Foal Health Research Articles

Nutritional composition, fatty acids profile and immunoglobulin G concentrations of mare milk of the Chilean Corralero horse breed

The objective of the present study was to characterize the nutritional composition, fatty acid profile, and IgG concentration of the milk produced by Chilean Corralero horse (CCH) mares from breeding farms located in southern Chile. Forty-five milk samples were collected from three of the biggest breeding farms (coded as A, B and C) specialized in breeding and selection of CCH in Chile (15 mares sampled per farm). Farms differed in days in milk (DIM). A negative association between DIM and ash, milk protein, milk solids, saturated fatty acids (SFA), and gross energy (GE) was found, whereas DIM had a positive association with monounsaturated fatty acids (MUFA). Milk components like fat, lactose, and energy content varied independently of DIM, indicating other influencing factors such as farm-specific management practices. Offspring sex moderately affected GE content, with milk from mares bearing female offspring having higher GE. Macronutrient profiles of the CCH mares’ milk were within the reported range for other horse breeds but tended to have lower fat and total solids. Compared to cow and human milk, horse milk is richer in lactose and lower in fat and protein. Immunoglobulin G concentration was only affected by the farm (B > A) which could be linked to dietary factors and pasture composition rather than maternal parity or other known factors. Overall, CCH mare milk has notable nutritional characteristics, with implications for both foal health and potential human consumption, posing less cardiac risk compared to cow’s milk as indicated by lower atherogenic and thrombogenic indices.

Tumor necrosis factor-α is transferred to equine neonates via colostrum but is not associated with their health status

We followed the hypothesis that equine neonates with reduced transfer of tumor necrosis factor-α (TNFα) are at increased risk of neonatal infection. We investigated TNFα concentrations in colostrum of healthy mares and blood of their neonates in a non-hospitalized population of Warmblood mares where delivery, neonatal adaptation and health was closely monitored by veterinarians. Concentration of TNFα and IgG was determined in colostrum respective milk and in neonatal blood collected immediately after delivery and 18 h thereafter in 97 foals that were assigned to groups failure of passive transfer (FPT; n = 31) and control (CON; n = 66) based on serum IgG concentration at 18 h of age. Foal health was assessed repeatedly during the first 24 h of life. Statistical analysis was done with p < 0.05 indicating significance. There were no significant differences between foal groups FPT and CON regarding age and parity of dams, gestation length (FPT 343 ± 10, CON 340 ± 8 days) and foal sex. Concentrations of TNFα in colostrum at birth and in foals at 18 h varied but did not differ between groups (colostrum FPT 6.1 ± 9.1, CON 9.9 ± 31.5 ng/ml; foal FPT 2.3 ± 5.9, CON 2.4 ± 5.3 ng/ml; n.s.). There was an increase in the mean serum TNFα concentration until 18 h in foals (n.s. between groups). Results of the present study confirm previous findings of TNFα transfer from the mare to the neonate via colostrum but do not suggest that transfer of TNFα via colostrum is important for protection of the neonate against infectious diseases.

Gross and histological examination of Wharton's Jelly in the equine umbilical cord

Wharton's jelly (WJ) is fundamental for the well-being of the fetus, binding to the umbilical vessels and protecting them from twisting and compression. Gross and microscopic studies have been undertaken on the umbilical cord (UC) of human placentae in both normal and high-risk pregnancies, however there is limited research on equine UC. The aim of this study was to describe microscopically and immunohistochemically the equine UC in normal pregnancies, with particular attention to WJ. Forty-seven healthy mares, with no complications during pregnancy, admitted to the hospital for attending delivery were enrolled. Clinical data was collected at foaling on foal health and placental characteristics. UC samples were collected from three sites (amniotic, allantoic and in the region of vein anastomosis) for histology. The thickness of different layers of arteries and veins and WJ in different UC portions were measured (μm). Wharton's Jelly was weighted (g) and its sections were stained with Masson's trichrome, orcein technique and silver impregnation. Immunohistochemistry was undertaken using antibodies raised-against collagen type I, V, VI and fibrillin. Forty-seven UCs, from 19 colt and 28 filly foals, were analyzed for WJ weight and 8/47 UCs were examined histologically. Warton's jelly was only found in the amniotic portion of the UC closest to the foal's abdomen. The weight of WJ (4.0 ± 3.3 g) did not vary between colts and fillies and it was not correlated with any of the clinical or UC parameters measured. The tunica media of arteries and veins was thicker in the amniotic portion of the UC, as described in human UCs in late pregnancy. This finding could be an adaptation to aid in resisting compression because of fetal movements and UC twisting. The umbilical vein was thicker than the umbilical arteries in the tunica media and tunica adventitia in the sections examined throughout the length of the cord. This preliminary study describes gross and histological WJ's structure in the equine species. However, further studies are required to better characterize UC's changes throughout pregnancy and in the presence of mare's or fetal disease.

