Pre-breeding Examination Research Articles

Twin management in the mare: A review.

Twin gestation in the mare is undesirable and can have disastrous consequences. As in many cases, the key to success in twin management lies in a thorough follow-up and accurate recording of clinical findings in the pre-breeding examination. A pregnancy diagnosis in the mobility phase is imperative for a good outcome in the event of twin reduction. If a twin gestation is not diagnosed during this early pregnancy stage, several other procedures exist for managing post-fixation twins (>16 days) with varying degrees of success. Most twin pregnancies are the result of multiple ovulations (dizygotic twins). However, monozygotic twins are also sporadically diagnosed, due to the increasing number of transferred in vitro produced equine embryos. In these cases, the most optimal treatment strategy still needs to be determined. This review provides an overview of the various twin reduction techniques described with the expected prognosis as well as of some less reported techniques with their results. In addition, physiological events and the reduction techniques are demonstrated to the user in virtual 3-dimensional illustrations.

Determining the clinical utility of a single pre-breeding examination for predicting subsequent reproductive performance in seasonal pasture-based dairy heifers

Heifers that conceive early in the breeding season are key to the maintenance of a compact calving pattern in seasonal dairy herds. The purpose of this prospective observational study was to determine whether a single pre-breeding examination is useful in predicting future reproductive and calving performance in dairy heifers. This evaluation was based on a matrix of easily measurable variables which could be applied to seasonal, pasture-based dairy heifers. The matrix variables were; body weight (≥55% mature body weight at mating start date), body condition score (≥3.5), and the presence of a corpus luteum. Seasonal, pasture-based dairy heifers (n = 572) on six commercial dairy farms were examined at an average of 28 days prior to the breeding season. At this examination, they were classified as READY (meeting all three of the above criteria), INTERMEDIATE (meeting one or two of the above criteria) or PROBLEM (meeting none of the above criteria) based on the matrix and then exposed to a routine artificial insemination (AI) breeding period followed by bull breeding depending on individual farm management. Subsequent pregnancy status was determined by transrectal ultrasonography initially at 30–60 days in calf (DIC), and confirmed at over 60 DIC. After the breeding season, 519 (96%) of heifers were determined to be pregnant, of which 345 (64%) became pregnant within the first three weeks of the breeding season. Farmers collected calving data; including calving difficulty score, from the heifers the following spring. A logistic regression model was used to analyse the association between the matrix categories and the following outcomes: reproductive (21 day submission rate, 1st AI conception rate, 3 wk and 6 wk in calf rate) and calving (assistance and dystocia). Heifers classified as PROBLEM had significantly lower odds of conceiving to the first AI serve and of becoming pregnant within the first three and six weeks of the breeding season (P ≤ 0.05). In conclusion, the proposed matrix could be practically useful for classifying heifers prior to the breeding season.

Double cervices in a Gypsy Vanner mare

A 7-year, purebred Gypsy Vanner, maiden mare was presented with abnormal cervical tissue that was detected during prebreeding examination. External vulvar examination, transrectal and ultrasonographic examination of uterus, and internal vaginal vault and cervical examination (via speculum and endoscopy) were conducted. Karyotype analysis included sex chromosome study with dual-color fluorescence in situ hybridization and polymerase chain reaction for SRY gene. Mare had normal 64,XX karyotype with no evidence of mosaicism. Two distinct, patent, cervical ora separated by a frenulum, leading to a single uterine body, were observed. It was recommended to avoid breeding because of dystocia risk. To the authors’ knowledge, this is the first reported case of this nature in a mare.

