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Kerala Veterinary and Animal Sciences University, Wayanad
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ThesisItem Open Access EFFECT OF PROCESSING AND FREEZING PROCEDURES ON THE ACROSOME MORPHOLOGY OF BUCK SPERMATOZOA(College of Veterinary and animal Science,Mannuthy, 1998) RANJINI. A.; K. Prabhakaran NairSix pooled semen samples (two ejaculates) of good quality from five Malabari crossbred bucks were processed and frozen in two different protocols to evaluate the effect of processing and freezing procedures on the acrosome morphology of buck spermatozoa. in protocol I. the samples were diluted 10 fold in Tris buffer before centrrfuging twice and the final pellet was re-suspended in the non glycerolated fraction of Tris yolk diluent. The sample was glycerolated {six per cent), equilibrated (four hours), frozen (eight minutes), and thawed (25° C for 30 seconds). In protocol II. centrifugation was done only once, after 15 fold dilution in Tris buffer. The re suspended pellet was glycerolated (seven per cent), equilibrated (three hours), frozen (10 minutes) and thawed (60° C for 10 seconds). The semen characters such as motility. live sperm, sperm abnormalities and acrosome abnormalities were evaluated at the end of washing and initial extension (stage I), cooling to 5° C (stage II). glycerolisation and equilibration (stage III) and freezing and thawing (stage IV). The results were compiled to evaluate the effect of different processing and freezing procedures on the semen characters in general and acrosome morphology in particular. The semen sample used for split sample dilution had a mean volume of 1.328 + 0.067 ml. creamy in colour. DDDD density, ++++ mass activity. pH of 7.275 ± 0.040 and a concentration of 2972 ± 293 millions per ml. No significant difference in the above semen characters were found between bucks. The initial sperm motility of 82.000 + 0.606 was found to drop significantly during processing and freezing and the final post thaw motility obtained was 44.000 + 0.790 in protocol 1. Similarly in protocol II the initial motility dropped from 81375 ± 1.089 to 44.750 + 1.075 at the end of stage IV. Even though there was significant drop in motility between stages in both the protocols, there was no significant difference in the corresponding stages of the two protocols. It could be inferred that good post thaw motility was obtained in both the protocols. The fact that a single washing and centrifugation was only adopted in protocol II makes it a more acceptable procedure for buck semen freezing. The mean live sperm percentage of fresh semen was evaluated using both NE and NEG staining technique. The percentage of live sperms of 90.050 + 0.801 was found to decrease to 54.250 + 0.593 after freezing and thawing in protocol by NE staining. Similarly in protocol II, the mean percentage of live sperms was found to reduce to 53.125 + 0.793 with the same staining. Even though there was significant difference in the live sperm percentage between stages within protocol I and II no significant difference in the live sperm percentage between the corresponding stages of protocol I and II . With NEG staining the initial live sperm percentage of 80.850 + 1.494 was found to drop to 54.875 + 0.677 in protocol I as against 53.400 ± 0.730 in protocol II. While there was significant difference in the live sperm percentage between stages within protocol I and II there was no variation between corresponding stages of the two protocols. A significantly lower percentage of live sperms was recorded with NEG staining when compared with NE staining probably on account of the fact that the differentiation of live and dead sperm was difficult in the former staining method as live sperms were stained light blue instead of colourless. The mean percentage of abnormal sperms of 3.050 + 0.245 in fresh semen did not register any significant increase during processing. However, there was significant increase in the percentage of sperm abnormalities during freezing and thawing with the final abnormality percentage of 7.125 + 0.706 in protocol I and 6.300 + 0.36 in protocol II. The initial acrosomal abnormality of 8.825 in the fresh semen steadily rose to 23.375 in protocol I as against 19.825 in protocol II at the end of stage IV. There was no significant difference in the percentage of various acrosomal abnormalities between corresponding stages of the two protocols. However, there was significant increase in the acrosomal abnormalities during glycerolisation, equilibration, freezing and thawing under both the protocols. It was concluded that the processing and freezing under two different protocols did not significantly alter the post thaw motility, percentage