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PubMed2006

Comparison of a camera - software system and typical farm management for detecting oestrus in dairy cattle at pasture.

AIM: To compare the sensitivity, specificity, predictive values and accuracy of detection of oestrus using a novel oestrus detection strip (ODS) and a camera-software device (CSD) with typical farm management practices of visual observation and use of tail paint in dairy cattle at pasture. METHODS: Dairy cows (n = 480) in a seasonal-calving herd managed at pasture under typical commercial conditions in New Zealand were stratified by age, body condition score and days in milk, then randomly allocated to one of two groups prior to the planned start of mating (PSM). Tail paint was applied to all cows and oestrus detected by visual observation of oestrous behaviour and removal of paint, by farm staff. One group (n = 240) was fitted with ODS and also monitored for signs of oestrus using a CSD, while the Control group (n = 240) was monitored using tail paint and visual observations only. Cows detected in oestrus were artificially inseminated (AI), and pregnancy status determined using rectal palpation and ultrasonography, 51-52 days after the end of a 55-day A period. Results of pregnancy diagnosis were used to confirm the occurrence of oestrus, and the sensitivity, specificity, predictive value and accuracy of detection of oestrus compared between oestrus detection methods. RESULTS: The sensitivity and accuracy of oestrus detection in the Control group, using visual observation and tail paint, were low. Compared with the Control group, detection of oestrus using the ODS and CSD resulted in greater sensitivity (85% vs 78%; p = 0.006), specificity (99.6% vs 98.0%; p < 0.001), positive predictive value (PPV; 88% vs 51%; p < 0.001) and overall accuracy (99.0% vs 98.0%; p < 0.001). Negative predictive value (NPV) did not differ significantly between groups (99.4% vs 99.3%; p = 0.28). Pregnancy rate to first service was higher in the CSD group than in the Control group (72% vs 39%; p < 0.05). Use of the CSD significantly increased the cumulative proportion of cows pregnant to AI over the breeding period (p = 0.044). CONCLUSION AND CLINICAL RELEVANCE: The ODS and CSD was satisfactory for detection of oestrus in seasonal calving dairy herds grazing on pasture and could improve the sensitivity and accuracy of detection of oestrus in herds where these are low.

Animals↗
PubMed1994

Insulin-like growth factor binding proteins show distinct patterns of expression in the rat uterus.

An intrinsic insulin-like growth factor (IGF) system, complete with IGF ligands, receptors, and biological responses, is present in the rat uterus, where it is thought to regulate uterine homeostasis by autocrine/paracrine mechanisms. It is known that IGF binding proteins (IGFBP) modulate IGF-I and IGF-II action, but very little information is available concerning their cellular localization in the uterus. Therefore, we have employed in situ hybridization to localize IGFBP-1, -2, -3, -4, -5, and -6 mRNAs in the adult rat uterus during the estrous cycle. IGFBP-1 was undetectable in all uteri examined. IGFBP-2 mRNA was localized only in the luminal epithelium of the endometrium. It was abundant during proestrus (P1000 h, P2000 h) and early estrus (E0200 h), but was relatively low at other stages of the cycle. IGFBP-3 mRNA was localized to the stroma cells juxtaposed to the endometrium. A weak signal was detected on estrus morning (E0200 h, E1000 h), but high levels of IGFBP-3 mRNA were observed in the stroma cells on Day 12 of pregnancy. IGFBP-4 mRNA was localized only in the luminal epithelium of the endometrium. It was moderately abundant at diestrus I and II, but the signal was very low or absent at other times in the cycle. IGFBP-5 mRNA was localized in the circular and longitudinal muscle layers of the myometrium. The IGFBP-5 hybridization signal was maximal at diestrus, weak on proestrus, and moderate during estrus. IGFBP-6 mRNA was also expressed in the myometrium. The signal was strong on estrus morning (E0200 h and E1000 h) and low or absent at other times in the cycle. These results provide the first direct evidence that the genes encoding the six IGFBP are expressed in a tissue-specific manner in the adult rat uterus. Equally important, the levels of the mRNA for each IGFBP appear to change throughout the estrous cycle, but not in a parallel fashion. These results support the hypothesis that inducible and tissue-specific expression of IGFBP-2 to -6 may be involved in modulating the activity of the IGF ligands during the proliferative and secretory phases of the uterine cycle.

