Post partum ovarian activity and uterine involution in the suckled swamp buffalo (Bubalus bubalis)

Ovarian activity and uterine involution were monitored by rectal palpation, oestrus detection and plasma progesterone analysis from 3 to 4 days to approximately 150 days post partum in 38 suckled swamp buffaloes (Bubalus bubalis). The intervals from parturition to regression of the corpus luteum (CL) of pregnancy and involution of the uterus were 10 and 28 ± 6 (S.D.) days respectively. First detected oestrus and first elevation of plasma progesterone (> 0.7 ng/ml) occurred at 88 ± 26 and 96 ± 22 days in 8 and 12 buffaloes respectively. During the first 150 days post partum, 26 of 38 suckling buffaloes (68%) were acyclic (anoestrus) and of 12 animals (32%) exhibiting ovarian cycles, 4 were not detected in oestrus. The tentative diagnosis, based on rectal palpation, that CL were present between days 30 and 90 after parturition (without concurrent luteal levels of progesterone in plasma) suggests that confirmation should be by laparoscopy. It is concluded that a delay in the resumption of ovarian cyclicity post partum represents an important factor contributing to the prolonged calving to conception interval in the suckled swamp buffalo.     

Progesterone levels and relationship with the diagnosis of a corpus luteum by rectal palpation during the estrous cycle in Zebu cows

To assess the accuracy of rectal palpation for detecting functional luteal tissue during the estrous cycle in Zebu cattle, 20 mature non-lactating Indobrazil cows were palpated twice weekly for 7 1/2 weeks. Blood samples were drawn for progesterone analyses at each palpation. Circulating serum progesterone levels were below 0.5 ng/ml from days 0-4 (Day 0 = day of estrus); they increased thereafter, reaching maximum levels of 3.1 ng/ml on days 9 and 10. Values declined sharply to less than 0.5 ng/ml on day 18. Regardless of the stage of the estrous cycle in 71.3% of the cases (117 out of a total of 164 observations) the circulating progesterone levels corresponded to the results of rectal examination. The criteria to assess this relationship were that the presence of CL as determined by rectal palpation would be accompanied by levels of progesterone higher than 0.5 ng/ml, whereas absence of CL would be accompanied by levels less than 0.5 ng/ml. The correlation was significantly higher (P<0.05) on days 5-17 (77.9%) than on days 0-4 (57.5%) and 18-20 (65%). To assess the correlation of both rectal examination and progesterone levels with the stage of the estrous cycle, we expected that on days 0-4 and 18-20 no palpable CL and progesterone levels less than 0.5 ng/ml would occur, whereas on days 5-17 palpable CL and progesterone levels higher than 0.5 ng/ml would be found. On this basis, a correlation of 45% (18 out of 40 observations) between expected and observed values was found on days 0-4, 76% (79 out of 104) on days 5-17 and 60% (12 out of 20) on days 18-20 of the estrous cycle. Of the total of 55 observations which fell outside the expected values, 71% was due to a wrong diagnosis of CL; 14.5% was due to progesterone levels higher or lower than the expected values, and 14.5% to both laboratory and rectal palpation findings.     

Use of milk progesterone enzyme immunoassay for early pregnancy diagnosis in cows

An enzyme immunoassay using beta-galactosidase as the tracer was applied to determine milk progesterone level in cows. The novel method was reliable and practicable and required only a spectrophotometer and a centrifuge as major equipment. The milk progesterone enzyme immunoassay successfully diagnosed early pregnancy in cows. Milk samples were collected from 268 Holstein-Friesian cows in commercial dairy herds on 20, 21 or 22 days(usually 21 days) after insemination. Progesterone level in skim milk higher than 1.0 ng/ml indi-cated pregnancy. Pregnancy was confirmed by rectal palpation on 60 to 120 days after insemination. The accuracy of the milk progesterone test was 60.0 % (132 220 ) for a positive diagnosis and 100 % (48 48 ) for a negative result. A high incidence of embryonic death, 27.9 % (51 183 ), may have reduced accuracy for a positive test result. The enzyme immunoassay may be an alternative to radioimmunoassay in milk progesterone analysis for pregnancy diagnosis.     

