A study was carried out on 16 indigenous ewes in Bangladesh in order to assess the reproductive physiology, the pattern of vaginal cell exfoliation and progesterone profiles during the estrous cycle period. The mean estrous cycle length and duration of estrus were 15.8±0.12 days and 31.1±0.57 h respectively. The exfoliated epithelial cells were categorized into parabasal, intermediate, superficial and keratinized and their relative occurrences. The percentages of parabasal, intermediate and superficial cell type during proestrus were similar. The percentage of superficial cell type during estrus was 61.7%, which was significantly (p<0.01) differ from other types of cells and stages of estrus cycle. Metoestrus was predominant with neutrophils in addition with other cell types. Dioestrus was dominated by neutrophils. On days 0 to 5 of the cycle the progesterone concentration was 0.09 to 1.6±0.07 ng/ml. The length of diestrus was 5∼10 days with a range of mean progesterone level of 1.6±0.07 to 2.8±0.11 ng/ml. Progesterone levels increased significantly (p<0.01) after Day 5 and maximum level was 2.8±0.11 ng/ml observed on Day 10 of the estrous cycle. Thereafter it dropped rapidly to basal level of 0.11±0.04 ng/ml on Day 0 (p<0.01). These results indicate that the pattern of exfoliation of vaginal cells along with progesterone concentration could be used to determine the reproductive stages of indigenous ewe.

The present study was designed to observe the oestrus responses in the indigenous ewe induced by cloprostenol sodium manufactured by two different companies (Ovuprost®, BOMAC, Newzealandand Prostenol®, Techno, Bangladesh). Twelve local ewes were divided into 3 groups (n= 8). The ewes in Group I and II were induced by intramuscular injection of 100 μg (0.4 ml) of cloprostenol sodium (Ovuprost® and Prostenol®), respectively. The 2nd injection in each group was given at 9 days apart. The ewes in Group III were kept as control for observing natural oestrus characteristics and comparing the responses with induced oestrus. Hundred and 75% ewes showed oestrus following 2nd injection of Ovuprost® and Prostenol®, respectively. The average time of onset of oestrus following 1st and 2nd injection of Ovuprost® and Prostenol® were 50.5 ± 3.5 vs 48.0 ± 0.0 h and 49.9 ± 1.9 vs 49.5 ± 1.7 h, respectively. There was no significant difference between the two types of cloprostenol sodium group on the onset of oestrus. The average duration of oestrus was 27.5 ± 0.7 vs 27.5 ± 0.0 h and 25.9 ± 3.3 vs 24.2 ± 0.3 h in Ovuprost® and Prostenol® treated ewes, respectively. For natural oestrus, the duration of oestrus was 25.2 ± 3.3 h. There was no significant difference among the cloprostenol sodium produced by two different companies and natural oestrous ewes on the duration of oestrus. The higher percentages of cornified cells were present in induced oestrus (90 and 85%) compared with natural oestrus (80%), although there was no significant difference among them. The pregnancy rates were 75, 66.7 and 100% in Ovuprost®, Prostenol® and natural oestrous ewes, respectively. The above results indicate the suitability of using cloprostenol sodium for synchronization of oestrus in indigenous ewes in Bangladesh.

This study was designed to adopt two estrus synchronization protocols in zebu and crossbred heifers and their effects on pregnancy rate after timed artificial insemination (TAI). A number of 120 cyclic heifers were allotted for two different treatment groups and one control group. Heifers under protocol A were injected with GnRH at first day followed by a single dose of at Day 11 and injection of GnRH at the day of AI; and heifers belonged to protocol B were treated with GnRH, two injections at 11 days apart and injection of GnRH at AI. AI was done at fixed time (within 72~96 hours after injection) in both protocols and pregnancy was confirmed by rectal palpation on 80~120 days of post AI. In control group; local heifers were conceived higher (30%) proportion than that of crossbred heifers (25%; p<0.05). In protocol A, the local breed were conceived higher (38.9%) proportion compared with crossbred (25%; p<0.05). In protocol B, local breed heifers were conceived higher (38.9%) proportion compared with crossbred heifers (33.3%; p<0.05). The overall pregnancy rate in protocol A and protocol B was 33.3% and 36.6%, respectively. The proportion of pregnancy rate of local heifers (38.9%; Protocol A) was significant (p<0.05) in comparison with local heifers (30%) in control group (p<0.05). The overall pregnancy rate between pooled control group (28.3%) and treatment group (35%) was significantly (p<0.05) differ from each other's. Results of present study concluded that estrus synchronization followed by fixed time AI could be applied for higher pregnancy rate in zebu and crossbred heifers.

