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PubMed2004

Comparison of three estrus detection systems during summer in a large commercial dairy herd.

The objective of the study was to compare three systems for estrus detection and combinations of these systems on a large commercial dairy (1075 lactating cows) during stress of summer heat. At 37-45 days in milk (DIM), 255 cows were fitted with a HeatWatch device (HW; DDx Inc., Denver, CO), an activity sensor ALPRO (ALPRO; DeLaval Inc., Kansas City, MO), and visually observed (VO) three times daily. Pregnancy status was determined by uterine palpation per rectum 35-49 days following artificial insemination (AI). Effects of DIM, parity, standing events, inseminator, and interval between onset of estrus and AI on conception rates were determined using logistic regression. Efficiencies for detection of estrus, determined by comparing detected periods of estrus with a theoretical total of 570 periods, were 49.3% (VO), 37.2% (ALPRO), 48.0% (HW), and 80.2% for all three systems simultaneously. Conception rates (LSM+/-S.E.) for cows detected by one or more of the three systems were 6.2+/-3.9 for VO, 19.8+/-5.6 for ALPRO, 17.3+/-5.0 for HW, 22.8+/-7.0 for VO+ALPRO, 26.9+/-4.6 for VO+HW, 23.2+/-5.2 for ALPRO+HW, and 18.4+/-4.7 for VO+ALPRO+HW. Inseminations performed during no and mild heat stress (temperature-humidity index; THI< or =76) had greater conception rate (P<0.05; 38.8%) compared to AI performed during moderated heat stress conditions (THI>76; 17.6%). Number of mounts were higher for primiparous versus multiparous cows (P<0.05). Cows over 80 DIM during estrus exhibited fewer (P<0.05) standing events. The highest conception rate occurred with the combination of VO+HW, which confirms the premise that combination of multiple systems enhances both the efficiency and accuracy of estrus detection.

Animals↗
PubMed1986

Testosterone of estradiol treatment of heifers or freemartins to detect estrus in confined dairy cattle.

Dairy heifers and freemartins were injected with either testosterone or estradiol and then used to detect estrus in mature dairy cows maintained indoors year-round on slatted-concrete floors. During a 15-mo period, 1,026 occurrences of estrus were confirmed from 339 cows. Observations by the herdsmen detected 92% of all occurrences of estrus compared to the heifers (39%) and freemartins (23%). There was great variation among animals in their ability to detect estrus. Conception rates were not affected by the method of detection of estrus.

Journal Article↗
PubMed1998

Serum testosterone concentration, efficiency of estrus detection and libido expression in androgenized beef cows.

Twenty multiparous, cyclic, nonlactating beef cows were blocked by dominance rank and randomly and equally allotted to 1 of 4 treatment groups: an untreated control group, a synovex-treated group which received 8 Synovex-H implants with no additional hormones, a testosterone-treated group which received 500 mg, i.m. and 1500 mg, s.c. testosterone enanthate on Day 1 with additional 1000 mg, s.c. doses of testosterone enanthate every 14 d, and a synovex + testosterone-treated group which received 8 Synovex-H implants with 500 mg, i.m. and 1500 mg, s.c. testosterone enanthate on Day 1 only. Blood samples were collected via jugular venipuncture once a week beginning 3 wk prior to start of treatment. In addition, samples were collected just prior to treatment; once a day for 1 wk after initiation of treatment; and then twice a week until 225 d after treatment. Efficiency of estrus detection was assessed 22 d prior to start of treatment and every 14 d thereafter for 98 d, using estrus detection trials with synchronized females or modified libido tests. Scores for estrus detection trials included total mounts in 1 h and the percentage of estrous cows detected. Libido was scored on a scale of 0 through 6. All testosterone treatments raised plasma testosterone concentrations above control and pretreatment levels (testosterone and synovex + testosterone > synovex > control; all P < 0.05). Synovex-, testosterone- and synovex + testosterone-treated females performed more mounts in 1 h than the controls (18, 9, 6 and 1, respectively; all P < 0.05). All testosterone-treated cows mounted a higher number of estrous females than the controls (P < 0.05). Only synovex + testosterone- and testosterone-treated cows received libido scores above pretreatment and control values. However, libido of testosterone-treated cows decreased over time, while that of synovex + testosterone-treated females remained high until Day 98. Libido scores correlated positively with the number of mounts in 1 h and the percentage of estrous females detected (0.70 and 0.44, respectively), and the correlation coefficient for these two factors was 0.63. In conclusion, the synovex + testosterone treatment was most effective for producing estrus detector females and libido testing was useful for evaluating sexual activity in androgenized females.