Comparison of ovarian palpation, milk progesterone and plasma progesterone in the cow

Holstein cows were examined twice weekly, beginning at 13 to 18 days after parturition, using palpation per rectum and milk progesterone (P4) assay to determine the functional status of the corpus luteum (CL). These results were then compared with P4 concentrations in the plasma to determine which test was the more accurate in detecting functional luteal tissue, or if both tests were needed for optimal accuracy. The tests were found to be comparable except when the plasma P4 concentration was <1. 0 ng/ml. At this level, errors due to palpation occurred more frequently than those due to milk P4 concentrations since the still palpable CL of pregnancy could be mistaken for a functional CL at 14 to 21 days after parturition. However, at all the other concentrations including when plasma P4 was <1.0 ng/ml and the cows were more than 21 days post partum, neither the milk P4 assay nor palpation per rectum could be considered the better indicator of luteal status. Therefore, we conclude that the combined use of both tests does not afford better assessment of luteal function than either test alone.     

Uterine involution and postpartum ovarian activity in Nili-Ravi buffaloes

Uterine involution and postpartum ovarian activity were studied in 53 Nili-Ravi buffaloes. Mean intervals to uterine involution (26 days), regression of the corpus albicans of pregnancy (22 days), resumption of follicular activity (21 days) and first postpartum estrus (56 days) were not affected by the month of calving or age. Mean interval to formation of first corpus luteum (CL) after calving as indicated by progesterone in plasma (>/= 1.5 ng/ml) was 23.8 +/- 1.7 days, but only 52% of these CL were palpable. The number of CL formed before first postpartum estrus ranged from zero to five per buffalo; mean values based upon progesterone and palpation were 1.6 +/- 1.3 and 0.8 +/- 0.2, respectively. Based upon either progesterone or palpation, length of first postpartum luteal phase (7.9 or 6.6 days) was shorter than the luteal phase immediately preceeding the first estrus (12.1 or 8.9 days). Intervals from regular cyclic ovarian activity was not established until first estrus and intervals from the end of one luteal phase to the onset of the next were as long as three weeks. High concentrations of progesterone (>/= 1.5 ng/ml) on the day of behavioral estrus were seen in 23% of the buffaloes studied.     

Predictive value of palpation per rectum for detection of the CL in Zebu cattle as evaluated by progesterone concentrations and ultrasonography

The main objective of this study was to calculate the predictive value of the positive and negative diagnosis of the presence of a corpus luteum by palpation per rectum in Zebu cattle. Gyr breed (n = 16) heifers were palpated by a veterinarian every 3 d during March and April, and every 5 days during May. The presence or absence of a CL was recorded for 442 examinations. A blood sample was obtained after each examination, and a functional CL was considered to be present if plasma progesterone concentrations were above 1 ng/ml. Progesterone results were used as the reference to calculate the sensitivity and specificity of palpation per rectum for the diagnosis of a functional CL on different months. Predictive values for the positive and negative diagnoses were calculated using different hypothetical rates of the prevalence of CL. To evaluate the morphological basis of an erroneous diagnosis, ultrasonographic scanning of the ovaries was performed in 264 cases and the physical presence or absence of a CL was registered. The calculations were repeated using the ultrasonographic findings as the reference to evaluate the sensitivity and specificity of the diagnosis of a structural CL by per rectum palpation. Several heifers were not cyclic in March but began to cycle during the study. Thus, the prevalence of both functional and structural CL increased with time. As a result, the proportion of palpation diagnoses classified as true positives increased in May, while the proportion of true negatives decreased. Although the values of sensitivity and specificity remained constant from month to month, the predictive values changed markedly in May, when the predictive value of the positive test increased while the predictive value of the negative test decreased. These changes were due to differences in the prevalence of a CL and not to differences in the palpable characteristics of CLs in different months. The prevalence of a structural CL was always higher than that of a functional CL. The Cohen's Kappa test for concordance revealed better correspondence between palpation per rectum and ultrasound (k = 0.82) than between progesterone and either ultrasound (k = 0.68) or palpation (k = 0.66). These results show that a large proportion of the errors imputed to deficient palpation when progesterone concentrations are used as a reference are in fact the result of lack of correspondence between the physical and functional presence of a CL.     

