Reproductive parameters in Merino-Precoz ewes, in relation to the age

Christian Crempien L.1
 

Production records, for a period of 8 years were analized and 7009 entries, of Merino-Precoz ewes, up to 7 years of age and with 6 lambing seasons, were considered to establish correlations between reproductive variables observed at lambing and the age of the dam. The variables studied were: 1. percentage of ewes lambed, 2. percentage of single lambings, 3. twin lambings, 4. cuocient of single/twin lambings, 5. percentage of dry ewes, 6. mortality from mating to lambing, 7. lambs born/ewes mated, 8. lambs born/ewes at lambing, 9. rate of prol ificacy. Those equations found with a high coefficient of correlation and their degree of significance are Iisted below with the same number (P = 0.01 , for all the equations) :

2. Y = 86.202429 - 7.214609x + 0.625179x2 r = 0.984
3. Y = 7.618142 + 6.798964x - 0.514107x2 r = 0.987
4. Y = 6.031429 - 1.311786x + 0.110357x2 r = 0.985
7. Y = 101.438713 + 6.383319x - 0.403036x2 r = 0.959
8. Y = 100.561002 + 7.363248x - 0.511250x2 r = 0.962
9. Y = 1 .086186 + 0.070961x - 0.005446x2 r = 0.987

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1 Estación Experimental La Platina (INIA), Casilla 439/3, Santiago, Chile.