Animals↗
PubMed1990

Delayed sexual maturation during prepubertal cannabinoid treatment: importance of the timing of treatment.

Treatment of prepubertal female rats with delta-9-tetrahydrocannabinol (THC) delays first estrus and ovulation. The present study was conducted to determine if treatments initiated at different prepubertal ages would be equally effective in delaying sexual maturation and if changes in prepubertal hormone secretion accompanied the delay. Treatments with THC (10 mg/kg) or vehicle were initiated at 24, 27 or 30 days of age and continued until first estrus was detected by vaginal smears. In one experiment, serum luteinizing hormone (LH) and prolactin (PRL) were measured at 24, 27 or 30 days of age after different durations of treatment. First estrus was delayed (4.8 +/- 1.1 days) when THC treatment started at 27 days of age, but not when treatment started at 24 or 30 days of age. Serum LH was reduced after 1 or 4, but not 7, days of treatment; however, LH suppression was associated with pubertal delay only when it occurred at 27 to 30 days of age. Serum PRL, which increased with age, was suppressed after 1 day of THC treatment at 27 or 30 days of age, but only the former was associated with delayed puberty. Suppression was not evident at 24 days of age after 1 day of THC, or at other ages after treatment for longer than 1 day. These results define a narrow interval, encompassing the ages of 27 to 30 days, during which THC exposure resulted in pubertal delay. Such treatment reduced serum LH and PRL levels, but reductions also occurred with treatments that did not result in maturational delay. The relationship of hormone suppression to the delay thus remains unclear, although the timing of suppression might be a factor.

Analysis of Variance↗
PubMed1994

Towards a shorter calving interval in South African dairy herds.

The effects of a progestagen treatment regimen on the calving-to-conception period and number of inseminations per conception in a Holstein-Friesland herd [n = 60] were investigated. No significant (P > 0.05) differences were observed in days from calving to conception (80.5 vs. 82.3) and inseminations per conception (1.52 vs. 1.41) between the treatment and the control groups, although the treatment possibly contributed to an improved oestrus detection rate.

Anestrus↗
PubMed1999

Effect of estrus synchronization with norgestomet on the integrity of oocytes from persistent follicles in beef cattle.

Our objective was to determine whether oocyte integrity is compromised when oocytes are recovered from progestogen-induced persistent follicles. Beef cows were presynchronized using PGF2alpha (PGF). Cows detected in estrus after PGF were assigned to either NOR (one 6-mg norgestomet implant for 10 d starting on d 16 of cycle; day 0 = estrus; n = 112) or CON (control, no implant [n = 128] and presynchronized 8 d later than NOR). All cows received 25 mg of PGF at the end of treatment (NOR, d 26; CON, d 18). Treatments produced persistent preovulatory follicles (NOR) or normal preovulatory-size follicles (CON), which were measured via ultrasonography 1 d before slaughter. Ovaries were collected from all animals (NOR, d 27; CON, d 19) along with random (RAN) ovaries from cattle slaughtered on the same days. Cumulus oocyte complexes (COC) were aspirated from the preovulatory follicles with recovery rates of 63% across treatments. Small follicles (2 to 7 mm diameter) from NOR, CON, and RAN cows were also aspirated to recover COC. Preovulatory follicles were larger (19.5+/-.9 vs. 13.6+/-.4 mm, P<.05), serum P4 was lower (.4+/-.1 vs. 3.9+/-.2 ng/mL, P<.05), and serum E2 was higher (28.7+/-1.6 vs. 7.6+/-.8 pg/mL, P<.05) in NOR than in CON cows. Cumulus oocyte complexes recovered from preovulatory follicles (62 NOR, 64 CON) were matured, fertilized, and cultured in vitro for comparison of embryonic development. A subset (24 NOR, 34 CON) of COC were assigned morphological quality grades. A separate set of recovered COC (10 NOR, 15 CON) was fixed within 1 h after recovery for assessment of the stage of meiosis. Treatments did not differ for oocyte quality grade or stage of meiosis. However, COC from NOR cows had more layers of cumulus cells (P<.05), and more of those COC had undergone cumulus expansion (29.2 vs. 5.9%, P<.05 for NOR vs. CON, respectively). Development of cleaved embryos to the morula and blastocyst stages from preovulatory follicles (22.6% NOR, 18.9% CON) or small follicles (42% NOR, 40% CON, 42% RAN) did not differ with treatment. Oocyte quality and in vitro developmental competence were not compromised for oocytes from induced persistent follicles compared with oocytes from normal preovulatory follicles. Increased expansion of cumulus cells associated with oocytes from progestogen-induced persistent follicles may be relevant to the reduction of in vivo fertility associated with such follicles.

