Selective serotonin reuptake inhibitors (SSRI) are the most common antidepressants used by pregnant women. However, adverse pregnancy outcomes have been described in women taking SSRI during pregnancy—placental lesions, premature birth, poor neonatal adaptation. We aimed to investigate the effects of fluoxetine (Prozac® most commonly used SSRI) treatment during the last month of gestation on pregnancy complications, placental and neonatal health in a non-depressed sheep model. On day 119 ± 1 postbreeding (experimental day 0; E0) of a 151-day expected gestation, Hampshire ewes were randomly assigned to receive fluoxetine (n = 9 ewes, 15 lambs; daily intravenously treatment with 10 mg/kg on E0 and E1 and 5 mg/kg daily thereafter until parturition) or to a control group (n = 10; 14 lambs; vehicle only). Blood samples from ewes were collected throughout the experimental period and postpartum; blood from lambs were collected postpartum. Analysis of variance was used for statistical analysis. Fluoxetine treatment reduced placentome growth during the last month of pregnancy. Gestation length was decreased by 4.5 days in fluoxetine-treated ewes. Birthweight was reduced in lambs exposed to fluoxetine in utero; weights remained decreased until postnatal day 3. Placentome diameter by birthweight ratio was not different between groups suggesting that the decreased placentome diameter was accompanied by decreased lamb birthweight. During the first week postnatal, lambs exposed to fluoxetine in utero had decreased blood pH and decreased total carbon dioxide, bicarbonate, and base excess and increased lactate (days 3–6), collectively indicative of metabolic acidemia. Additionally, ionized calcium was decreased between postnatal days 0 to 4 in lambs exposed to fluoxetine in utero. Using a non-depressed animal model clearly defines a role for SSRI on the occurrence of perinatal complications and neonatal morbidity. The decreased placentome diameter, shortened gestation, decreased birthweight, decreased calcium levels, and neonatal acidemia suggest the occurrence of intrauterine growth restriction. The persistence of neonatal acidemia for several days postpartum suggests poor neonatal adaptation to extrauterine environment.

In lactating dairy cattle, the corpus luteum (CL) is a dynamic endocrine tissue vital for pregnancy maintenance, fertility, and cyclicity. Understanding processes underlying luteal physiology is therefore necessary to increase reproductive efficiency in cattle. A common technique for investigating luteal physiology is reversetranscription quantitative PCR (RT-qPCR), a valuable tool for quantifying gene expression. However, reference-gene-based RT-qPCR quantification methods require utilization of stably expressed genes to accurately assess mRNA expression. Historically, selection of reference genes in cattle has relied on subjective selection of a small pool of reference genes, many of which may have significant expression variation among different tissues or physiologic states. This is particularly concerning in dynamic tissues such as the CL, with its capacity for rapid physiologic changes during luteolysis, and likely in the less characterized period of CL maintenance during pregnancy. Thus, there is a clear need to identify reference genes well suited for the bovine CL over a wide range of physiological states. Whole-transcriptome RNA sequencing stands as an effective method to identify new reference genes by enabling the assessment of the expression profile of the entire pool of mRNA transcripts. We report the identification of 13 novel putative reference genes using RNA sequencing in the bovine CL throughout early pregnancy and luteolysis: RPL4,

Our objective was to determine the effect of route of administration of dinoprost tromethamine 7 d after treatment with GnRH on circulating 13,14-dihydro-15-keto-prostaglandin F2α (PGFM) and progesterone (P4) concentrations in lactating dairy cows. Multiparous Holstein cows fitted with indwelling jugular catheters were randomized 7 d after the last GnRH of an Ovsynch protocol (G2, d 0) to receive 25 mg of dinoprost tromethamine either intramuscularly (IM) or subcutaneously (SC). The SC cows had greater circulating PGFM concentrations 15 to 90 min after treatment than the IM cows; however, circulating P4 concentrations during induced luteolysis did not differ at any time based on route of administration.