Microbial Profiling of Amniotic Fluid, Umbilical Blood and Placenta of the Foaling Mare.

The presence of a microbiome/microbiota in the placenta is hotly debated. In previous studies, the presence of bacteria in equine amniotic fluid and umbilical blood was independent of foal health. The objective of the present study was to determine if the same bacteria are present in the equine placenta as in amniotic fluid and umbilical blood. Samples were obtained from 24 parturient mares and foals. Placental bacterial DNA was extracted, and the microbiome was identified using 16S rRNA sequencing. All amniotic fluid samples contained some polymorphonucleocytes; bacteria were isolated from four samples. Aerobic or anaerobic growth was found in 18 and 3 umbilical blood samples, respectively. Serum amyloid A was <5 mg/L in all 24 samples, total WBC varied between 2900 and 10,700/µL, and fibrinogen varied between 0 and 5.16 g/L. In jugular blood, serum amyloid A was <5 mg/L in all 24 foals, total white blood count was 3200 to 8100/µL, and fibrinogen was 0.44 to 4.42 g/L. The diversity of bacterial microbiota was similar in all placental regions at the phylum level but differed at the genus level; the most abundant phyla were Proteobacteria (42-46.26%) and Actinobacteria (26.91-29.96%). In conclusion, bacteria were found in the fetal compartments and placenta of healthy equine pregnancies; however, we can neither prove nor disprove the hypothesis that the placenta has its own microbiome.

117 Factors affecting birth weights in Thoroughbred foals born in Kentucky, United Kingdom, and Australia

Kentucky (KY), United Kingdom (UK), and Australia (AUS) are major breeding regions for Thoroughbreds. Birth weights (BW) are commonly measured in each region and are perceived as important parameters for assessing foal health and future athletic ability. This study was conducted to evaluate how foal BW is affected by gender, mare age, parity, month of birth (MOB), and geographic location. Birth weight was measured with electronic scales in 3,062 foals over multiple years in KY (12 farms, 2013–2018, n = 801), UK (6 farms, 2007–2019, n = 934) and AUS (1 farm, 2013–2019, n = 1,327). Differences between gender were measured using unpaired t-tests and differences related to month of birth, mare age, parity, and location were measured using a one-way ANOVA. All results are reported as mean ± SD. BW was greater in KY foals (56.5 ± 6.6 kg) compared with UK (55.3 ± 6.5 kg; P < 0.01), or AUS (53.9 ± 6.6 kg; P < 0.01). AUS foals were also smaller than UK foals (P < 0.01). Fillies were on average 1.2 kg smaller than colts in each region (P < 0.01). Parity significantly affected BW in each region. Primiparous (para 1) mares produced smaller foals in all regions compared with multiparous mares that produced 2 foals (para 2) or multiparous mares that produced morethan 2 foals (para > 2). Foals out of para 2 mares were smaller than foals out of para > 2 mares (P < 0.01). In all regions combined, foals out of para 1 mares (48.7 ± 5.8 kg) were 5.4 kg lighter than para 2 (54.1 ± 5.8 kg) (P < 0.01) and 8.6 kg lighter than foals out of para > 2 mares (57.2 ± 5.8 kg) (P < 0.01). Mare age was highly correlated with parity (r = 0.89). Age of primiparous mares (5.7 ± 1.3 y) was unaffected by region. In all regions, month of birth affected BW with foals born earlier in the season being lighter than those born in subsequent months. However, most of this difference was due to a larger proportion of para 1 and para 2 mares foaling earlier in the season. BW in multiparous (para > 2) mares was not affected by MOB in any region except the UK where para > 2 foals born in January were smaller than in all subsequent MOB (P < 0.01). Although region and gender affected BW, by far the greatest effect was due to parity. Foals out of para 1 and para 2 mares were on average 15% and 5% lighter at birth than para > 2 mares in each region. These large differences warrant further investigation.

