Optimización y mejora de la inseminación artificial en la raza caprina murciano-granadina

Resumen

OBJECTIVES Improve the fertility rate obtained through Artificial Insemination (AI) in the Murciano-Granadina (MG) goat breed, acting at the level of the male goat (seminal quality and age, sperm freezing) and the female (avoid vaginal alterations after heat synchronization and early and reliable pregnancy diagnosis) always taking into account animal welfare. METHODOLOGY This Thesis has been divided into 6 experiments Experiment 1: 10 MG goats. Determination of reaction time (RT), service capacity and seminal quality when using a female, another male or an inanimate dummy as a sexual stimulus. Ejaculate volume, individual motility (IM) and the percentage of motile spermatozoa (%MOT) were evaluated from each ejaculate obtained by artificial vagina (AV). Experiment 2: 18 MG male goats between 3 months and 7 years old were used to study their sexual behavior (RT and mating capacity) and the quality of their ejaculate. The sexual stimulus used was always a female goat. Collection by AV. Experiment 3: adaptation of the seminal freezing protocol published by Thilmant (1997) to the goat species and study of 3 different extenders. Subjective and CASA evaluation of seminal quality and sperm survival during 5 hours of 78 goat ejaculates. Experiment 4: Comparison of the damage caused by two oestrus synchronization systems using different intravaginal devices: Group 1 (N= 13) FGA sponge + 50x106 CFU capsule of Lactobacillus plantarum (Lp) strain I1001. Group 2 (N= 15) CIDR® of progesterone with the same Lp capsule. Group 3 (N=4) FGA sponge (no Lp capsule). Treatment duration: 11 days. Study of the rate of coming into heat, vaginal pH and bloody discharge, cells of the immune system and pregnancy rates. Experiment 5: comparison of fertility rates of 2 groups of goats Treatment group (N=15) introduction of an Lp capsule for 8 weeks, together with measurement of vaginal pH. FGA sponge synchronization for 6 days. Control group (N=15) synchronization with FGA sponge without Lp capsule. I at 48 and 53 hours after removing the sponge. Frozen semen according to experiment 3 and IMIDA extender. Determination of the fertility percentage of both groups by ultrasound. Experiment 6: intravaginal ultrasonography was compared with the determination of serum P4 21 days post-AI. Determine which method provides an earlier reliable diagnosis. Intravaginal ultrasound scans of 30 females every two days from day 14 to 30 post AI, to visualize the gestation vesicle. P4 determination was performed on the same day as the AI and 21 days later. RESULTS AND CONCLUSIONS The collection of semen from male goats can be done using a female or another male as a sexual stimulus, without affecting seminal quality or libido. The use of a dummy provided a lower number of males that mount and ejaculate on it, higher RT, lower ejaculate volume and sperm concentration. It would be interesting to repeat the study along with some body fluid in order to improve the results. Male goats of the MG breed under one year of age present lower RT and greater service capacity than adults. Bucks between 6.5 and 8 months have an optimal seminal quality, although there is great variability between specimens. In in vitro tests, the IMIDA extender and the semen freezing protocol published by Thilmant (1997) are suitable for seminal cryopreservation in the goat species. The use of FGA sponges produced greater alteration of the vaginal mucosa, lower rate of coming into heat and lower accumulated fertility than CIDR®, but without significant differences. The introduction of the probiotic Lp intravaginally for 8 weeks did not cause significant differences in the pregnancy rate or in the vaginal pH. It would be interesting deeper studies on the reproductive tract microbiota of fertile goats. Serum progesterone quantification on day 21 post-AI is effective in recognizing empty females, but causes errors in females classified as pregnant. Transvaginal ultrasound on day 30 post-AI is an economic method, safe for the animal and effective in diagnosing early pregnancies, so waiting these 9 days is convenient when giving an accurate pregnancy diagnosis.