15-keto-13-14-dihydroprostaglandin-f2alpha and Dystocia

This study aimed to examine the etiology of canine dystocia by measuring the relative expression of oxytocin receptor (OXTR) mRNA and the concentration of serum progesterone, plasma PGF

Topics: Animals; Calcium; Dinoprost; Dog Diseases; Dogs; Dystocia; Female; Pregnancy; Progesterone; Receptors, Oxytocin

Plasma concentrations of progesterone, oestradiol-17beta, oestrone, oestrone sulphate and PGFM have been measured daily during the first peri-partum period of 45 Hereford x Friesian heifers bred at 11 months of age. Anatomical measurements of dam and calf were also recorded. Twelve of the calvings were scored easy, 33 difficult. Each of five models (fitted by linear logistic regression) relating difficulty of calving to the hormonal and anatomical measurements, predicts with at least 94% accuracy the calving score (easy or difficult) among the calvings. The models predict that increases of progesterone concentration on the day before calving, of oestrone sulphate concentration on the day after calving and of heifer heart girth decrease the odds of difficult calving, whereas increases of heifer body length and of calf head circumference increase the odds of difficult calving.

Topics: Animal Feed; Animals; Animals, Newborn; Body Weight; Cattle; Cattle Diseases; Dinoprost; Dystocia; Estradiol; Estrogens; Estrogens, Conjugated (USP); Estrone; Female; Insemination, Artificial; Labor, Obstetric; Logistic Models; Male; Multivariate Analysis; Numerical Analysis, Computer-Assisted; Pregnancy; Progesterone; Radioimmunoassay

Crossbred beef heifers (N = 36) were assigned to one of three treatment groups: untreated controls (C; N = 15); Group R4, treated with pig relaxin (1.0 mg i.m.) 4 days pre partum (N = 11); or Group R7, treated with pig relaxin (1.0 mg i.m.) 7 days pre partum (N = 10). Bioactivity of the pig relaxin (UMC-R-P8) was determined by the mouse interpubic ligament assay to be greater than or equal to 3000 U/mg, both before and after the experiment was conducted. Peripheral serum immunoreactive relaxin values were 7.5, 3.4, 2.5, and 1.5 ng/ml at 2, 4, 6 and 8 h after injection of relaxin, respectively. Gestation lengths were 282.9 +/- 1.1, 285.5 +/- 1.3 and 285.6 +/- 1.5 days for Groups C, R4 and R7 (C vs R4 + R7; P congruent to 0.08). Calving difficulty score (1 to 4) tended to be greater (P congruent to 0.08) for Group R4 and R7 heifers (C vs R4 + R7; 1.3 +/- 0.24 vs 1.75 +/- 0.28 + 2.04 +/- 0.32), but the incidences of dystocia and retained placentae were not influenced by treatment (P greater than or equal to 0.10). The mean concentration and concentration profile of daily serum progesterone, oestradiol-17 beta, dihydroprostaglandin F-2 alpha and relaxin were not affected by treatment from 6 days pre partum through 2 days post partum. Cervical diameter, cervical softness score, pelvic measurements, and vulva opening length during the periparturient period were not affected (P greater than or equal to 0.10) by treatment, but all of these characteristics changed over time (P less than or equal to 0.01), relative to calving. We conclude that i.m. administration of pig relaxin (greater than or equal to 3000 U) does not effectively alter periparturient characteristics of beef heifers. Discrepancies between these results and those reported for intracervical administration cannot be readily explained.

Topics: Animals; Cattle; Cattle Diseases; Dinoprost; Dose-Response Relationship, Drug; Dystocia; Estradiol; Female; Gestational Age; Injections, Intramuscular; Pregnancy; Progesterone; Relaxin; Swine