The Influence of Age on Clinical Biochemical Parameters in Pure-bred Arabian Mares

Specific reference intervals are needed for each animal species for the appropriate interpretation of the results obtained from serum biochemical tests. The aim of this study was to investigate the blood composition of pure-bred Arabian mares to evaluate the need for defining reference values for different age groups. In all, 90 clinically healthy mares from five farms were used in the trial. For the determination of the effect of age, 90 mares were assigned to six groups. Groups A, B, C, D, E, and F comprised 15 foals aged ≤5 months (mean ± SD: 2.45 ± 1.88), 15 foals aged 6 to 18 months (mean ± SD: 9.33 ± 2.93), 15 mares aged 2 to 5 years (mean ± SD: 3.91 ± 0.7), 15 mares aged 6 to 12 years (mean ± SD: 8.66 ± 2.3), 15 mares aged 14 to 20 years (mean ± SD: 17.81 ± 2.13), and 15 mares aged >20 years (mean ± SD: 22.8 ± 1.93), respectively. Glucose, blood urea nitrogen (BUN), albumin, creatinine, total bilirubin, direct bilirubin, total protein, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), calcium, iron, magnesium, and phosphorus concentrations were measured in the blood serum samples. There were significant age-related alterations for most of the biochemical parameters, except for ALT, LDH activities, and glucose, albumin, magnesium, and iron levels. The results of the present study showed that direct bilirubin (P < .01), ALP, and phosphorus decreased significantly (P < .001), whereas BUN, calcium (P < .01), creatinine, total protein, and total bilirubin increased (P < .001) with age. In foals, ALP activity, direct bilirubin, and phosphorus levels were higher, whereas BUN, creatinine, total protein, total bilirubin, and calcium levels were lower as compared with older animals. Biochemical values determined in the present study serve as reference ranges for pure-bred Arabian mares and can be used for health control and diagnosis of diseases.     

Serological status of mares in parturition and the levels of antibodies (IgG) against protozoan family Sarcocystidae from their pre colostral foals

Protozoa from the family Sarcocystidae are agents of reproductive and neurological disorders in horses. The transmission of these protozoa may occur via horizontal or vertical means, and the frequency and potential of the later is not fully elucidated in horses. Thus, the aim of study was to correlation levels of antibodies in mares with pre colostral foals seropositive and assess the level and distribuition of antibodies against Neospora spp., Sarcocystis neurona and Toxoplasma gondii, in mares and pre colostral foals at the parturition. The blood samples were collected from mares immediately after parturition and from newborns before the ingestion of colostrum, and sera were analyzed for the presence of IgG by ELISA. It was found that 21.5%, 33.7% and 27.6% of mares were seropositive for Neospora spp., S. neurona and T. gondii, respectively; foals had antibodies at a rate of 8.3%, 6.6% and 6.6% for Neospora spp., S. neurona and T. gondii, respectively. Additionally, paired samples from mares and pre-colostral foals revealed an overall negative correlation between the serum reactivity against these three parasites and suggested that seronegative mares, or those with low to intermediate antibody levels, have a higher risk of giving birth to seropositive foals.     

Anti-abortion and Fertility Vaccine Potential of Defined Double Deletion (ΔaroAΔhtrA) Mutant (S30) of Salmonella Abortusequi in Equids

The present study on defined double deletion (ΔaroAΔhtrA) mutant (S30) of Salmonella enterica serovar Abortusequi evaluated it for safety, immunogenicity, and efficacy as a vaccine candidate in equids. The candidate strain was found safe in equids (foals, male and female horses and donkeys, and pregnant and nonpregnant mares) and induced good humoral and cell-mediated immunity on administration through oral route. The strain was not excreted in feces of vaccinated animals. The vaccine candidate administered orally (1 × 10¹¹ cfu per animal) protected mares even after 180 days of inoculation against abortion on challenge with wild-type S. Abortusequi strain whereas in nonvaccinated control, all mares aborted. The vaccination in infertile mares resulted in regaining of fertility in 67%–80% thoroughbred mares at two different breeding farms. Further, the humoral immunity was transferred to foals from vaccinated mothers through colostrum, but no placental transfer was evident. Thus, the vaccine under study may be recommended for use in equids to control S. Abortusequi infection–associated abortions and also to enhance fertility of temporarily infertile mares in endemic areas.     