Reproductive tract disease in Irish grazing dairy cows: Retrospective observational study examining its association with reproductive performance and accuracy of 2 diagnostic tests

The detection of reproductive tract disease (RTD) 3 wk postpartum is important because of its effect on subsequent reproductive outcomes. Numerous methods for the diagnosis of RTD are described, some of which are more practical and instantaneous in terms of diagnosis. Two of these methods involve identification of purulent vaginal discharge (PVD) and evidence of ultrasonographic uterine changes indicative of endometritis (UE). The objectives of our retrospective observational study were (1) to assess the association of PVD or UE score at the prebreeding examination (PBE) with the hazard of pregnancy within the subsequent breeding season; (2) to determine the test sensitivity (Se) and specificity (Sp) at the point of sampling of both tests using a Bayesian latent class model; and (3) to determine the effect of varying positivity thresholds on test accuracy. To achieve these objectives, we analyzed an initial data set of 5,049 PBE from 2,460 spring-calved cows in 8 herds between 2014 and 2018. Each PBE was conducted once between 25 and 86 d in milk. At each PBE, vaginal discharge was obtained with a Metricheck device (Simcro) whereas uterine contents were assessed using transrectal ultrasonography. Purulent vaginal discharge was scored on a scale of 0 to 3 depending on discharge character, and UE was scored on a scale of 0 to 4 depending on the presence and consistency of intraluminal fluid. Cows with scores of ≥2 in either test had received treatment. Fertility data were available from 4,756 PBE after data exclusion. The association between PVD or UE score at the PBE and subsequent hazard of pregnancy was analyzed using a Cox proportional hazards model. Cows with a PVD score of 2 or 3 were less likely to conceive than cows with a PVD score 0 [score 2 hazard ratio (HR) = 0.74; 95% confidence interval (CI): 0.59-0.94; score 3 HR = 0.65; 95% CI: 0.51-0.84]. Cows with a UE score of 1, 2, 3, or 4 were less likely to conceive than cows with a UE score of 0 (score 1 HR = 0.82; 95% CI: 0.73-0.93; score 2 HR = 0.79; 95% CI: 0.62-1.00; score 3 HR = 0.43; 95% CI: 0.43-0.90; score 4 HR = 0.39; 95% CI: 0.26-0.58). To determine the Se and Sp of PVD or UE score for diagnosis of RTD at the time of PBE, a Bayesian latent class model was fitted on 2,460 individual cow PBE. Flat priors were used for the Se and Sp of UE, whereas informative priors were used for PVD Se (mode = 65%, 5th percentile = 45%) and Sp (mode = 90%, 5th percentile = 80%) and RTD prevalence (mode = 20%, 5th percentile = 10%). Posterior estimates (median and 95% Bayesian probability intervals; BPI) were obtained using 'rjags' (R Studio). The optimal test thresholds (PVD and UE score ≥1) were selected by assessing the effect of different thresholds on test estimates and using a misclassification cost analysis. Based on these, median (95% BPI) Se for PVD and UE score ≥1 were 44% (29-60%) and 67% (33-100%), respectively. Median Sp for PVD and UE score ≥1 were 90% (86-93%) and 91% (86-93%), respectively. Higher scores in both tests were associated with impaired fertility, and UE scoring with a threshold of ≥1 had the highest test Se and Sp estimates although test Se was conditional on days in milk when the PBE occurred.

237 Incidence and Implications of Disparate Uterine and Ovarian Development Observed Among Heifers Evaluated During the Peripubertal Period

