Pregnant Buffaloes Research Articles

COMPARATIVE MORPHOLOGICAL FEATURES OF THE PLACENTAL BARRIER AND LOCALIZATION OF ESTROGEN RECEPTORS α IN THE PLACENTA OF COWS AND BUFFALOES

The present study was conducted to identify the morphological characteristics of the placental barrier and localization of estrogen receptors α in the cow and buffalo placentas. Placentomes were collected from 3 pregnant cows and 3 pregnant buffaloes at the 5th and 6th months of gestation respectively. The placentomes were fixed by using 10% neutral buffered formalin for immunohistochimestry and were post fixed in 3% glutaraldehyde for light microscopy. Indirect immunoperoxidase staining methods using monoclonal antibody against bovine ERα as primary antibody was applied. The morphometric data were obtained by using Q500 MC Image processing and analysis program. Histological examination revealed that there is a great similarity in the structure of the placental barrier of cows and buffaloes, whereas typical six slayers of tissue were seen separating the fetal blood from the maternal one. These layers were maternal endothelium, thin layer of maternal connective tissue, maternal uterine epithelial cells, fetal trophoblast cells, fetal connective tissue and fetal endothelium. Nuclear immunoreactivities occurred mainly in the maternal crypt epithelium and maternal connective tissue cells. In about 1000 maternal uterine cryptal cells, 87.6% were positive cells for ERα in the cow placenta and about 67.8% were positive cells in the buffalo placenta. The present study concluded that although there is a great similarity in the structure of the placental barrier and expression of ERα in the placentas of cows and buffaloes interbreeding between the two species is impossible due to the different number of chromosomes set. The placenta of cows seems to be less responsive to estrogen in comparison to that of buffaloes.

Use of GnRH to induce an accessory corpus luteum in buffaloes fixed time artificially inseminated

The objective of this study was to induce an accessory corpus luteum (CL) in buffaloes fixed time artificially inseminated. Two hundred and forty buffaloes received the treatment sequence GnRH/PGF2α/GnRH after which were inseminated artificially. Six days after the insemination, the animals were divided in two groups (G1 = Control and G2 = GnRH) and received 0 µg or 25 µg of GnRH to induce an accessory CL. After twenty four days (D40), pregnancy diagnosis was performed by ultrasonography and 79 buffalo (G1, n = 39; G2, n = 40) were randomly selected to verify the ovary status by ultrasound. Fifty three pregnant buffaloes (G1, n = 32; G2, n = 21) were followed to verify the birth rate. Data were analyzed by Chi-square test. The conception rate, the accessory CL rate and the birth rate were higher in G2 than in G1 (P<0.05). The use of GnRH to induce an accessory CL in buffaloes increased the conception and birth rates. Thus, the increase of the cost of Ovsynch protocol with the thirty dose of GnRH is rewarded by the increment on conception and birth rates and reduction of days open.

Strategies to reduce embryonic mortality in buffalo cows

The aim of the present study was to examine whether treatment with a GnRH agonist, hCG or P4 on Day 25 after AI increased P4 concentrations and reduced the incidence of embryonic mortality (EM) in pregnant buffaloes mated in mid-winter in a Mediterranean environment. The trial was carried out in two farms characterized, in previous years, by low (LEM Group), 153 buffaloes (DIM=150±7 days), and high (HEM Group), 284 buffaloes (DIM=163±5 days), incidence of embryo mortality. Animals were synchronized by Ovsynch-TAI Program and artificially inseminated. On day 25, pregnant buffaloes were randomly assigned to four groups: Control (no treatment), GnRH agonist (buserelin acetate, 12.6 µg), hCG (1500 IU) and P4 (341 mg of P4 i.m. every 4 days for three times). Progesterone (pg/ml) was determined in milk whey on Days 10, 20 and 25 after AI in all buffaloes and in Days 30 and 45 only in buffaloes pregnant on day 25 and assigned to four groups of treatment. Pregnancy diagnosis was undertaken on Day 45 by ultrasound. All treatments increased P4 milk whey and reduced embryonic mortality in buffalo cows bred in the farm characterized by high EM.

