[Choosing the insemination time for meat-breed cows].
Explore the source record for details and available documents.
Animals↗
SEARCH · PubMed Health
Results for “Estrus Detection”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Prostaglandin F2 alpha for lactating dairy cows with a palpable corpus luteum but unobserved estrus.
Two experiments in 17 dairy herds were for the effectiveness of prostaglandin F2 alpha (treatment) in reducing luteolysis and inducing intervals to conception of 308 cycling lactating dairy cows. Cows with unobserved estrus before first insemination (Experiment 1) and nonpregnant cows with unobserved estrus after insemination (Experiment 2) were eligible for treatment. Cows in Experiment 1 were assigned alternately either to an untreated control group of 85 or to a group of 138 that received 25 mg prostaglandin F2 alpha after detection of a corpus luteum by ovarian palpation. Cows were inseminated either at estrus or at 72 and 96 h posttreatment in the absence of detected estrus. Intervals from treatment to estrus, to first service, and to conception were longer for controls than for treated cows. Conception at first service was similar for controls (39%) and for treated (43%) cows. Procedures were similar for Experiment 2. Intervals from treatment to estrus and treatment to first service were longer for control cows, and treatment to conception tended to be longer for 39 controls than for 46 treated cows. Conception at first service was similar controls (52%) and treated (44%) cows. Prostaglandin F2 alpha was 91% effective for inducing luteolysis based on progesterone concentrations in blood serum. Successful treatment was dependent upon accurate diagnosis of a functional corpus luteum. Days from treatment to conception were reduced for cows with unobserved estrus if treated cows were inseminated at estrus or by appointment in the absence of detected estrus.
Animals↗
Effects of increased dietary energy after mating on developmental uniformity and survival of porcine conceptuses.
Two experiments were conducted to examine the effect of the feeding of a high-energy diet during early gestation on survival of porcine conceptuses. In the first, 91 second-estrus gilts were inseminated 24 h after detection of standing estrus and randomly assigned to a recommended energy (RE: 22.2 MJ of DE/d) or high-energy diet (HE: 36.0 MJ of DE/d) obtained by addition of cornstarch to RE. Gilts were slaughtered 9, 10, or 11 d later, and numbers of corpora lutea (n = 1,268) and recovered conceptuses (n = 977) were recorded. Conceptuses were photographed, and surface areas were measured using an image analysis system. Standard deviations (SD) for mean areas from 82 litters with 899 embryos were used as a measure of size variability within and between litters, and 472 of these were cultured for measurement of estrogen (E) concentrations by enzymeimmunoassay. Conceptus survival was similar for RE and HE groups (76.2 +/- 21 vs 78.8 +/- 17.5%; P > .05). Mean surface areas and SD increased (P < .05) between d 9 and 11, but they were the same for both diets (P > .1). No difference was detected between diets in E produced by d 9 and 10 blastocysts after 24 h in vitro (P > .1). In contrast, d-11 RE embryos produced more E than did HE embryos after 3 h (.77 +/- .11 vs .37 +/- .11 ng/mL; P < .01) and 24 h (3.02 +/- .40 vs 1.29 +/- .39 ng/mL; P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Changes in vulvar and vestibular tissue of the bovine during the estrous cycle as determined by the use of near-infrared interactance.
Near-infrared interactance spectra of the vulva and vestibule of cows were analyzed throughout the estrous cycle to determine if they could be used to detect tissue changes that are associated with estrus. The spectra were collected daily from 16 cyclic Holstein cows beginning at 40 days post partum and continuing for 3 estrous cycles, or until pregnancy was verified. Spectra collected on the day when estrus was exhibited were compared with spectra collected on the nonestrous days. There were spectral differences at 1695 to 1705, at 1790 to 1800 and at 1880 to 1900 nm (P<0.05), regions that are associated with changes in carbohydrate, protein, and water content of the tissues, respectively. Discriminant analysis of interactance measurements at the significant wavelengths was used to develop an equation to predict the day of estrus. The error rate associated with the equation was 26%. Results indicate that near-infrared analysis can detect changes in vestibular and vulvar tissue during the estrous cycle. However, accurate estrus detection using near-infrared interactance techniques will require additional study to reduce variation in the results.