The effects of obesity and insulin dysregulation on mare reproduction, pregnancy, and foal health: a review.

Obesity is a growing welfare concern in modern equine populations and predisposes horses to disturbances in energy metabolism such as insulin dysregulation. However, equine metabolic syndrome has only been recognized in recent decades. Functioning energy metabolism is pivotal to normal body homeostasis and affects essentially all organ systems, including reproduction. Previous literature suggests that obesity has an effect not only on the reproductive processes in mares but also on offspring health, predisposing the offspring to later-onset orthopedic and metabolic problems. This review focuses on the effects of obesity, insulin dysregulation and hyperinsulinemia on the reproductive functions of mares and the implications on foal health before and after birth. The points of interest are the cyclicity and ovarian function, uterine environment, gestation, the postpartum period, and the newborn foal. The aim is to review the current state of knowledge, and identify outstanding questions that could stimulate future research. This topic is important not only from the equine industry and production perspective but is also relevant for the welfare of future populations and individuals.

Success rate in a clinical equine in vitro embryo production program

In vitro embryo production (IVEP) via Ovum Pick-Up (OPU) and Intracytoplasmic Sperm Injection (ICSI) has become a popular breeding technique in Warmblood mares because of the high success rate and several practical advantages. IVEP offers a solution for a variety of reproductive issues including, but not limited to, sub-fertility in stallions or mares, poor quality or scarce frozen semen, difficulty in synchronizing donor and recipient mares, and inefficient use of recipient mares. In 515 OPU-ICSI sessions performed in our facility in 2021, a mean of 25.9 antral follicles were aspirated yielding an average 13.8 immature oocytes, which were shipped overnight to a specialized ICSI laboratory (Avantea). One or more blastocysts (range: 0–13 blastocysts) were produced from 78% of procedures with a mean of 2.12 blastocysts per session; the likelihood of pregnancy after transfer of a cryopreserved thawed IVP blastocysts in 2021 (n = 781) was 77.7%. Several donor mare, recipient mare, stallion and embryonic factors influence the likelihood of producing an in vitro blastocyst or achieving pregnancy. Approximately 60% of the transferred IVP blastocysts yield a foal; moreover, neither gestation length nor the health of foals is noticeably influenced by IVEP. On the other hand, a skewed sex ratio towards colts is apparent among IVEP foals resulting from day 7 but not day 8 embryos, suggesting that male embryos develop more rapidly in vitro. Although serious complications after OPU are uncommon, owners should be aware of their existence, because some complications can be life-threating.

Perinatal mortality in horses and camelids

The neonatal health of foals and crias is affected by the quality of the uterine and placental environment before birth, threats theyface during birth, and vulnerabilities of the first week of life. When identifying the cause of neonatal death, careful examinationof the dam, fetal membranes, and the fetus is critical. The most common threats for horses and camelids are failure of passivetransfer, bacterial sepsis, diarrhea, and congenital defects. Identification of compatible lesions and confirmation with laboratorytesting will allow better management of the herd.

Induction of parturition in horses – from physiological pathways to clinical applications

Based on the marked variability in physiological equine gestation length, induction of foaling in mares often results in the birth of dysmature foals. Precise prediction of preparedness of the mare for foaling is thus essential. Treatment with glucocorticoids mimics the fetal signal that initiates birth. Repeated daily dexamethasone treatment in late gestation results in birth of mature foals but the time from initiation of treatment to foaling is highly variable and complications such as dystocia have been reported. Contrary to most expectations, treatment of prepartum mares with progestogens does not delay but advances the onset of foaling. Prostaglandin F2α (PGF2α) and its analogues are effective to induce foaling but even in mares ready for parturition, foal health remains to some extent unpredictable. This may be caused by a relatively long interval between PGF2α treatment and birth, exposing the fetus for several hours to uterine contractions. Oxytocin reliably induces foaling towards the end of pregnancy, but when given at high doses is effective also in the pre-viable period of gestation, resulting in birth of premature foals. Recent research has focused on reducing the amount of oxytocin with the aim to induce foaling only in mares prepared for foaling. Mares selected on clinical criteria receive 1 dose of 2.5 to 3.5 IU of oxytocin. Mares not responding to oxytocin are judged not yet ready for foaling and treatment is repeated the earliest after 24 h. This protocol at present is the most reliable and safest way to induce parturition in mares.