Ovary response and embryonic mortality in buffaloes treated with GnRH or hCG

The aim of the present study was to examine whether treatment with a GnRH agonist or hCG in pregnant buffaloes on Day 25 after AI induce ovulation and increased P4 concentrations. The trial was carried out on 98 pluriparous buffaloes (DIM = 163 ± 75 days) diagnosed pregnant by ultrasound on day 25 after AI, and randomly assigned in two treatment groups GnRH (12 µg of Buserelin Acetate i.m) and hCG (1500 I.U. i.m.) after measurements of follicular diameter and evaluated ovulation. Milk samples were collected on Days 30 and 45 after AI, to assess P4 concentrations in whey. Differences between the follicular diameters of ovulation and P4 were tested by ANOVA. The incidences of animals which responded to the two treatments were analysed by Chi square test. The treatments on day 25 after AI induced ovulation respectively in 68.6% (GnRH) and 57.4% (hCG) of the buffaloes. No differences were found between diameter of follicle ovulated. Ovulation increased milk whey progesterone levels and reduced embryonic mortality in buffalo cows.

Hemato-biochemical andclinico-epidemiological aspects of parturient hemoglobinuria in Nili-Ravi buffaloes

For this study, 60 buffaloes suffering from parturient hemoglobinuria (PHU) were randomly selected from field cases occurring in three districts of Punjab, Pakistan and simultaneously, 60 clinically healthy buffaloes of similar description from the same localities were included for case control study. Clinico-epidemiological data were collected. Blood/serum samples from all buffaloes were collected and analyzed. The most prominent clinical sign was passing of red to coffee colored urine. Milk production was reduced and respiration and pulse rates were significantly accelerated. Ruminal motility was significantly weak and reduced along with characteristic straining while defecating. The case fatality was 15%. A significantly high occurrence of PHU was observed in the winter season (41.8%). Maximum number of affected buffaloes (25.0%) was in 4th lactation. Twenty-seven (45.0%) buffaloes developed hemoglobinuria in the post calving period and majority (59.3%) of these were within 1-23 days of calving. Of the 33 (55.0%) PHU affected pregnant buffaloes, 18 (54.6%) were in their third trimester. The highest cases of PHU were observed in buffaloes producing 10 or more liters of milk/day (42.5%). Recurrence of PHU was observed in 18.3% buffaloes. Mean values of total erythrocyte counts, hemoglobin concentration and packed cell volume were lower (P<0.001), while erythrocyte sediment rate was higher (P<0.001) in PHU affected buffaloes as compared to the values in healthy buffaloes. Neutrophils were significantly higher, while lymphocytes and erythrocytic glucose-6-phosphate dehydrogenase (G6PD) were lower, in PHU affected buffaloes than in healthy buffaloes. Serum phosphorus, copper and selenium were significantly (P<0.001) lower, whereas potassium, iron and molybdenum (P<0.001) were higher in buffaloes suffering from PHU than healthy buffaloes.

Values of Prostaglandin during Pre and Post-Partum and at parturition in buffaloes

This study was carried out at Mehallet Mousa Animal production Research station, Animal production Research institute- ministry of agriculture, Egypt. This work was carried out on ten late pregnant buffaloes for studying prostaglandin (PG F2α) during pre and post partum periods. Blood samples were collected five days prepartum and one week postpartum.Prostaglandin was determined by Elisa (Enzyme-Limked immunosorbant Assay). The results, showed that the plasma prostaglandin levels on day three, two and one prepartum was higher than on day five prepartum. On The day of delivery (0 day) a sudden sharp increase in PGF2& con concentration occurred (180.83±4.23 pg/ml) followed by a gradual decrease in the plasma concentration. Of PGF2α on day four, five, six and seven postpartum, small respectively.

