A spreadsheet-based model demonstrating the nonuniform economic effects of varying reproductive performance in Ohio dairy herds.

A spreadsheet-based model was developed to estimate the economic effect of varying reproductive performance in dairy herds. Scenarios were created to model an average cow with respect to production, herd lifetime, and reproductive events. Average milk yield per day of life as well as lifetime calf and replacement heifer production were examined. Additional inputs representing milk, feed, semen, calf, and salvage prices were used to calculate net cash flow for each day of herd life for the average cow in a scenario. Economic comparison of different scenarios was accomplished using an equivalent annual cash flow (annuity) methodology.Herd performance measures and prices representative of Ohio dairy herds were used to establish a baseline average cow that had a 160-d calving-to-conception interval [days open (DO)]. Alternative scenarios that differed from baseline in DO, annual culling rate, and feed and milk prices were created to characterize the effects of changes. Under scenario inputs representative of typical Ohio dairy herds, the model indicated that a lower annual culling rate (25%) was preferable to higher annual culling rates (34 or 45%). The model estimated maximum average milk yield per day of life to occur at 110 DO. At 34% annual culling rate, calves and replacement heifers produced per lifetime declined as DO increased; beyond 150 DO, the modeled cow produced less than 1 replacement heifer per lifetime. The model also estimated a loss of $1.37 per cow per year for a 1-d increase in DO beyond 160 d. At 20% higher feed and milk prices, the model estimated a loss of $1.52 per cow per year; at 20% lower feed and milk prices, the model estimated a loss of $1.23 per cow per year. Furthermore, the model suggested that the loss associated with a 1-d increase in DO changed as DO changed. Using baseline inputs, the model calculated losses for a 1-d increase of $0.44 per cow per year at 130 DO and $1.71 per cow per year at 190 DO. The nonuniform nature of the cost of additional DO is important to veterinarians and producers. The implication is that inefficient reproduction becomes marginally more costly to producers as performance declines and warrants increased attention. Conversely, marginal benefits of improved reproduction decrease as performance improves. Herds with strong reproductive performance have less opportunity to capture economic benefits of improvement.

Reproductive performance in Ohio dairy herds in the 1990s.

The objective of this study was to evaluate trends in reproductive performance in Ohio dairy herds during the 1990s. Stringent criteria for herd inclusion were applied to DHI records to ensure high quality and reliability of the data. The final data set contained 44,425 monthly herd summary records from 1772 herds from years 1992, 1994, 1996 and 1998. Outcomes of interest were calving interval length, calving-to-conception interval, days to first breeding, services per conception and first service conception rate. PROC MIXED in SAS (version 8.1) was used and the monthly records were treated as repeated measures nested within years and herds. First-order autoregressive covariance structure was used to model the covariance between the repeated measures within herds. The data were analyzed for the entire herd as well as for the first lactation cows separately. During the 1990s reproductive performance declined in Ohio dairy herds. Herd average calving interval lengthened from 13.6 to 14.1 months and calving-to-conception interval increased from 136 to 150 days between 1992 and 1998, respectively. Days to first service and number of services increased while first service conception rate declined on a herd level. The reproductive performance of first lactation cows, however, remained constant during this same period. Overall herd reproductive performance was associated with herd size and fat-corrected rolling herd average milk production (FCM). As milk yield increased, first service conception rate decreased and services per conception increased. Larger herds had lower first service conception rate and needed more services per conception, but they started breeding their cows earlier resulting in a slightly shorter calving interval and calving-to-conception interval compared to smaller herds.

Association between milk urea nitrogen and fertility in Ohio dairy cows.

The purpose of this study was to evaluate the association between milk urea nitrogen (MUN) and fertility of dairy cows using field data. The data came from 24 dairy herds belonging to Ohio Dairy Herd Improvement Cooperative Inc. Reproductive data and MUN measurements from cows that calved between June 1998 and May 1999 and that had been bred at least once were included in the study. Survival analysis, using the Cox proportional hazards model, was performed and days from calving to conception or to the end of the study was used as the outcome. Cows that had not been reported pregnant during the study were considered censored. The mean of monthly MUN values of cows before conception (or the end of the study for censored cows) was used to reflect the MUN status of a cow. Animals were categorized into quartiles based on MUN values in these data. Parity, calving season, peak milk yield, number of services, and herd were included in the models as fixed effects. Cows with MUN levels below 10.0 were 2.4 times more likely and cows with MUN levels between 10.0 and 12.7 mg/dl were 1.4 times more likely to be confirmed pregnant than cows with MUN values above 15.4 mg/dl. Our results indicate that increasing MUN levels appear to be negatively related to dairy cow fertility and are associated with a lower risk of detectable pregnancy at herd checks. They also suggest that the levels of MUN that are adversely associated with fertility might be lower than reported earlier.