Selenium and Vitamin E Concentrations in Miranda Jennies and Foals (Equus asinus) in Northeast Portugal

Simple SummaryDespite the importance of donkeys through history and their productive resuscitation during the last decades, reference values for common elements are not yet readily available. Such a challenge becomes even more noticeable when practitioners aim at evaluating the physiological and pathological concentrations of certain elements across the different stages that a donkey can go through along its life. The aims of this study are to determine baseline selenium and vitamin E concentrations for Miranda donkeys both jennies and foals. Miranda donkeys are considered to be endangered and it is possible that selenium and vitamin E may be associated with foal survival. Critical points may be identified related to overdosing or deficient levels of selenium and vitamin E, at different stages of development of gestation in utero during fetal development, parturition, and post foaling. Our study suggests that vitamin E and Se levels can have a major impact and effect on foal health and mortality levels. Multiple factors including location, diet, management practices, parity and time of breeding, and age of jenny may affect blood profiles in jennies, which ultimately may affect the profiles of her foals. The increase in donkeys treated by practitioners in recent years has led to an increased interest in finding more information on basic biochemical preliminary reference values. The aims of this study were to measure Se and Vit E levels in plasma from Miranda jennies peripartum and postpartum and in their foals to compare blood profiles of the jenny and foal related to the overall foal’s health. Twenty-two healthy peripartum and postpartum Miranda donkeys were sampled (12 jennies and 10 foals) in the northeast of Portugal (Atenor and Paradela) from May to November, 2018. Amounts of selenium in soil were significantly correlated (0.97) to concentrations of selenium in jennies (42.412 μg/L in Atenor and 9.612 μg/L in Paradela) and foals (19.378 μg/L in Atenor and 6.430 μg/L in Paradela). Selenium levels were lower in foals than adults and in males than females. Vitamin E was associated with overall foal health. Foals with a mean vitamin E of 3.585–5.307 mg/L showed signs of weakness, but carpal flexural deformities were observed when the average vitamin E was 11.520 mg/L. Low vitamin E levels (5.307 mg/L) in jennies were related to foal mortality. Diets, location, parity, and age affect blood profiles of jennies and, ultimately, foal health.

109 Is the equine gut colonised in utero by amniotic bacteria?

Until very recently it was believed that the uterus was sterile, with microbial colonisation of the foal's gastrointestinal tract (GIT) commencing at birth. GIT colonisation is an integral developmental process, critical for an optimal functioning immune system and ongoing health of the foal. The in utero colonisation paradigm has now challenged this concept, indicating that the amniotic fluid (AF) composition contains non-pathogenic microbiota that potentially commence colonisation of the GIT during the process of fetal swallowing. In turn, preparing the foal for life outside the womb. This study examined the presence of microbiota in the AF of healthy pregnant mares, identifying microorganisms that have the potential to colonise the fetal GIT in utero. AF samples were obtained from 14 healthy mares in the second stage of parturition, before the rupture of the amnion. When the amnion was clearly visible, the surface was seared with a sterile spatula and AF extracted with a sterile needle and syringe. The sample had no contact with any other surface of the mare and was immediately snap-frozen and stored at −80°C for microbiota analysis. Genomic DNA was extracted and processed for 16S rRNA gene amplicon sequencing, followed by bioinformatic analysis of the results using QIIME2 and CalypsoV8.84 software packages. Microbiota was detected in all AF samples. Communities were of low diversity, as indicated by the α diversity parameters Chao1, Evenness, Richness and Simpson's Index. Operational Taxonomic Units (OTUs) of the top 20 taxa showed some host variation. The most abundant OTUs across the majority of samples were classified to the phyla Opisthokonta (100% of samples), Bacteroidetes (79%), Actinobacteria (57%) and Firmicutes (57%). At the family level, Staphylococcacea (79%) and Microbacteriaceae (71%) were the most abundant. These microbes have been previously detected across other locations of the equine microbiome, including the oral, esophageal, distal GIT and vaginal ecosystems. Our results have demonstrated the presence of a complex microbial ecosystem of low diversity in the AF of healthy equine pregnancies, likely of maternal origin. The environmental and gastrointestinal microbes detected in the AF displayed similarities to other equine ecosystems, suggesting microbial translocation from the mare to the AF. Further research would be required to determine if these AF microbes are being ingested by the fetus, thus commencing GIT colonisation in utero . Deciphering microbial colonisation of the foal's GIT has important implications for maternal management before parturition and could lead to the development of strategies to enhance foal health outcomes.

