Leptospirosis is a worldwide veterinary and public health concern, and well recognized infectious disease of horses. Seroprevalence rates vary with geography, but many studies have confirmed a high exposure rate. The correlation between seropositivity and shedding status has not been made in horses, however. The aims of this study were to use semi-nested PCR on urine from apparently healthy horses to determine period prevalence of leptospiral shedding and to correlate these findings with MAT results to establish associations with client based survey data regarding horse management and environment. Serum and free-catch urine were collected from 204 healthy horses between May 2016-December 2017. Serum was used to determine GGT, creatinine concentrations, and six serovar MAT. Urine samples were submitted for PCR testing of leptospiral 23S rRNA. Client consent and survey data were collected for all subjects. Potential risk factors included drinking water source, exposure to livestock and dogs, geographical location, season, and precipitation. Two horses were positive on urine PCR for leptospirosis (shedding prevalence 1%), yet only one had a high reciprocal MAT titer of ≥ 800. Both horses were negative on urine PCR one month later without treatment. Approximately 77% of horses (157/204) were seroreactive (MAT reciprocal titer ≥ 100) with titers to serogroup Australis detected more frequently than others (47.5%; (97/204)). Apparently healthy horses infrequently shed Leptospira spp. in urine, yet seroreactivity in clinically normal horses is high (77%), confirming high exposure rates to Leptospira spp. in the Central Midwest.

Our objectives were to determine lactational and reproductive outcomes in response to increased milking frequency (MF), injection of estradiol cypionate (ECP), and treatment with bovine somatotropin (bST). Lactating dairy cows (n = 144) were blocked by lactation number (1 vs. 2+) and assigned randomly to a 2 x 2 x 2 factorial experiment consisting of 8 treatment combinations: 1) MF consisting of 4x daily milking (4x) for the first 30 d in milk (DIM) vs. 2x daily milking (2x), with all cows milked 2x after 30 DIM; 2) 10 mg of ECP given postpartum at 8 +/- 3 DIM versus controls that received ECP diluent (oil); and 3) biweekly bovine somatotropin (bST), starting sometime after 60 DIM, versus no bST. Ovulation before the first artificial insemination was synchronized by using Heatsynch (GnRH injection 7 d before PGF2alpha followed in 24 h by ECP), and cows were artificially inseminated after detected estrus or at 48 h after ECP, whichever came first. Pregnancy was assessed by transrectal ultrasonography 28 to 30 d after artificial insemination. Daily yield and weekly components of milk were measured during the first 90 DIM. Intervals to first and second postpartum ovulation were unaffected by treatment, but cows were in estrus earlier after 2x (24 +/- 4 d) than 4x (41 +/- 4 d) daily MF, and sooner after ECP (25 +/- 3 d) than after oil (39 +/- 4 d) treatment. Pregnancy rates among 4x cows increased for ECP versus oil (52.8 vs. 27.8%) more than for cows with 2x MF treated with ECP versus oil (50.0 vs. 39.4%). Increased MF increased daily milk yields and energy-corrected milk yields during the first 30 DIM. Although milk yields were increased acutely by ECP during the 10 d after its injection, subsequent milk yields were decreased for ECP-treated cows previously milked 4x daily. Treatment with bST increased overall daily milk yields most in cows previously milked 2x daily and treated with oil and those milked 4x daily and treated with ECP. We concluded that early postpartum ECP injection increased pregnancy rates, but generally had detrimental effects on milk yields after 30 DIM for ECP-treated cows previously milked 4x daily, unless those cows also were treated with bST.