Adverse response of non‐indigenous cattle of European breeds to live attenuated Smithburn Rift Valley fever vaccine

Three hundred eighteen European cows and 115 buffaloes were vaccinated with locally prepared Smithburn vaccine, of which, 100 cows and 20 buffaloes were pregnant. Twenty-eight cows aborted within 72 days post-vaccination, buffaloes did not abort. Blood samples collected 77 days post-vaccination from aborted cows, 17 pregnant cows, 5 pregnant buffaloes, and 32 non-pregnant cows. Sera were tested by ELISA for anti-RVF IgM and IgG. All aborted cows were strongly positive for IgG. Five of 17 cows and two of five buffaloes that did not abort were IgG positive. The percentage of IgM positives in aborted cows was 25% and 0% in non-aborted cows. The percentage of IgG positives in pregnant non-aborted cows was lower than in non-pregnant cows. The percentage of IgG positives of non-pregnant cows was lower than pregnant aborted cows. Virus was isolated from one aborted fetus. The nucleotide sequence of fetus virus was compared to Smithburn of Onderstepoort, local Smithburn and virus isolates from 1993 to 1994 and 1977 RVF outbreaks. The nucleotide sequences of Onderstepoort and Egyptian Smithburn vaccines were almost identical. The sequences of 1993-1994 isolates were identical to 1977 outbreak virus. Virus from the fetus had two mutations; it is apparently a variant that is genetically distant from local Smithburn and Onderstepoort vaccines. Fetus virus was genetically distant from virus of 1993/1994 and 1977 outbreaks. In conclusion, antibody response to vaccination with local Smithburn had occurred in some, but not all the cows and buffaloes. Virus isolation from the fetus suggests in utero transmission of used vaccine virus, which resulted in high abortions in European cows.

Studies on Vitamin Mineral Interactions in Relation to Passive Transfer of Immunoglobulins in Buffalo Calves

Status of blood minerals and their absorption by neonate calves as influenced by fat soluble vitamins supplementation in their respective mothers, mineral supplementation in calves themselves has been evaluated. The objective was to know the impact of antioxidant vitamin supplementation to advance pregnant buffaloes, on enhanced acquired immunity during first few hours after birth, in relation to weight gain in buffalo calves. Advance pregnant buffaloes (n = 30) consisting of average body weight of 550±15 kg and of 4- 6 parity were fed on 25 kg green (green Jawar-Sorghum bicolor), 2-3 kg wheat straw and 3-4 kg concentrate mixture individually per day. Intramuscular injections of vitamin triplex A D3 E consisting of -2,500,000 IU of vit A -Palmitate; 2,500,000 IU of vitamin D3 and 1,000 IU of vit E (dl-alpha tocopherol acetate) were given per dose, a month prior to parturition, twice at 15 days interval to 15 dams. Rest of the 15 pregnant buffaloes served as negative controls. Secretion of immune proteins, immunoglobulin (Ig) enhanced by 80% in colostrum. The blood serum levels of Zn, Cu, Ca, Mg were measured from birth to 90 days in calves. A significant (p<0.05) difference between the blood serum Zn levels of calves born to vitamin supplemented and non-supplemented dams was measured and a positive correlation between blood serum Zn levels and injections of vitamins was identified. Association of Zn and Cu with passive immunity status has been identified in these calves. A significant positive correlation between Zn and Cu was also identified which showed a change under the impact of vitamin supplementation in buffaloes. The study signifies the role of micronutrients supplementation in dams prior to parturition, in calf immunity development. The study indicates significant mineral - vitamins interactions during this process. (Asian-Aust. J. Anim. Sci. 2006. Vol 19, No. 6 : 825-830)

Reproductive Performance of Dairy Buffaloes Supplemented with Varying Levels of Vitamin E

