SE 09. Evaluation of the dairy herd systems and performance of Holstein heifers under comertial and technical conditions in specialized dairy farms in Panama

The system for raising and growing dairy heifers was evaluted in three specialized dairy farms. Feeding and nutrition, health care and overall managment were studied from time of birth to the end of gestation in Holstein heifers. A total of 400 Holstein heifers were studied after selecting data by records and breed characteristics. Mayor variables were body weight, heart girth and height at withers, and birth record was used to follow the relationship between these variables and age from birth. Biological trends for each dairy farm concerning body weight, heart girth and height at whiters were generated across the first 24 months after birth. The body weight at farm A, B and C were 855.39, 807.37 and 657.45 lb at 24 months (P<.01). The nutritional analysis showed that feeding systems and management used to raise and grow dairy heifers on those farms allowed remarkable deficit on dry matter intake, as well as metabolizable energy, protein, calcium and phosphorum consumption. The highest nutritional deficit was correlated with the lowest body weight mean and trend across de first 24 months. All raising systems showed nutritional failure reagarding dry matter, energy, protein and critical minerals such as calcium and phosphorum, which was tipically during the first eigth months of age respectivelly. The study of these three systems, quite well representing what is done in some other dairy farms in Panama, showed enough evidence of nutritional deficiencies and management failures reduce the performance of the dairy heifers, affecting the early animal performance and overall protuctivity