Resumen

JIMENEZ-PEREZ, Florencio A et al. Evaluation of Four Methods for Heat Detection in Dual Purpose Heifers. Rev. Cient. (Maracaibo) [online]. 2009, vol.19, n.4, pp.366-370. ISSN 0798-2259.

A successful Artificial Insemination (AI) program depends strictly on heat detection. It is considered that heat detection rates are lower than 50% percent in most dairy herds. The purpose of this study was to evaluate four different methods for heat detection which include: Visual Observation (VO), Tail Painting (TP), Kamar™ (K) and Estrotect™ (E). The study was performed at Fundo Tasajeras, located in Encontrados, municipality of Catatumbo, state of Zulia, Venezuela; using 200 Dual Purpose Crossbreed Heifers (DP) selected using simple randomized sampling (SRS), which were gathered in four experimental groups of 50 animals each: Group 1, Visual Observation; Group 2, Tail Painting procedure; Group 3, placement of the Kamar™ Device; Group 4, using Estrotect™ patch. In heifers with heat detected, a blood sample was taken from the yugular vein in order to determine serum progesterone concentrations (P4), by using the radioinmunoanalysis technique (RIA). The experimental design, the method for heat detection was considered as an independent and discrete variable and for dependent variable was heat. All the gathered data were analyzed by using the Logistic Procedure (Proc Logistic) as per SAS. The results showed an effectiveness of 96% for the VO method, 94% for E, 84% for K, and 14% for TP. At the same time, significant differences (P<0.05) were found when comparing VO vs. TP and OV vs. K, unlike with the methods VO vs. K where no significant differences were evident (P>0.05). These results showed that the participation of insemination technicians (VO) in the programs of AI is a must, thus making evident the importance of the VO as an effective method for detecting heat.

Palabras clave : Heat detection; visual observation; heifers; dual purpose herds.