A study was conducted on four crossbred bulls, used as artificial insemination (AI) sires, to correlate their semen quality with their non return rate (NRR). Semen was collected once a week via an artificial vagina, diluted in egg yolk-citrate and maintained at for three days. It was evaluated for sperm motility, viability, morphology immediately after collection and was examined daily for sperm motility, viability and morphology of acrosome, mid piece and tail for a total of three days. A total of 2016 cows were inseminated by two AI technicians. The proportions of sperm with normal heads were 83.4% (63.7~91.7%), the proportion of spermatozoa exhibiting normal morphology (acrosome, mid piece and tail), motility and viability were 89.2% (82.3~92.0%), 71.3% (61.7~75.0%) and 76.7% (65.7~85.0%), respectively in fresh ejaculates. Sperm motility and sperm viability was significantly ( <0.05) lower in Holstein-Friesian Local bull than in other bulls during all three days of storage. The overall NRR for four bulls was 82.7% (72.9-87.5%). Bulls with higher sperm motility, viability and normal morphology of spermatozoa of individual bull had significantly (each <0.05) higher NRR. The highest ( <0.01) NRR (87.5%) was observed in a Red Chittagong bull whose semen qualities were significantly ( <0.05) higher than Holstein-Friesian Local bull (NNR 72.9%). The results of the present study concluded that NRR at 56 days post AI is related to parameters of semen quality. Therefore, semen evaluation may allow the discarding of bulls with poor fertility in an AI program.

Ovulation synchronization (ovsynch) has proved to increase the number of insemination in cattle by overcoming the problems of heat detection. The aim of this study was to do ovsynch in water buffaloes where heat detection is a major reproductive problem and to determine the conception rates after timed artificial insemination (TAI). Twenty cyclic buffaloes at 60 days postpartum were selected by examining 24 unobserved estrus buffaloes based on milk progesterone assay (progesterone concentration 1.0 ng/ml) from the Mymensingh district of Bangladesh. Ovsynch treatment regimen was started irrespective of the stage of estrous cycle. Gonadorelin (500 ) was injected intramuscularly at Day 0 followed by Alfaprostol (8 mg) at Day 7. A second injection of Gonadorelin was given at Day 9 and TAI was done with frozen semen from Mediterranean buffalo bulls at 16~20 hours of the second Gonadorelin injection. Milk progesterone ELISA at Day 10~12 post AI confirmed ovulation in 16 out of 20 (80%) buffaloes (progesterone concentration 1.0 ng/ml). High progesterone concentration ( 1.0 ng/ml) at Day 10~12 and Day 22~24 of AI showed pregnancy in six out of 20 (30%) buffaloes. Pregnancy was further confirmed by ultrasonography at Day 40 in these six buffaloes. In conclusion, ovsynch followed by TAI could be applied in cyclic buffaloes for overcoming the estrus detection problems; however, more studies are needed to increase the conception rate.

Successful in vitro embryo production heavily relies on the normal maturation and fertilisation of oocytes. We examined the normal and abnormal fertilisation of zebu cattle oocytes matured in vitro. Immature cumulus oocyte complexes (COCs) from zebu cattle ovaries at slaughter were matured in vitro (IVM) for 24 h. The oocytes were either fixed, stained and examined for nuclear changes or fertilised in vitro (IVF) with Percoll-separated, heparintreated spermatozoa (1.0 /mL) of zebu (n = 7) and crossbred bulls (n = 7). After 18 h of sperm-COCs co-incubation at C with 5% in humidified air, the presumptive zygotes were fixed, stained and examined for pronuclei. The number of oocytes retrieved per ovary was 5.4 0.7. The percentage of matured oocytes was 73.0. The difference in motility of spermatozoa before and after Percoll seperation was significant (p<0.001). The percentages of normal and abnormal fertilisation (polyspermia and oocytes with one pronucleus) varied significantly depending on individual bulls (p<0.05). A protocol for IVF of IVM oocytes in Bangladeshi zebu cattle is developed. A future study may elucidate the capacity of such IVM-IVF oocytes to develop to the blastocyst stage for transfer to surrogate mother.