Massive vulvar edema in 2 prepartum dairy cows

Abstract

Two late gestation Holstein cows about to begin the third lactation developed massive vulvar edema. These were the only affected animals in the herd of 500 milking cows. The vulvar edema spontaneously regressed postpartum for both cows. Massive vulvar swelling is seldom observed in dairy cows in advanced pregnancy and is not described in the literature.

The 2 cases of massive vulvar edema of pregnancy described in this report occurred in nonlactating second parity Holstein cows that were enrolled in an unrelated observational study. Thirteen other second-parity nonlactating Holstein cows at the Cornell Teaching and Research Dairy Unit in Harford, New York, were enrolled as part of a larger study starting 28 d before the expected due date. Second parity cows (average weight 790 ± 17.3 kg) were enrolled over a period of 4 mo. Average body condition score of these cows was 3.72/5 (± 0.12). Both of the affected cows had prepartum vulvar swelling at the time of enrollment and neither had the condition in the previous pregnancy. Cows used in this study were born on-farm and the late gestation vaccination protocol included: J-Vac (Mérial, Duluth, Georgia, USA) and Covexin-8 (Intervet; Merck Animal Health, Summit, New Jersey, USA) at 8 wk before the due date; and J-Vac (Mérial), Scourgard (Zoetis, Florham Park, New Jersey, USA), and Triangle 10 (Boehringer Ingelheim Vetmedica, St. Joseph, Missouri, USA) at 4 wk before the due date.

Case description

Cow A weighed 700 kg and was in 3.5/5 body condition score at enrollment. The vulva was already markedly enlarged at the time of enrollment. Cow B weighed 776 kg and was in 3/5 body condition score. These cows were enrolled 3 wk apart and were the only affected animals at the time in the 500 milking cow dairy herd. The swelling was cool to the touch and the cows did not show signs of discomfort. There were no other abnormal findings on physical examination and the cows were kept in the study. The sampling protocol for these cows was: weekly body weight measured on a scale, body condition scoring by 3 independent observers, wet weight of daily feed offered and refused, daily rectal temperature measurement, blood sampling from the coccygeal vessels 3 times a week until 10 d before the due date, after which blood was collected daily, glucose tolerance test at 10 d before the due date, daily milk production, milk component analysis, daily transrectal ultrasound of the ovaries starting day 7 postpartum, and uterine samples collected by low-volume uterine lavage for cytology and bacteriology transported in sample tubes (Port-A-Cul tubes; BBL Becton, Dickson and Company, Sparks, Maryland, USA) and submitted to the Animal Health Diagnostic Center at Cornell University within 2 h after collection on the day of calving, around day 17 and at day 30 postpartum. All protocols were approved by the Cornell University Institutional Animal Care and Use Committee.

In cow A, the vulvar lips were clearly edematous (Figure 1). The vulvar swelling increased from ~30 cm wide at the time of enrollment into the study to ~40 cm shortly before calving. The swelling was cool to the touch and pitted when pressure was applied. Cow A calved a 38-kg live heifer calf at 282 days of gestation. The calving was assisted by 2 farm personnel who had to pull the calf with substantial force. As a result, cow A had a first degree perineal laceration which was repaired within 2 h of calving by the farm veterinarian. The fetal membranes passed within 6 h of calving. The vulvar edema was noticeably decreased on the day after calving and reduced to approximately 20 cm in width, and was much less turgid within 1 wk postpartum. Normal lochia changed to a purulent discharge on day 6 postpartum and persisted for 3 wk. Plasma total protein values were 84, 68, and 71 g/L at 7 d before calving, 1 d, and 7 d postpartum, respectively. The cow did not develop fever (<39.2°C) at any time during the study and ovulated the first dominant follicle postpartum which was 17 mm in diameter on day 18 postpartum. A uterine sample collected 26 h after calving grew few alpha-hemolytic Streptococcus colonies and few non-hemolytic Staphylococcus spp. colonies on aerobic culture. There was no growth on anaerobic, mycoplasma or ureaplasma cultures. The uterine sample grew few alpha-hemolytic Streptococcus colonies on day 17 postpartum but had no growth on anaerobic, mycoplasma, and ureaplasma cultures on days 17 and 30 postpartum. On cytology, polymorphonuclear cells constituted 62.5% of nucleated cells at day 1, 50.5% on day 17, and 1.5% on day 30 postpartum. Cow A was bred twice and was pregnant to the second insemination at 108 days postpartum. The vulvar swelling did not recur in the subsequent pregnancy.