Effects of vitamin E and selenium administration on pregnant,heavy draft mares on placental retention time and reproductive performance and on white muscle disease in their foals

This study investigated the effects of administering vitamin E and selenium to pregnant heavy draft horsemares on the incidence of retained placenta and postpartum reproductive performance and on the prevention of the white muscle disease in their foals. In study A, 1,000 mg of vitamin E and 50 mg of selenium (E-SE 20 mL) were given to 22 mares 3 weeks before expected parturition (335 days counted from last mating), whereas 28 mares were used as controls. In study B, E-SE were administered 2 weeks before expected parturition at 2 dose levels, with 25 mares receiving 20 mL E-SE, 19 mares receiving 10 mL, and 29 mares kept as controls. Vitamin E and selenium were assayed in serum collected from some of the mares before administration of E-SE and again postpartum and from the foals immediately after birth. Serum selenium concentrations before E-SE administration were deficient (<65 ng/mL) in all mares (n = 48) but were increased in the postpartum sample from treated mares regardless of the dose or timing of administration (n = 31) (P = .05). Only study B mares were deficient in vitamin E prepartum, and both dose levels of E-SE had corrected this in the postpartum sample (P = .01). All foals were selenium deficient regardless of whether their dams had received E-SE or not, although concentrations were higher in foals from treated study A mares than from controls (P = .05). Mares with the highest selenium concentrations prepartum (40 ng/mL and over) had shorter placental retention times than mares with lower selenium concentrations (P = .05) and did not respond to E-SE with a further reduction in retention time. By contrast, mares with prepartum selenium concentrations between 20 and 40 ng/mL tended to respond to E-SE with a shortened placental retention time (P = .07). E-SE administration reduced the mean number of days from parturition to last mating (nonpregnant term) in study B mares (P = .05) and in mares with adequate prepartum vitamin E concentrations (>300 g/mL, P = .05). We conclude that maintaining high level serum vitamin E and selenium concentrations of prepartum mares is expected to increase fertility of selenium-deficient mares. Therefore, the regimen of vitamin E and selenium administrations to selenium deficient mares should be developed.     

Studies of maternally-acquired antibodies in the foal to equine influenza A1 and A2, and equine rhinopneumonitis

Serum and colostrum were collected from 50 mares at parturition. Pre- and post-nursing serum samples were obtained from their foals. Bi-weekly serum samples were obtained from 25 of the foals for eight weeks. Hemagglutination-inhibiting (HAI) antibody titers to equine influenza viruses A₁ and A₂ (EIVA₁ and EIVA₂) and serum-neutralizing antibody titers to equine herpes virus 1 (EHV₁) were measured in serum and colostrum samples. IgG levels in serum and colostrum were determined.No antibody was detected in any foal's pre-nursing serum sample. Foal post-nursing antibody and IgG levels were equivalent to those measured in their dam's sera (EHVA₁ p=0.86; EHVA₂ p=0.54; EHV₁ p=0.91; IgG p=0.58). The half-life of maternally-acquired serum antibody in the foals was determined to be: EIVA₁=28.88 days (26.4 to 31.7 days); EIVA₂=29.1 days (26.7 to 32.1 days); EHV₁=31.0 days (28.1 to 34.8 days). Colostrum contained antibody and IgG at levels ranging from 2 to 8 times higher (4.3 average) than those detected in the mare's serum.     

Immunologic Profiles of Peripheral Blood Leukocytes and Serum Immunoglobulin G Concentrations in Perinatal Mares and Neonatal Foals (Heavy Draft Horse)

