Impact of Buserelin Acetate or hCG Administration on the Day of First Artificial Insemination on Subsequent Luteal Profile and Conception Rate in Murrah Buffalo (Bubalus bubalis)

This study was designed to investigate the impact of buserelin acetate (BA) or human chorionic gonadotropin (hCG) administration on the day of first artificial insemination (AI) on subsequent luteal profile (diameter of corpus luteum (CL) and plasma progesterone) and conception rate in Murrah buffalo. The present experiment was carried out at two locations in 117 buffalo that were oestrus‐synchronized using cloprostenol (500 μg) administered (i.m.) 11 days apart followed by AI during standing oestrus. Based on treatment (i.m.) at the time of AI, buffalo were randomly categorized (n = 39 in each group) into control (isotonic saline solution, 5 ml), dAI‐BA (buserelin acetate, 20 μg) and dAI‐hCG (hCG, 3000 IU) group. Out of these, 14 buffalo of each group were subjected to ovarian ultrasonography on the day of oestrus to monitor the preovulatory follicle and on days 5, 12, 16 and 21 post‐ovulation to monitor CL diameter. On the day of each sonography, jugular vein blood samples were collected for the estimation of progesterone concentrations. All the buffalo (n = 117) were confirmed for pregnancy on day 40 post‐ovulation. The conception rate was better (p < 0.05) in dAI‐BA (51.3%) and dAI‐hCG (66.7%) groups as compared to their control counterparts (30.8%). Furthermore, the buffalo of dAI‐hCG group had improved (p < 0.05) luteal profile, whereas the buffalo of dAI‐BA group failed (p > 0.05) to exhibit stimulatory impact of treatment on luteal profile when compared to control group. In brief, buserelin acetate or hCG treatment on the day of first AI leads to an increase in conception rate; however, an appreciable impact on post‐ovulation luteal profile was observed only in hCG‐treated Murrah buffalo.     

Comparative efficacy of oestrus synchronization protocols in buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>)

This study was conducted to test the efficacy of gonadotropic hormone (GnRH)-based synchronization protocols (Ovsynch, Heatsynch, and Ovsynch Plus) in buffaloes under field condition. Based on anamnesis and transrectal palpation twice at 10-day interval and serum progesterone (P₄) concentration, 150 anoestrous buffaloes and delayed pubertal heifers were selected to induce oestrus using GnRH-based protocols. These selected animals were randomly divided into three groups: group I: Ovsynch (n = 50), group II: Heatsynch (n = 50), and group III: Ovsynch Plus (n = 50) regimen. Before treatment initiation, blood samples were collected for P₄, beta-hydroxy butyric acid (β-OHB), and mineral estimation, in addition to the monitoring of oestrus signs. In this investigation, no significant difference (P > 0.05) in oestrus signs was deduced among three groups. Oestrus induction rate (OIR) was comparable (P > 0.05) among the groups (Ovsynch 82%, Heatsynch 86%, and Ovsynch Plus 88%). Conception rate (CR) following fixed time artificial insemination (FTAI) was slightly higher with Ovsynch Plus group (28%) as compared to Ovsynch (24%) and Heatsynch (18%) groups, though non-significant. Furthermore, serum glucose, β-OHB, macrominerals (calcium, potassium, and magnesium), and trace minerals (copper, zinc, and iron) remained comparable (P > 0.05) among the groups. In conclusion, all the protocols (Ovsynch, Heatsynch, and Ovsynch Plus) are efficient in oestrus induction in anoestrous buffaloes under field condition with Ovsynch Plus protocol resulting in higher CR as compared to other protocols.     

Integration Between Different Hypothalamic Nuclei Involved in Stress and GnRH Secretion in the Ewe

This study investigated possible integrated links in the neuroanatomical pathways through which the activity of neurones in the paraventricular nucleus and arcuate nucleus may modulate suppression of gonadotrophin‐releasing hormone (GnRH) secretion during stressful situations. Double‐label immunofluorescence and laser scanning confocal microscopy were used to examine the hypothalamic sections from the follicular phase ewes. Noradrenergic terminals were in close contact with 65.7 ± 6.1% corticotrophin‐releasing hormone (CRH) and 84.6 ± 3.2% arginine vasopressin (AVP) cell bodies in the paraventricular nucleus but not with β‐endorphin cell bodies in the arcuate nucleus. Furthermore, γ‐amino butyric acid (GABA) terminals were close to 80.9 ± 3.5% CRH but no AVP cell bodies in the paraventricular nucleus, as well as 60.8 ± 4.1%β‐endorphin cell bodies in the arcuate nucleus. Although CRH, AVP and β‐endorphin cell terminals were identified in the medial pre‐optic area, no direct contacts with GnRH cell bodies were observed. Within the median eminence, abundant CRH but not AVP terminals were close to GnRH cell terminals in the external zone; whereas, β‐endorphin cells and terminals were in the internal zone. In conclusion, neuroanatomical evidence is provided for the ewe supporting the hypothesis that brainstem noradrenergic and hypothalamic GABA neurones are important in modulating the activity of CRH and AVP neurones in the paraventricular nucleus, as well as β‐endorphin neurones in the arcuate nucleus. These paraventricular and arcuate neurones may also involve interneurones to influence GnRH cell bodies in medial pre‐optic area, whereas the median eminence may provide a major site for direct modulation of GnRH release by CRH terminals.