Taxa de prenhez em fêmeas bovinas leiteiras submetidas à inseminação artificial em tempo fixo em condições semiáridas

Abstract

The objective of this study was to analyze the pregnancy rate in dairy cows submitted to artificial insemination in fixed time (TAI). 3575 TAI protocol information was analyzed in dairy cows livestock file 117 farms distributed in 11 northern municipalities of Minas Gerais in the years 2013 and 2014. The animals negative diagnosis cycling or anestrus underwent protocol TAI, being inseminated 11 days after the application of intravaginal device (CIDR). Data were subjected to the chi-square test at 5% significance (P <0.05) using the PROC FREQ procedure of Statistical Analysis System software (SAS, 2000). The results indicated that the reproductive and productive category factors, body condition score (BCS), ovarian structure, reuse CIDR® implants, genetic group semen donor, inseminator skill, application of prostaglandin (PGF2a) and time of year, were significant . However, the genetic composition of cow and the insemination time were not significant p <0.05. The lowest pregnancy rate in the IATF was to gilts (47.22%). Animals of the heifer and cow categories lactating without calf were those that had a higher pregnancy rate (63.07% and 62.32%), respectively. Animals with higher body score 3.5 and 3.0 had the highest pregnancy rates (65.57% and 62.10%). The ovarian structure for animals with diameters from 5 to 8 mm (M) was observed higher pregnancy rate (63.03%). The animals used the second and third devices use were those who had higher pregnancy rates, and similar rates were observed (62.52% and 62.09%), respectively. The number of artificial inseminations by inseminating had significant effect (P <0.05) on pregnancy rate, and the inseminating with the highest number of inseminated cows (> 100) performed better. As for inseminations of pregnancy results carried out in different periods of the year (dry and rainy season) the highest pregnancy rate was observed in those inseminated animals during the dry season. Factors such as nutrition, reproductive and productive category and the ovarian structure, the implant reuse, season and availability of personnel qualification significantly influenced the success of the use of this biotech. Thus, the standardization of procedures necessary for the commercial application of TAI in mining semi-arid region is critical to achieving significant results.