The purpose of this study was to examine sequential changes in the immunologic parameters of perinatal mares and neonatal foals of the heavy draft horse. Blood samples were collected from clinically healthy pregnant mares and their newborn foals every week from 1 month before the expected foaling date, and 1 hour, 1 day (24-48 hours), and 1, 2, 3, and 4 weeks after foaling. Peripheral blood samples were used to examine total leukocyte counts (n = 20), differential leukocyte counts (n = 20), lymphocyte subpopulations (n = 13), lymphocyte responses to mitogens (n = 10), neutrophil phagocytic function (n = 12), and serum immunoglobulin G (IgG) concentrations (n = 10). In perinatal mares, remarkable changes observed included increased neutrophils, decreased lymphocytes, decreased CD4⁺ T lymphocytes, and decreased lymphocyte responses to mitogens at delivery. These changes were speculated to be the result of physical stress associated with delivery. In neonatal foals, increase in the phagocytic function of neutrophils, and increase in serum IgG concentration after suckling colostrum and increase of lymphocytes accompanied by physiologic growth were observed. Compared to dams, foals showed lower phagocytic function of neutrophils before suckling and fewer lymphocytes and lower lymphocyte responses to mitogens within 1 day after birth. This study revealed immunologic dynamics in perinatal mares and neonatal foals. Immunologic functions are suppressed in foaling mares and are immature in neonatal foals, especially before colostral intake. We expect these data will be useful for further studies in the field of clinical immunology, and preventive medicine.     

Colostral and serum IgG, IgA, and IgM concentrations in Standardbred mares and their foals at parturition

Immunoglobulin G, IgM, and IgA concentrations were measured in serum collected from 36 Standardbred mares within 12 hours of foaling, in colostrum collected within 6 hours of foaling, and in serum collected from foals 24 to 48 hours after birth. In serum collected from mares after parturition, mean concentrations of IgG, IgM, and IgA were 2,463.9 +/- 1,337.3 mg/dl, 136.4 +/- 218 mg/dl, and 305.2 +/- 237.5 mg/dl, respectively. In serum from foals, mean concentrations of IgG, IgM, and IgA were 1,953.3 +/- 1,635 mg/dl, 33.8 +/- 30.4 mg/dl, and 58.4 +/- 42.2 mg/dl, respectively. In colostrum, mean concentrations of IgG, IgM, and IgA were 8,911.9 +/- 6,282.2 mg/dl, 957 +/- 1088.1 mg/dl, and 122.9 +/- 77.3 mg/dl, respectively. The IgG concentrations in foal serum were poorly correlated with IgG concentrations in colostrum (r = 0.462, P less than 0.01). Correlations of IgM or IgA concentrations in serum from foals with IgM or IgA concentrations in colostrum and correlations of IgG concentrations in serum from mares with those in colostrum were not significant (P less than 0.01). Of 36 foals, 1 (2.8%) had a serum IgG concentration less than 400 mg/dl. Of 36 foals monitored for 4 months, 6 developed infectious respiratory tract disease requiring antimicrobial therapy at ages varying from 55 to 113 days; these infections were probably not related to failure or partial failure of passive transfer of antibody.     

Passive transfer of Theileria equi antibodies to neonate foals of immune tolerant mares

Equine babesiosis, a tick transmitted haemoprotozoan disease caused by Theileria equi is globally distributed and responsible for heavy economic losses to the equine husbandry. Equids reared in endemic areas usually pick up infection at an early age and become immune tolerant throughout their life span. We studied the level of passively transferred antibodies in neonate foals born from pre-immuned mares. Latently T. equi infected pre-immuned pony and donkey mares (three each) were selected and T. equi antibody titres in neonates was monitored till 90 days post foaling (DPF) by applying Dot-ELISA on sequentially collected serum samples from foals and their dams. A very high antibody titre was observed in pre-immuned pony and donkey mares. The maximum antibody of 1:60 to 1:80 was observed in pony's and donkey's foal on 2–16 and 2–10 DPF, respectively and thereafter it declined to less than 1:20 on 63–77 and 56–63 DPF. Simultaneously parasite carrying status in neonate foals and their dam was also monitored by applying PCR on blood samples. We could demonstrate PCR amplification in dam's blood samples while no amplification was recorded in neonate's blood samples. This study indicated that new-born foals were born naïve and passively transferred immunity was transitory which wanes after 63–77 DPF.     