Journal Article↗
Estrus-related odors in cows: time of occurrence.
One Catahoula Leopard Cowdog and three German Shepherd dogs, previously trained to detect odors characteristic of estrus in cows, were used in three experiments to determine when estrus-related odor first appears, how long it persists, and when it disappears in relation to time of estrus. Samples were swabs of reproductive tract fluids taken from vaginas of cycling cows on the day of estrus, at diestrus (8 to 10 days after estrus), and at daily intervals before and after estrus. Estrous odor emerges slowly during the 3 days before estrus, reaches a definite peak in intensity on the day of estrus, and disappears within 1 day thereafter.
Animals↗
Efficacy of the Ovsynch protocol for synchronization of ovulation and fixed-time artificial insemination in Murrah buffaloes (Bubalus bubalis).
Two experiments were conducted to assess the timing and synchrony of ovulation, plasma LH concentrations, and pregnancy rate in Murrah buffaloes (Bubalus bubalis) treated with the Ovsynch (GnRH-PGF(2 alpha)-GnRH) protocol. In Experiment 1, 10 non-lactating cycling buffaloes received 10 microg of a GnRH analogue i.m. (buserelin acetate) without regard to the stage of the estrous cycle (day of treatment, day 0), followed by 25mg of PGF(2 alpha) i.m. (dinoprost thromethamine) 7 days later. A second-treatment of the same GnRH analogue (10 microg, i.m.) was given 48 h after PGF(2 alpha). Ovulation was confirmed by transrectal palpation (at 2-h intervals) from the second-GnRH treatment to detection of ovulation or up to 96 h after the second-GnRH treatment. Plasma LH concentrations were determined in blood samples collected at 15-min intervals for 6h, starting at the second-GnRH treatment, and thereafter at 2-h intervals until 2h after detection of ovulation. Ovulation occurred in 9/10 buffalo (90%) 23.3+/-1.3h (mean+/-S.E.M.; range 20--32 h) after the second-GnRH treatment. Peak LH concentrations 13.5+/-3.5 ng/mL (range 3.9--40.0 ng/mL) occurred 2.1+/-0.1h (range 1.2-3.0 h) after the second-GnRH treatment. In Experiment 2, 15 lactating, cycling buffaloes were subjected to the Ovsynch protocol, with fixed-time AI 12 and 24h after the second-GnRH treatment and 75 lactating buffaloes were inseminated, approximately 12h after detection of spontaneous estrus. Pregnancy rates were 33.3% for TAI and were 30.7% for buffaloes inseminated following spontaneous estrus (P=0.84). In conclusion, the Ovsynch protocol effectively synchronized ovulation in Murrah buffaloes and resulted in conception rates (to two fixed-time inseminations) that were comparable to those achieved with a single AI after detection of spontaneous estrus.
Animals↗
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.
Animals↗
Behavioral estrous signs can predict the time of ovulation in mithun (Bos frontalis).