Animals↗
PubMed1984

Serum and milk progesterone in Syncro-Mate-B treated postpartum beef cows.

Fifteen post-partum (61.5+/-6.1 days) cyclic beef cows (4.1+/-0.3 years old) were randomly assigned to receive the Syncro-Mate-B (SMB) treatment on day 0 (estrus), day 9 or day 18 of their cycle with implant removal nine days later. An additional five post-partum (41.7+/-5.6 days) beef cows (3.2+/-0.4 years old) not detected in estrus and without corpora lutea also received the SMB treatment. Blood samples (10ml) were obtained via venipuncture on the day of implantation and one, three, five, seven and nine days after implantation and ten days after the post-treatment estrus. Milk samples (25 ml) were obtained by hand stripping at the same periods. Nineteen of twenty cows were synchronized, i.e. estrus occurred within five days of implant removal. Progesterone concentrations in both serum and milk were similar and followed similar patterns for each group. The day-9 treated cows had greater serum and milk progesterone concentrations than the other groups of cows on days 1, 3, and 5 after implantation. In conclusion, cows treated with SMB had similar serum and milk progesterone concentrations, endogenous progesterone secretion was inhibited by SMB treatment and the inhibition was influenced by prior luteal function.

Journal Article↗
PubMed1978

The use of heat mount detectors in a large Iranian dairy herd.

Heat mount detectors were applied in a large Iranian dairy herd in an attempt to appraise their value for fertility improvement. A total of 100 cows with a recorded anoestrous period of at least 60 days were selected, 69 of them suffering from suboestrus or silent heat and 31 from true anoestrus due to inactive ovaries. The results indicate that inaccurate observation of heat is a major limiting factor in the reproductive performance of this herd and that heat detectors could be a valuable tool for improvement of oestrus detection and consequent reduction of the interval from calving to conception.

Animals↗
PubMed1988

Oestrus detection in dairy cows by milk temperature measurement.

The milk and body temperatures of 15 cows were monitored twice daily at milking times, over a total of 30 oestrous periods. The best determination of oestrus was based on a temperature rise of at least 0.2 degree C over the corresponding mean temperature of the three preceding days. This resulted in 72 +/- 16 per cent of oestruses, predicted by serial progesterone assays, being successfully detected by serial progesterone assays, being successfully detected and 11 +/- 3 per cent of false positives. The variable extent of the temperature rise at oestrus and the large daily fluctuations in temperature for individual cows, resulted in a moderate oestrus detection rate accompanied by an unacceptable level of false positives.

Animals↗
PubMed1980

An assessment by progesterone assay of the accuracy of oestrus detection in dairy cows.

