Testicular steroidogenesis is suppressed during experimental autoimmune encephalomyelitis in rats

Multiple sclerosis (MS) is an autoimmune disease that usually occurs during the reproductive years in both sexes. Many male patients with MS show lower blood testosterone levels, which was also observed in male rats during experimental autoimmune encephalomyelitis (EAE), an animal model of MS. To better understand the causes of decreased testosterone production during EAE, we investigated the expression status of genes and proteins associated with steroidogenesis in the testes. No changes in the number of interstitial cells were observed in EAE animals, but the expression of the insulin-like 3 gene was reduced at the peak of the disease, implying that the Leydig cell functional capacity was affected. Consistent with this finding, the expression of most steroidogenic enzyme genes and proteins was reduced during EAE, including StAR, CYP11A1, CYP17A1 and HSD3B. No signs of testicular inflammation were observed. Recovery of steroidogenesis was observed after injection of hCG, the placental gonadotropin, or buserelin acetate, a gonadotropin-releasing hormone analogue, at the peak of EAE. Together, our results are consistent with the hypothesis that impaired testicular steroidogenesis originates upstream of the testes and that low serum LH is the main cause of decreased testosterone levels during EAE.

Effect of GnRH treatment following a short-term estrous induction protocol on estrus and ovulation in Saanen goats, during the transitional period

The objective of this study was to compare the effect on the ovulation time and estrus parameters of a GnRH agonist (buserelin acetate) administered 24 or 36 h following a short-term estrus induction and synchronization treatment in non-lactating Saanen goats during the transitional period. Goats received 20 mg FGA sponges for 6 days plus 300 IU eCG and 125 μg d-cloprostenol 24 h prior to sponge removal. After removal of the sponges, goats were given either 1 ml physiological saline (0.9% NaCI) solution (Group1; n = 9) after 12 h, 0.004 mg GnRH (Group2; n = 10) after 24 h or 0.004 mg GnRH (Group3; n = 10) after 36 h. The follicle development and ovulation in the ovaries were monitored by transrectal ultrasonography starting from the sponge application until the fifth day of the estrus cycle. Blood samples were collected on the same days to determine the plasma concentrations of progesterone (P4) and estradiol (E2). No statistical differences among groups were detected in any synchronization parameters, ultrasonic evaluations and plasma P4 and E2 concentrations. The evaluation of pooled data showed that the response of Saanen goats to treatments was comparable to the results of other published trials. Results of this study indicate that administration of GnRH at 24 h or 36 h after sponge removal, at the end of a short estrus induction and synchronization protocol, does not affect plasma P4 and E2 concentrations, estrus parameters and ovulation time in goats, during the transition period.

113 Different doses of equine chorionic gonadotrophin on pregnancy and twin rates of Bos taurus beef heifers subjected to J-Synch protocol for fixed-time artificial insemination