Abstract Rapid development in the reproductive tract occurs in the peripubertal period, with variable rates of development of reproductive tissues potentially resulting in perceived disparities in ovarian and uterine development at pre-breeding examination. Data collected from 22,173 heifers evaluated over five consecutive breeding seasons (2014–2018) were analyzed retrospectively to assess relationships between observed disparities in uterine and ovarian development and the timing of conception within the breeding season. Pre-breeding evaluations were conducted 35–45 days prior to breeding. Weight, hip height, and pelvic area were recorded. A single veterinarian conducted all reproductive evaluations via rectal palpation, and heifers were assigned individual scores for ovarian (2=infantile, 3=no significant structures, 4=large follicle and/or corpus luteum) and uterine (2=infantile, 3=mid-sized, distended tract, 4=well-vascularized, distended or coiled tract) development respectively. Heifers received artificial insemination (AI) based on detected estrus following the 14-day MGA-PG protocol. Pregnancy diagnosis was performed via transrectal ultrasonography. Pregnancy rates to AI (P/AI) were greater for scores 4-4 (n = 14,567) in comparison with 3-3 (n=3,941; P < 0.0001) or 2-2 (n = 44; P < 0.0001) and likewise were greater (P < 0.0001) for scores 3-3 in comparison with 2-2. Heifers with disparate scores of 2–3 (n = 38) did not differ (P = 0.53) from those with disparate scores of 3-2 (n = 53) with respect to P/AI, but either disparity was associated with greater (P < 0.01) P/AI relative to scores of 2-2 and reduced P/AI relative to scores of 3-3 (P < 0.01). Scores of 4-3 (1,698) and 3-3 did not differ (P >0.44) in P/AI, but P/AI tended (P = 0.06) to be greater among scores 3–4 (1,832) in comparison with 3-3. Similar (P > 0.33) P/AI was observed among heifers scored 4-4, 4-3, or 3–4. In summary, disparate ovarian and uterine development impacted timing of conception within the breeding season among heifers with lower tract scores. Such disparities were observed among 0.4% of heifers evaluated.

Determining potential pregnancy status differences based on a new method of yearling heifer prebreeding examination

The study objective was to evaluate the Ready-Intermediate-Problem (RIP) replacement heifer evaluation matrix's ability to classify heifers into groups with differing reproductive outcomes. Beef heifers (n = 341) from six Kansas herds were classified according to RIP matrix guidelines and then exposed to AI breeding, bull breeding, or a combination of both as per the management plans for each participating herd. Following the breeding season the heifers were evaluated to determine pregnancy status, AI pregnancy status, days bred, and the number of 21 day cycles needed during the breeding season to become pregnant. After the breeding season, 298 (87%) of the heifers were pregnant, 204 (68%) of which became pregnant in the first 21 days of the breeding season. There was a significant interaction (P = 0.01) in RIP classification and pregnancy by 21 day cycle. Ready classified heifers had a significantly greater risk of becoming pregnant after a single AI exposure (P = 0.03) and in the first 21-day cycle (P = 0.02) compared to Problem classified heifers, and significantly less risk of being non-pregnant at the end of the breeding season (P < 0.01) compared to Problem classified heifers. The RIP matrix can be useful for classifying heifers prior to the onset of the breeding season. Further research is needed to evaluate the matrix in other settings and populations of U.S. beef heifers as well as at different intervals between evaluation and the start of breeding season.

Uterine disease and its effect on subsequent reproductive performance of dairy cattle: a comparison of two cow-side diagnostic methods