The use of a milk progesterone assay in determining the extent to which dairy cows are presented for insemination at the wrong time is reported. Milk samples were taken from cows at the time of insemination and were subjected to plasma progesterone assay. In a preliminary study samples were obtained from 96 cows in an experimental herd at insemination. The calving rate of these cows was compared with the milk progesterone level at insemination. Eight cows which had levels of progesterone much above the normal oestrus level 9 more than 0.3 ng per ml) failed to conceive. As the progesterone level at insemination rose, calving rate declined. A further 1177 milk samples taken from cows being inseminated in commercial dairy herds were also examined. Ninety-one animals (7.7%) had levels of milk progesterone in excess of those observed at normal oestrus. A negative correlation was confirmed between non-return rate and milk progesterone level at insemination. These investigations show that the proportion of cows from the national herd which have high progesterone levels when presented for insemination is similar to that found under experimental conditions and suggests that the problem of heat detection may be a relatively constant factor in reduced conception to artificial insemination.

Animals↗
PubMed1982

Management and economic effects of different levels of oestrus detection in the dairy herd.

Computer simulation of the dairy herd production cycle has permitted an assessment of the effects of oestrus detection rate on herd performance. Calving to first service interval is inversely related to the level of oestrus detection and in turn both these parameters govern the subsequent calving to conception interval and the herd culling rate for failure to conceive. Where the breeding season is nine to 10 months long, a poor oestrus detection rate is reflected in an increased culling rate for failure to conceive and a high mean calving index. This results in a reduction in annual milk yield and margin over purchased feed per cow. Where the breeding season is restricted to four months or less, a low level of oestrus detection is reflected almost solely in a high rate of culling for failure to conceive.

Animal Husbandry↗
PubMed1986

Pregnancy diagnosis in swine: a comparison of the accuracies of mechanical and endocrine tests with return to estrus.

The relative accuracies of various commercially available detection procedures in the evaluation of pregnancy status were evaluated in 51 sows of mixed parity. Sows were mated 1 to 3 times during estrus to one or more boars. A blood sample was obtained from each sow between 19 and 23 days after estrus (first day of estrus = day 1) and again between 26 and 30 days and was analyzed by radioimmunoassay for content of progesterone and estrone sulfate, respectively. Sows were considered pregnant if progesterone concentrations were greater than 5 ng/ml and if estrone sulfate concentrations were greater than 0.5 ng/ml. At daily intervals, sows were exposed to mature, sexually aggressive boars and observed for signs of estrus. Between 31 and 35 days of gestation, sows were evaluated for pregnancy by use of the following mechanical devices: a Doppler ultrasound pregnancy detector fitted with an abdominal probe, the Doppler detector with a rectal probe, an amplitude-depth ultrasound pregnancy detector (diode ruler), and another amplitude-depth ultrasound detector from a different manufacturer (oscilloscope). Relative to the proportion of sows that farrowed, the overall accuracies of the techniques were returns to estrus, 98%; estrone sulfate, 92%; progesterone, 92%; Doppler with rectal probe, 86%; Doppler with abdominal probe, 86%; diode ruler amplitude-depth ultrasound, 73%; and oscilloscope amplitude-depth ultrasound, 86%. Estrus detection resulted in the lowest prevalence of sows that were predicted to farrow, but did not subsequently farrow (false-positive diagnoses) and the lowest prevalence of sows that were not predicted to farrow, but subsequently did farrow (false-negative diagnoses).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Induction of fertile estrus in prepuberal gilts by treatment with a combination of pregnant mare's serum gonadotropin and human chorionic gonadotropin.