Leptin and Ghrelin and the Indices of Lipid Metabolism as Related to Sex Steroid Hormones in Trotters

This study examined the influence of sex steroid hormones on lipid metabolism in horses. The group of 34 clinically healthy Standardbred trotters aged 2 to 4 years was studied during an exercise test. The horses were divided into groups according to their sex. These groups were: 11 stallions, 16 mares, and seven geldings. Concentrations of testosterone, 17-β-estradiol, leptin, ghrelin, glycerol, free fatty acids (FFA), and triacylglycerols (TG) were measured in plasma obtained from blood samples taken at rest and after the end of the exercise. At rest, plasma ghrelin concentration was significantly higher in geldings than in stallions and mares (1,541 ± 206 vs 1,280 ± 288 and 1,310 ± 267 pg/mL, respectively; P = .012). Leptin was lower in geldings than in mares (2.65 ± 0.93 vs 4.70 ± 2.31 ng/mL; P = .036). The post-exercise rise in plasma ghrelin and TG concentrations was significantly higher in mares than in geldings (+220 ± 330 vs -25 ± 206 pg/mL; P = .049 and 0.31 ± 0.14 vs 0.13 ± 0.15 mmol/L; P = .016, respectively). The increase in plasma FFA level was higher in geldings than in stallions (535 ± 178 vs 334 ± 191 μmol/L, P = .046). In conclusion, lipolysis rate in geldings is higher than in noncastrated trotters.     

Effect of ω-3 Fatty Acid Supplementation to Gestating and Lactating Mares: On Milk IgG,Mare and Foal Blood Concentrations of IgG,Insulin and Glucose,Placental Efficiency,and Fatty Acid Composition of Milk and Serum From Mares and Foals

Limited research has been conducted to evaluate effects of fatty acid (FA) supplementation on mare and foal FA profiles and foal immunity. Dietary polyunsaturated FAs, particularly ω-3 FAs, increase fluidity of intestinal cell membranes. Fluidity of mammary tissues may also be altered to allow more incorporation of immunoglobulin G (IgG) into milk. Therefore, the goal of this study was to determine effects of incorporating dietary ω-3 FAs on mares, her milk, and her subsequent foal. Pregnant mares were assigned to one of three diets beginning 28 days before expected foaling date until 84 days after foaling. Diet 1 was a commercial feed (CON); diet 2 was diet 1 plus a fish oil blend (FO); and diet 3 was diet 1 plus a blend of fish and soybean oil (FSO). Mare serum FA concentrations were not affected by treatment (P > .05) with the exception of 20:5, which had a treatment × time interaction (P < .05). Mare milk FA concentrations were not affected by treatment (P > .05) with the exception of 16:1 and 20:5. Foal serum FA concentration was not affected by treatment with the exception of 18:2, which had a treatment × time interaction, and 20:5 (P < .0001), which was greatest in FO foals and least in CON foals. Dietary supplementation of ω-3 FAs did increase 20:5 in mare serum, milk, as well as serum of their subsequent foals. No differences were found for mare plasma IgG (P = .1318), serum insulin (P = .3886), plasma glucose (P = .2407), or milk IgG (P = .1262) concentrations for treatment. Foal plasma IgG (P = .2767), serum insulin (P = .4843), or plasma glucose (P = .1204) were not affected by treatment. Omega-3 FA in mare serum, milk, and foal serum were able to be manipulated by diet; however, IgG concentration was unchanged.     

Sick Neonatal Foals Do Not Demonstrate Evidence of Oxidative Stress

Critical illness in humans is associated with alterations in oxidative stress and the concentration of antioxidant molecules; however, this association has not been examined in equine neonates. The purpose was to determine the concentration of various antioxidant molecules, as well as a marker of oxidative stress, in the serum and plasma of normal and sick neonatal foals and their dams. Results demonstrated that the concentration of selenium was less (61.71 vs. 77.93 ng/mL; P = .002) in sick versus healthy neonates, whereas the concentration of vitamin E was slightly higher in sick compared with healthy foals (4.36 vs. 3.17 mg/mL); however, this did not achieve statistical significance (P = .31). The vitamin E concentration was greater (5.37 vs. 3.43 mg/mL; P = .01) and serum selenium was less in sick mares (129.50 vs. 184.78 ng/mL; P = .0001) compared with healthy mares. In addition, the serum concentration of selenium is lower in neonates than in their dams in the perinatal period (70.10 vs. 173.34 ng/mL; P = .0001). Glutathione peroxidase activity was less in sick foals (7.04 nmol/min/mL) compared with healthy foals (9.13 nmol/min/mL) (P = .19), and 3-nitrotyrosine (3-NT) concentration/mg protein was less in sick foals versus healthy foals (geometric mean, 1.24 vs. 2.07 nmol 3-NT/mg protein). This difference did not achieve statistical significance (P = .09); however, when a subset of critically ill foals was examined, the assayed concentration of 3-NT/mg protein was even less (0.99 nmol 3-NT/mg protein) and did statistically differ from healthy foals (P = .03).     