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The objective of this study was to determine how milking frequency, estradiol cypionate (ECP) postpartum therapy given at 1 week after calving, and biweekly bovine somatotropin (bST) administration alter lactational and reproductive outcomes in dairy cattle. Holstein cows (n=144) were randomly assigned to eight treatments (18 cows per treatment): 1) twice daily milking frequency (2x), 10-mg injection of ECP at 1 week after calving (ECP), and bST (given biweekly according to label beginning in the ninth week of lactation); 2) 2x milked, oil (cottonseed oil vehicle for ECP), bST; 3) 2x milked, ECP, and no bST; 4) 2x milked, oil, and no bST; 5) four-times daily milking frequency (4x; first 30 days in milk then 2x thereafter), ECP, and bST; 6) 4x milked, oil, and bST; 7) 4x milked, ECP, and no bST; and 8) 4x milked, oil, and no bST. Milk yields were recorded at each milking during the first 90 days of lactation. Milk samples were collected weekly at each milking and composited to determine milk components (percentages of fat, protein, lactose, solids-not-fat [SNF], milk urea nitrogen [MUN], and somatic cell count [SCC]). Energy-corrected milk yields were calculated for the first 90 days and for whole lactation yields (305-2x-ME standardized lactation records). Ovulation before first AI was synchronized beginning between 59 and 72 DIM using 100 :g of GnRH given 7 days before 25 mg of PGF2", followed in 24 hr by 1 mg of ECP. Cows were inseminated after detected estrus or at 48 hr after ECP. Pregnancy rates were assessed by transrectal ultrasonography 28-30 days after AI. Postpartum ECP therapy increased milk production for first-lactation 2x cows, but decreased milk yields of the multiparous 4x cows until bST restored those yields. Pregnancy rates were greater for the 4x cows given the postpartum ECP therapy injection, despite fewer cows cycling before AI. In conclusion, postpartum ECP therapy increased pregnancy rates in 4x cows, but had a detrimental effect on milk yields of 4x milked cows unless bST was administered. SummaryThe objective of this study was to determine how milking frequency, estradiol cypionate (ECP) postpartum therapy given at 1 week after calving, and biweekly bovine somatotropin (bST) administration alter lactational and reproductive outcomes in dairy cattle. Holstein cows (n=144) were randomly assigned to eight treatments (18 cows per treatment): 1) twice daily milking frequency (2x), 10-mg injection of ECP at 1 week after calving (ECP), and bST (given biweekly according to label beginning in the ninth week of lactation); 2) 2x milked, oil (cottonseed oil vehicle for ECP), bST; 3) 2x milked, ECP, and no bST; 4) 2x milked, oil, and no bST; 5) four-times daily milking frequency (4x; first 30 days in milk then 2x thereafter), ECP, and bST; 6) 4x milked, oil, and bST; 7) 4x milked, ECP, and no bST; and 8) 4x milked, oil, and no bST. Milk yields were recorded at each milking during the first 90 days of lactation. Milk samples were collected weekly at each milking and composited to determine ...

Background: Neonatal foals are born essentially agammaglobulinemic and therefore must ingest colostrum or receive immunoglobulins to maintain health. Failure of passive transfer treatment involves administration of equine colostrum, plasma or commercial powdered colostrum (CPC). Anecdotal reports suggest a risk of anaphylaxis associated with plasma transfusion in neonates that received CPC prior to gut closure. Bovine serum albumin (BSA) in CPC may serve as a target for BSA-specific immunoglobulin E (IgE) in donor equine plasma. Objectives: To determine presence of BSA-specific IgE in samples collected post-routine vaccination in healthy horses, horses experiencing adverse vaccine reactions and commercial equine plasma. Study Design: Prospective Observational Methods: Serum was collected from 65 healthy horses at day 0, 14, 28, 90, 180, 270 and 365 post-vaccination, 26 horses after vaccine reaction at day 1, 180 or 270 post-vaccination, 4 horses not vaccinated and 10 horses from a commercial plasma donor herd. BSA-specific IgE was determined using enzyme-linked immunosorbent assay (ELISA). Results: BSA-specific IgE was not detected in non-vaccinated horses and was identified in all vaccinated horses. Younger horses demonstrated higher fold changes in post-vaccination BSA-specific IgE expression compared to older horses. No significant difference in BSA-specific IgE levels between commercial plasma donors and healthy horses was identified. No significant difference in post-vaccination anti-BSA IgE levels between reactor and healthy horses at day 180 and 270 post-vaccination were identified. Main Limitations: Small number of reactor horses at day 180 and 270 post-vaccination with most samples being collected 24 hours. There were no healthy horse samples for 24 hours post-vaccination; therefore, it was not possible to compare the two groups at this timepoint. Conclusions: Horses may express BSA specific IgE following vaccination. There may be risk of hypersensitivity type reaction when veterinarians administer commercial plasma to neonatal foals that have consumed CPC prior to gut closure.