Development of a direct enzyme immunoassay of milk progesterone and its application to pregnancy diagnosis in cows

The purposes of this study were to develop an enzyme immunoassay (EIA) for determination of progesterone in unextracted whole milk and to apply it to pregnancy diagnosis. Paper fibers covalently coupled to antibody specifically and competitively bound ³H-progesterone and 11α-hydroxyprogesterone hemisucccinate-horseradish peroxidase and were stable for 9 mo at ?20°C. The sensitivity, recovery, precision, and cross reactivity of the EIA and a radioimmunoassay (RIA) of milk progesterone were evaluated, and showed that this EIA was comparable to the RIA. Milk samples were collected once daily for one estrous cycle from ten lactating Holstein cows and the progesterone levels were determined by RIA. Milk progesterone in 70 samples measured by EIA were highly correlated (r = 0.90) with the values of RIA for the same samples. Milk samples for pregnancy diagnosis by EIA of milk progesterone were obtained daily from days 20 to 24 after 115 artificial inseminations of 85 lactating Holstein cows. Pregnancy diagnosis by EIA was confirmed by rectal palpation at 30 to 60 days after insemination or return to estrus. The accuracy based on single, two, three, four, and five consecutive samples was from 67.2 to 80.0%, 77.3 to 84.0%, 79.2 to 87.5%, 82.0 to 85.4%, and 85.4%, respectively, for pregnancy diagnosis; and from 95.0 to 98.3% for nonpregnancy.     

Ability of induced corpora lutea to maintain pregnancy from the third month of gestation to term in cattle

The local relationship between the pregnant uterine horn and the CL during maternal recognition of pregnancy is well-documented. It continues beyond that time; pregnancies were maintained in lutectomized cows when CL were induced on the ovary ipsilateral, but not contralateral, to the uterine horn of pregnancy during Days 28-53. This study evaluated factors affecting maintenance of pregnancy by CL induced after Day 53, in lutectomized cows that had received exogenous progesterone from Day 29 to 15 days after induction of a CL. Twenty-four suckled beef cows were lutectomized on Day 29 of gestation; pregnancy was maintained with progesterone from two controlled internal drug releasing (CIDR) inserts, exchanged every 5 days. Beginning on Day 53, ovaries and viability of pregnancy were evaluated by ultrasonography every 5 days. When a follicle >or=10 mm in diameter was present ipsilateral to the fetus, each cow received 1,000 IU of hCG. Following induction of a CL (20 of 24), progesterone was reduced to a single CIDR for 5 days, then removed. Retention of pregnancy was confirmed by rectal palpation and calving. Cows with induced CL maintained pregnancy to term, including four with the CL contralateral to the fetus. Three cows failed to form normal CL by Day 98 and lost pregnancy after removal of exogenous progesterone. One cow that did not respond to hCG lost pregnancy during exogenous progesterone. In conclusion, CL induced after Day 53 maintained pregnancy to term, even when induced contralateral to the pregnant uterine horn.     