The effect of vitamin E supplementation on plasma α-tocopherol level, total antioxidant level and reproductive performance in Murrah buffaloes was studied during periparturient period. Twenty-four advance pregnant buffaloes were randomly divided into four equal groups as T1, T2, T3 and T4 and were supplemented with 0, 1,000, 1,500 and 2,000 IU of α-tocopheryl acetate (Merck) from 60 days prepartum to 30 days postpartum and 0, 500, 750 and 1,000 IU from 30 to 60 days postpartum, respectively. Blood samples were collected at -60, -45, -30, -15, -7, 0, 7, 15, 30 and 60 days of parturition and were analyzed for plasma α-tocopherol and total antioxidant activity (TAA). The intake of DM, CP and TDN did not vary among different groups. Plasma α-tocopherol and TAA around parturition (-7 to 15 day) in T3 and T4 were significantly higher than the control group. There was 17% reduction in retention of fetal membranes (RFM) and metritis in T4 than control. The post partum estrus interval averaged 58.00, 55.33, 51.83 and 43.00 days in T1, T2, T3 and T4 respectively. There was significant reduction in days open in both T3 and T4 in comparison to T1 group (127,130 Vs.146). All the vitamin E supplemented groups showed reduction in days open than their previous lactation performance. Supplementation of vitamin E at 1,500 IU d -1 from 60 day prepartum to 30 day post partum to buffaloes exhibited beneficial effect on plasma α-tocopherol level and TAA around parturition and continuation of its supplementation at 1,000 IU d -1 from 30 to 60 days of lactation improved post partum reproductive performance of buffaloes. (Asian-Aust. J. Anim. Sci. 2006. Vol 19, No. 1 : 19-25)

Embryonic mortality in buffaloes synchronized and mated by AI during the seasonal decline in reproductive function

The aim was to determine the factors that contribute to embryonic mortality in buffaloes mated by AI during a period of increasing day length which corresponds to a natural decline in reproductive activity. Italian Mediterranean buffalo cows ( n = 243) showing regular estrous cycles were synchronized using the Ovsynch-TAI program and mated by AI at 16 and 40 h after the second injection of GnRH. Blood samples were collected on Days 10 and 20 after the first AI and assayed for progesterone ( P 4). Pregnancy diagnosis was undertaken on Days 26 and 40 after the first AI using rectal ultrasonography. Buffaloes with a conceptus on Day 26 but not on Day 40 were judged to have undergone embryonic mortality and for these animals uterine fluid was recovered by flushing and analysed for common infectious agents. Estrus synchronization was achieved in 86% of buffaloes and the pregnancy rate on Day 40 was 34%. Embryonic mortality between Days 26 and 40 occurred in 45% of buffaloes and was associated with the presence of significant infectious agents in only 10 buffaloes (8%). Concentrations of P 4 on Day 10 after AI were higher ( P < 0.05) in buffaloes that established a pregnancy than in buffaloes that showed embryonic mortality that was not associated with infectious agents. Similarly, on Day 20 after AI P 4 concentrations were higher ( P < 0.01) in pregnant buffaloes compared with non-pregnant buffaloes and buffaloes that had embryonic mortality. It is concluded that a reduced capacity for P 4 secretion can explain around 50% of embryonic mortalities in buffaloes synchronised and mated by AI during a period of low reproductive activity and that other as yet unidentified factors also have a significant effect on embryonic survival.

