Clinical and endocrinaological studies on postpartum ovarian activity in Lanka buffaloes ( bubalus bubalis)
| dc.contributor.author | Mohan, Vadivel | |
| dc.date.accessioned | 2024-09-10T05:54:03Z | |
| dc.date.available | 2024-09-10T05:54:03Z | |
| dc.date.issued | 1990-01 | |
| dc.description.abstract | Long calving interval has been recorded as the important cause of poor fertility in Lanka buffaloes. However, buffaloes raised in some locations show. short calving intervals and better fertility than animals in many other areas. The reasons for these differences could he genetic or environmental (ie. climatic, management, nutrition etc.) Further, the endocrinological changes associated with resumption of ovarian activity and the effect of suckling on these changes have not been studied in Lanka buffaloes. Therefore, four experiments were conducted to determine the following : 1. reason(s) Lor the differences in fertility in different locations; Zs endocrinological changes during the postpartum period and 3. effect of suckling on resumption of ovarian. activity and other fertility indices. First, sixteen buffalo cows from a “low fertility" area and a "high fertility" area (n=8 each) were brought to a different environment and maintained over a period of 3 years under a uniform system of management. Postpartum ovarian activity was monitored in these animals by observation for signs of oestrus, weekly rectal examination of internal genitalia and weekly measurement of plasma progesterone concentrations. Results showed that there were no differences (p>0.05) in calving interval, time taken for uterine involution, duration of postpartum anoestrus and in number of services required for conception between these two groups. Calvings were distributed throughout the year and the mean calving interval was similar to what was reported for this area. Second, the endocrinological changes associated with the early postpartum period was monitored in 14 Lanka buffalo cows. On days 7,14, 21 and 28 postpartum, sequential blood samples were collected at 15 min. intervals for 8 hour periods. Subsequently intravenous administration of two injections of 12.5 ug GnRH was done two hours apart, followed by a further 4 hours of blood sampling at the same frequency. Plasma LH concentrations were measured by a heterologus RIA (detection limit 0.25 ng/ml).The validity of this RIA for measuring biologically active LH was checked by assaying some of the samples with a specific bioimmunoassay developed during this study. The LH concentrations remained below the detection limit of the assay and LH pulses were not seen in these animals up to day 28 postpartum. The pituitary did not respond to low doses of exogenous GnRH by increased LH release during this period. Third, 18 pluriparous Lanka buffalo cows were allotted to 1 of 3 treatment groups to study the effect of suckling on pituitary and ovarian function. Calves were allowed to suckle continuously in group AS (ad lib. suckling) and for two periods of 20 minutes in group RS (restricted suckling). different environmental conditions. The pre GnRH mean LH concentrations increased in all three groups with the days postpartum. The mean LH for group RS was higher (p*%0.05) than that for other two groups. There was no differences (p>0.05) between groups AS and AS/S. The resumption of pulsatile LH secretion was delayed in group AS and AS/S when compared to the group RS. The absence of pulsatile LH release in animals belonging to group AS and AS/S was associated with long periods (more than 90 days) of anoestrus. Similarly the pituitary response to exogenous GnRH, which increased (p<0.05) with days postpartum in all three groups, was higher (p<0.05) in group RS. These results suggest that the long calving intervals commonly recorded in Lanka buffaloes are mainly due to’ long periods of postpartum anoestrus. The reproductive efficiency of Lanka buffaloes is influenced by environmental and managemental factors which may be responsible for the differences in the fertility of Lanka buffaloes in different locations. Further, suckling can delay the resumption of ovarian activity during the postpartum period in Lanka buffaloes. This acts by delaying the reappearance of pulsatile LH secretion postpartum. Thus restricted calf suckling could be a practical and effective method for improving the efficiency of reproduction in Lanka buffaloes. | |
| dc.identifier.uri | https://ir.lib.pdn.ac.lk/handle/20.500.14444/921 | |
| dc.language.iso | en | |
| dc.publisher | University of Peradeniya | |
| dc.subject | Animal Husbandry | |
| dc.subject | Buffalo | |
| dc.subject | Sri Lanka | |
| dc.title | Clinical and endocrinaological studies on postpartum ovarian activity in Lanka buffaloes ( bubalus bubalis) | |
| dc.type | Thesis |