abnormal and dead sperms and acrosomal abnormalities. A good post thaw motility and low acrosomal abnormality was obtained with a single washing of buck semen with 15 fold Tris buffer which was comparable with double washing with 10 fold Tris buffer.ThesisItem Open Access PROSTAGLANDIN THERAPY FOR POST - PARTUM CLINICAL ENDOMETRITIS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 1993) T. C. JACOB; E MadhavanThe object of the investigation was to evaluate the therapeutic values of PGF2 alpha, for evolving a non antibiotic alternative for the treatment of post partum clinical endometritis. For this, 42 cross-bred cows, belonging to University Livestock Farm, Mannuthy, having post partum clinical endometritis were divided into four groups. Group I consisted of 10 animals which were watched for their natural oestrus and inseminated twice at 24 hours interval. In group II, 11 animals were observed for their natural oestrus and inseminated twice at 24 hours interval and were given post insemination intrauterine antibiotic treatment 24 hours later based on antibiotic sensitivity test. Eleven animals in group III were subjected to induction of oestrus by administration of PGF2 alpha (Lutalyse) 25 mg intramuscular 8-12 days of their cycle and inseminated twice at 24 hours, at the induced oestrus. Group IV consisted of 10 animals subjected to induction of oestrus as in group III and inseminated twice at 24 hours interval and were given post insemination intrauterine antibiotic therapy based on sensitivity tests, 24 hours later. The observations made and inferences drawn are given below. The interval from the administration of PGF2 alpha to the onset of oestrus ranged from 48-120 hours (mean 61.81 hours) and 36 to 72 hours (mean 54.0 hours) in group III and IV, respectively. The mean duration of oestrus was 21.6 hours, 23.36 hours, 28.36 hours and 31.60 hours in the four groups respectively. The duration of oestrus showed significant variation between groups I and IV (f = 2-8910) and between groups II and IV (f = 2.6445). The percentage of intense, medium and weak oestrus was 66.66, 23.80 and 9.52 per cent respectively in natural oestrus and 66.66, 19.04 and 14.28 in induced oestrus respectively. The difference in the intensity of oestrus between natural and induced oestrus was not significantly different, although, a slightly high incidence of weak oestrus was observed, when oestrus was induced with Lutalyse. Physical changes of the reproductive tract like oedema of the vulva, congestion of vulval mucosa and sliminess did not show any variation between the natural oestrus and induced oestrus. The percentage of animals showing purulent discharge, discharge with flakes and cloudy discharge showed a marked reduction when treated with PGF2 alpha alone and a combination of PGF2 alpha and antibiotics. Similarly the percentage of animals showing clear discharge increased enormously by above treatments. The bacterial organisms isolated from the uterine discharges were citrobacter spp. 23.84 per cent. Bacillus spp. 23.80 per cent, S. aureus 14.28 per cent, Pseudomonas 14.28 per cent, Corynebacterium spp. 9.52 per cent, Coagulase negative staphylococci, 9.52 per cent and the yeast Candida guilliermondii 4.76 per cent. Gentamicin was the most sensitive antibiotic for most of the organisms isolated, followed by chloramphenicol, oxytetracycline and sulphadiazine. Penicillin was the most resistant followed by streptomycin and nitrofurantoin. Significant difference in the overall conception rate was observed between different groups; the overall conception rate was significantly higher in group IV than in group I and II (t' = 4.8341 between groups I & IV and t' = 2.9186 between groups II & IV). Significantly higher conception rate was observed in group III than group I also (f = 5.5886). The number of inseminations required per conception was lowest in group III and highest in group I. Thus, it appeared that PGF2 alpha in combination with antibiotic was beneficial in the treatment of clinical endometritis. But since the number of inseminations required for conception was lower in group III than group IV and because, there is no significant difference in the overall conception rate, between these two groups, it could be inferred that administration of antibiotics along with PGF2 alpha did not have any added advantage. Furthermore, considering the harmful effects of administration of antibiotics, it may be stated that PGF2 alpha alone would be beneficial in the treatment of post partum clinical endometritis and can be recommended as the drug of choice.ThesisItem Open Access SEASONAL FERTILITY OF BILLY GOATS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 1995) C. IBRAHEEM KUTTY; V SudarsananBiweekly data