The aim of this study was to compare vaginal mucus scoring and ultrasonographic assessment of uterine content as predictors of future reproductive performance of dairy cows. Holstein-Friesian cows (n = 493) from seven commercial dairy farms were enrolled in this study. All cows received one prebreeding examination (PBE) between 21 and 38 days after parturition. During the PBE, vaginal mucus was scored (MS) and the transrectal ultrasonographic examination of the uterus to assess content (UTS) took place. The MS was scored on a scale of 0 to 3 using a Metricheck device and appearance of the uterus on transrectal ultrasound was scored on a scale of 0 to 4 based on the presence and consistency of intraluminal fluid. Other data collected from each cow included the farm ID (F_ID), conception rate to first service, length of breeding window, lactation number, calving month, body condition score (BCS) at calving, BCS loss after calving, BCS at PBE, days in milk at PBE, 305 day milk yield, economic breeding index (EBI), EBI fertility subindex and EBI health subindex. For each cow these parameters were analyzed using univariate Cox proportional hazard model to evaluate the effect of variables on the reproductive performance, measured as positive pregnancy status (PS) at the end of the breeding season. Receiver-operating characteristic analysis of the diagnostic tests compared with each other took place as well. Cows with positive UTS were 7.75 times more likely to have a positive MS as well (P < 0.01). The PS hazard ratios for cows with UTS0, 1, 2, 3, and 4 were 1; 0.84; 0.53; 0.78; 0.28, respectively (P < 0.001). For the cows with MS0, 1, 2, and 3, the PR hazard ratios were 1; 1.02; 0.51; 0.75; respectively (P = 0.01). Conception rate to first service, breeding window, and PS were significantly better for the cows with UTS0, 1 and 2 compared with the cows with UTS3–4 and MS2+3 (68%; 18%, [P = 0.020]; 29; 75 days, [P = 0.001]; 95%; 55%; [P = 0.010], respectively). There was a significant effect of days in milk at PBE in relation to the subsequent PS (P = 0.04). Cows in lactation number 5 or more were less likely (r = 0.69) to get in calf before the end of the breeding season than cows in their first lactation. Cows that calved later in the season were less likely to become pregnant before the end of the breeding season (P < 0.03). Younger cows (lactation <5) and cows with MS and UTS scores of 0 and −1 had significantly better reproductive performance (P < 0.04). Receiver-operating characteristic analysis showed that MS did not always reflect UTS, but cows with positive UTS were 7.75 times more likely to have a positive MS (P < 0.01) and a high UTS had a larger negative effect on time to PS than a high MS (P < 0.05). In conclusion, both prebreeding vaginal mucus evaluation with the Metricheck device and an ultrasound scan of the uterus serve as a good predictor of the subsequent PS. There is overlap between the two systems, but the best predictor for future reproductive outcome of the cow is a combination of both.

Ultrasonographic reproductive tract measures and pelvis measures as predictors of pregnancy failure and anestrus in restricted bred beef heifers

Previous reports have shown that reproductive tract score (RTS) can predict reproduction outcomes in seasonally bred beef heifers, although the accuracy can vary. Some ultrasonographic measures of the female reproductive tract and pelvis area have also been associated with reproductive outcome in young heifers. The objectives of this study were to determine which transrectal ultrasound or pelvis measures taken at a single examination are independent predictors of reproductive failure and whether the RTS system can be optimized with this information. In this observational study, year-old beef heifers (n = 488) in 2 birth cohorts were followed from just before the first breeding until confirmation of pregnancy. A single pre-breeding examination included body condition score, RTS, ultrasound measures of the reproductive tract (length and diameter of the left and right ovaries, presence and diameter of a CL, largest follicle diameter and left uterus horn diameter) and transverse and vertical diameters of the pelvis. Additional farm records including dam parity, sire, birth weight and birth date, weaning weight, weaning date, prebreeding body weight, AI dates, and semen used were available. Breeding consisted of 50 days of AI, followed 5 to 7 days later by a 42-day bull breeding period. Pregnancy failure was defined as the failure to become pregnant after the AI and bull breeding periods, while anestrus was defined as the failure to be detected in estrus during the 50-day AI period. From the prebreeding data and farm records, independent predictors of pregnancy failure and anestrus were identified using stepwise reduction in multiple logistic regression models. Age at the onset of breeding was the only consistent independent predictor of pregnancy failure and anestrus in both cohorts of this study (P < 0.05). Body condition score, uterus horn diameter, absence of a CL, largest follicle of less than 13 mm, and pelvis area (PA) were the prebreeding examination variables that remained in prognostic models (P < 0.1). Combining either the model based on the 3 remaining ultrasound measures or RTS with PA provided more accurate prognostic models for pregnancy failure and anestrus than using RTS alone (P < 0.05). It is concluded that ultrasound measures have prognostic value for pregnancy failure in restricted bred yearling heifers as a result of their association with anestrus, and that smaller PA has additional prognostic value for poorly performing heifers.