Prevalence of fetal maldispositions in equine referral hospital dystocias.

A retrospective investigation was performed to determine the population characteristics of horses presented for dystocia at 2 equine referral hospitals and the types of fetal maldispositions among these horses. The study population consisted of a similar number of Thoroughbreds (25%), Standardbreds (24%) and draft horses (22%). Most of the current literature pertaining to equine obstetrics is based on a predominately draft horse population (63%). The latter population appeared to have more transverse presentations (P = 0.06), possibly because of the higher number of draft mares. In our study, 43% (6/14) of the transverse presentations occurred in draft breeds. Furthermore, 18% of the draft mare dystocias (6/33) were transverse presentations whereas only 8% (6/73) of the 2 major light breeds (Thoroughbred n = 3; Standardbred n = 3) had transverse presentation dystocias. Despite the significant breed differences between the 2 populations (P < 0.001), the prevalence of all other fetal maldispositions was not different from those previously reported. Severe dystocia was often multifactorial, with 86% of cases involving malposture and over half (58%) of these involving more than one extremity. Head and/or neck deviation were a major reason for referral. In 30% of cases malposition was a factor, and abnormal presentation was involved in 24% of referrals.

Two-dimensional polyacrylamide gel electrophoresis of bovine semen after cryopreservation in half-milliliter straws.

One of the problems encountered with two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) is the streaking of proteins so that individual spot identification is compromised. This study was conducted to determine whether a low loading dose (50 microg) of protein would permit resolution of more discrete protein spots using megapixel camera technology, and if so, to present a nomenclature for future comparisons of the identified proteins. If the major proteins could be identified in a 50-microg sample we aimed to determine whether they could be identified in the supernatant (seminal plasma plus extender) of cryopreserved semen. Two ejaculates were obtained from each of 6 bulls and bovine seminal plasma (BSP) protein concentration was standardized to 50 microg/10 microl. Isoelectric points (pI) and molecular weights (MWt) of BSP proteins were determined by measuring spot mobility on 2-D PAGE (15% polyacrylamide). Three distinct protein spot constellations (a,b,c) could be readily seen by the naked eye and a faintly stained constellation "d" was identified by the megapixel camera. The image analysis software located 6 protein spots in both constellation "a" (MWt 26 kDa; pI 4.2 to 4.8) and "b" ( MWt 27 kDa; pI 6.6 to 8.0). Constellation "c" contained 13 protein spots distributed in a right-angled triangle with its base towards the acidic end of the gel (MWt 14.7 to 18.8 kDa; pI 5.3 to 7.4). Only spots c(2), c(3), c(5), c(8), and c(13) were present in all 12 samples. Streaking can be eliminated by using 50 microg protein for 2-D PAGE, and the major protein spots are readily identified by megapixel camera technology. Protein spots c(3), c(5), c(13) and constellation "a" appear to correspond with Manjunath's proteins (BSP-A(1), -A(2); -A(3); -30 kDa). Killian's 2 low fertility proteins may lie in the "c" constellation, and 1 of the high fertility proteins may lie in the "b" constellation. The 3 major BSP proteins can be visualized in the supernatant of cryopreserved semen. We believe that the technique may prove useful for retrospective analysis of processed semen batches that achieve less than satisfactory results in the field.

Bovine uterine torsion: 164 hospital referral cases.

Uterine torsion is more common in the cow than any other domestic species. The etiopathogenesis of the condition remains open to speculation. Available hospital referral records of bovine uterine torsions (n = 164) were collated, and additional comparisons for season, age and breed were made using the VDMP data base of 24 North American veterinary schools. There was no effect of season. Brown Swiss cows were at a significantly higher risk (P = 0.0001), while Hereford, Angus, and Jersey cows were at a lower risk for uterine torsion when compared with Holstein-Friesian cows, the largest breed population (P = 0.01). Most cows (81%) were at term. Clinical signs of torsion included fever (23%), tachycardia (93%), tachypnea (94%), straining (23%), anorexia (18%) and vaginal discharge (13%). In 34% of the cases the torsion was precervical, with no vaginal involvement being noted. The severity of the torsion was predominately 180 to 270 degrees (57%) and 271 to 360 degrees (22%). Counter-clockwise torsion was present in 63% of the cases. Vaginal delivery was possible after manual correction (20%) or rolling of the cow (18%). Cesarean section was performed immediately in 35% of the cases, after failed detorsion attempts in 7%, and due to failure of the cervix to dilate following successful correction of the torsion in 20%. Calf birth weights exceeded breed means in 89% of the cases, and a significantly greater proportion (63%) of the fetuses were male. Fetal survival rate was 24% (14% of dead fetuses were emphysematous), and the cow survival rate was 78% (10% were euthanized). The fetal membrane retention rate was 57%. It was found that large term fetuses appear to predispose a cow to uterine torsion.