on body weight, scrota! circumference, testicular length and diameter and weekly data on semen parameters as volume, colour, pH, consistency, density, sperm concentration, mass activity, initial motility, sperm abnormality, vitality, metabolism and resistance to hyperosmotic medium of seven billy goats were observed for a period of one year. The data was grouped into four pertaining to four seasons aixived at on the basis of a simultaneously kept daily record of maximum-minimum temperature, humidity and day length. It was statistically analysed to find out that the differences between seasons were significant to be attributed to the environmental variables. Mean body weight, scrota! circumference and testicular length and diameter were 43.62±1.11 kg, 25.08 +0.12 cm, 8.57+0.07 cm and 5.32+0.03 cm respectively. There was no significant difference between the seasons except in testicular diameter and they were foimd to maintain an inverse relationship with day length and humidity. Mean volume, pH, initial motility, sperm concentration, total number of sperm per ejaculate, live sperm per cent, abnonnal spenn per cent, MBR time and R value were 0.75=0.04 ml, 6.25+0.02, 73.51 ±0.98 per cent, 3600±144 millions/ml, 2660.6 + 133.96 millions, 83.44+0.76, 4.33=0.43, 277.1 ±14.27 seconds and 84.75 ±12.39 ml respectively. There was no significant difference between seasons in these parameters except pH, initial motility, live sperm per cent and R value. They were found to have a significant difference between seasons and were found to maintain either direct or indirect relationship with humidity and day length. Semen on extension with milk antibiotic extender and on storage under relfigeration was found to fast deteriorate rendering it unusable in 24 h. Semen on the day of collection and extension, was used for artificial insemination and result of insemination was found to be independent of the significant or nonsignificant seasonal differences of semen parameters. But, during the period of smdy, there were two peaks in conception and two peaks in birth corresponding to it. The pattern appeared to be an adjustment of reproduction by the female to the varying food availability and climate with little involvement of the male.ThesisItem Open Access SUPEROVULATION AND EMBRYO RECOVERY IN RABBITS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES Mannuthy - Thrissur, 1997) SATHESH KUMAR, S.; Suresh Nair, S.P; SATHESH KUMAR, S.Superovulation was induced in Newzealand White and Soviet Chinchilla breeds of rabbits by administration of a single dose of 150 lU PMSG followed by double mating at induced cycle and 150 lU HCG soon after second mating to induce ovulation. The onset and intensity of oestrum, number of ovulations, embryo recovery and quality of embryos were studied and compared with those of the controls of the respective breeds. The mean interval from PMSG administration to onset of oestrus in both the breeds was 56.0 ± 5.1 h. It was further observed that most of the treated animals showed intense oestrum when compared to controls. The ovulation rate based on the number of corporalutea in control animals of Newzealand White breed was 4.7 ± 1.2 as against 22.0 ± 1.35 in the treated group. There was significant difference (P<0.01) in the ovulation rate between the groups. The percentages of embryo recovery, fertile embryos and transferrable embryos in the control group were 47.22, 86.7 and 92.3 while those of the treatment group were 31.67, 100 and 87.8 respectively. There was no statistically significant difference between the groups. While the control animals in Soviet Chinchilla breed had an ovulation rate of 6.7 ± 0.65, the treated rabbits showed a higher ovulation rate of 20.0 ± 3.2. There was significantly higher ovulation rate (P<0.01) in treated group when compared to controls. The embryo recovery rate, fertilized embryos and transferrable embryos in the control group were 53.33 per cent, 77.8 per cent and 93.8 per cent respectively. The corresponding values in the treatment group were 36.27 per cent, 69.82 per cent and 93.1 per cent respectively. There was no significant difference between the groups. No breed influence on the above parameters could also be noticed in this study It may be concluded that superovulation could be successfully induced in Newzealand White and Soviet Chinchilla breeds of rabbits with single dose of 150 lU PMSG, followed by 150 lU HOG soon after second mating. Eventhough there was superovulation, the embryo recovery rate was comparatively lower in the treated group probably on account of an altered oestrogen-progesterone profile interfering with the transport of the zygote, however the fertilization rate and the quality of the embryos were unaffected with the superovulation