The impact of cow nutrient status during the second and third trimesters on age at puberty, antral follicle count, and fertility of daughters

Fluctuating feed resources to beef cows across the production cycle is a proven method for decreasing input costs; however, limiting nutrients during late gestation have been demonstrated to decrease ovarian follicle numbers in female offspring in some studies. We hypothesize that limiting nutrients to mature (≥3yr) crossbred beef cows during the second and third trimesters would result in daughters that would have decreased follicle numbers detectable by ultrasonography as yearlings. Over four breeding seasons, pregnant beef cows (n=397) were assigned to either Low (L), Moderate (M) or High (H) nutrient intake during the second or third trimester, resulting in four dietary treatment groups (L–H, L–L, M–H, and M–M). Heifers (n=416) born to these cows were weighed at weaning and moved to a dry lot where they were monitored for behavioral estrus with the aid of heat detection patches. Two weeks before their first breeding season, heifers were submitted for ultrasonographic examination of their ovaries to determine antral follicle numbers. Heifers were placed with bulls for 60d and pregnancy status was determined 45d after the bulls were removed. Growth and reproductive traits were analyzed using the MIXED Procedure of SAS with maternal diet and year as fixed effects. Maternal dietary intake did not affect heifer growth rates, age at puberty, or antral follicle counts (P≥0.40). However, an increased proportion of the heifers born to dams fed a high nutrient diet during the third trimester (L–H or M–H) calved in the first 21d of their first calving season (P=0.004). Antral follicle counts detectable by ultrasonography at yearling pre-breeding examination were greater in heifers that calved during the first 21d of their first calving season (P=0.02); however, these heifers did not differ in age at puberty (P=0.60). From this study, we conclude that: (1) limiting nutrient intake during late gestation in mature (≥3yr) beef cows does not influence the ovarian reserve or reproductive performance of daughters; (2) increasing maternal nutrient intake during the third trimester can improve the first service conception rates of daughters; and (3) pre-breeding ultrasonography to determine antral follicle counts is a good indicator of fertility for choosing replacement heifers.

Case Reports: Bull pre-breeding examination

LivestockVolume 15, Issue 7 p. 15-18 Case Reports: Bull pre-breeding examination Colin D Penny BVM&S CertCHP DBR DipECBHM MRCVS, Colin D Penny BVM&S CertCHP DBR DipECBHM MRCVS LARGE ANIMAL PRACTICE, ROYAL (DICK) SCHOOL OF VETERINARY STUDIES, EASTER BUSH VETERINARY CENTRE, ROSLIN, MIDLOTHIAN. EH25 9RGSearch for more papers by this author Colin D Penny BVM&S CertCHP DBR DipECBHM MRCVS, Colin D Penny BVM&S CertCHP DBR DipECBHM MRCVS LARGE ANIMAL PRACTICE, ROYAL (DICK) SCHOOL OF VETERINARY STUDIES, EASTER BUSH VETERINARY CENTRE, ROSLIN, MIDLOTHIAN. EH25 9RGSearch for more papers by this author First published: 25 November 2010 https://doi.org/10.1111/j.2044-3870.2010.tb00321.xCitations: 1AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume15, Issue7November‐December 2010Pages 15-18 RelatedInformation

Case Reports: Bull pre-breeding examination

UK Vet Vol 15 No 6 October 2010 CATTLE PRACTICE INTRODUCTION There are now many practices in the UK developing a bull-breeding soundness examination service for their clients, after being trained in the procedures of electroejaculation (EEJ) and semen evaluation. The recent launch of the BCVA Bull Pre-Breeding Examination (PBE) Certificate means there is now a standard reporting format available for those BCVA members who wish to issue certificates after examination of bulls. It is important when examining bulls for certification purposes that each stage of the examination is carried out thoroughly and to a high standard to ensure the process has credibility. For a bull to be certified as suitable for breeding, using the new BCVA certificate, it must pass a physical examination, achieve minimum standards for scrotal circumference and produce a semen sample that has a progressive motility of ≥ 60% with ≥70% morphologically normal sperm (see Penny [2009] for a detailed description of PBE).

Prebreeding examination of the stallion

A PREBREEDING examination of a stallion can range from simply performing basic health tests at the start of the season to conducting a more detailed examination for insurance purposes, breed...