SDS-PAGE characterization of the proteins in equine seminal plasma.

The aims of this project were to document the protein profile of equine seminal plasma and determine the variability between stallions in the relative composition of proteins in the ejaculate. A single ejaculate was obtained from 14 stallions of varying breed and age. The gel fraction was removed by an in-line filter. The semen was centrifuged and the supernatant seminal plasma aspirated without disturbing the sperm pellet. The seminal plasma was recentrifuged and stored in cryovials at -70 degrees C. Samples were thawed, recentrifuged, assayed for protein concentration (BCA protein assay), divided into aliquots, then stored at -70 degrees C. A standard protein concentration of 50 microg was loaded in each 10 microl sample. SDS-PAGE was performed using 15% polyacrylamide and a mixture of molecular weight standards. The electrophoresed gel was stained for proteins with Coomassie blue, air-dried, then scanned by a megapixel camera interfaced to a computer. Image analysis software calculated integrated optical density (IOD) values for each lane, and bands within a lane. Each band IOD was expressed as a percentage of the total lane IOD, thus reflecting the relative concentration of each protein within the ejaculate. A total of 14 bands were identified, ranging from a large 120 kDa protein down to a small 14 kDa protein. No sample contained all 14 protein bands. Seven protein bands (101 kDa, 32 kDa, 26 kDa, 22 kDa, 18 kDa, 16 kDa, 14 kDa) were present in all samples, however the relative concentrations of protein within those bands varied between stallions. We demonstrated that although there is a characteristic equine seminal plasma protein profile on SDS-PAGE gels, there is between stallion variability in the relative amounts of each protein.

Testicular prosthesis in a Quarterhorse stallion: a case report.

A testicular prosthesis was surgically removed from the scrotum of a Quarterhorse stallion presented for evaluation of a large, firm, unilateral scrotal mass. The prosthesis was constructed from methyl methacrylate moulded around a roll of fiberglass casting tape. The prosthesis had been surgically implanted in the scrotum approximately 4 yr prior to presentation in order to give the appearance of 2 testicles in the scrotum for showing and breeding purposes. The horse had been used to successfully breed mares prior to presentation and produced 4.046 x 10(9) progressively motile, morphologically normal spermatozoa in an ejaculate collected 4 mo after surgery to remove the prosthesis. Ethical issues raised by this case are discussed.

Effect of intramuscular polysulfated glycosaminoglycans on bovine semen production and quality of the cryopreserved semen.

Polysulfated glycosaminoglycans (PSGAG) are widely used to treat cartilage disease in horses. The drug's safety in breeding animals has not been documented. This study determined whether im PSGAG is detrimental to the bull's health and, in particular, the quantity of semen produced or the quality of the cryopreserved product. No clinically significant effect of treatment on hematologic or serum biochemistry parameters was detected, but a significant treatment x time interaction for mean corpuscular volume warrants further investigation. There was an unexplained treatment effect on total daily sperm numbers collected, even though the pre-treatment values were included as co-variates in the statistical analysis to control for any day 0 variability. There was no effect on the percent forward motile sperm in the fresh ejaculate. Although there was no significant effect of treatment on the post-thaw semen data, the power of each statistical analysis was low, ranging from 10% to 19%. Further studies using larger sample sizes are warranted. These preliminary studies suggest that im PSGAG is safe to use in bulls on an experimental basis.

Calbindin-D9k expression in the pregnant cow uterus and placenta.