Postpartum ovarian activity,uterine involution and fertility in indigenous buffaloes at a selected village location in Sri Lanka

Reproductive events were monitored over a period of 30 months in a sample of 55 indigenous (Lanka) buffalo cows belonging to five farmers selected at random in a specific village in the dry zone low-country region of Sri Lanka. The animals were maintained under the existing traditional methods of extensive grazing management and low-intensity utilization for milk and draught power in a crop-livestock system. Annual calving rate was 87.2%, with 82.4% of all calvings occurring between December and March (peak calving season). Involution of the uterus, based on rectal palpation, was completed at an interval of (mean ± SD) 32.9 ± 8.2 days post-partum. The majority (70.8%) of first services postpartum were recorded between February and April. The interval from calving to first service was 57.3±49.2 days for 80 animals which calved during the peak calving season and 156.2 ± 95.6 days for eight animals calving outside the peak season (overall 66.4 ± 61.4 days, n = 88). The intervals to uterine involution and first service were correlated (r=0.53, P < 0.01) and both were significantly influenced by month of calving, but not by age or parity of the cow. The interval from calving to palpation of the first corpus luteum was 52.3 ± 16.8 days, and to the first elevation of progesterone above 0.5 ng/ml of fat-free milk was 54.9 ± 17.9 days.Of the 36 cases where complete progesterone profiles and clinical data were available, first services were recorded in 27 (75%) before palpation of a corpus luteum or elevation of progesterone after calving, and conception to this service was confirmed in 24 (88.9%). Elevation of progesterone preceded first service in seven (19%); the resultant luteal phases were short in four and normal in three. Overall conception rate to first service was 77.7% and the number of services per conception was 1.29. The calving to conception intervals ranged from 23 to 502 days (mean 71.5 ± 66.2, mode 41–60, n = 82) and the calving intervals from 329 to 816 days (mean 384.9 ± 62.9, mode 351–370, n=79).These findings confirm that Lanka buffaloes are capable of maintaining high fertility under certain traditional systems of management. The major cause of long calving intervals was prolonged postpartum acyclicity, which occurred mainly in animals calving outside the peak calving season.     

Pregnancy diagnosis in swine: A comparison of the technique of rectal palpation and ultrasound

The accuracy of pregnancy diagnosis in swine by rectal palpation and by ultrasound was compared using sows and gilts thirty days or more after breeding. A total of eighty-four pigs were included in this experiment and they were examined an average of thirty-nine days following breeding. Forty-nine animals were slaughtered within a few days of pregnancy examination and thirtyfive were allowed to farrow. Pregnancy status was correctly diagnosed by palpation per rectum in eighty-three of the eighty-four pigs (98.8%) and by ultrasound in eighty-one of the eighty-four pigs (96.6%) examined. The accuracy of the two methods was not significantly different.     

Milk progesterone measurement in dairy cows: Correlation with estrus and pregnancy determination

Progesterone levels in fore milk, determined by a highly specific radioimmunoassay, were compared for the assessment of estrus by a veteran herdsman and an experienced inseminator, in cows presented for insemination. In addition, an examination was made of the relative accuracy of using milk progesterone levels for the determination of pregnancy at 24, 40 and 44 days after insemination, as compared with rectal palpation at 45–50 days post-breeding.Fat-free fore milk progesterone levels were similar to jugular plasma levels at 24 days post-insemination and reached roughly 60% of the level of unextracted fore milk at this time. Accuracy of estrus diagnosis by herdsman, inseminator and milk progesterone level was 84%, 93% and 96%, respectively. For pregnancy diagnosis, milk progesterone determination in 85 cows showed 78% accuracy in predicting pregnancy and 100% accuracy in predicting non-pregnancy. At 40 days post-insemination false positives dropped to 10% and at 44 days only 7% of the cows were incorrectly diagnosed as pregnant. The false positives in this study were largely due to embryonic mortality as reflected by abnormal intervals of return to estrus. Two milk progesterone determinations, at 24 and either 40 or 44 days post-insemination ensure maximum reliability for early pregnancy diagnosis.     