Animals↗
PubMed1999

Modeling of energy balance in early lactation and the effect of energy deficits in early lactation on first detected estrus postpartum in dairy cows.

The general pattern of energy balance in early lactation was modeled. For this purpose, several lactation curves were investigated. The best fitting curve was fit in a random regression model that provided predicted energy balance curves for all lactations. By use of these curves, total energy deficit per lactation, postpartum interval of return to positive energy balance, and nadir of energy balance was determined. In predicted energy balances, nadir of energy balance was present, but variation in postpartum interval to nadir was small. First lactation cows had a smaller energy deficit in early lactation than did older cows. Differences among cows in nadir and total energy deficits in early lactation were large. Both were related to the postpartum interval to first detected estrus with a larger energy deficit and a smaller nadir corresponding to a larger postpartum interval to first detected estrus. From this study, it can be concluded that large energy deficits in early lactation delay first detected estrus.

Animals↗
PubMed1998

Timing of insemination for dairy cows identified in estrus by a radiotelemetric estrus detection system.

The optimal time of artificial insemination (AI) was determined from data for 2661 AI in 17 herds utilizing a radiotelemetric system for estrus detection that has the potential for continuous 24-h surveillance to monitor behavioral events associated with estrus. The system consisted of pressure-sensitive radio frequency transmitters affixed over the sacrum region of cows. The activation of the sensor sent a radiotelemetric signal to a microcomputer via a fixed antenna. Cow identification, date, time, and duration of each standing event were recorded in the software program provided with the system. Each farm selected a 3-h interval to AI for cows that were identified in estrus during the previous 24 h. Pregnancy status was determined from data for return to estrus and palpation of the uterus 35 to 75 d following AI. Standing events during estrus averaged (+/- SD) 8.5 +/- 6.6 per cow, and the number of events per estrus across herds averaged from 6.2 +/- 5.1 to 12.8 +/- 9.9 per cow. The duration of estrus ranged from 5.1 +/- 3.8 to 10.6 +/- 6.8 h across herds; the mean was 7.1 +/- 5.4 h. The interval from the first standing event to AI affected the probability of pregnancy; the highest conception rates for AI occurred between 4 and 12 h after the onset of standing activity. The probability of pregnancy was higher for cows > 100 d in milk, exhibiting > 2 standing events during estrus, and inseminated during March, April or May.

Animals↗
PubMed1994

Electronic animal identification for controlling feed delivery and detecting estrus in gilts and sows in outside pens.

The objective of the present study was to evaluate the feasibility of delivering feed and detecting estrous behavior by computer-controlled equipment in a nonconfinement environment. In Exp. 1, gilts were assigned to treatment when detected pregnant by ultrasound at 30 to 35 d after artificial insemination. They were assigned to be fed individually in stalls once/day (0830) with a scoop (controls, n = 20) or with an electronic sow feeding station (ESF, n = 20). The ESF gilts received their feed in 98.6-g aliquots at 80-s intervals as they visited the feeding station. Control vs ESF gilts did not differ (P > .8) for backfat (2.2 vs 2.1 cm) or weight (170 vs 172 kg) before farrowing, total and live pigs/litter (9.3 and 8.7 vs 9.1 and 8.8), or litter birth weight (12.7 vs 12.1). In Exp. 2, proceptive behavior, as measured by visits to a boar's pen, were recorded electronically, and observed estrus was evaluated in two groups of sows during their first (n = 11) and second and third (n = 19) estrous cycles and in one group of gilts (n = 14). A partition prevented visual and physical contact between the boar and the visiting females except where the electronic estrus detection (EED) station was installed. Feed delivery software was used to monitor boar visitation even though no feed delivery equipment was present at the boar pen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1988

Detecting estrus in synchronized heifers-using tailpaint and an aerosol raddle.

