Successful induction of lactation in a barren Thoroughbred mare: growth of a foal raised on induced lactation and the corresponding maternal hormone profiles

Effect of Supplementary Feeding on Milk Volume, Milk Composition, Blood Biochemical Index, and Fecal Microflora Diversity in Grazing Yili Mares

Grazing is a common approach to rearing. We investigated the effects of supplementation during grazing on milk yield and composition, blood biochemistry, and fecal microflora in Yili horses. The control mares grazed normally, while those in groups I and II received 1 kg/d of concentrate and 1 kg/d of concentrate + 0.4 kg/d of coated FA, respectively. Milk volumes were significantly higher in groups I and II than in the control group, and among the previous two, milk volumes were significantly higher in group II than in group I. Milk fat, lactose, and protein levels were significantly higher in group II than in the others. BUN was highly significantly lower in group I than in the control group. Specific FAs, total SFA, and total UFA were significantly higher in group II than in the other groups. After feeding, plasma GLU, free FA, TG, LDL, and VLDL were significantly higher in group II than in the other groups. The control group, group I, and group II had 4984, 5487, and 5158 OTUs, respectively, and 3483 OTUs were common to all groups. The abundance of Bacteroidetes and Firmicutes was >75%. The abundance of Verrucomicrobia was significantly higher in groups I and II than in the control group and, among the previous two, significantly higher in group II than in group I. The abundance of Treponema_saccharophilum significantly differed between the control and other groups, and WCHB 1_41, Kiritimatiellae, and Verrucomicrobia abundances significantly differed between groups II and the other groups.

Effect of pseudopregnancy duration in nonpregnant sows on induced lactation

This study was conducted to examine the effects of different pseudopregnancy periods in nonpregnant sows on artificial lactation induction efficiency and milk composition. Sixteen pseudopregnant sows (n = 4 per group) were treated with 5 mg of estradiol dipropionate at 28 (Group D38), 35 (Group D45), 42 (Group D52), and 49 (Group D59) days after the end of estrus, followed by prostaglandin F_2α as 0.175-mg cloprostenol twice at 12 h intervals 10 days later. The overall success rate of lactation induction was 81.3%. The lactation rates were significantly higher in Groups D38, D45, and D59 (100.0%) than in Group D52 (25.0%). The milk immunoglobulin (Ig) G concentration was significantly higher in Group D38 than in Group D59. However, IgA levels and milk compositions (protein, ash, and lactose) did not differ among the groups. Lactation induction was successful between 38 and 59 days of pseudopregnancy. Apart from IgG, pseudopregnancy length did not affect milk components from 38 to 59 days of pseudopregnancy.

Artificial lactation by exogenous hormone treatment in non-pregnant sows

This study aimed to determine if lactation can be induced by exogenous hormonal treatment in non-pregnant sows. In experiment 1, pseudopregnant animals were divided into four groups and given: 1) 5 mg of estradiol dipropionate (EDP) 5 days before (n = 4), 2) 5 mg of EDP 10 days before (n = 3), 3) 10 mg of EDP 5 days before (n = 3) or 4) 10 mg of EDP 10 days (n = 3) before PGF2α treatment. Artificial lactation was induced in seven pseudopregnant sows (53.8%) by exogenous hormonal treatment. There was no significant effect of either an increased EDP dosage or interval from the EDP treatment to PGF2α treatment on the induction rate of artificial lactation. In experiment 2, milk samples were collected from artificial lactating and natural lactating sows (n = 6). IgG and IgA levels in the milk collected from both groups were significantly associated with time during the experimental period. Milk IgG levels 24 h after PGF2α treatment in artificial lactating sows were higher than those in the colostrum of lactating sows. In experiment 3, hormonal profiles in pseudopregnant sows with (n = 3) or without (n = 3) EDP treatment were determined. There was a significant difference in estradiol-17β levels on days 8, 7 and 5 before PGF2α treatment between groups. Progesterone and prolactin concentrations did not differ between groups. The present study revealed for the first time that lactation could be induced by exogenous hormonal treatment in non-pregnant sows and that the milk collected from these sows contained high immunoglobulin levels.

Seasonal expressions of prolactin, prolactin receptor and STAT5 in the scented glands of the male muskrats (Ondatra zibethicus)

Prolactin (PRL) production in mammals has been demonstrated in extrapituitary gland, which can activate autocrine/ paracrine signaling pathways to regulate physiological activity. In the current study, we characterized the gene expression profiles of PRL, prolactin receptor (PRLR) and signal transducers and activators of transcription 5 (STAT5) in the scented glandular tissues of the muskrats, to further elucidate the relationship between PRL and the scented glandular functions of the muskrats. The weight and volume of the scented glands in the breeding season were significantly higher than those of the non-breeding season. Immunohistochemical data showed that PRL, PRLR and STAT5/phospho-STAT5 (pSTAT5) were found in the glandular and epithelial cells of the scented glands in both seasons. Furthermore, we found that PRL, PRLR and STAT5 had higher immunoreactivities in the scented glands during the breeding season when compared to those of the non-breeding season. In parallel, the gene expressions of PRL, PRLR and STAT5 were significantly higher in the scented glands during the breeding season than those of the non-breeding season. The concentrations of PRL in scented glandular tissues and sera were measured by enzymelinked immunosorbent assay (ELISA), and their levels were both notably higher in the breeding season than those of the nonbreeding season. These findings suggested that the scented glands of the muskrats were capable of extrapituitary synthesis of PRL, which might attribute PRL a specific function to an endocrine or autocrine/paracrine mediator.

Post-partum concentrations of serum progesterone, oestradiol and prolactin in Arabian mares demonstrating normal maternal behaviour and Arabian mares demonstrating foal rejection behaviour

The aim of this prospective study was to investigate possible endocrine components to foal rejection behaviour in post-partum Arabian mares. Arabian mares were divided into two groups based on their maternal behaviour: (1) mares with normal post-parturient behaviour (8 mares); and (2) mares that demonstrated foal-rejecting behaviour post-partum (15 mares). Most mares were visited and sampled twice, in the first and third days post-partum. Serum samples were used for measurement of progesterone, oestradiol and prolactin concentrations. There were no statistically significant differences in oestradiol, progesterone or prolactin concentrations between the groups. In the rejecting mares, there was a statistically significant decrease in the progesterone (mean±standard deviation, SD, 3.14±6.2ng/dL on day 1 and 0.49±0.18ng/dL on day 3) and prolactin (mean±SD 216.2±325.4ng/mL on day 1 and 145.2±311.4ng/mL on day 3) concentrations between days 1 and 3, while the oestradiol concentration did not change significantly. In the non-rejecting mares, progesterone concentrations decreased significantly (mean±SD 0.8±0.23ng/dL on day 1 and 0.43±0.22 on day 3) while the oestradiol and prolactin concentrations did not change significantly. The oestradiol to progesterone ratio was significantly higher in non-rejecting mares on day 1 (mean±SD 114.8±140.2 on day 1 and 143.4±72.6 on day 3) and this ratio increased significantly from days 1 to 3 in the rejecting mares (mean±SD 47.3±21.1 on day 1 and 122.1±123.7 on day 3).