Operation-management factors associated with early-postnatal mortality of US foals

Prevalence and performance effects of neonatal disease in Thoroughbred and Standardbred foals in South-Eastern Australia

BACKGROUND

There is little information on foal mortality and the epidemiology of diseases in the neonatal period in Australian equine breeding enterprises.

METHODOLOGY

This was a prospective cohort study of 1219 foals on 15 breeding farms in south-eastern Australia to identify the proportion of foals recognised on farm as abnormal at birth or within the first 48 h postpartum, determine the prevalence and risk factors for neonatal disease and assess the subsequent performance of foals in the study population.

RESULTS

Overall, 27 foals died within 6 weeks of birth in the study population (2.2%), 142 foals (11.6%) were reported as abnormal at birth, and 304 (25.3%) were regarded as abnormal in the first 48 h postpartum. Non-septic orthopaedic disease (NSOD) was the most common abnormality recognised. Premature foals and foals born after dystocia or abnormal parturition were more likely to have clinical abnormalities recognised, but the intensity of nursing care did not predict outcome. Prophylactic administration of antimicrobial drugs was associated with increased mortality and septic disease. Maternal periparturient problems, foal gender, abnormality at birth and the presence of septic disease or neonatal maladjustment were associated with decreased performance outcomes, whereas measures to assess and augment passive immune transfer were associated with improved athletic performance.

CONCLUSIONS AND RELEVANCE

Information in the current study is important for the treatment and management decisions on farm and to identify industry welfare and production priorities. Although the incidence of all outcome variables was variable, factors recognised on farm in the peri-parturient period were predictive of subsequent athletic performance.

How type of parturition and health status influence hormonal and metabolic profiles in newborn foals

Thyroid hormones, insulin growth factor I (IGF-I) and non-esterified fatty acids (NEFA) represent important hormonal and metabolic factors associated with perinatal growth and maturation. Their action could be influenced by the type of parturition and the health status of the foal and therefore the aim of this work is to evaluate their plasma concentrations in newborn foals during the first 2 wks of life. Three groups of subjects were enrolled: 15 healthy foals born by spontaneous parturition, 24 healthy foals born by induced parturition and 26 pathologic foals. From each of the healthy foals, blood was collected at 10, 20 and 30 minutes, 3 and 12 hours from birth, daily from Day 1 to Day 7, and at Day 10 and 14 of life. In pathologic foals samples were collected twice a day from the day of admission at the hospital until the day of discharge or death. Thyroid hormones (T3 and T4) and IGF-I were analyzed by radioimmunoassay and NEFA by enzymatic-colorimetric methods. In all the three groups a declining trend of T3 and T4 plasma concentrations was detectable, with lower levels in the pathologic group compared to healthy foals. Spontaneous foals showed higher levels of T3 at 7 d compared to induced foals, while T4 levels were higher in spontaneous vs. induced foals before 6 h of life, at three and seven days. IGF-I showed increasing plasma concentrations in all three considered groups. No differences were found between healthy and pathologic foals. NEFA in spontaneous and induced healthy foals showed a declining trend with higher levels during the first hours of life. Pathologic foals presented higher levels compared to spontaneous foals only at 24 h and 10 d. These data suggest that the type of foaling could influence the reference ranges for thyroid hormones. Moreover, pathologic foals showed some hormonal and metabolic differences related to their health status. Above all changes of thyroid hormones levels, early in postnatal life, could be a cause, and not only a consequence, of the diseased condition of these foals.

Use of stored equine colostrum for the treatment of foals perceived to be at risk for failure of transfer of passive immunity

OBJECTIVE-To assess the use of stored equine colostrum for the treatment of foals perceived to be at risk for failure of transfer of passive immunity (FTPI). DESIGN-Cohort study. ANIMALS-232 Thoroughbred foals and 191 Thoroughbred mares (41 mares gave birth to 1 foal on 2 occasions). PROCEDURES-Postpartum, presuckle colostrum samples were collected from mares; samples with a colostral refractive index (cRI) > or = 23% were frozen (-20 degrees C [-4 degrees F]) and stored for > or = 7 days but < 2 years. Foals of dams that produced colostrum with a cRI value < 20% were treated with > or = 300 mL of stored colostrum that was thawed and administered via nasogastric tube on 1 to 4 occasions within 6 hours after parturition. Serum samples were obtained from colostrum-treated and nontreated foals 24 hours after treatment or suckling, respectively, for determination of serum IgG (sIgG) concentration. RESULTS-8 foals and their respective dams were excluded from the analyses. For the remaining 30 treated and 194 nontreated foals, mean +/- SD sIgG concentration was 1,597 +/- 574 mg/dL. Thirteen (5.8%) foals had sIgG concentrations < 800 mg/dL, of which 1 (0.4%) had an sIgG concentration < 400 mg/dL. Nine of these foals had suckled mares producing colostrum with a cRI value > or = 20%, and 2 foals had been treated with stored colostrum. CONCLUSIONS AND CLINICAL RELEVANCE-Treatment with stored colostrum appeared to be effective for prevention of FTPI in at-risk foals. However, foals were still at risk for FTPI despite suckling of or treatment with colostrum with adequate cRI values.

Concentrations of 15-ketodihydro-PGF2alpha, cortisol, and progesterone in the plasma of healthy and pathologic newborn foals

Information regarding the plasma hormone profiles of prostaglandins (PGs), cortisol (C), and progesterone (P4) during pathologic processes in newborn foals is scarce. The aim of this study was to determine the plasma concentrations of these hormones in diseased foals (n=40) and healthy at-term foals (n=24) (Equus caballus) during the first 2 weeks of life. Blood samples were collected daily, before any treatment with nonsteroidal drugs in diseased foals, and plasma was analyzed by radioimmunoassay. 15-Ketodihydro-PGF(2alpha) (PGM) was consistently higher in diseased foals than in healthy foals, probably related to roles of PGs in completing organ maturation and/or the presence of oxidative stress or inflammation. Similar trends were observed for C and P4. In diseased newborns, only PGM was significantly higher in nonsurviving foals, although C showed a similar profile. When specific diseases were considered, the levels of PGM and C were lower in premature foals at 12h of life, whereas the concentration of P4 was higher than in controls. The results of this study demonstrate the differences in plasma hormone levels between healthy and pathologic newborn foals, particularly during the first 2 d of life, probably reflecting the inability of diseased foals to cope with the transition between fetal and neonatal life.