The objective of this study was to investigate the relationship of different behavioral estrous signs and time of ovulation to identify if behavioral estrous sign(s) can be used as predictor of time of ovulation in mithuns. Data were collected for 54 ovulations from 16 mithuns. The animals were monitored for onset of estrus by observing different behavioral estrous signs at 2 h interval and bull parading thrice a day for 30 min and were further confirmed by plasma progesterone profile. All animals were also observed for any of the estrous signs at every 2 h interval for 30 min and mounting behavior was studied by bull parading at every 2 h for 30 min after onset of estrus. Time of ovulation was detected by rectal palpation at 2 h interval from onset of estrus till ovulation. Behavioral signs of estrus was more intense in primiparous than multiparous mithuns. Ovulation occurred at 26.1+/-1.1 h (ranging between 20 and 31 h) after the onset of estrus. As the method used to determine the onset of estrus is time consuming, labor intensive and no device is yet available to detect onset of estrus automatically, so this cannot be used practically as a predictor of time of ovulation. The mithun cow at estrus to be mounted by bull was recorded in all cases (100%). Ovulation occurred 23.5+/-1.5 h (ranging between 19 and 27 h) after first mounting. Although promising, mounting cannot be assessed automatically, which limits its practical use as a predictor of ovulation. Standing heat was recorded in 98.1% of total estrus studied in mithun cows and ovulation occurred 21.8+/-1.3 h (ranging between 19 and 25 h) after first observed standing heat. Standing heat can be detected automatically using mounting detectors. Hence, standing heat can be used practically as ovulation predictor in mithuns. In conclusion, cow to be mounted by mithun bull is the best predictor of ovulation, but non-availability of devices to detect it automatically restricts its practical application. Standing heat that recorded 98.1% estrus cases in mithun cows, can also be detected automatically using mounting detector, therefore be used widely as an ovulation predictor in field condition for mithun cows.
Animals↗
Embryonic loss from 30 to 60 days post breeding and the effect of palpation per rectum on pregnancy.
This study was conducted over a 12-mo period to determine the rate of bovine embryo death between 30 and 60 d of gestation. In addition, palpation per rectum as a means of pregnancy detection was evaluated as a possible cause of embryo death. Estrus was synchronized in Holstein heifers (n = 1358), weighing > or = 385 kg, with a single intramuscular injection of 25 mg prostaglandin F(2alpha). Estrus was primarily detected by the absence of paint marks on the tailhead. The heifers were artificially inseminated with semen from 5 Holstein sires. Blood was collected between 30 and 45 d after breeding, and sera were evaluated for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Palpation for fetal membrane slip was conducted by an experienced technician in approximately one-half of the inseminated heifers. To determine embryonic survival, a second blood sample was collected at approximately 60 d from 862 heifers that were determined to be pregnant at the first blood sampling. Embryonic loss averaged 5.3% during the interval between the initial detection of pregnancy at 30 to 45 d and the subsequent detection of pregnancy at 60 d of gestation. Embryo loss in heifers that were palpated was 6.5% compared with that of 4.3% in the control heifers (X(2): P = 0.145). These findings establish that there was substantial loss of embryos between 30 and 60 d post breeding but that embryo loss was not affected by palpation per rectum.
Journal Article↗
Induction of estrus in non-lactating dairy goats with different estrous synchrony protocols.
The objective of this study was to evaluate two protocols of estrous synchronization in non-lactating Toggenburg goats. Nineteen goats were allocated, according to body condition score and weight, into two groups (A and B) and evaluated utilizing two treatments (T1 and T2). Animals in the T1 and T2 groups received an intravaginal sponge (day 0) containing 60 mg medroxyprogesterone acetate for 6 and 9 days, respectively, plus 200 IU equine chorionic gonadotrophin (eCG) and 22.5 microg cloprostenol 24 h before sponge removal. Females were bred only at the second estrus and received 22.5 microg cloprostenol 7 days later to prevent pregnancy. Percentages of animals in estrus did not differ (P > 0.05) between T1 (89.5%) and T2 (84.2%). From 33 females in estrus (T1 + T2), 28 (84.8%), 2 (6.1%), and 3 (9.1%) were identified in estrus at 06:00, 12:00 and 18:00 h, respectively. Additionally, 6 (18.2%), 0 (0.0%) and 27 (81.8%) were no longer detected to be on estrus at 06:00, 12:00 and 18:00 h, respectively. Interval from sponge removal and the onset of estrus (IE) did not differ (P > 0.05) between T1 (46.1 +/- 15.0 h) and T2 (53.6 +/- 16.1 h). Duration of estrus did not differ (P > 0.05) between T1 (30.0 +/- 12.0 h) and T2 (27.2 +/- 11.2 h). Both protocols were effective in inducing estrus in non-lactating goats. The onset and end of the estrus relative to hour of the day should be considered in estrous detection, natural breeding, and artificial insemination in goats.