138EARLY EMBRYO MORTALITY IN BUFFALO (BUBALUS BUBALIS) DURING THE SPRING PERIOD

Embryo development is linked to several factors, such as intrinsic defects within the embryo, an inadequate maternal environment or failure of maternal response to embryonic signals. Reproductive seasonality in buffalo species (Bubalus bubalis) is responsible for the lower reliability of the pregnancy diagnosis by progesterone assay in spring, probably due to the high incidence of early embryo mortality (EEM) for hormonal reasons (Campanile et al., 1989; Proc. 2th National Meeting ‘Studio dell’efficienza riproduttiva degli animali di interesse zootecnico’: 51–57). The aim of the study was to identify the causes of EEM in buffaloes inseminated during the spring period. Italian Mediterranean Buffalo cows (n=209) in a good state of health were synchronized using the Ovsynch-TAI Program (Pursley et al., 1995 Theriogenology 44, 915–923) and inseminated 16 and 40 hours after the second administration of GnRH. Artificial inseminations were performed by the same technician. Ten to 20 days after the first insemination two blood samples were collected from each animal for assessing P4 levels by RIA. Days 24 and 40 after the first insemination, pregnancy diagnosis was assessed by rectal ultrasonography (Aloka SSD-500) with a 5MHz sector scanner. In animals with EEM a uterine flushing was carried out and recovered fluid was analyzed for the principal infectious agents. Microbiological analyses were carried out according to Quinn et al. (1994 Clinical Veterinary Microbiology, Wolfe Publishing, Mosby, Europe) and a PCR analysis was performed only for Bubaline Herpes Virus (BuHV1), Toxoplasma and Neospora. Statistical analysis was assessed by Student’s t-test. The incidence of cyclic buffaloes after synchronization treatment (94%) and pregnancy rate at 40 days (34.4%) were similar to those reported in a previous study (Neglia et al., 2003 Theriogenology 60, 125–133). EEM between 24 and 40 days was 45% and only in 9 buffaloes (15.3%), these results correlated with the presence of infectious agents (Streptococcus spp. group B and G, Bacillus licheniformis, Proteus mirabilis, Staphylococcus spp.). P4 levels on Day 10 were higher (P&amp;lt;0.05) in pregnant (P) buffaloes than in those with EEM. On Day 20, P4 levels were higher (P&amp;lt;0.01) in P buffaloes than in those with EEM and those not pregnant. It is hypothesized that the reduced activity of hypophysis, correlated with an increase in hours of light, may be responsible for decreased P4 concentrations and EEM in buffalo. Table 1 P4 blood levels in pregnant (P) and non pregnant (NP) buffaloes and in buffaloes with EEM 10 and 20 days after insemination

Growth and passive immunity in response to micronutrient supplementation in new-born calves of Murrah buffaloes given fat soluble vitamins during late pregnancy

A total of 30 advanced pregnant buffaloes were randomly selected from the institute herd and divided into two groups of 15 buffaloes each. The animals in the treated group (Ttdm) were administered with two i.m. injections of fat soluble vitamins AD 3E Triplex, a month prior to expected date of calving. The rest of the buffaloes were kept as control (Utdm) group. Calves born to the buffaloes within each group were further subdivided into three subgroups with five calves in each group. The calves of these subgroups were designated as (i) unsupplemented control (Co), (ii) supplemented with mineral mixture (Ms), and (iii) supplemented with fat soluble vitamins and minerals (Vms). The metabolic status of these calves was monitored by thyroid hormone profile. Levels of serum immunoglobulins (Ig) and minerals were evaluated as function of growth and immunity. Vitamin supplementation to buffaloes during advanced pregnancy enhanced the total Ig secretion in colostrum by 7.7, 2.5, 29, and 80%, respectively, in the the first 4 days. Calves born to supplemented dams showed higher absorbed Ig levels in blood serum up to 45 days postpartum. Ig absorption improved by 30 and 18%, respectively, on days 1 and 15 in mineral supplemented calves. However, the combined action of vitamins and mineral in Vms group of calves suppressed the levels of total Ig in blood serum. The levels were reduced by 42 and 83%, respectively, on days 1 and 15 after birth. Suppression in blood serum Ig levels was of higher order in calves born to unsupplemented dams. Higher monthly body weight gain was noted in calves of supplemented dams. The effects of antioxidant and fat soluble vitamins in combination with minerals on passive immunity and growth in buffalo calves are discussed.

Some physiological responses of pregnant Egyptian buffalo to niacin supplementation

Eighteen pregnant buffaloes in the third and fourth parities were used in this study. The animals were divided into three equal groups, according to their body weight. Animals of the first (G1) and second (G2) groups were given daily 6 and 12 g of niacin/head, respectively. Supplementation was given 4 weeks antipartum and continued until week 12 postpartum. Animals of the third group (G3) served as controls. The results showed that buffaloes which were given niacin had an increase ( P<0.05) in plasma glucose, hemoglobin, and total protein concentrations. Plasma sodium and cholesterol concentrations decreased as a result of niacin supplementation as compared with the control group, with no difference due to the level of niacin. The results indicate that animals in G1 and G2 groups consumed more ( P<0.01) food and more ( P<0.05) metabolizable energy. They produced more ( P<0.05) fat corrected milk and tended to have a shorter ( P<0.01) interval from calving to detected estrous. They also required less ( P<0.01) services per conception and had shorter ( P<0.01) days open as compared with the control. It was concluded that supplementation of niacin at 6 g/h/day led to improvement of the productive and reproductive performance of pregnant buffaloes.