Optimizing the accuracy of detecting a functional corpus luteum in dairy cows

The objectives were to evaluate the accuracy of detecting a functional CL by transrectal palpation and ultrasonography, and to optimize the accuracy of detecting a functional CL by ultrasonography in Holstein cows. In Experiment 1, four veterinarians performed transrectal palpation in 1250 cows at 37 d in milk (DIM), two veterinarians repeated transrectal palpation in 823 cows at 58 DIM, and one veterinarian performed 206 ultrasonographic examinations at 37 DIM. In Experiment 2, 987 and 983 ultrasonographic examinations were performed at 21 and 24 d after AI by one veterinarian for detection and measurement of CL. Cows with a blood progesterone concentration > or =1ng/mL were assumed to have a functional CL. Sensitivity and specificity were optimized using receiver operating characteristic analysis. In Experiment 1, sensitivity of transrectal palpation for diagnosing a functional CL ranged from 33.3 to 59.9% at 37 DIM and from 48.3 to 68.4% at 58 DIM, whereas specificity ranged from 76.7 to 93.2% at 37 DIM and from 73.3 to 86.7% at 58 DIM. Sensitivity and specificity for ultrasonography were 89.4 and 45.7%, respectively. In Experiment 2, the sensitivity and specificity of ultrasonography were 97.3 and 38.1% at 21 d after AI, and were 97.9 and 51.0% at 24 d after AI. Sensitivity and specificity were optimized using a cutoff diameter of 23mm at 21 d and 22mm at 24 d, which resulted in sensitivity and specificity of 87.2 and 83.0% at 21 d, and 89.5 and 89.4% at 24 d after AI, respectively. Sensitivity was low and specificity was high for transrectal palpation, whereas ultrasonography resulted in high sensitivity and low specificity. Using a cutoff diameter during ultrasonography improved accuracy of detection of a functional CL compared with either ultrasonography without cutoff or transrectal palpation.     

Serum progesterone concentration in pyometritic and normal postpartum dairy cows

Two studies were conducted to evaluate the concentration of serum progesterone in pyometritic cows and relate it to palpation of ovarian structures per rectum . In Trial 1, serum samples from 34 pyometritic cows were assayed for progesterone. Mean serum progesterone concentrations were 6.8 +/- 0.7 ng/ml. In Trial 2, each of 54 pyometritic cows was paired with a control cow on the basis of days post partum (18-50 days). Mean concentration of progesterone was 9.7 +/- 1.0 ng/ml for the pyometritic cows and 5.7 +/- 0.8 ng/ml in control cows (P<0.005). Progesterone concentration was greater (P<0.005) in both groups of cows with palpable corpora lutea (CLs). Ninety-six percent of the pyometritic cows had palpable CLs compared to 57% of the control group. Comparing serum progesterone only in cows with a palpable CL, the mean concentration was still greater (P<0.005) in the pyometritic group (10.6 +/- 1.0 ng/ml) than the control group (6.6 +/- 1.0 ng/ml). Compatability of rectal palpation findings and concentrations of serum progesterone were 92.6% for the pyometritic group and 72.2% for the control group. Progesterone concentration increased (P<0.05) by increased days post partum in Trial 2 (n=54) but not in Trial 1 (n=23). In both Trials 1 and 2, uterine size due to pyometra increased (P<0.05) with increased days post partum. No other associations were found.     

Transrectal real-time ultrasound scanning for diagnosing pregnancy and for monitoring embryonic mortality in dairy cattle

A total of 309 ultrasonographic tests was performed on 100 inseminated dairy cows during the course of the first trimester of pregnancy and on 13 noninseminated controls. The reliability (defined as the proportion of cows pregnant or nonpregnant by rectal palpation at 60–90 days compared to those diagnosed as pregnant or nonpregnant by ultrasonography) and accuracy (defined as the proportion of cows correctly identified as pregnant or nonpregnant) of the ultrasonographic results at different intervals after A.I., are reported. It was found that near 100% reliable results could be obtained for positive diagnosis from 45 days onwards and that the ultrasonographic results were 100% reliable for negative diagnosis from 40 days onwards. Furthermore, 7 out of 100 inseminated cows which were diagnosed as negative by early pregnancy diagnosis 21–24 days after A.I. were found to be positive at the ultrasonographic test after 30 days but interestingly enough failed to carry the conceptus until rectal palpation occurred (60 days). The total late embryonic mortality was 23%.     