A synchronization treatment was initiated when each of 1227 heifers (four trials) was tailpainted. The tailpaint was sprayed with an aerosol raddle at the end of the treatment period. The heifers were in herds of 20 to 279 animals. Each herd was observed for estrus at selected post treatment intervals. A heifer was considered to be (or to have been) in estrus when the raddle was rubbed off. In three of the trials, animals which had the raddle removed were inseminated at 48 h following the end of the synchronization treatment. The tailpaint of an inseminated animal was scored from 0 (less than 10% of the paint remained) to 5 (more than 90% of the paint remained) and was then reraddled with a second color. The detection-insemination sequence was always repeated at 72 and 96 h, and sometimes at 120 h. Animals which had been previously inseminated, but then had paint scores reduced by at least 2 units were reinseminated 24 h later. Over the four trials, 94.5% of the heifers were detected in estrus through the use of the tailpaint and raddle system. The remaining 67 animals included only 10 (0.8%) which had ovulated without being detected in estrus. The reinsemination rate on consecutive days was 11.3% and was highest among animals that had a tailpaint score of 4 or 5 at 48 h. The proportion of animals detected in estrus at selected posttreatment intervals varied with the different synchronization treatments used within one herd, or with the same treatment used in different herds. The combination of tailpaint, raddling, tailpaint scoring and reraddling is a simple sequence which can be effectively used to detect estrus among heifers synchronized in research or commercial herds.

Journal Article↗
PubMed1979

Prostaglandin in milk, days open, and estrus detection in dairy cows treated with prostaglandin F2 alpha.

Prostaglandin F2 alpha was used to induce estrus in postpartum dairy cows to decrease calving interval and time spent on heat checks. The amount of prostaglandin residue in milk after treatment also was investigated. Twenty-two control cows, checked for heat twice daily, were bred at estrus after 55 days postpartum. Sixty-three cows checked on days 55 to 60 were either bred if in estrus or treated with 30 mg of prostaglandin F2 alpha injected intramuscularly on day 60 and bred at induced estrus or at 75 h posttreatment. Twelve cows were in heat between days 55 and 60 and were bred. Twenty-nine of 51 treated cows were seen in estrus; all of these were bred and 51.7% conceived at this time. Treated cows had fewer days to first service than did controls, but days open were not different, 105.7 versus 101.8. Fertility was similar. Controls required more heat checks than did treated cows (39 to 8.2). Milk from 17 cows at two milkings before and ten milkings after treatment had similar concentrations of prostaglandin (698 +/- 27 pg/ml) except for the first posttreatment milking when prostaglandin concentration almost doubled (1.293 +/- 143 pg/ml).

Animals↗
PubMed1983

[A prospective study of the usefulness of an intravaginal electric resistance meter for estrus detection in cattle].

The use of a device for measuring vaginal electrical resistance was tested in dairy cattle at the time of 496 inseminations as well as in five heifers and four gilts throughout the oestrous cycle. The device can be used in oestrus detection when there is a reliable and consistent difference in vaginal electric resistance, which can be estimated between the day(s) of oestrus and during the other days of the oestrus cycle. However, the results of tests using this device in cattle and gilts showed marked variations within animals during successive heats and cycles as well as between animals on corresponding days of the oestrus cycle. This experiment therefore showed that the device was not an effective aid in heat detection.

Animals↗
PubMed1997

Efficiency of the OVATEC unit for estrus detection and calf sex control in beef cows.

Seventy five spring calving Gelbvieh and Angus cows were utilized over a three year period to evaluate the usefulness of the OVATEC intravaginal probe for indicating the onset of estrus and providing the possibility to influence the sex of the offspring by choosing a breeding time in relation to critical changes in cervical mucus conductivity. Cows were randomly assigned by breed each year into one of four treatments: (1) probed and inseminated when impedance values declined, creating conditions expected to favor X-bearing sperm and with it an increase in the conception of females (PF); (2) probed and inseminated when impedance values were rebounding, expected to favor Y-bearing sperms and with it an increase in the conception of males (PB); (3) standing estrus (AI); or (4) natural service by bull (NS). Cows grazed or were fed hay from tall fescue-legume pastures. Lutalyse was used to synchronize estrus in a two injection scheme. Vaginal probe readings were taken at first injection, second injection and every 12 h thereafter for 6 days. Visual observations for estrus were obtained for PF, PB and AI every 12 h postsecond injection. Rectal palpations of ovaries were obtained at standing heat in all but NS treatments. In cycling cows, probe readings increased prediction of estrus onset (P < 0.10) compared to visual observations and were similar (P > 0.95) to rectal palpations in all probed cows. PF cows delivered heifer calves at greater rates (P < 0.025) than all other treatments whereas PB cows delivered bulls at greater rates (P < 0.05) than all other treatments. Heifer to bull ratios were not different (P > 0.95) for AI or NS treatments. The results of this study indicate that the potential exists for increasing female offspring conceptions utilizing cervical mucus conductivity as a gauge for insemination times.