Factors affecting number of surface ovarian follicles and oocytes yield and quality in Egyptian buffaloes.

Three experiments were conducted to evaluate factors affecting number of surface ovarian follicles and oocytes yield and quality in buffalo. In Experiment 1, ovaries (n = 126) were collected in pairs from slaughtered anoestrus, early pregnant and cyclic buffaloes. Ovarian follicles (1-3, 4-9 and > or = 10 mm diameter) were counted, aspirated and oocytes were recovered and evaluated. In Experiment 2, ovaries were divided into 2 groups. Group 1, ovaries bearing a CL (n = 74) and Group 2 non-bearing CL (n = 74), ovarian follicles (2-8 mm) were counted, aspirated and oocytes evaluated. In Experiment 3, oocytes were recovered using aspiration or slicing methods. In all experiments, oocytes were classified into good, fair, poor and denuded. Results showed that the development of small and total ovarian follicles are continuous and independent in early pregnant or cyclic buffalo cows, however, it significantly decreased (P < 0.01) in the ovaries of anoestrus buffaloes. Number of medium and large size follicles was significantly increased (P < 0.01) in cyclic buffaloes on Days 10-16 and 17-22 of oestrous cycle, while large follicles was significantly decreased (P < 0.01) in the ovaries of pregnant buffaloes. A significantly higher (P < 0.01) percentage of poor and denuded oocytes were recovered from ovaries of anoestrus and pregnant buffalo. While, the highest (P < 0.01) percentage of good quality oocytes were recovered from ovaries of cyclic buffaloes on Days 1-3 and 10-16 of oestrous cycle, eliciting that the stage of oestrous cycle is affecting the quality of buffalo oocytes. In addition, the presence of a CL stimulates the development of a significantly higher (P < 0.01) number ovarian follicles which produced a significantly higher (P < 0.05) number of good quality oocytes. Slicing of buffalo ovaries produced a significantly higher number of fair, poor and denuded oocytes. In conclusion, number of ovarian follicles and yield and quality of oocytes were affected by the reproductive status, stage of the oestrous cycle, presence of a CL and the method of oocytes retrieval.

Relationship of progesterone in plasma and whole milk of buffaloes during cyclicity and early pregnancy.

Blood and milk samples were collected on alternate days from 5 cycling buffaloes on 16 occasions and 2 pregnant buffaloes on 13 and 8 occasions. The blood and milk samples were analysed for progesterone by sensitive direct radioimmunoassay (RIA) procedures developed in this laboratory. The calculated correlation values (r) between plasma and milk progesterone concentrations during cyclicity were 0.8143, 0.5454 and 0.8147 on 0 to 4, 6 to 14 and -6 to -2 days, prior to next oestrus (day 0 = day of oestrus) and the correlations for individual buffaloes during cyclicity were in the range of 0.82 to 0.89 for plasma and milk progesterone concentration. The correlation between milk and plasma levels during early pregnancy in buffaloes was very low (0.1472). The linear regression equation between milk (Y, ng/ml) and plasma (X, ng/ml) progesterone concentration was Y = 1.8 + 3.61X which indicated that the milk progesterone levels were about 4 times higher than those in plasma. It was concluded from this study that in certain situations, such as during cyclicity when large variations occur in corpus luteum activity, the milk and plasma progesterone concentrations from the same buffalo are highly correlated. However, the correlation is very poor when corpus luteum activity remains more or less unchanged, as seen during pregnancy.