treatment.ThesisItem Open Access REPRODUCTIVE PERFORMANCE OF COWS UNDER HOMOEOTHERMAL DISTURBANCES(COLLEGE OF VETERINARY AND ANIMAL SCIENCE,MANNUTHY, 1995) ATHMAN, K V; Sudarsanan, VBased on the data on the maximum, minimum temperature and humidity for a period of two years, a year of study was divided into four seasons of JJA, SON, DJF and MAM. The mean maximum environmental temperature of the seasons were 29.56, 31.52, 32.73 and 34.88°C respectively. Two thousand two hundred and ninety eight cows brought to the AX centre from the homesteads of Mannuthy were grouped into 11 treatments of pre and post insemination rests and no rests. They were bred by artificial insemination and results of insemination were assessed on the basis of non-return. Mean conception rate of the seasons were statistically analysed to know the effect of environmental temperature and the effect of pre and post insemination rests to the animals. There was no significant difference in conceptions between seasons, between the post insemination rests and no rests and between pre insemination rests of 30 and 60 minutes and no rest. Conception per cent was icantly higher in the animals those were given pre insemination rest for 90 and 120 minutes. Animals with light coat colour had a significantly higher conception rate than those with dark colour irrespective of the seasons. Animals inseminated in the afternoon were generally found to have a better conception rate than those inseminated in the forenoon. There was no significant difference in the conception rate of heifers and cows both between seasons and between themselves. So also, there was no significant difference in conception rate of parity groups both between seasons and between themselves. Statistical analysis of seasonal mean weight of foetal membranes, mean number of cotyledons and mean area of cotyledons and mean birth weight of calves did not show any correlation to suggest influence of seasonal environmental temperature on placental development and birth weight of calves.ThesisItem Open Access SUPEROVULATORY RESPONSE, EMBRYO COLLECTION AND TRANSFER IN CROSSBRED COWS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES Mannuthy - Thrissur, 1996) UNNIKRISHNAN, M. P.; Suresan Nair, S.P.; UNNIKRISHNAN, M. P.Out of eleven crossbred cows superovulated with 2000 lu of PMSG on day eleven and 25 mg pgp, alpha 48 h later, nine animals ,81.8t, exhibited oestrum after an average interval of 39.44 ± 2.44 h. Average duration of oestrum was 40.00 ± 2.00 h with 66.7 per cent of them exhibiting intense heat signs and 33.3 per cent exhibiting only moderate heat signs. Average number of corpora lutea and unovulated follicles in both the ovarres put together was 6.67 r 0.50 and 6.22 s o 57 respectively, ovarian response was more in right ovary than in left ovary, though not statistically significant. Average fluid recovery on flushing was 79.5 per cent which was comparatively low. The average e^ryo recovery and percentage of embryo recovery were 3.38 ^ 0.70 and 53.11 , 10.18 respectively, which was comparatively lower. The reason for poor recovery of embryo was attributed to poor fluid ery on flushing. The average number and percentage of fransferrable embryo recovered were 1.50 i 0.53 and 33 34 i 10^14. Reason for these lower rates were attributed to loss of ryo quality, due to prolonged action of PMSG. Donors of parity over three performed better on =, us i.ng, than those below three. Animals o®f^PSi^ovulation and -animals of age group six to nine years produced more transf err;,hi o k ransferrable embryos than cows of age group ten and above. A conception rate of 30 per cent was achieved after ^^^^sfer of enibryos to naturally synchronised recipients. Heifers appeared to be better recipients than cows. Although a high incidence of abortion was encountered, birth of an embryo transfer male calf was also recorded in the study. All the donor cows came into regular oestrous cycle within four months of superovulation treatment.ThesisItem Open Access INTRA-UTERINE INFUSION OF HOMOLOGOUS PLASMA IN THE TREATMENT OF ENDOMETRITIS IN COWS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES Mannuthy - Thrissur, 1995) VENUGOPAL, R.; Prabhakaran Nair, K.; VENUGOPAL, R.The present study was undertaken on infertile cows with uterine infections, with the objective to evaluate the beneficial effect of intra-uterine infusion of homologous plasma as a non antibiotic alternate therapy for bovine endometritis. The luminal secretions of cows with clinical endometritis allotted to group I (n=13) and II (n=10) were aseptically collected at the time of oestrum and subjected to plate count to assess the uterine bacterial load prior to treatment. Cows belonging to group I were given 25 to 35 ml