Effects of an analog of PGF2(alpha) (ONO-1052) on cows with luteinized ovarian cysts following treatment with GnRH analog (fertirelin acetate)

Effects of PGF2(alpha) analog (ONO-1052) on cows with luteinized cysts following treatment with GnRH analog (fertirelin) in inducing estrus and shortening an interval from treatment to conception were investigated in a field trial. Seventy-five cows with follicular cysts diagnosed by rectal palpation were treated intramuscularly (i.m.) with 400 mug fertirelin (an analog of GnRH). Luteinization of follicular cysts were tentatively judged by rectal palpation. Forty-one cows were considered to have luteinized cysts and were either treated i.m. with ONO-1052 (28 cows) or left untreated as controls (13 cows). Thirty-four other cows were considered to have not responded to fertirelin and retreated with 10,000 MU hCG (19 cows) or fertirelin (five cows). This tentative judgment of luteinization of the cysts by rectal palpation after treatment was later confirmed by determining serum progesterone concentration before and 10 to 14 days after treatment. Only in the cows with luteinized cysts which were confirmed by serum progesterone analysis; increased from a pretreatment level below 1.0 ng/ml to a value of 1.0 ng/ml or higher 10 to 14 days after treatment, effects of ONO-1052 combined with fertirelin were investigated. Of the 18 cows with luteinized cysts thus confirmed following fertirelin injection and treated with ONO-1052, 15 (83.3 %) cows came into estrus within 26 +/- 14 (mean +/- SD) days after the first treatment; eight cows within three to five days and four cows within 22 to 28 days, and 14 cows (77.8 %) conceived within 100 days (42 +/- 26 days). On the other hand, the five control cows with luteinized cysts that were not treated with ONO-1052 required significantly longer to exhibit normal estrus (54 +/- 13 days; P<0.05) and to conceive (54 +/- 13 days). These results indicate that ONO-1052 combined with fertirelin may be useful to shorten the interval from treatment to normal estrus and to conception in cows with follicular cysts.     

Efficacy of PGF(2alpha) to synchronize estrus in water buffalo cows (Bubalus bubalis) is dependent upon plasma progesterone concentration,corpus luteum size and ovarian follicular status before treatment

This study was conducted to identify factors affecting PGF(2alpha) efficacy to synchronize estrus in water buffalo cows. After detection of a corpus luteum (CL) by rectal palpation, cows were treated (im) with dinoprost (12.5, 25 or 50mg) or D(+) cloprostenol (75, 150 or 300 microg) in a total of 66 treatments. Blood samples were collected 0, 24 and 48 h after treatment and ultrasound examinations and observations for estrus were performed daily to the day of ovulation or to 6 days after treatment. No PGF(2alpha) dose-response pattern was observed and overall rates of luteal regression (progesterone <1.0 ng/ml at 48 h), estrus, no detected behavioral estrus with ovulation occurring, and ovulation were 71.2, 36.4, 19.7 and 54.5%, respectively. To analyze plasma progesterone concentrations and ovarian dynamics, cows were divided in three groups according to their response to treatment. Cows that failed to have ovulations from a follicle after treatment (Group A, n = 30) had (P < 0.05) a lower plasma progesterone concentration (2.98 ng/ml) and smaller CL area (CLA; 187.3 mm(2)) before treatment as compared with cows that had an ovulation from a follicle (4.43 ng/ml and 223.7 mm(2), respectively; Groups B and C, n = 36). In cows that failed to ovulate, plasma progesterone concentration decreased in the first 24 h, but did not decline further and was >1.0 ng/ml 48 h after treatment. Moreover, no significant change in CLA after treatment was detected, indicating that treatment induced only partial luteolysis. In cows that ovulated, plasma progesterone concentration and CLA decreased continuously from treatment to ovulation (consistent with complete luteolysis). Threshold values of 2.8 ng/ml for plasma progesterone concentration and 189 mm(2) for CLA were identified as the best predictors of ovulation before treatment (83.3 and 80.6% sensitivity and 58.6 and 65.5% specificity, respectively, with positive and negative predictive values around 71%). When the origin of the ovulatory follicle was investigated, the interval from treatment to ovulation was shorter (91.9 versus 113.3 h; P < 0.05), and the ovulatory follicle had a slower growth rate (1.02 versus 1.55 mm per day; P < 0.005), a lesser increase in diameter from treatment to ovulation (4.7 versus 8.0 mm; P < 0.001), and a greater maximum diameter (13.2 versus 12.1 mm; P < 0.05) in cows that ovulated from the largest follicle present in the ovary before treatment (Group B, n = 27) compared with cows that ovulated from the second largest follicle present in the ovary before treatment (Group C, n = 9). In summary, the efficacy of PGF(2alpha) for causing luteolysis and synchronizing estrus and ovulation in buffalo cows was dependent upon plasma progesterone concentration, CL size and ovarian follicular status before treatment.     