Milk progesterone determination in buffaloes post-insemination

Milk progesterone levels were studied in 17 buffaloes between post-insemination and 30 days thereafter. Six animals were confirmed pregnant. Seven of 10 animals took > 24 days to return to oestrus and the pattern of change of progesterone levels indicated a steady increase from 1 ng/ml on day 2 to 20 ng/ml on day 14 post-insemination, falling subsequently to about 5 ng/ml, 2 days prior to oestrus. In pregnant buffaloes, the milk progesterone levels showed a continuous increase up to 20 days post-insemination but did not decline thereafter. In individual buffaloes returning to oestrus, a cut-off milk progesterone level of > 10 ng/ml was considered for pregnancy diagnosis, 20, 22 and 24 days post-insemination. The test was 60, 75 and 75% accurate for detection of pregnancy on days 20, 22 and 24 respectively and 100% for non-pregnancy diagnosis on all three days. Individual animals showed a highly variable oestrous cycle length, which has been suggested as a contributory factor for false pregnancy diagnosis by milk progesterone test in this species. Milk progesterone assay may also identify silent heats, and clinical disorders.

Serum testosterone concentrations in advanced pregnancy in water buffaloes ( Bubalus bubalis)

Peripheral testosterone levels were measured by radioimmunoassay of 65 serum samples taken at various intervals from 11 buffaloes in advanced pregnancy. Average testosterone levels measured at day 210 of gestation (248 ± 39 pg/ml) remained similar up to the last week of gestation. No difference in testosterone levels was recorded between buffaloes carrying male and female fetuses. Pregnant buffaloes had significantly higher testosterone levels than non-pregnant buffaloes.

Radioimmunoassay of cortisol in peripheral blood plasma of buffaloes peripartum

Changes in the concentration of cortisol were observed in the jugular venous plasma of pregnant buffaloes on days 30, 15, 5, 2 and 1 prepartum, at partum, at regular 6-hr intervals up to 72 hr postpartum and on days 4, 6, 10, 18, 34 and 50 postpartum. A radioimmunoassay (RIA) procedure for cortisol standardized in the laboratory was used. Mean plasma cortisol levels showed little fluctuation (P<0.05) between days 30 and 2 prepartum with the values ranging from 1.28 ± 0.23 to 1.46 ± 0.13ng/ml. A small (but nonsignificant) rise in the hormone level was observed one day prepartum followed by a sharp increase to a high mean value of 3.78±0.36 ng/ml (P<0.05) at parturition. A sharp decline (P<0.05) to a low mean value was recorded within 6 hr postpartum followed by marked fluctuations in the hormone level up to 72 hr postpartum. The hormone levels subsequently varied narrowly between 1.74±0.39 and 2.01±0.27 ng/ml up to 50 days postpartum.

Seasonal variations in plasma glucocorticoid levels in buffalo cows ( Bubalus bubalis)

The changes of glucocorticoid concentrations were measured by radioimmunoassay for blood plasma of cycling, non-inseminated and pregnant buffaloes during different seasons. The glucocorticoid values were lower ( P<0.001) in hotter (hot dry and hot humid) months than in cooler (warm and cold) months.

Gonadal steroid hormone level in blood plasma and milk of primiparous and multiparous nonpregnant and pregnant buffaloes

Changes in the concentration of progesterone and estradiol-17β were measured by radioimmunoassay in 11 primiparous and 17 multiparous buffaloes at estrus and daily post insemination and in 6 nonbred buffaloes at 6 hour intervals from 4 days before expected estrus to one day after estrus. Plasma progesterone concentration at estrus was 0.1 ng/ml which rose to a peak level of 3.47 ng/ml on day 17. It fluctuated around this level in those animals which conceived, but followed a declining trend in those which failed to do so and attained lowest values on the day of next estrus. Temporal changes of the hormone revealed that the occurrence of major decline varjed between 16 and 62 h before estrus. The average concentration in milk was about three to four times higher than in plasma. The concentration of estradiol-17β about 23.50 pg/ml at estrus and fluctuated around 10 pg/ml in animals that returned to estrus with a peak around estrus. Temporal changes of hormone revealed that peak level occurred 8–17 h before estrus. The concentration of estradiol in pregnant animals fluctuated around 10 pg/ml. The concentration in milk was about 2–3 times higher than in plasma. There was no significant (P > 0.05) difference in the concentrations of progesterone and estradiol-17β between primiparous and multiparous animals.