Producción de leche y duración de lactancia en cabras (capra hircus) Alpinas y Nubias importadas de Venezuela

Abstract

THE PRESENT STUDY WAS CARRIED OUT TO DETERMINE THE FACTORS THAT AFFECT MILK YIELD AND LACTATION LENGTH IN A HERD OF ALPINE AND NUBIAN GOATS (CAPRA HIRCUS) IMPORTED FROM THE UNITED STATES TO VENEZUELA. THIS HERD WAS MAINTAINED IN CONFINEMENT UNDER INTENSIVE MANAGEMENT IN HALF COVERED STALLS. ANIMALS WERE FED GRASS HAY AND CONCENTRATE. MILK YIELD WAS MEASURED TWICE A DAY EVERY 14 DAYS. DATA WAS ANALYZED USING A MIXED LINEAR MODEL THAT INCLUDED THE EFFECTS OF BREED (ALPINE, NUBIAN), DAM NESTED WITHIN BREED, NUMBER OF KIDDING (1-5), TYPE OF KIDDING (SINGLE, TWIN), YEAR OF KIDDING (1989-1993), SEASON OF KIDDING (DRY, RAINY), AND THE INTERACTION YEAR OF KIDDING X SEASON OF KIDDING. BREED HAD A SIGNIFICANT EFFECT (P<0.01) ON MILK YIELD; LEASTSQUARES MEANS WERE 262.2 AND 137.0 KG FOR ALPINE AND NUBIAN GOATS, RESPECTIVELY. SIGNIFICANT EFFECTS (P<0.01) OF NUMBER OF KIDDING, YEAR OF KIDDING, SEASON OF KIDDING, AND THE INTERACTION YEAR OF KIDDING X SEASON OF KIDDING ON MILK YIELD WERE FOUND. MILK YIELD INCREASED ALONG WITH NUMBER OF KIDDING, DIMINISHED AS YEARS PROGRESSED, AND WAS HIGHER DURING THE DRY SEASON. BREED HAD ALSO A SIGNIFICANT EFFECT (P<0.01) ON LACTATION LENGTH; LEAST-SQUARES MEANS WERE 272 AND 210 DAYS FOR ALPINE AND NUBIAN GOATS, RESPECTIVELY. A POSITIVE EFFECT (P<0.01) OF NUMBER OF KIDDING ON LACTATION LENGTH WAS ALSO FOUND. IT IS CONCLUDED THAT MILK PRODUCTION IN GOATS OF EXOTIC BREEDS IN THE VENEZUELAN DRY TROPICS IS VERY SUSCEPTIBLE TO ENVIRONMENTAL FACTORS. IN ADDITION, THE LOW AVERAGE MILK YIELDS, AND THE FACT THAT THEY DIMINISHED AS YEARS PROGRESSED, INDICATED THAT THIS HERD HAD PROBLEMS ADAPTING TO CLIMATE AND/OR MANAGEMENT GIVEN. ALPINE GOATS PROVED TO BE SUPERIOR TO NUBIANS UNDER THE CONDITIONS OF THIS STUDY.