Antibody response in vaccinated pregnant mares to recent G3BP[12] and G14P[12] equine rotaviruses

Background

Both the G3P[12] and the G14P[12] type of equine group A rotavirus (RVA) have recently become predominant in many countries, including Japan. G3 types are classified further into G3A and G3B. The G3A viruses have been circulating in Europe, Australia, and Argentina, and the G3B viruses have been circulating in Japan. However, only an inactivated vaccine containing a single G3BP[12] strain is commercially available in Japan. To assess the efficacy of the current vaccine against recently circulating equine RVA strains, we examined antibody responses in pregnant mares to recent G3BP[12] and G14P[12] strains by virus neutralization test.

Findings

After vaccination in five pregnant mares, the geometric mean serum titers of virus-neutralizing antibody to recent G3BP[12] strains increased 5.3- to 7.0-fold and were similar to that against homologous vaccine strain. Moreover, antibody titers to recent G14P[12] strains were also increased 3.0- to 3.5-fold.

Conclusions

These results suggest that inoculation of mares with the current vaccine should provide foals with virus-neutralizing antibodies against not only the G3BP[12] but also the G14P[12] RVA strain via the colostrum.     

Exercising the Pregnant Mare from Day 16 to Day 80 of Gestation

Our previous research has demonstrated moderate exercise can be detrimental to early pregnancy in the mare, but little work has examined exercise after pregnancy has been detected. We exercised mares (n = 8) 6 days a week for 45 min from Day 16 until Day 80 of gestation. Color Doppler ultrasonography was used to evaluate embryonic vesicle size, fetal length, and uterine blood flow. Blood was sampled every other day to analyze cortisol and progesterone concentrations. Results indicated that exercising pregnant mares (n = 4) led to greater (P < .01) cortisol concentrations 30 min after the exercise period. No overall treatment effect could be detected in progesterone concentrations; however, following Day 60 of gestation, progesterone concentrations were lower (P < .05) in exercised mares. Additionally, progesterone concentrations peaked earlier in exercised mares at Day 52 of gestation compared to peak levels at Day 68 of gestation for control mares. No significant effects were detected in embryonic vesicle size. Fetal length tended (P = .06) to be longer in the conceptus of exercised mares. Uterine blood flow did not differ between groups but increased as pregnancy progressed (P < .001) in both groups. All mares in this study went on to deliver healthy foals and suffered no difficulties during parturition. These results indicated that moderate exercise was not detrimental to mare pregnancy.     

West Nile Virus Antibody Titers and Total Immunoglobulin G Concentrations in Foals from Mares Vaccinated in Late Gestation

This study was conducted to determine whether prepartum vaccination of mares would enhance passive transfer of West Nile virus (WNV)-specific antibodies and to characterize the pattern of decline for maternally derived WNV antibodies in foals. Seventeen light horse mares were allocated to WNV or control treatments. At 30 days before expected foaling, mares were vaccinated for encephalomyelitis, tetanus, herpesvirus, and influenza. At this time, WNV mares were vaccinated with a killed WNV vaccine. Blood samples were taken from mares 30 days before expected foaling, from mares and foals within 24 hours of foaling (0 days), and from foals at 7, 30, 60, 90, 120, 150, and 180 days of age as well as 30 days after an initial (PV1) and subsequent (PV2) WNV vaccination. Serum was analyzed for titer to WNV and total immunoglobulin G (IgG). Although WNV titer did not change over time in control mares, an increase (P < .05) was observed in WNV titer for WNV mares vaccinated 30 days before expected foaling. Foals of WNV dams had greater (P < .05) WNV titers than foals of control dams. Mean WNV titers of all foals increased from 0 to 7 days and declined through 180 days of age. Total IgG of foals increased from days 0 to 7, declined from days 30 to 120, and increased from days 150 through PV2. These results suggest that vaccination of mares for WNV in late gestation has a beneficial effect on foal WNV titer.     

