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Summary.
Chemical analyses were conducted on uterine fluid and blood serum collected from eighty-eight normal adult dairy cows during various days of the oestrous cycle. Uterine fluid contained higher concentrations of reducing substances, potassium, inorganic phosphate and alkaline and acid phosphatase activity than blood serum while levels of calcium and sodium were higher in blood serum than in uterine fluid, supporting the concept that bovine uterine fluid is a product of active secretion and not of simple diffusion from the blood. Concentrations of reducing substances, total protein, potassium, chloride, inorganic phosphate and alkaline and acid phosphatase activity in bovine uterine fluid were all found to vary with the stage of the oestrous cycle, indicating that, in the case of these substances at least, secretion into the uterine lumen is under hormonal control. The level of alkaline phosphatase in the blood serum was also found to vary with the stage of the oestrous cycle.
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Summary.
Uterine fluid and blood serum samples were collected from 100 adult dairy cows during various stages of the oestrous cycle and analysed for their free amino acid content. A total of twenty-five free amino acids and amino compounds were identified in uterine fluids while only twenty-three were identified in blood serum. The concentration of the total and of most of the individual free amino acids was greater in uterine fluid than in blood serum at all stages of the oestrous cycle. The total content of free amino acids and the concentration of several individual free amino acids in uterine fluids showed cyclical variations. The significance of free amino acids in uterine fluids is discussed.
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Since the introduction of 6α-methyl-17α-acetoxyprogesterone (map or medroxy-progesterone acetate) many trials and research projects have been conducted using this orally active progestin. Considerable variation in conception rate following synchronization of oestrus with this compound has been reported (Hansel, 1965; Zimbelman, 1965). The objective of the current study was to evaluate the effect of a specific dosage of map (Repromix R , The Upjohn Company, Michigan) on fertility when administered under specifically controlled conditions.
Forty Holstein heifers, 15 to 18 months of age, were used in this study. These animals, as part of another experiment, were being fed two different types of hay (Hay types A and B) with twenty animals assigned to each group. Ten animals were selected from each group to be recycled while the remaining ten animals from each served as
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Faecal oestradiol and progestogen metabolite excretion was monitored in adult, female cheetahs (Acinonyx jubatus) (n = 26) for 1–24 months. Increased faecal oestradiol excretion was associated with mating or equine chorionic gonadotrophin (eCG) administration for artificial insemination, whereas increased progestogen metabolites were observed during natural and human chorionic gonadotrophin (hCG)-induced pregnant and nonpregnant luteal phases. On the basis of oestradiol excretory patterns, duration of the oestrous cycle (mean ± sem) was 13.6 ± 1.2 days with high oestradiol concentrations lasting for 4.1 ± 0.8 days. In non-gonadotrophin-treated cheetahs, 75% showed evidence of oestrous cyclicity; however, none evaluated for 1 year or longer were continuously cyclic. Rather, cyclicity was interrupted by periods of anoestrus, often exceeding several months in duration. These inactive ovarian periods were unrelated to season and were not synchronous among females. Mean duration of gestation (breeding to parturition) was 94.2 ± 0.5 days, whereas duration of faecal progestogen metabolite excretion during the nonpregnant luteal phase was 51.2 ± 3.5 days. On the basis of progestogen metabolite evaluations, spontaneous ovulation (non-mating induced) occurred only once in two females (2 of 184 oestrous cycles; 1.1%). Peak eCG-stimulated, preovulatory oestradiol concentrations were similar to those associated with natural oestrus, whereas progestogen metabolite profiles after hCG resembled those during pregnant and nonpregnant luteal phases after natural mating. In summary, results confirm that the cheetah is polyoestrus and ovulation is almost always induced. However, new evidence suggests that many females inexplicably experience periods of anoestrus unrelated to season, while 25% of the cheetahs examined expressed no ovarian activity during the study period.