The objective was to evaluate the effect of different doses of equine chorionic gonadotrophin (eCG) on pregnancy (P/AI) and twin rates of beef heifers in a progesterone and oestradiol-based treatment (J-Synch protocol) for fixed-time AI (FTAI). A total of 1,404 Bos taurus beef heifers with a body condition score 4.8±0.5 (mean±s.e.m., scale 1–8) were used in three different locations. The presence of a corpus luteum (CL) was determined by ovarian ultrasonography (5.0MHz) at the beginning of the J-Synch protocol. On Day 0, the heifers received 2mg of oestradiol benzoate (intramuscular, IM) associated with an intravaginal device containing 0.5g of progesterone. At device removal, on Day 6, 500µg of cloprostenol sodium was administered IM and the females were randomly assigned to one of two experimental groups to receive 200 (n=702) or 300 (n=702) IU of eCG (Zoetis) IM. Heifers were also tail-painted. On Day 0 females with paint rubbed-off were FTAI 64 h after device removal, and those that remained with the paint received 8 μg of buserelin acetate 64 h after device removal to be FTAI 8 h later. FTAI was performed at 64 to 72h after device removal, and pregnancy diagnosis was performed by ultrasonography 30 to 35 days after insemination. Data were analysed by logistic regression using GLMM. The results are shown in Table 1. Pregnancy rate was not different between heifers treated with 200 or 300IU of eCG (P=0.513) and was not affected by the presence of CL at the beginning of the protocol (P=0.513). Twin rate was greater in heifers treated with 300IU than with 200IU of eCG (P=0.005), and it was not affected by the presence of CL (P=0.362). Interaction between eCG treatment and presence of CL was not significant for pregnancy or twin rates (P=0.532). In conclusion, although 300IU of eCG increased the twin rate compared with 200IU, no differences were found in P/AI. We suggest that the dose of eCG in the J-Synch protocol could be adjusted to 200IU in Bos taurus beef heifers. Table 1. Pregnancy per AI (P/AI) and twin rates obtained with different doses of eCG (200 or 300IU) in a J-Synch protocol for fixed-time AI in cycling (CL) and anestrous (no CL) Bos taurus beef heifers Variable 200 IU 300 IU P-value CL no CL Total CL No CL Total eCG CL eCG×CL P/AI (%) 61.6% (135/219) 59.8% (289/483) 60.4% (424/702) 60.2% (133/221) 59.5% (286/481) 59.7% (419/702) 0.513 0.513 0.513 Twin rate (%) 3.0% (4/135) 3.5% (10/289) 3.3% (14/424) 6.8% (9/133) 9.4% (27/286) 8.6% (36/419) 0.005 0.362 0.532

Effects of Buserelin acetate and semen extension on fertility in rabbit does under artificial insemination

The productivity of rabbit farms can be increased and become more homogeneous through the use of Artificial Insemination (AI). However, this possibility is limited with low conception in artificially inseminated does without ovulation induction. This study aimed at determining the conception rate of rabbit does induced with buserelin acetate and inseminated with extended semen at varied dilution ratio. A total number of Twenty eight multiparous non-lactating rabbit does were randomly allotted into four treatments housed individually in a completely randomised design. Rabbits were used as a teaser for semen collection using an artificial vagina and after semen collection and evaluation; ejaculates from ten bucks with more than 60% motility were pooled and extended. Forty eight hours before the AI, the does were hormonally synchronized (i.m) for oestrus with 20IU PMSG. Does in treatment 1(control) were inseminated with unextended semen without buserelin but injected with normal saline, while does on treatments 2, 3 and 4 were inseminated with extended semen in ratio 1: 1, 1:2 and 1: 3 (semen: extender), respectively and were all intramuscularly induced using 0.8µg of buserelin after insemination. Results showed that some of the does induced with buserelin acetate intramuscularly (treatments 2, 3 and 4) were pregnant, while none of the control rabbits was pregnant. The ratio 1: 1 extended semen (treatment 2) recorded the highest percentage conception (85.71%) followed by treatment 3 (71.43%) and treatment 4 (57.14%). There was significant (P<0.05) difference in gestation length (32.50, 31.00 and 32.75), litter size (4.83, 8.60 and 3.25), live kits at birth (3.50, 6.60 and 1.75) for treatments 2, 3 and 4 respectively and the average litter weight was not significantly different among the treatments. This study suggests that diluting semen in ratio 1: 1 produced highest conception rate with intramuscular administration of 0.8µg buserelin acetate than extending semen in ratios 1: 2 and 1: 3.