The Effects of Selenium Source on Measures of Selenium Status of Mares and Selenium Status and Immune Function of Their Foals

The effect of organic and inorganic sources of selenium (Se) on measures of Se status of mares and their foals, Se concentrations of colostrum and milk, and indices of immune function of foals was studied. Twenty late-gestation Standardbred mares were randomly assigned to one of two groups. All mares received an identical balanced ration, except for the source of supplementary Se: one group received organic Se (Se yeast) and the other group received inorganic Se (sodium selenite), fed to deliver 0.3 mg/kg supplementary Se based on total ration dry matter. Mares received the experimental diet from 2 months before estimated due date until 1 month after foaling. Source of Se did not affect Se concentrations in maternal plasma, red blood cells, colostrum, or milk. At 1 month of age, foals from mares fed organic Se had higher red blood cell Se concentration than foals from mares fed inorganic Se (P < .05). Measures of immunity included serum immunoglobulin G concentration, lymphocyte proliferation in response to concanavalin A, and relative cytokine gene expression of stimulated lymphocytes (interferon gamma [IFNγ], interleukin [IL]-2, IL-5, IL-10, tumor necrosis factor alpha [TNFα]) and neutrophils (IL-1, IL-6, IL-8, IL-12, TNFα). Relative gene expression of IL-2, TNFα, and IFNγ by foal lymphocytes was associated with the source of Se supplementation provided to the mares. We conclude that the source of dietary Se provided to mares may influence the immune function of foals at 1 month of age through changes in relative gene expression of certain lymphocyte cytokines.     

Disposition of desfuroylceftiofur acetamide in serum,placental tissue,fetal fluids,and fetal tissues after administration of ceftiofur crystalline free acid (CCFA) to pony mares with placentitis

Macpherson, M. L., Giguère, S., Hatzel, J. N., Pozor, M., Benson, S., Diaw, M., Sanchez, L. C., Vickroy, T. W., Tell, L., Wetzlich, S., Sims, J. Disposition of desfuroylceftiofur acetamide in serum, placental tissue, fetal fluids, and fetal tissues after administration of ceftiofur crystalline free acid (CCFA) to pony mares with placentitis. J. vet. Pharmacol. Therap.  36 , 59–67. The objective of this study was to determine the pharmacokinetics of CCFA in mares with placentitis and evaluate the disposition of the drug in fetal fluids, fetal membranes, colostrum, and serum of foals. A secondary objective was to obtain pilot data regarding the efficacy of CCFA for improving foal survival in mares with placentitis. Twelve pregnant pony mares were enrolled in the study, inoculated with Streptococcus zooepidemicus, intracervically and assigned to one of three groups: CEFT (n = 3; administered CCFA only; 6.6 mg/kg, IM, q96h); COMBO (n = 6; administered combination therapy of CCFA, altrenogest, and pentoxifylline); UNTREAT (n = 3, no treatment). Treatment was initiated at the onset of clinical signs. Concentrations of desfuroylceftiofur acetamide (DCA), the acetamide derivative of ceftiofur and desfuroylceftiofur metabolites, were measured using high‐performance liquid chromatography. Maximum and minimum serum concentrations of DCA at steady state in treated mares were 2.40 ± 0.40 μg/mL and 1.06 ± 0.29 μg/mL, respectively. Concentration of DCA in colostrum was 1.51 ± 0.60 μg/mL. DCA concentrations in placenta and fetal tissues were very low (median = 0.03 μg/mL) and below the minimum inhibitory concentration of relevant pathogens. DCA was not detected in amniotic fluid or foal serum. Treatment did not appear to improve foal survival (CEFT: 0/3; COMBO: 2/6; UNTREAT: 2/3). Bacteria were recovered from the uterus of most mares postpartum and from blood cultures of most foals regardless of treatment.     