Uterus unicornis in two mares

Two American Paint Horses, a 3-year-old nulliparous mare and a 7-year-old primiparous mare, presented for recent infertility and a pre-breeding examination, respectively. Examination of the internal reproductive tract of both mares using transrectal palpation and ultrasonography revealed the presence of the cervix, uterine body, left uterine horn and bilateral ovaries. The right uterine horn could neither be palpated nor imaged. The clinical diagnosis of uterus unicornis in one mare was confirmed at necropsy, which revealed combined aplasia of the right uterine horn and oviduct.

In this issue

In this issue

Ethics and genetic selection in purebred dogs.

There is an ongoing revolution in medicine that is changing the way that veterinarians will be counselling clients regarding inherited disorders. Clinical applications will emerge rapidly in veterinary medicine as we obtain new information from canine and comparative genome projects (Meyers-Wallen 2001: Relevance of the canine genome project to veterinary medical practice. International Veterinary Information Service, New York). The canine genome project is described by three events: mapping markers on canine chromosomes, mapping gene locations on canine chromosomes (Breen et al. 2001: Genome Res. 11, 1784-1795), and obtaining the nucleotide sequence of the entire canine genome. Information from such research has provided a few DNA tests for single gene mutations [Aguirre 2000: DNA testing for inherited canine diseases. In: Bonagura, J (ed), Current Veterinary Therapy XIII. Philadelphia WB Saunders Co, 909-913]. Eventually it will lead to testing of thousands of genes at a time and production of DNA profiles on individual animals. The DNA profile of each dog could be screened for all known genetic disease and will be useful in counselling breeders. As part of the pre-breeding examination, DNA profiles of prospective parents could be compared, and the probability of offspring being affected with genetic disorders or inheriting desirable traits could be calculated. Once we can examine thousands of genes of individuals easily, we have powerful tools to reduce the frequency of, or eliminate, deleterious genes from a population. When we understand polygenic inheritance, we can potentially eliminate whole groups of deleterious genes from populations. The effect of such selection on a widespread basis within a breed could rapidly improve health within a few generations. However, until we have enough information on gene interaction, we will not know whether some of these genes have other functions that we wish to retain. And, other population effects should not be ignored. At least initially it may be best to use this new genetic information to avoid mating combinations that we know will produce affected animals, rather than to eliminate whole groups of genes from a population. This is particularly important for breeds with small gene pools, where it is difficult to maintain genetic diversity. Finally, we will eventually have enough information about canine gene function to select for specific genes encoding desirable traits and increase their frequencies in a population. This is similar to breeding practices that have been applied to animals for hundreds of years. The difference is that we will have a large pool of objective data that we can use rapidly on many individuals at a time. This has great potential to improve the health of the dog population as a whole. However, if we or our breeder clients make an error, we can inadvertently cause harm through massive, rapid selection. Therefore, we should probably not be advising clients on polygenic traits or recommend large scale changes in gene frequencies in populations until much more knowledge of gene interaction is obtained. By then it is likely that computer modelling will be available to predict the effect of changing one or several gene frequencies in a dog population over time. And as new mutations are likely to arise in the future, these tools will be needed indefinitely to detect, treat and eliminate genetic disorders from dog populations. Information available from genetic research will only be useful in improving canine health if veterinarians have the knowledge and skills to use it ethically and responsibly. There is not only a great potential to improve overall canine health through genetic selection, but also the potential to do harm if we fail to maintain genetic diversity. Our profession must be in a position to correctly advise clients on the application of this information to individual dogs as well as to populations of dogs, and particularly purebred dogs.