102 Detecting coprophagy in foals and its relationship with foal gut health

Abstract Consumption of maternal feces is commonly observed in foals; however, the role of this activity in foal health is unknown. Therefore, this study aimed to determine the occurrence of coprophagy in foals and how it relates to foal gut health. Milk samples and foal feces were collected from 12 mare-foal pairs at 12 h, 3, 5, 7, 10, 14, and 21 d after foaling. Milk yield was estimated after muzzling foals for 2 h intervals at 7 and 14 d postpartum. To detect coprophagy in foals, nine mares were fed chromic oxide (10 g/d) with their concentrate in nosebags twice daily. Mares had ad libitum access to forage. Fecal samples were collected immediately after defecation and used to enumerate cellulolytic bacteria, lactobacilli, and lactate-utilizing bacteria using culture-based techniques. Enumeration data were log10 transformed before statistical analyses. Frozen feces were used to analyze neutral detergent fiber (NDF) using a Fiber Analyzer (Ankom Technology, NY, USA), then ashed and digested to analyze chromic oxide via atomic absorption. Fecal scores were recorded daily to monitor for signs of diarrhea. Changes over time were evaluated using repeated measures ANOVA and relationships between variables were analyzed using Pearson’s correlation coefficient (SAS 9.4). Coprophagy was detected as early as 3 d after birth and detected in all foals by 7 d of age. Peak coprophagy occurred at 14 d after birth. Milk yield was negatively related to fiber and chromic oxide in foal feces (r = -0.64 and -0.70, respectively; P &amp;lt; 0.05). Chromic oxide in foal feces was positively related to the number of cellulolytic bacteria and NDF (r = 0.97 and 0.79, respectively; P &amp;lt; 0.05). Bouts of diarrhea tended to be negatively related to chromic oxide (r = -0.59; P = 0.0928). Maternal feces is likely an important source of fiber and microbial inoculum for foals, aiding in colonization of beneficial microbes.

PSVII-41 Mare colostrum and milk composition through 36 h post-parturition

Abstract Sixteen Quarter Horse mares (mean±SEM; 12±5 yr; 5.1±1.0 BCS; 579±9 kg BW) were used to evaluate the time course of the nutrient profile of colostrum and milk following parturition. Mares received a commercial concentrate designed to meet NRC (2007) requirements for gestating mares and were fed to maintain a BCS between 5 and 7. Horses were group housed in dry lots with ad libitium access to coastal Bermudagrass hay and water. As soon as parturition was observed, colostrum was collected by hand pre-suckle (0 h post-parturition), and at 6, 12, 24, and 36 h post-parturition. Samples were evaluated for concentrations of protein, fat, lactose, somatic cell count (SCC), urea nitrogen, and non-fat solids (NFS) by a commercial laboratory. Differences between means were determined using PROC MIXED in SAS (v9.4) with time as a repeated measure. Following parturition, colostrum protein and NFS decreased from h 0 to 6 (protein: 13.1±0.7 to 9.7±0.8%; NFS: 20.9±0.8 to 16.8±0.9%) and from h 6 to 12 (P0.04). Protein continued to show a trend for a decrease from h 12 to 24 (P = 0.08), plateauing around 3%. NFS remained around 10% from h 12 to 36. Conversely, lactose did not change from h 0 to 6 (3.6±0.2 to 3.9±0.2%) but increased from 6 to 12 h (5.5±0.2%) post-parturition (P &amp;lt; 0.0001). Fat, SCC, and urea nitrogen remained unchanged through 36 h post-parturition. These results indicate colostrum protein concentration decreases as early as 6 h post-parturition, and the non-fat solid portion of milk shifts from primarily proteins to lactose. However, the impact of these changes on foal health should be more clearly defined.