Administration, Intravaginal↗
Immunological detection and characterization of an estrus-associated antigen in the goat oviduct.
The present study was designed to investigate the possibility that the goat oviduct produces specific substance(s) similar to the oviductal glycoprotein (BOGP) of the bovine oviduct. Oviductal flushings obtained from goats at the follicular and luteal phases of the estrous cycle were examined by immunoblotting for the presence of material that cross-reacted with monoclonal antibodies (MAbs) specific for BOGP. The MAbs immunoreacted with a broad band with a molecular mass of protein of about 97 kDa in the flushings of goat oviducts after fractionation of proteins by electrophoresis under reducing conditions. The antigen was present in flushings obtained from the ampullar segments of oviducts from goats at the follicular stage, but this antigen could hardly be detected in the flushings from the ampulla at the luteal phase and or the flushings from the isthmus at either the follicular or the luteal phase. This antigen was not detected in uterine flushings, follicular fluid, or serum. An immunohistochemical study demonstrated that the MAbs reacted specifically with the epithelial cells of the goat oviduct. Intense labeling was observed in the ampullar and fimbrial epithelia of goat oviducts at the follicular phase, but the immunohistochemical reaction was very weak at the luteal phase. In the isthmus, the reaction was faint during both the follicular and the luteal phase. No specific immunohistochemical reactivity with the MAbs was observed with other tissues from the reproductive tract or with nonreproductive tissues. Immunofluorescent staining showed that the antigen was associated with the zona pellucida of goat ovarian eggs that had been incubated with ampullar flushings from goats at the follicular stage.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Discrimination among colony mates' anogenital odors by guinea pigs (Cavia porcellus).
Controversy exists in the literature regarding whether odor is used by guinea pigs in detection of physiological estrus in female counterparts. Three experiments are presented which used an aversively motivated learning task to examine the ability of adult guinea pigs to discriminate among odors from non-specific anogenital swabbings of colony mates. The first and second experiments examined the ability of male and female guinea pigs to discriminate among odors of colony mates controlled for age and sex. Both males and females were able to discriminate among individual animals on the basis of odor. Since individual animals could be discriminated, the third experiment, examining detection of physiological estrus, tested the ability of males and females to discriminate preserved odor samples from the same female during conditions of estrus and nonestrus. Both males and females were able to discriminate between the conditions. Results are discussed with reference to the involvement of odor in the social behavior of guinea pigs.
Age Factors↗
Influence of premature induction of a luteinizing hormone surge with gonadotropin-releasing hormone on ovulation, luteal function, and fertility in cattle.