Double ovulation and twin pregnancy are undesirable traits in dairy cattle. Based on previous physiological observations, we tested the hypothesis that increased LH action [low-dose human chorionic gonadotropin (hCG)] before the expected time of diameter deviation would change circulating FSH concentrations, maximum size of the second largest (F2) and third largest (F3) follicles, and frequency of multiple ovulations in lactating dairy cows with minimal progesterone (P4) concentrations. In replicate 1, multiparous, nonbred lactating Holstein dairy cows (n = 18) had ovulation synchronized. On d 5 after ovulation, all cows had their corpus luteum regressed and were submitted to follicle (≥3 mm) aspiration 24 h later to induce emergence of a new follicular wave. Cows were then randomized to NoP4 (untreated) and NoP4+hCG (100 IU of hCG every 24 h for 4 d after follicle aspiration). Ultrasound evaluations and blood sample collections were performed every 12 h for 7 d after follicle aspiration. All cows were then treated with 200 μg of GnRH to induce ovulation. In replicate 2, cows (n = 16) were resubmitted to similar procedures (i.e., corpus luteum regression, follicle aspiration, randomization, ultrasound evaluations every 12 h, GnRH 7 d after aspiration). However, cows in replicate 2 received an intravaginal P4 device that had been previously used (~18 d). Only cows with single (n = 15) and double (n = 16) ovulations were used in the analysis. No significant differences were detected for frequency of double ovulation, follicle sizes, and FSH concentrations across replicates (NoP4 vs. LowP4 and NoP4+hCG vs. LowP4+hCG), so data were combined. Double ovulation was 40% for control cows with no hCG (CONT) and 62.5% with hCG (hCG). Double ovulation increased as the maximum size of F2 increased: <9.5 mm and 9.5-11.5 mm (7.7%) and ≥11.5 mm (94.1%). The hCG group had more cows with F2 > 11.5 (69%) than with 9.5 ≥ F2 ≤ 11.5 (25%) and F2 < 9.5 (6%). In agreement, F2 and F3 maximum size were larger in the hCG group, but FSH concentrations were lower after F1 > 8.5 mm compared with CONT. In contrast, FSH concentrations were greater before deviation (F1 closest value to 8.5 mm) in cows with double ovulations than in those with single ovulations, regardless of hCG treatment. In addition, time from aspiration to deviation was shorter in cows with double rather than single ovulation and in cows treated with hCG as a result of faster F1, F2, and F3 growth rates before diameter deviation. In conclusion, greater FSH and follicle growth before deviation seems to be a primary driver of greater frequency of double ovulation in lactating cows with low circulating P4. Moreover, the increase in follicle growth before deviation and in the maximum size of F2 during hCG treatment suggests that increased LH may also have a role in stimulating double ovulation.

Introduction Peripheral serotonin is an important regulator of many aspects of lactation. Administration of the serotonin precursor, 5‐hydroxytryptophan (5‐HTP), has been shown to alter some aspects of energy metabolism and endocrine signals in dairy cattle. However, neither the effect of 5‐HTP on insulin sensitivity nor the long‐term effect on milk production have been studied in ruminants. The objectives of this study were to determine the effects of intravenous (IV) infusion of 5‐HTP on response to an IV glucose tolerance test (GTT) and on lactation performance in dairy cows. We hypothesized that 5‐HTP would alter insulin sensitivity and improve lactation performance. Twenty‐four Holstein cows were assigned to IV infusion of either 5‐HTP (1 mg/kg/day) or saline in a 2‐period crossover design. Treatments were infused via jugular catheters for 1 h/day, with 3 days of infusion followed by 4 days of rest, repeated through the 21‐day period. The GTT was performed immediately after IV infusion on day 3. For the GTT, differential effects were observed for glucose, insulin, and free fatty acids (FFA). Neither maximal glucose nor area under the curve (AUC) were affected by 5‐HTP (P≥0.15). On the other hand, basal insulin (difference of 0.116 µg/L, P=0.004) and AUC (P=0.04) were both decreased for 5‐HTP, with maximal insulin tending to be decreased by 0.35 µg/L (P=0.06). Basal FFA concentration was unaffected by treatment (P =0.55), but both minimal (difference of 82 µmol/L, P=0.015) and AUC (P=0.034) FFA were increased by 5‐HTP treatment. During the final 7 days of the period, feed intake was decreased by 4.0 kg/day during infusion days for 5‐HTP cows (P<0.01), but not on rest days (P=0.34). Milk yield was decreased for 5‐HTP cows only during infusion days (4.4 kg/day, P<0.01), returning to control levels on rest days (P=0.69). Similarly, milk protein yield was decreased (80 g/day, P<0.01) and milk fat yield tended to be decreased (140 g/day, P=0.06) by 5‐HTP on infusion days, recovering on rest days. Over the 21‐day period, 5‐HTP cows lost 0.87 kg/day of body weight, while control cows gained 0.45 kg/day (P<0.01). Given the glucose and insulin responses during the GTT, it is evident that less insulin was required to clear the same glucose load for cows receiving 5‐HTP. However, it is unclear if the lack of responsiveness in FFA to glucose challenge is due to effects of serotonin on the adipose tissue, or if there is a relationship between these FFA and decreased synthetic capacity of the mammary glands. Overall, this level of 5‐HTP altered insulin sensitivity, and acutely but transiently depressed production. More work is needed to delineate the effects of 5‐HTP on energy metabolism and production.