Prevalence and reproductive effects of Ureaplasma diversum in beef replacement Heifers and the relationship to blood urea nitrogen level

A systematic sample of replacement heifers from 5 herds underwent prebreeding vaginal swab cultures for Ureaplasma diversum Heifers from three of the herds were subsequently sampled at pregnancy examination Sampled heifers were given a vaginal lesion score (VLS), reproductive tract score (RTS) and body condition score (BCS), and peripheral blood was collected for serum blood urea nitrogen (BUN) estimation Culture results revealed an overall prevalence of Ureaplasma diversum of 51% (87/171) at prebreeding and 65% (64/98) at pregnancy examination. Within herd prevalence ranged from 36% to 64% at prebreeding and 54% to 76% at pregnancy examination Prevalence tended to differ between herds (P = 0.08) At the prebreeding examination, heifers with a BCS of 5 5 or less were more likely to be culture positive than heifers with a BCS greater than 5 5 (p < 0 05) No relationship was noted between BUN, VLS, RTS, or pregnancy status and prebreeding culture status. There was little variability among the heifers for any of these variables, with vaginal lesion scores generally being mild, RTS scores being high and BCS scores being moderate. At pregnancy examination, heifers that were culture negative tended to be more likely to be pregnant (odds 3.7, P = 0.10) than culture positive heifers

Survey of cystic ovarian disease in practice

The "DAISY" computerised recording system (University of Reading) was used to look at records of Cystic Ovarian Disease (COD) over two 12 month periods in a cattle practice in south west England. Over 24 dairy herds with good records were assessed to include 190 cows in year 1 and 180 cows in year 2 presented with COD. A definition of the disease was established as a fluid filled structure on the ovary exceeding 25mm in diameter with no palpable luteal structure present. The economic effect of the disease was compared both within herds and between herds to assess the importance of the condition. At the incidence levels recorded there was no effect on overall herd performance although the condition did affect individuals quite profoundly. Age incidence showed a lower level of COD in 1st lactation animals. Older cows had a relatively constant incidence which followed the age profile of the herds. The overall pregnancy rate was very high (81 - 89%). Treatments consisted of those with and without manual rupture of the cyst, with and without Gonadotrophin Releasing Hormone (GnRH), and with and without Progesterone treatments. Some cases received no treatment at all. The survey showed there was no difference in outcome between treatments involving cyst rupture and those not and that there was no difference between treatment and non treatment involving progesterone or GnRH. GnRH showed a longer interval to subsequent service than rupture or progesterone and there was a lower incidence of recurrence using progesterone treatments. The presenting signs of COD show that in dairy herds with a high level of routine fertility involvement nymphomania or nyphomanism is not common. The clinical presentation of COD in the study herds was 17% at a pre-breeding examination, 58% in cows presented with no observed oestrous, 12% at a negative pregnancy diagnosis, 12% with an irregular heat or service interval. Reviewing data from a variety of veterinary surgeons is difficult. Diagnosis and treatment show considerable bias between operatives and makes it difficult to reach conclusions.

Canine Breeding Management

A prebreeding examination should be performed on animals of both sexes to ensure their optimal health at the time of breeding. At this time, the medical and reproductive histories should be reviewed to detect potential negative influences upon the reproductive tract. Serologic testing for canine brucellosis should be performed to detect and remove infected animals from the breeding program. Examination of the female reproductive tract may be limited to the caudal vagina, vestibule, and vulva. Defects that cause pain and reluctance to breed may be detected with thorough digital and visual inspection. The male reproductive tract can be examined along nearly its entire length without special techniques. Semen may be collected for initial evaluation of testicular function and fertility. Swelling of the vulva and a hemorrhagic vaginal discharge will alert the observant owner to the onset of proestrus. Vaginal cytology may be examined every few days after the observed onset of proestrus to determine the onset of estrus. Breeding should be performed by natural or artificial insemination every 2 to 4 days during estrus to achieve optimal conception rates. The bitch should not be exhibited or trained during the period of potential pregnancy. Unnecessary drugs should not be administered. A diagnosis of pregnancy may be made by abdominal palpation 28 to 30 days after the last breeding. Serum progesterone levels may be measured if pregnancy is not established to determine if ovulation occurred and if sufficient levels of progesterone are present to maintain pregnancy. Optimal breeding management techniques can often result in the maximum reproductive efficiency desired.