We tested the hypothesis that luteal function and fertility would be reduced in cattle induced to ovulate prematurely compared with those ovulating spontaneously. Estrus was synchronized in 56 beef cows (24 that were nonlactating and 32 that were nursing calves). At 6.4 +/- 0.1 d after estrus, all follicles > or = 5 mm were aspirated (day of aspiration = d 0) with a 17-gauge needle using the ultrasound-guided transvaginal approach. On d 1.5 and 2, cows were administered 2 luteolytic doses of PGF2alpha. Ovarian structures were monitored by transrectal ultrasonography from d -2 to 12, or ovulation. Emergence of a new follicular wave occurred on d 1.7 +/- 0.1. When the largest follicle of the newly emerged wave was 10 mm in diameter (d 4.8 +/- 0.1), cows were assigned on an alternating basis to receive 100 microg of GnRH (GnRH-10; n = 29) to induce ovulation or, upon detection of spontaneous estrus, to the spontaneous (SPON) treatment (n = 24). Cows were bred by AI at 12 h after GnRH (GnRH-10) or 12 h after the onset of estrus (SPON) as detected using an electronic surveillance system. Blood samples were collected every other day beginning 2 d after ovulation until pregnancy diagnosis 30 d after AI. Ovulation and AI occurred in 29/29 cows in the GnRH-10 and in 24/24 cows in the SPON treatment. Ovulation occurred later (P < 0.05) in the SPON (d 7.7 +/- 0.1) than GnRH-10 (d 6.8 +/- 0.1) treatment. Double ovulations were detected in 47% of cows, resulting in 1.5 +/- 0.1 ovulations per cow. Diameters of the ovulatory and the second ovulatory (in cows with 2 ovulations) follicles were greater (P < 0.05) in the SPON (12.0 +/- 0.3 mm and 10.5 +/- 0.4 mm, respectively) than in the GnRH-10 (10.7 +/- 0.1 mm and 9.2 +/- 0.3 mm) treatment. Cross-sectional areas of luteal tissue and plasma concentrations of progesterone during the midluteal phase were greater (P < 0.05) in the SPON (3.62 +/- 0.2 cm2 and 6.4 +/- 0.3 ng/mL) than in the GnRH-10 (3.0 +/- 0.2 cm2 and 5.4 +/- 0.2 ng/mL) treatment. The conception rate to AI in the SPON (100%) treatment was greater (P < 0.05) than in the GnRH-10 (76%) treatment. The animal model used in this study resulted in unusually high conception rates and double ovulations. In conclusion, premature induction of the LH surge reduced the diameter of ovulatory follicle(s), the luteal function, and the conception rate to AI.
Animals↗
Steroids and plasminogen activator concentrations in follicular fluid of gilts at first and third estrus.
An experiment was conducted to determine whether morphological and functional characteristics of follicles differed at a similar stage of pubertal (first) and third estrus in the same gilts. Nine prepubertal gilts were checked three times daily for estrus and laparotomized 6 h after detected first and third estrus. Samples of vena cava and ovarian venous blood were collected, follicle numbers and diameters were recorded, and follicular fluid (FF) was aspirated from all follicles 8 to 12 mm in diameter. Sera and(or) FF were analyzed for progesterone (P4), estradiol-17 beta (E2), testosterone (T), androstenedione (A4), 5 alpha-dihydrotestosterone (DHT), plasminogen activator (PA), and plasmin (PLM). Overall mean number of follicles > or = 8 mm in diameter did not differ between gilts at first and third estrus (P > .05) but gilts at first estrus had more follicles 4 to 8 (P < .05) and 8.1 to 10 mm in diameter (P < .01) and fewer 10.1 to 12 mm in diameter (P < .07) than at third estrus. Mean FF concentrations of E2, T, and A4 at third estrus were significantly greater than at first estrus, whereas FF concentrations of P4, DHT, PA, and PLM were similar at first and third estrus (P > .05). Mean concentrations of E2 in systemic and ovarian venous sera were also greater in gilts at third than at first estrus (both P < .05). Systemic concentrations of P4 in gilts at first and third estrus did not differ (P > .05).(ABSTRACT TRUNCATED AT 250 WORDS)
Androstenedione↗
Estrus and estrogen changes in mated and unmated free-living European ground squirrels.
The course of behavioral and vaginal estrus and patterns of circulating estrogens were followed in free-living European ground squirrels (Spermophilus citellus) after their emergence from hibernation. Normally mating females were compared to a second group in an area where males had been removed from the population before female emergence. Both groups showed vaginal estrus, but the patterns differed. Mating shortened vaginal estrus to a 3-day period compared to 8 days in unmated females. The extent (cell number) of cell cornification during estrus and the cellular components (percentage distribution) of metestrus did not differ between the two groups. Females in the area without males had significantly higher estrogen levels during estrus and metestrus compared to those in the control area. European ground squirrels were found to be monestrous, as none of the unmated females reentered estrus after metor diestrus was detected. The prolongation of vaginal estrus in unmated females can be viewed as either a physiological inevitability or an adaptation to low mate availability. The extension is still relatively short compared to other sciurid species and perhaps a product of constraints producing a strict time frame for reproduction.