Triglyceride concentrations in neonatal foals: Serial measurement and effects of age and illness

Few studies have evaluated the effects of age and illness on serum triglyceride concentrations in neonatal foals. The objectives of this study were to evaluate triglyceride concentrations in neonatal foals and their dams through serial measurement immediately postpartum and at 1–2 days and 10–12 days of age, as well as to measure them in sick foals.Serially measured serum triglycerides in seven healthy foals varied with age. Median (range) triglyceride concentrations were 28mg/dL (12–50mg/dL), 89mg/dL (51–264mg/dL), and 60mg/dL (28–135mg/dL) immediately postpartum, at 1–2 days of age, and 10–12 days of age, respectively (P<0.001). Triglyceride concentrations varied hourly by up to 117mg/dL in individual foals. The dams had lower triglycerides (median, 20mg/dL; range, 12–49mg/dL) than the foals, once foals were >24h old. Sick foals <24h old had lower triglycerides than sick foals aged 1–7 days (median, 41mg/dL [range, 16–116]; median, 110mg/dL [range, 24–379mg/dL]; P<0.001). Age and triglyceride concentration showed a non-linear association independent of foal health status (P=0.01). Sick foals with positive bacterial cultures had higher triglycerides than those with negative cultures (median, 111mg/dL [range, 10–379mg/dL] and median 53mg/dL [range, 17–271mg/dL], respectively; P=0.033). Nonsurvivors had higher triglycerides than survivors (median, 116mg/dL [range, 41–379mg/dL] and median, 55mg/dL [range, 10–311mg/dL], respectively; P=0.04). In conclusion, triglycerides were highest in healthy neonatal foals aged 1–2 days, and in nonsurviving sick foals and those with positive bacterial cultures. Age was associated with triglyceride concentration regardless of health status.

Neonatal Care and Management of Foals Derived by Somatic Cell Nuclear Transfer.

There are few reports on the birth of foals resulting from equine adult somatic cell nuclear transfer (NT). On evaluation of reports of 28 live-born adult somatic-cell NT (clone) foals, 3 died within 2 weeks of birth of complications. Approximately 50 % of all reported cloned foals had complications, some requiring aggressive supportive care. The most common abnormalities reported were neonatal maladjustment syndrome, enlarged umbilical remnant, and angular deformity of the forelimbs, similar to problems described in cloned cattle. In contrast, large offspring syndrome and gross abnormalities of the fetal membranes which are described in cloned cattle are not reported in cloned foals. Reports of the health of foals produced by nuclear transfer suggest that NT foals should be treated aggressively as at-risk foals until all parameters are normal.

Gross placental morphology and foal serum biochemistry as predictors of foal health

The aim of this study was to verify if changes in blood glucose, creatinine, urea, and fibrinogen concentrations evaluated at birth reflect gross placenta abnormalities, and are useful to identify foals that suffered from placental dysfunction. A total of 92 mares were included in the present study: 68 delivered healthy foals and they were included in group 1; 24 delivered sick foals and they were included in group 2. In group 2, foals' clinical diagnoses included perinatal asphyxia syndrome (PAS; n = 20) and prematurity and/or dysmaturity (n = 4). The proportion of sick foals was greater when placental abnormalities were observed (χ2 [1, n = 89] = 5.00; P = 0.025). Serum creatinine concentration at birth was higher in sick than in healthy foals (P = 0.003), and blood glucose concentrations at birth was smaller in sick than in healthy foals (P = 0.007). No difference was found in blood chemistry results between survivors and nonsurvivors of group 2. Serum creatinine concentration was higher in foals born from grossly abnormal than in foals born from grossly normal placenta (P = 0.029), and it was higher in foals affected by PAS (311.17 μmol/L) than in healthy foals (238.24 μmol/L) (P = 0.004). In a clinical setting, serum creatinine and blood glucose concentrations should be evaluated at birth, particularly in foals born from grossly abnormal placenta. The association of clinical and laboratory data could be particularly important to promptly identify and treat foals with a higher risk to develop PAS.