of homologous plasma as intra-uterine infusion on the day of oestrum whereas in control group (group II) the cows were given 25 to 35 ml of sterile normal saline as intra-uterine infusion. Luminal secretions of all the cows were collected aseptically at the succeeding oestrus following treatment and the uterine bacterijal load was estimated. Cows which shov^ed recovery in terms of clinico-gynaecological findings were bred artificially. Following plasma therapy definite improvement as evidenced by clear uterine discharge, higher uterine tone and intensity of oestrum was noticed in the treatment group. These changes were not pronounced in the control group. The mean uterine bacterial load showed reduction after intra-uterine treatment in both group I and II, however the reduction was statistically insignificant. The mean duration from intra-uterine treatment to succeeding oestrus was prolonged in group I (28.23 ± 4.67 d) as against normal in group II (20.3 ± 0.4 d). The first insemination conception rate recorded in group I was 53.85 per cent as against 40 per cent in group II showing that there was definite improvement in conception rate following plasma treatment. Repeat breeder cows with subclinical first degree endometritis allotted to group III were administered 25 to 35ml homologous plasma 24 h after insemination whereas repeat breeders (group IV) were left untreated following insemination. The mean conception rate for group III was 36.36 as against 20 per cent for group IV. This result also signifies the beneficial effect of plasma treatment in improving conception rate of repeat breeders. An in vitro test to study the antibacterial effect of plasma was carried out by measuring the reduction in turbidity of a bacterial suspension on addition of plasma. It was found that the reduction in turbidity was significant (P<0.05) in plasma tubes compared to saline tubes. Maximum reduction had occurred within 0 to 1 h interval in plasma tubes. This indicated an immediate antibacterial effect of plasma It could be inferred from the above findings that homologous plasma drawn from the cow at the time of oestrum has significant bactericidal and bacteriostatic properties and when infused into the uterus of cows affected with endometritis helps in quicker clinical recovery and better conception rate. Post insemination plasma infusion into the uterus also improved conception rate in repeat breeders. Hence plasma treatment is recommended as an effective less expensive and non antibiotic alternate therapy for endometritis and repeat breeding in cows.ThesisItem Open Access CERTAIN HAEMATOLOGICAL PARAMETERS AND BLOOD BIOCHEMICAL CONSTITUENTS IN COWS WITH NORMAL AND IMPAIRED FERTILITY(COLLEGE OF VETERINARY AND ANIMAL SCIENCE,MANNUTHY, 1993) ANI.S. DAS; Neelakanta Iyer, CPA Study was conducted to asses the influence of certain haematological parameters like haemoglobin (Hb) and packed cell volume (PCV) and biochemical constituents like total serum protein, serum phosphorus, total blood cholesterol and blood glucose in crossbred cows and the efficacy of replacement therapy of glucose and phosphorus on fertility in deficient animals. Animals which had apparently normal breeding history and conceived with one or two inseminations were classified into group I. Animals that were hard to settle and apparently deficient in nutrition but clinically free from ary genital affections were classified into group II. Blood samples were collected from all these animals at oestrus and levels of Hb, PCV, serum total protein, serum phosphorus, blood glucose and total blood cholesterol were estimated. After estimation of blood constituents the cows in group II were divided into two. Animals in group II A were inseminated without any treatment and animals in group II B were administered 15 ml of Tonophosphan by intravenous injection or 540 ml of 25 per cent dextrose as intravenous infusion or both based on the deficiency of phosphorus or glucose alone or in combination. The levels of Hb, PCV, serum phosphorus, blood glucose, total serum protein and total serum cholesterol were 11 10.06+0.06 g per cent, 31+1.33 per cent, 4.85+0.343 mg per cent, 46.10+3.19 mg per cent and 7.00+0.99 g per cent and 95.09+8.67 mg per cent respectively in normally fertile cows. In cows with impaired fertility which were deficient in different constituents the corresponding levels were 6.86+0.75 g per cent, 21.50+0.50 per cent, 3.65+0.068 mg per cent, 31.13+0.726 mg per cent, 4.57+0.30 g per cent and 71.36+1.66 mg per cent respectively, all of which were significantly lower than their corresponding levels in normally fertile cows (P <0.10). The overall conception rate was 81.80 per cent 11.11 per cent and 77.77 per cent in group I, group IIA and II B