Figure 1.

Cow A with massive vulvar edema, 1 week prior to parturition. The edema was present 28 d before the due date and increased in size until parturition.

In cow B, the vulvar swelling was milder and had a distinctly different appearance (Figure 2). The vulvar lips were not as edematous and only increased minimally in the last month of gestation. The swelling was cool to the touch and did not pit on pressure. Cow B delivered a 50.5-kg live heifer calf with mild traction by the calving pen personnel at 284 days of gestation and the fetal membranes were passed within 12 h. There were no injuries from parturition and the swelling subsided shortly after calving. Plasma total protein values were 72, 66, and 74 g/L at 7 d before calving, the day after calving, and 7 d after calving, respectively. Lochia was normal and the cow did not develop fever (>39.2°C) at any time during the study. She ovulated the first dominant follicle postpartum, which was 12 mm in diameter on day 15 postpartum. A uterine sample collected at 26 h postpartum grew few Escherichia coli (phylogenetic type B1) colonies, few alpha-hemolytic Streptococcus spp. colonies, few Staphylococcus intermedius colonies, and few non-hemolytic Staphylococcus spp. colonies on aerobic culture, and had no growth on mycoplasma or ureaplasma cultures. Escherichia coli phylogenetic type was determined by PCR as previously described (1). Anaerobic culture was not performed on this sample as the cow had calved during the weekend and the sample could not be submitted on the day of sample collection. Uterine sample on day 16 yielded many Trueperella pyogenes colonies on aerobic culture, few Clostridium perfringens colonies on anaerobic culture, no growth on mycoplasma culture, and few Ureaplasma spp. colonies on ureaplasma culture. Uterine sample collected on day 31 postpartum had no growth on aerobic, anaerobic, mycoplasma, or ureaplasma cultures. On cytology the proportion of polymorphonuclear cells were 30.5%, 39.5%, and 42% of nucleated cells, for the day after calving, 16 d, and 31 d postpartum uterine samples, respectively. At day 44 postpartum, cow-B developed coliform mastitis in both hind quarters and was treated with intravenously with 1 L saline 7.2% solution, 5 mL 23% calcium gluconate, 500 mL 50% dextrose and flunixin meglumine (FlunixiJect; Butler Schein Animal Health, Dublin, Ohio, USA), 0.64 mg/kg body weight (BW), q24h for 3 d. She had higher fever by the following day and oxytetracycline (Bio-Mycin 200; Boehringer Ingleheim Vetmedica, St. Joseph, Maryland, USA), 9 mg/kg BW, IV, q24h was administered for 3 days. The systemic signs improved but milk production remained low and cow-B was culled at 79 days postpartum.

Figure 2.

Cow B with vulvar edema, 3 weeks prior to parturition. The edema was less severe than in cow A and was not confined to the vulvar lips. The swelling was also present 28 d before the due date.

The remaining 13 second-parity cows entering the third lactation were the control group of unaffected cows. The average calf weight for the 13 unaffected cows was 49 kg (± 1.8 kg). The gender distribution of the calves was 9 male (4 of which were assisted calvings) and 4 female calves (1 of which was assisted calving). All calves were born live and 2 cows developed metritis postpartum. Plasma total protein values were 79 (± 1.1), 65 (± 1.2), and 71 (± 1.5) g/L, for 7 d before calving, the day after calving, and 7 days after calving, respectively. All cows had positive culture on the day of calving with all but 1 cow having positive aerobic culture and the only cow with no growth on aerobic culture had positive anaerobic culture. Eschericia coli phylogenetic type B1 was the most commonly isolated bacterium on aerobic culture from uterine samples collected at the day of calving (7/13 cows) followed by alpha-hemolytic Streptococcus (6/13 cows); C. perfringens was the most commonly isolated anaerobic bacterium (6/11 cows). The proportion of cows with positive aerobic or anaerobic bacterial cultures dropped to 8/13 on day 17 and 6/13 on day 30 postpartum. The proportion of polymorphonuclear cells in uterine cytology also dropped from 58% to 40% and finally 10% at the day of calving, day 17 and day 30 postpartum, respectively.

Repeated measures analysis of variance (ANOVA) (SAS version 9.2, SAS Institute, Cary, North Carolina, USA) was performed to determine if endocrine profile was significantly different between affected and non-affected second-parity cows entering their third lactation controlling for days peripartum and evaluating two-way interactions. Continuous variables were transformed as necessary to fulfill model assumptions. There were no significant two-way interactions but time was significant in all models. Peripartum endocrine profile for plasma estradiol (Figure 3) and progesterone (Figure 4) of affected cows were similar to other second parity cows enrolled in the study although there was a tendency (P = 0.08) for affected cows to have higher plasma estradiol. Due to the small number of affected animals, the power of the analysis was low.