Animals↗
Induced puberty in prepuberal zebu heifers treated with norgestomet and pregnant mare serum gonadotropin.
Three experiments were conducted to examine the progestogen plus PMSG treatment for its effectiveness in inducing synchronous puberty in prepuberal zebu heifers in three different seasons. In Experiment 1, ten Ongole heifers (age 21 months) were treated with Norgestomet implants for nine days and an intramuscular injection of 400 IU of PMSG two days before implant removal. Ten heifers (age 25 months) were kept as untreated controls. Animals were inseminated 12 h after detection of cyclic estrus (not bred at induced estrus) until all animals conceived. The proportion of treated animals showing estrous, ovulatory, and cyclic activity were 100%, 75% and 25% respectively, while the average age at first conception was significantly less (P < 0.05) than in the control group. In Experiment 2, 18 Ongole heifers (age 22 months) were divided into treatment and control groups. Fixed-time inseminations were done 48 and 72 h after implant removal and 12 h after being detected in heat at other times. Estrus was seen in all while 63% became pregnant (P < 0.05). At the end of the 100-day experiment, the percent pregnant were 33 and 63 in the control and treatment groups, respectively. In the third study, twenty-six Ongole heifers (age 22 months) were assigned to treatment and control groups. Eighty-eight percent of the animals exhibited estrus, 75% ovulated (P < 0.01) and 25% conceived to fixed-time insemination. The pregnancy rate at the end of the experiment was 10 and 56% (P < 0.01) respectively in control and treated groups. Estrous response and fertility were better in the cooler month (February) and the treatment imposed in the hotter month (May) resulted in a significantly higher (P < 0.05) age and body weight at conception.
Journal Article↗
Estrous intensity and conception rates in Holsteins.
During 34 mo, 732 inseminations were evaluated in Holstein cows and heifers of breeding age. Females were submitted for insemination after detection of either 1) standing estrus, 2) mounting activity, or 3) other subtle symptoms of estrus (clear mucus, general appearance of genitalia or tailhead, and excessive vocalization). Conception rates were similar following standing estrus and mounting activity (50 versus 46%). Although higher conception rates occurred following standing or mounting activity than after detection of subtle estrous symptoms, one of three inseminations resulted in conception after insemination in the latter group. Clear mucus in half of the females upon cervical manipulation at insemination was associated with higher conception. Service number, age, and maximum ambient temperature on day of insemination also affected conception rates. Methods of thawing semen, ease of cervix penetration at insemination, service sire, inseminator, and time of estrous detection and insemination had little effect on fertility. Acceptable conception rates were achieved with more liberal interpretation of estrous symptoms.
Age Factors↗
Development of a TIRF-based biosensor for sensitive detection of progesterone in bovine milk.
A total internal reflectance fluorescence (TIRF)-based biosensor for progesterone in bovine milk was developed and tested by measuring the progesterone level in daily milk samples for 25 days, covering a whole estrus cycle. The detection is based on total internal reflectance fluorescence. The assay has been designed as a binding-inhibition test with a progesterone derivative covalently immobilized on the sensor surface and a monoclonal anti-progesterone antibody as biological recognition element. First an existing progesterone assay was optimized by reducing the assay time per measurement, resulting in an assay time of about 5 min and reaching a limit of detection (LOD) of 0.04 ng mL(-1) and a quantification limit (LOQ) of 0.34 ng mL(-1). After calibration the assay was tested by measuring the progesterone level in daily milk samples over several weeks. An estrus cycle of a cow could be measured. As results become available within minutes without any preparation or pre-concentration of the milk samples the fully automated TIRF-based biosensor for progesterone can be used in-line in the milking parlor and thus could be an important tool for reproductive management of dairy cattle detecting heat and predicting pregnancy, which are critical parameters in milk production.
Animals↗