Weaned Sows with Small Ovarian Follicles Respond Poorly to the GnRH Agonist Buserelin

The GnRH agonist buserelin (GnRH), used to synchronize ovulation in weaned sows, attains only 70–80% effectivity, owing to several reasons of ovarian origin. This study evaluated in particular whether mean ovarian follicle size at treatment and the season of weaning are among those influencing GnRH responsiveness. The experiment was carried out in a temperate-region farm with 352 sows of 1–6 parities weaned either in winter–spring (WS, 174 sows) or in summer–autumn (SA, 178 sows). The sows were randomized into two groups: GnRH (10 µg of buserelin acetate at 86 h after weaning, 172 sows) and control (180 sows). The ovaries were transrectally scanned from weaning to ovulation and the sows clustered according to their mean follicular size at treatment time: small (<0.5 cm in diameter), medium (0.5 to 0.64 cm) and large (0.65 to 1.09 cm). In total, 88.33% of the GnRH-treated sows ovulated, with 82% of them within the expected time window (120–132 h after weaning). In contrast, 95.45% of the unresponsive sows had small follicles at the time of treatment and were mostly weaned in SA (20.45%) than in WS (4.76%). In conclusion, the conspicuous presence of sows having small ovarian follicles at treatment time compromises the efficiency of the GnRH agonist buserelin to synchronize ovulation in weaned sows, which occurs more frequently in summer–autumn weaning.

Evaluation of Double Ovsynch Protocol in Acyclic Jaffarabadi Heifers and Buffaloes with Respect to Ovarian Dynamics, Hormonal Profile and Fertility

Background: Anestrus is one of the most commonly encountered infertility problems in cattle and buffalo in India. Jaffarabadi is one of the heaviest buffalo breeds of the world and is a native of Saurashtra region of Gujarat. The breed is known for poor reproductive efficiency. To improve its reproductive efficiency, this study was undertaken on acyclic Jaffarabadi animals employing double Ovsynch protocol and its assessment through ovarian dynamics and blood biochemical and endocrine profile on a farm. Methods: The study included acyclic post-pubertal Jaffarabadi heifers (age 42±2 and 48±2 months; Gr-I and Gr-II, n=6 each) and the postpartum lactating acyclic buffaloes (Gr-III, n=6) using a double Ovsynch protocol, which consisted of i/m injections of 20 µg Buserelin acetate on days 0, 10, 17 and 26 and 500 µg Cloprostenol sodium on days 7 and 24, with a timed insemination on day 27. Ovarian dynamics was monitored by performing ultrasonography using real-time B-mode ultrasound scanner together with blood sampling for hormonal and biochemical profile on each day of hormone therapy and then on days 0, 12, 21 and 35 post-AI. The animals inseminated at induced estrus/FTAI were followed for return to estrus, if any. Pregnancy was confirmed in non-return cases on day 35 by ultrasonography and on day 70 by per rectal examination. The findings on ovarian dynamics, plasma endocrine and biochemical profile were compared statistically between groups and periods and fertility rates between groups. Result: In animals of treatment group I and II, a significant (p less than 0.05) increase in numbers of small follicles was observed on day 26. Number of large sized follicles was significantly (p less than 0.05) higher on day 26 in comparison to day 0 and day 7 in group III animals. Large and subordinate follicular diameters increased gradually, but the differences between periods were significant (p less than 0.001) only in group III with the highest diameter of large follicle on day 17. Plasma FSH and LH concentrations differed significantly (p less than 0.001) among groups at all-time intervals. Plasma LH in group I and III differed significantly (p less than 0.001). Plasma estrogen level was significantly (p less than 0.05) higher in group II than group III. Plasma progesterone concentrations in group I and II animals were significantly higher on day 35 post-AI. Plasma insulin levels were significantly (p less than 0.01) lower on all days for group III animals than group I and II. Blood glucose level was significantly (p less than 0.001) higher in group I on day 17 as compared to group II and III. Plasma total cholesterol was significantly (p less than 0.05) higher in group III as compared to group I and II. The conception rates at first service/FTAI in double Ovsynch treated animals of group I, II and III were 66.66, 83.33 and 16.66 %, respectively. Thus it was concluded that ovarian structures and the plasma endocrine profile reflected the ovarian response to different hormonal injections and that double Ovsynch protocol could be a better choice for improving conception rate in post-pubertal acyclic Jaffarabadi buffalo heifers as compared to multiparous acyclic buffaloes.