Date of Graduation

Spring 2017


Master of Natural and Applied Science in Agriculture


School of Agriculture

Committee Chair

Gary Webb


mare, prostaglandin, synchronization, estrous, lutalyse

Subject Categories



Prostaglandin F2α is commonly administered to manipulate the estrous cycle in mares, at a dosage of dinoprost tromethamine (Lutalyse®) at 10 mg, administered IM. My objectives were to compare three serial low-dose PGF2α protocols, and determine the most effective treatment in terms of number of injections, intensity of protocol, time allocated, and labor. Quarter Horse mares (n=11) were used in a crossover design. Lutalyse was administered at 1.1 mL per injection: treatment 1- PGF2α once 6d post-ovulation; treatment 2- PGF2α twice daily 0 d, 1 d, and 2 d, then once 3 d and 4 d post- ovulation; treatment 3- PGF2α twice daily on 2 d, then once 3 d and 4 d post- ovulation. Teasing scores were assigned daily. Rectal palpation and ultrasound were performed to measure follicular growth and detect ovulation. Blood samples were drawn on 3 d and 6 d post-ovulation to analyze plasma progesterone (P4) levels. One-way ANOVA and Tukey Method Pairwise Comparisons were used for data analysis. Between treatments on 3 d and 6 d post-ovulation, plasma P4 values were not statistically different. Mean intervals from ovulation to ovulation for treatments 1, 2, and 3 were 14.8 d ± 3.1, 12.9 d ± 6.3 d and 14.3 d ± 1.4 respectively. Mean intervals from first day of treatment to ovulation were 9.8 d ± 2.0, 12.9 d ± 6.3, and 12.6 d ±1.7. Results did not show significant statistical difference. Further research is needed on low-dose administration of PGF2α.


© Kaleigh Marie Potter

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