The accuracy of enzyme-linked immunosorbent assay and latex agglutination progesterone test for the validation of estrus and early pregnancy diagnosis in dairy cattle

The accuracy of the enzyme-linked immunosorbent assay (ELISA) and the latex agglutination (LA) on-farm progesterone kit for detecting estrus and diagnosing early pregnancy was investigated in this study. Italian Friesian dairy cows (n=82) from 6 dairy herds were used for the collection of foremilk samples at the time of breeding and at 19, 21, and 23 days post insemination. Pregnancy status was ascertained by uterine palpation per rectum 40 to 60 days post insemination. Progesterone levels were affected by herd, percentage of milk fat, and the day of testing x diagnosis interaction. Validation of estrus by qualitative on-farm tests was 74.6% (LA) and 100.0% (ELISA) accurate using 0.5 ng/ml of progesterone as the RIA estimate for estrus. The accuracy rate for early pregnancy diagnosis by RIA was 68.4 to 83.8% for day 19 and day 21, respectively, while the detection rate for nonpregnancy was 84.6 to 100% on day 19 and day 21, respectively, as compared with uterine palpation per rectum. The average accuracy rate for early pregnancy diagnosis ranged from 84.7 to 92.3% for the LA and ELISA tests, respectively; the nonpregnancy rate was correctly predicted 93.9% to 68.2% for the LA and ELISA tests, respectively.     

Concentrations of progesterone in milk as a monitor of early pregnancy diagnosis in dairy cows

