STUDY ON 305-DAY MILK YIELD FOR THE FIRST LACTATIONS OF JERSEY COWS, RAISED UNDER SMALL SCALE FAMILY CONDITIONS IN ALBANIA

Jersey cattle accounts for 3% of the cattle population in Albania.The advanced crosses amount to 33% of this population.The whole population is actually raised at small scale family farms, on average 2-3 cows.A low input production system is applied to these farms.Milk yield is low.The study of the Jersey cattle response to the low input production system and estimation of effects of non-genetic factors on milk yield make also possible that the programs for efficient selection and management of Jersey cows are compiled and applied to these farms.The manyfold analysis carried out by the data of 305-day milk yield for the first lactation, showed the effects of the factors "calving age" (P < 0.05); "calving month" and "herd" (P < 0.001) on the total phenotypic variance.Under conditions of the extensive production system, the effects of the factor "calving month" showed an anomaly in the succession of physiological processes that condition the milk yield during the first lactation.The adjustment of milk yield by means of separate multiplicative factors for the calving age and the calving month considerably reduces effects of these factors.It makes also possible the implementation of selection schemes under conditions of small scale farms, which raise 2-3 cows.Large differences at the extensive production system and the low level of inputs influence the increase of percentages of atypical curves of lactation.As a consequence, the loss of milk yield is estimated about 350-550 kg milk/year.The management of effects of non genetic factors "calving age" (P < 0.001, 0.01, 0.05), "calving month" (P < 0.001, 0.01, 0.05), on variations of a, b and c parameters of the normal curves of lactation makes possible to increase the milk yield during the first lactation.