Administration, Intravaginal↗
PubMed1993

Estrus detection by using vaginal cytologic examination in miniature swine.

Vaginal smears were obtained from four Yucatan miniature swine daily for 69 days and stained with hematologic stain. Epithelial cells were categorized as superficial, large intermediate, small intermediate, or parabasal. Leukocytes were also quantitated. External signs of estrus were recorded, including swelling, discharge, restlessness, or vocalization. Mean age of three of the swine was 147 days at the beginning of the study. The fourth pig was 317 days old. The three younger swine had their first observed estrus at the age of 178 days (range, 167 to 196 days). Mean cycle length was 17 to 21 days. The moving mean leukocyte count (i.e., each value was averaged with the values for the previous day and the following day) always exceeded the epithelial cell count (regardless of type), except during the 3 to 4 days when the pigs exhibited external signs of estrus. Further, epithelial cells were at their peak during estrus, decreasing markedly during diestrus, and increasing again during proestrus. The combined superficial plus large intermediate cell counts were significantly higher during estrus than during diestrus or proestrus. We conclude that daily vaginal smears can be used to determine the stage of estrus in Yucatan pigs.

Animals↗
PubMed1997

Removal of the caudae epididymides to create infertile boars for use in estrus detection programs.

Epididymectomies (removal of the caudae epididymides) were performed to create infertile boars. The simplicity of this procedure allowed for it to be easily performed on physically or chemically restrained boars that weighted 30 kg. Benefits of the use of epididymectomy, rather than vasectomy, to render boars infertile include low cost, simplicity, reduced surgical time, and minimum need of surgical instruments and materials. Epididymectomized boars are used in swine breeding management programs.

Animals↗
PubMed1991

[Estrus detection in the bitch with a progesterone rapid test (EIA)--a sensible supplement to vaginal cytology].

Vaginal smears were taken from 42 bitches and the results were compared with serum levels of progesterone, which were measured by a radioimmunoassay as well as by a qualitative enzyme-immunoassay. With the enzyme-immunoassay it was possible to differentiate low progesterone levels (less than 3.9 ng/ml) and high progesterone levels (greater than 4.2 ng/ml). Timing of insemination or mating of the bitches using both methods showed good pregnancy rates.

Animals↗
PubMed2000

Evaluation of reproductive performance in lactating dairy cows with prostaglandin F2alpha, gonadotropin-releasing hormone, and timed artificial insemination.

Nine hundred and twenty Holstein cows from 16 commercial dairy herds to evaluate three systematic breeding protocols: 14-d PGF2alpha, timed artificial insemination (AI), and GnRH-PGF2alpha, relative to AI following estrus detection without hormone intervention. The timed AI protocol involved GnRH, followed by PGF2alpha 7 d later and GnRH again 2 d after PGF2alpha, with AI 6 to 18 h after the second GnRH. The GnRH-PGF2alpha protocol consisted of GnRH followed by PGF2alpha 7 d later. Eight herds relied on visual observation to detect estrus, and eight herds utilized the HeatWatch estrus detection system. The average interval to first postpartum AI was shortest for the timed AI protocol (77.1 d) followed by the 14-d PGF2alpha protocol (81.6 d). There was no difference in days to first AI between the control (86.1 d) and GnRH-PGF2alpha (89.5 d) protocols. Percent pregnant per first AI did not differ among control (45.6%), 14-d PGF2alpha (43.7%), or GnRH-PGF2alpha (44.0%) protocols, but all protocols had a higher percent pregnant per first AI than the timed AI protocol (30.1%). Response to the GnRH-PGF2alpha protocol was limited because 44.0% of the cows submitted to the protocol were not detected in estrus < or = 10 d post-PGF2, administration and had an interval to first AI of 103.8 d. Cumulative percent pregnant by 120 d postpartum did not differ between control cows (53.1%) and hormonally treated cows (50.6%). Visual observation herds had a shorter interval to first postpartum AI (82.8 d) than the HeatWatch herds (84.8 d), with a higher overall rate of estrus detection across all protocols (75.3 and 67.6%, respectively).

Animals↗
PubMed1975

Influence of estrus detection on days open in dairy herds.

Data from 10 herds on a herd reproductive status program supported estimates of lost reproductive days per cow per year due to conception failure and missed heat as 23 and 10 days. The corresponding estimates from Ohio Dairy Herd Improvement were 14.7 and 40.3 days. The correlation within the 10 herds between days lost due to failure to conceive and total days open was .38 and between days lost due to missed heats and total days open .92.

Animals↗