cows. Conception rate of cows with lower levels of Hb (zero) was significantly lower than the conception rate (50 %) observed in animals with normal level of Hb (P <0.05). Similarly the same in cows with normal and low levels of PCV was 40.75 per cent and zero respectively. Cows with low levels of serum protein and serum phosphorus had conception rate of 40.70 per cent and 8.30 per cent against 46.70 per and 71.40 per cent in animals with normal values. Statistical analysis revealed significant difference in the case of phosphorus (P<0.01). Similarly cows with low levels of blood glucose and total cholesterol also had lix significantly low (P<0.01) conception rates (7.69 and 13.33% respectively) as against that in normal cows (70 and 69.20%). Animals when treated with phosphorus alone 71.42 per cent conceived as against 25 per cent in non treated group. Similarly 75 per cent of animals conceived when treated with glucose compared to 12.5 per cent conception rate in non treated group. When cows were given combined treatment of glucose and phosphorus conception rate was 87.5 per cent while none conceived in non treated group. This difference was statistically highly significant (P <0.01).ThesisItem Open Access MANAGEMENT OF OESTROUS CYCLE IN CROSSBRED CATTLE USING PROSTAGLANDIN(COLLEGE OF VETERINARY AND ANIMAL SCIENCE,MANNUTHY, 1994) AJIT KUMAR, g; MADHAVAN, EWith the object of studying the efficacy of administration of prostaglandin F2 alpha in the management of oestrous cycle and fertility of fixed time insemination in induced oestrus, 96 heifers and cows which were cycling, selected from Kerala Agricultural University Livestock Farms, v/ere allotted to three different groups. Sixteen heifers and 16 cows in group I v/ere given 25 mg PGF2 alpha (Lutalyse) intramuscularly v;hen they had functional corpora lutea, v/hile in group II, 16 heifers and 16 cows were administered two injections of PGF2 alpha 25 mg each 13 days apart. Sixteen heifers and 16 cows were treated as control (Group III). Tv/elve heifers (75%) and 16 cows (100%) in group I and all animals in group II responded to treatment. Mean tim.e taken for induction of oestrus was 56.64 and 65.44 h respectively in heifers and cov;s. This difference was statistically significant. Parity of cows significantly influenced the time taken for induction of oestrus. Duration of oestrus was significantly different between heifers (21.86 h) and cows (31.13h)' of the experimental group. Significant difference in the duration of oestrus v/as observed among cows between experimental and control groups. All experimental animals v/hich responded to PGF2 alpha showed marginal increase in physical characters of the reproductive tract like vulval oedema, hyperaemia of vaginal mucosa, vulval discharge and tonicity of uterine horns. Majority of the experimental animals shov/ed medium to high intensity of oestrus compared to natural oestrus. The first insemination and overall conception rates of heifers in group I, inseminated 72 h post-treatment, were 33.33 and 66.67 per cent respectively as against 33.33 and 50 per cent when inseminated 96 h post-treatment. Cows in group I recorded 25 and 62.50 per cent and 37.50 and 62.50 per cent first insemination and overall conception rates respectively when inseminated 72 h and 96 h posttreatment. When heifers and cov/s in group II were inseminated 72 h after the administration of the second dose of PGF2 alpha, 12.50 and 25 per cent conceived at first insemination with overall conception rate of 62.50 and 37.50 per cent respectively. The corresponding values in group II, when inseminated 96 h, were 25 and 12.5 per cent and 50 and 12.5 per cent respectively. Among control 6.25 per cent of heifers and 18.75 per cent of cows conceived at first insemination. The first insemination conception rate of heifers of experimental (25%) and control groups' (6.25%) were significantly different. However, overall conception rate did not differ between the three groups. There v;as no influence of parity or season on the conception rate. Similarly the time taken for induction of oestrus, duration of oestrus, physical changes of the reproductive tract during oestrus and intensity of oestrus did not affect the conception rate. Heifers and cows required 1.88 and 1.93 inseminations respectively per conception when treated with PGF2 alpha as against 3.14 and 3.33 in the control group. Though, the present investigation revealed that PGF2 alpha can be used in the management of oestrous cycle in crossbred heifers and cows with fixed time insemination, the high cost of the drug and the conception rate obtained warrant further studies on fertility in relation to detected .oestrus and fixed time insemination after the administration of PGF2 alpha.