Ten trials involving 678 presumed prepuberal gilts (5.5 to 7.5 mo old) were conducted in North Carolina, Illinois and Missouri to evaluate the reproductive performance of gilts given a combination of 400 IU of pregnant mare's serum gonadotropin and 200 IU of human chorionic gonadotropin (P. G. 600). Gilts that were presumed to be prepuberal received P. G. 600 or no treatment (control) on the day of movement from finishing facilities to pens for breeding. Detection of estrus, with the aid of mature boars, was conducted daily for 28 d; gilts in estrus were mated naturally. Treatment with P. G. 600 increased the percentage in estrus within 7 (57.5 vs 40.9%) or 28 d (72.9 vs 59.5%); average interval to estrus was reduced (P less than .05) from 10.4 to 7.5 d. Farrowing rate (78.5 +/- 3.1%), number of pigs born alive (8.6 +/- .2) or dead (.26 +/- .06) and number of pigs weaned (8.0 +/- .2) were unaffected by treatment. Gilts that were heavier than the median for each farm were in heat sooner and more were detected in heat, but no other reproductive traits differed between heavy and light gilts. Overall, the results reveal that P. G. 600 was useful for induction of fertile estrus in prepuberal gilts.

Analysis of Variance↗
PubMed1985

Progesterone as a predictor of cyclicity in Bolivian squirrel monkeys during the breeding season.

In a squirrel monkey breeding colony, two distinct groups of females were observed during the breeding season, December through March. One had low and the other had high estradiol (E2) and progesterone (P) concentrations. The conception rate in females with high E2 and P values was 74%. However, only 25% of monkeys with low steroid concentrations became pregnant during the breeding season. This study showed that all mature females in a colony may not be cycling concurrently and that two serum P measurements obtained at four-day intervals may be utilized to detect noncycling monkeys during the breeding season.

Animals↗
PubMed1982

Monitoring pre-service reproductive status in dairy cows.

Combinations of oestrus detection, ovarian palpation and milk progesterone assays were used to monitor pre-service reproductive status of cows in two dairy herds over two successive years. Non-cyclical cows were identified as having no luteal tissue in their ovaries on two occasions 10 days apart. Absence of luteal tissue was determined by the presence of basal mild progesterone initially followed either by a repeat of this result or by failure to palpate a corpus luteum per rectum. In the period 32 to 56 days post partum the number of non-cyclical cows on farm A years 1 and 2 was eight out of 31 (25 . 5 per cent), and 10 out of 62 (16 . 1 per cent) and on farm B years 1 and 2 was 10 out of 68 (14 . 7 per cent) and 11 out of 85 (12 . 9 per cent) respectively. The farm A herd was high yielding, (average lactation 6380 litres), whereas the farm B herd was of average yield (4717 litres). In both herds 60 day milk yield was not related to cyclical status of pre-service cows. There was however a trend toward a greater proportion of young cows being non-cyclical. With the exception of a prolonged calving to conception interval for farm A in year 1, whether a pre-service cow was cyclical or not had no effect on when the cow was first served or on when the animal conceived. The routine incorporation of pre-service monitoring to herd fertility control programmers may however be of value in recognising the incidence of non-cyclical cows and giving an early indication of oestrus detection efficiency.

Animals↗
PubMed2002

Development and validation of a biosensor-based immunoassay for progesterone in bovine milk.

We have developed a rapid automated immunoassay, using the BIACORE surface plasmon resonance (SPR) biosensor, to measure progesterone in bovine milk. The assay was designed as an inhibition assay with progesterone covalently immobilised to the carboxymethyl dextran matrix of a CM5 sensor chip. A fixed amount of monoclonal anti-progesterone antibody 39C5H7 was mixed 9:1 with the sample and the amount of free antibody was then determined using biomolecular interaction analysis (BIA) by injection of the mixture over the immobilised progesterone sensor surface. The assay was designed to cover the concentration range 0.5 to 50 ng/ml. The limit of detection (LOD) was 3.56 ng/ml. Reproducibility of the assay was very good with both intra-assay and inter-assay coefficients of variation <5%. As results become available within minutes of injection and the procedure involves fully automated instrumentation, we believe that this BIA assay for progesterone in milk could be used in-line in the milking parlour and, thus, provide an important tool for reproductive management of dairy cattle to detect heat and predict pregnancy.

Animals↗