Calbindin-D9k (CaBP9k) is a vitamin D-dependent, calcium binding protein first identified in the cytoplasm of the intestinal epithelial cell. Using biotin-streptavidin immunohistochemistry, CaBP9k was localized to the maternal caruncular epithelium, fetal chorionic epithelium, and trophoblastic binucleated cells of the bovine placenta. Within the maternal epithelium the intensity of staining increases from second trimester pregnancies to term pregnancies, indicating a higher intracellular concentration of CaBP9k in the epithelium at term. Luminal and glandular epithelium of the non-caruncular endometrium also stained positively for CaBP9k in all stages of pregnancy observed. No CaBP9k was identified within the stroma or myometrium of the pregnant cow uterus. The increased level of CaBP9k in the caruncular epithelium during the last trimester is hypothesized to be in response to the rising demand for calcium to aid in the mineralization of the fetal skeleton. CaBP9k may play a role in enhancing calcium transport across the placenta in cattle.

Ovarian remnant syndrome in a Toy Poodle: a case report.

Ovarian remnant syndrome was diagnosed in a 3-yr-old, female Toy Poodle presented with signs of estrus. The diagnosis was based on the clinical and laboratory changes in response to injection with hCG. The remnant of ovarian tissue was removed surgically under general anesthesia and the animal recovered uneventfully.

Cesarean section.

Cesarean section has become a common surgical procedure and there is a tendency for both veterinarians and their clients to regard it as routine. It is important to remember, however, that a cesarean section entails major abdominal surgery, with inherent risks, irrespective of the prevailing conditions or personnel involved.

Reproductive emergencies in the mare.

This article briefly reviews the clinical management of emergency conditions likely to be encountered by veterinarians responsible for the reproductive health of mares. The article discusses rectal tears, breeding injuries, uterine torsion, placental hydrops, and prepubic tendon rupture. A major component discusses a recommended approach to dystocias, and the management of such complications as uterine rupture and prolapse and postpartum hemorrhage. Management of retained fetal membranes and septic metritis is addressed.

Reproductive emergencies in the stallion.

Topics addressed in this article include complications of castration, scrotal and inguinal hernias, torsion of the spermatic cord, traumatic injuries to the external genitalia, and posthumous collection of spermatozoa. A concise overview of the clinical management of emergency cases is provided.

Serous cystadenoma in a normally cyclic mare with high plasma testosterone values.

Serous cystadenoma was diagnosed by histologic examination of a large ovary removed from a 16-year-old Thoroughbred mare with normal estrous cycles. Palpation and ultrasound examination per rectum had revealed an excessive number of follicles in the right ovary. The ovulation fossa was palpable on the right ovary, and the left ovary appeared to have normal activity. Plasma testosterone values were high at the time of examination (0.15 ng/ml), but decreased to normal values (0.09 ng/ml) after removal of the cystadenoma.

Teratocarcinoma of the ovary in a mare.

A 5-year-old Appaloosa mare had a history of mild intermittent abdominal discomfort and clinical signs that were suggestive of intestinal obstruction. Palpation per rectum revealed a large mass attached to the left uterine horn, with smaller masses extending dorsally and cranially and causing constriction of the rectum. At necropsy, numerous multilobulated masses were observed in the abdominal cavity and several nodules were seen in the lungs. The left ovary was large and contained both cartilage and hairlike material. Sections from all masses had similar histologic features and confirmed the tentative diagnosis of teratocarcinoma.

Histopathologic effects of dimethyl sulfoxide on equine endometrium.

Endometrial fibrosis is a major cause of infertility in broodmares. Because of the proven anti-inflammatory effects of dimethyl sulfoxide (DMSO) and its influence on collagen, the effect of DMSO on the endometrium was investigated in mares. Solutions of DMSO (25%, 50%, or 75%) were infused into the uterus of clinically normal mares. Examination of serially obtained biopsy specimens revealed epithelial ulceration and stromal inflammation that were proportional to the DMSO concentration infused, but vasodilatation was not observed. In all mares, the endometrium had returned to normal by day 21 after DMSO infusion.

Effect of serial intrauterine dimethyl sulfoxide infusions on the incidence of periglandular fibrosis in category II horse endometria.

High concentrations of dimethyl sulfoxide (DMSO) have been shown to cause gross structural changes in collagen fibers in vitro. As endometrial fibrosis is a major cause of infertility in mares, the effect of serial DMSO infusions on periglandular fibrosis of Category II endometria was investigated. Initially, six mares with Category I endometria were serially infused with DMSO to determine whether such therapy would incite fibrosis. Four mares, serially infused with saline, served as controls in each experiment. One hundred milliliters of 75% DMSO was infused initially, followed by the same volume of 25% DMSO daily for 6 d. Endometrial biopsies obtained 21 d after the last infusion displayed no significant difference in the incidence of periglandular fibrosis when compared with the Day 0 biopsies. Examination of treated uteri at necropsy showed no gross evidence of adhesions or ulcerations.