The impact of birthweight on mare health and reproductive efficiency, and foal health and subsequent racing performance

Although low birthweight is a risk factor for neonatal illness, the impact of high birthweight on the health of foals and mares, and on the foals' long-term athletic capability, is unknown. To investigate whether: 1) foals that are excessively heavy are associated with an increased prevalence of maternal illness in the first month post partum and reproductive dysfunction in the following season; 2) excessively light or heavy foals are at an increased risk of illness in the first month of life; and 3) birthweight is associated with racing success. Veterinary records from 230 Thoroughbred mares and 409 foalings were reviewed. Data relating to foaling, foal and mare health during the first month postpartum and subsequent breeding efficiency were extracted. Foals' racing records were obtained and the association between birthweight and these outcomes examined. Mares with heavy foals had a higher prevalence of minor nonreproductive problems than those with light and average foals. Compared to average foals, placental weight was lower in the light group and higher in the heavy group. Light foals took longer to stand, nurse and pass meconium, whereas gestation period and duration of Stage 2 parturition were longer in heavy foals. Heavy foals were at increased risk of nonseptic musculoskeletal conditions and conformational defects. Birthweight was not associated with racing outcomes. High birthweight was associated with increased prevalence of neonatal musculoskeletal conditions but birthweight did not have a major impact on mares' health and reproductive efficiency, orfoals' racing success. These data add to the understanding of the impact of birthweight on short- and long-term health outcomes in mares and foals.

Relationships between Early Foal Health, Future Performance and Their Dams Reproductive Health

The objectives of this study were to investigate: (i) relationships between early foal health and their dams' reproductive health at mating/conception as well as after parturition and (ii) health status during early foal life and its association with performance as an adult. The study included 35 foals showing clinical symptoms indicating septicaemia, sometimes in combination with other disturbances, within their first 18 h postpartum (Group I). Eighty-eight foals that were healthy during their first few days of life were used as control (Group II). All foals were born in the same region of Sweden and during the same period, and were expected to become performance athletes based upon the pedigree of their parents. Cytological and bacteriological examination of uterus at the time of mating/insemination at which the foal was conceived, revealed no difference between dams of Group I and Group II foals. Within 2-3 days after parturition, 29% and 4% of dams (p < 0.001) of Group I and Group II foals had metritis, respectively. At 30 days post-parturition, 64% of the dams of Group I foals and 32% of the dams of Group II foals (p = 0.002) had cytological indication of endometritis, and 57% of the dams of Group I foals and 21% of the dams of Group II foals (p < 0.001) showed bacterial growth upon culture. Altogether 29% of the Group I foals and 7% of the Group II foals were killed or died before 2 years of age (p = 0.001). The majority of the remaining Group I foals were poor performers and some were used just for pleasure riding. It is hypothesized that (i) mares--delivering foals that compromised within their first 18 h postpartum--might have suffered from an ascending infection during late gestation and (ii) health status during early foal life might be associated with their performance as adult.

Prevalence (treatment days) and severity of illness in hypogammaglobulinemic and normogammaglobulinemic foals

Summary Serum samples for determination of IgG concentration were obtained between postpartum hours 18 and 48 from 132 Standardbred foals. Results of the IgG assay were not known to farm personnel. None of the foals was given plasma iv for treatment of hypogammaglobulinemia. Foal health records were examined retrospectively to determine prevalence of infectious-type illness (foal treatment days [ftd]), prevalence of life-threatening infectious illness (foal treatment days-serious condition [ftd-sc]), and number of diseases (nod) per foal. Values for ftd, ftd-sc, and nod per foal were compiled for the first 21 days of life and for the first 90 days of life. The ftd, ftd-sc, and nod per foal values were compared for foals with &lt; 400 mg of IgG/dl and for foals with ≥ 400 mg of IgG/dl; the same variables were compared for foals with &lt; 800 mg of IgG/dl and for foals with ≥ 800 mg of IgG/dl. Statistical analysis indicated that IgG concentration was not associated with ftd, ftd-sc, or nod in foals of any of the groups. Also, despite a large subpopulation of hypogammaglobulinemic foals (13.6% with &lt; 400 mg of IgG/dl and 44.7% with &lt; 800 mg of IgG/dl), the 21-day and 90-day overall survival rates were 100 and 99.2%, respectively. The data strongly suggest that serum IgG concentration was not related to prevalence or severity of illness or to survival rate in this population of foals.