The objectives of the experiment were to evaluate the efficacy of using progesterone concentrations in milk and palpation per rectum on days 21 or 22 postbreeding to estimate pregnancy and evaluate management practices; and to investigate physiological occurrences leading to incorrect diagnosis of pregnancy when serial samples of milk were collected. Of particular interest were indications of early embyronic death and insemination of cows not in estrus. Milk samples were collected at the afternoon milking of days 0 or 1 (day 0 = day of estrus), 9 or 10, 21 or 22 and 27 or 28 following breeding in 200 lactating dairy cows. Tentative diagnosis of pregnancy was made based on concentrations of progesterone in milk on days 21 and 22 alone and on days 21 or 22 and 27 or 28. In addition all cows were palpated per rectum on days 21 or 22 postbreeding and a tentative pregnancy diagnosis was made. Pregnancy was confirmed by examination of the genital tract per rectum between 35 and 50 days after breeding. Values of 4 ng/ml or greater and/or the presence of a mature corpus luteum were considered positive signs of pregnancy. Progesterone in milk ranged from 0.1 to 18 ng/ml. On days 0 or 1, 9 or 10, 21 or 22 and 27 or 28 concentrations of progesterone in milk averaged 1.5 +/- 0.3, 11.1 +/- 0.5, 12.0 +/- 0.4 12.5 +/- 0.5 ng/ml for pregnant cows. Corresponding samples from nonpregnant cows averaged 1.2 +/- 0.2, 10.3 +/- 0.4, 3.0 +/- 0.4, 6.8 +/- 0.6 ng/ml, respectively. Ninety-six and 104 cows were classified as pregnant and nonpregnant on days 21 or 22 as compared to 78 and 118 cows diagnosed as pregnant and nonpregnant on days 21 or 22 and 27 or 28 combined. Pregnancy detection by progesterone in milk on days 21 or 22 with pregnancy determined via rectal palpation 35 to 50 days postbreeding was 77 and 100% accurate for positive and negative diagnosis, respectively. The percent agreement using progesterone in milk on days 21 or 22 and 27 or 28 combined was 95 and 100%, respectively, for positive and negative diagnosis. Diagnosis based on rectal palpation 21 or 22 days postbreeding was 63 92 (69%) and 76 88 (87%) for pregnant and nonpregnant cows, respectively. Ten of the 200 cows had progesterone concentratins in milk of > 4 ng/ml at the time of breeding. Six of these cows were pregnant from a previous insemination. The other four cows were nonpregnant and were inseminated during the luteal phase of the cycle. In conclusion, measurement of progesterone in milk is a useful tool in early detection of pregnant and nonpregnant cows and may be useful in detecting reproductive problems in a dairy herd. It will probably be most useful when used in combination with later pregnancy diagnosis per rectum .     

Effect of progesterone releasing intravaginal device (PRID) on fertility in the post-partum buffalo cow

Serum progesterone (P) profiles, following progesterone releasing intravaginal device (PRID) treatment (Experiment I) and use of the PRID for induction of fertile oestrus (Experiments II, III and IV), were studied in five non-cycling, buffalo heifers and 86 post-partum buffalo cows, respectively. The maximum P concentration (2.5 ng/ml) was attained 24 h after insertion of the device. Thereafter, P levels gradually decreased to 1 ng/ml at the time of removal of the device on day 12. In post-partum cows, the retention rate of the PRID was 100%, and more than 80% of the animals exhibited signs of oestrus after PRID removal. However, the conception rate following natural mating (26%) and fixed-time insemination (33%) at 60 and 84 h after PRID removal, was very low. Serum P levels and rectal palpation for active corpora lutea following PRID removal indicated a relatively high incidence of anovulatory oestrus post PRID treatment.     

Repeatability and accuracy of reproductive tract scoring to determine pubertal status in beef heifers

The objective of this study was to compare the repeatability and accuracy of palpation per rectum to transrectal ultrasonography and serum progesterone concentrations for determining pubertal status in beef heifers. One hundred and seventy-four rectal examinations were performed on 29 predominantly Angus heifers by two veterinarians (A and B) and assigned individual reproductive tract scores (RTS) during monthly examinations over a 3-month period. Heifers were examined in the morning by both veterinarians, randomized, and re-examined in the afternoon. The size and location of ovarian structures of each heifer were determined by ultrasonography. Heifers with follicles >10mm in diameter or corpora lutea were classified as pubertal. Serum progesterone concentrations at the time of the examination and 10 days later were determined by radioimmunoassay and used to classify heifers as prepubertal (<1 ng/ml in both samples) or pubertal (at least one sample >or=1 ng/ml). Kappa, which describes degree of agreement beyond chance, was used to determine repeatability of the RTS system. Multicategory Kappa for agreement was 0.64 within veterinarian, 0.46 between veterinarian, and 0.35 between palpation per rectum and transrectal ultrasonography. Sensitivity and specificity of palpation per rectum for diagnosis of pubertal status compared to serum progesterone levels were higher (82 and 69%, respectively) than sensitivity and specificity of ultrasonography (79 and 59%, respectively). This study validates the RTS system as a repeatable and accurate screening test to evaluate pubertal status in groups of heifers prior to the onset of the breeding season.