Figure 3.

Peripartum plasma estradiol levels for affected cows and controls. Plasma estradiol increased until shortly before calving then dropped to baseline levels by 1 d after calving. There was a tendency (P = 0.08) for affected cows to have higher estradiol compared with control cows.

Figure 4.

Periparturient plasma progesterone values. There was a decreasing trend for plasma progesterone levels and a sharp drop within 2 d of calving. There were no significant differences between the groups.

Discussion

Massive vulvar edema during pregnancy is an uncommon condition in dairy cows. At the Cornell University Teaching and Research Dairy Unit, the herd health personnel see 3 to 6 cases per year and it is rare for more than 1 individual animal to be affected at 1 time (Ray Axtell and Gladys Birdsall, Cornell University, Ithaca, New York, personal communication). Anecdotally, pluriparous cows are more commonly affected. Despite being an easily diagnosed and recognized condition among experienced dairy veterinarians and herdsman, massive prepartum vulvar edema is surprisingly not described in the veterinary literature.

The cause of massive prepartum vulvar edema in dairy cows is not known but the lesion resolves spontaneously after calving, suggesting a physical or endocrine contribution to the pathogenesis associated with late gestation. Treatment with furosemide, 500 mg, IV, q24h, maybe beneficial for reducing the edema in severely affected animals, but was not used in these 2 cows. Edema can result from excessive leakage of fluid from blood vessels or from impaired lymph drainage. Arterial supply to the vulva is from the internal pudendal artery, venous drainage from the internal pudendal vein, and lymphatics from the vulva drain primarily to the mammary lymph nodes (2). Each vulva lip would be perfused and drained from the ipsilateral vessels and lymphatics. The vulvar swellings were bilaterally symmetrical which lowers the likelihood of a unilateral pathology affecting perfusion or drainage.

Hypoproteinemia can cause edema by increasing fluid loss from vessels but this was not observed in the affected cows. Plasma total proteins were normal for cow A which had the more severe edema and low end of normal for cow B with the less severe edema. It is unclear if the edema is a result of increased blood flow, decreased venous drainage, decreased lymph drainage, or a combination of these.

Vulvar edema is a clinical sign of impending parturition and is associated with calving within 12 h (3). This physiological vulvar edema is mild and only occurs shortly before calving unlike the massive edema observed a month before calving as described in this report. Postpartum vulvar swelling with similar signs can occur subsequent to trauma from excessive obstetrical manipulations and is the more common presentation of massive vulvar edema in dairy cows. Infection by Clostridium septicum may result in a special form of malignant edema which is characterized by vulvovaginitis and occasionally metritis in postpartum dairy cows (4); however, it is unlikely to be the cause of massive prepartum vulvar edema. Vulvar swelling is a normal sign of estrus in cattle and other species. The subtle estrous swelling is associated with high estradiol concentrations and leads to edema of the vulva which then subsides after the estrus period. The late prepartum vulvar swelling may have been due to the rising circulating estradiol and decreasing progesterone levels. The estradiol levels in the more severely affected animal (cow A) were lower than the average of the control cows. However, cow B had much higher levels that resulted in the average concentrations in affected animals having a tendency to be higher than the average of the controls (Figure 3). The circulating estradiol concentration in prepartum cows peak in the last week before calving but vulvar edema observed in this report was already present 4 wk prior to calving when estradiol levels were still low.

Massive vulvar edema in pregnancy has been described in women and is often secondary to other morbidities such as diabetes (5), pelvic infection (6,7), preeclampsia (8) and systemic disease (9,10). The affected cows described in the present report did not show any systemic signs of infection or other systemic disorders. Reproductive outcome for both affected cows was good. Both cows A and B ovulated the first-dominant follicle postpartum and cow A was pregnant to the second insemination. Vulvar swelling did not recur in the subsequent pregnancy for cow A. Cow B was not bred prior to being culled for poor milk production.

In conclusion, massive prepartum vulvar edema is an uncommon condition of dairy cows. The etiology is unknown but the condition resolves spontaneously after calving. Recurrence in subsequent pregnancy appears to be unlikely. This report describes a condition that is known to dairy veterinarians but not documented in veterinary texts.