A Field Study of Serum,Colostrum, Milk Iodine,and Thyroid Hormone Concentrations in Postpartum Draft Mares and Foals

Iodine, thyroxine (T4) and triiodothyronine (T3) are required for normal fetal growth, maturation, and neonatal survival. There is a lack of robust information on iodine levels found in colostrum, milk, and serum of mares and foals after a healthy pregnancy. Our objective was to characterize colostrum, milk, and serum iodine levels in healthy postpartum mares and foals (n = 10) and explore relationships with thyroid hormone concentrations. Colostrum, milk, and jugular blood samples from draft breed mares and foals with an estimated average iodine daily intake of 39 mg per mare during pregnancy were obtained at Day 0 (foaling date) and/or 10 days later. Parameters studied were (1) mare basal concentrations of serum: TT3, TT4, and iodine; (2) iodine in colostrum at Day 0 and milk iodine (Day 10); and (3) foal basal: TT3, TT4, and serum iodine (Days 0 and 10). Median ± median error colostrum iodine levels (165 ± 15.1 μg/L) were higher than milk (48 ± 5.6 μg/L; P = .007) levels. Median ± median error foal serum iodine (268.5 ± 7.6 μg/L), TT4 (1,225 ± 47.8 nmol/L), and TT3 (14.2 ± 1.1 nmol/L) at foaling date were higher than at 10 days (serum iodine: 70 ± 3.6 μg/L; TT4: 69.6. ± 20.4 nmol/L; and TT3: 5.4 ± 0.3 nmol/L). In conclusion, equine mammary tissue concentrates iodine beyond plasma levels, making colostrum and milk a significant source of iodine. Foal serum iodine levels are high in the neonatal period and are positively correlated with TT4, which is important for neonatal adaptation.     

Hematological and Biochemical Profiles in Peripartum Mares and Neonatal Foals (Heavy Draft Horse)

Peripartum mares and neonatal foals are physiologically unstable. Although hormonal changes around the parturition have been well studied in the field of endocrinology, hematological and biochemical changes have been studied little. The purpose of this study was to examine hematological and biochemical changes in peripartum mares and neonatal foals (n = 23; heavy draft horse). The number of white and red blood cells, hemoglobin concentration, hematocrit, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration, platelet count in peripheral whole blood, and the concentration of glucose, nonesterified fatty acid, total cholesterol, triglyceride, total protein, albumin, globulin, blood urea nitrogen, creatinine, aspartate aminotransferase, gamma-glutamyltransferase, alkaline phosphatase, creatine kinase, iron, calcium, inorganic phosphate, magnesium, sodium, potassium, and chlorine in serum were measured. The main changes observed in peripartum mares suggested the following: (1) dehydration at the foaling, (2) physical stress by the foaling, (3) muscle damage by the foaling, and (4) change of energy metabolism associated with the beginning of lactation. The main changes observed in neonatal foals suggested the following: (1) dehydration (hemoconcentration) at the birth, (2) intake of colostrum, (3) beginning of urination, (4) functional change of hematopoiesis, (5) change of liver metabolism associated with the beginning of enteral nutrition, and (6) change of milk composition. This study revealed hematological and biochemical dynamics in peripartum mares and neonatal foals.     

Systemic and mucosal immunity induced by attenuated Salmonella enterica serovar Typhimurium expressing ORF7 of porcine reproductive and respiratory syndrome virus

Oral administration of attenuated Salmonella vaccine may provide valuable advantages such as low cost, easy preparation, and safety. Attenuated Salmonella vaccines also serve as carriers of foreign antigens and immunomodulatory cytokines. Presently, an attenuated Salmonella enterica serovar Typhimurium strain was used as a carrier for open reading frame 7 (ORF7) protein of porcine reproductive and respiratory syndrome virus (PRRSV), a swine pathogen of significant global economic importance. Initially, an attenuated S. enterica serovar Typhimurium expressing ORF7 gene derived from PRRSV Korean isolate was constructed. Following oral administration of a single dose of the attenuated Salmonella vaccine expressing PRRSV ORF7, humoral and cell-mediated immune responses specific for ORF7 were induced at both systemic and mucosal sites including spleen, mesenteric lymph node, Peyer's patch, and laminar propria, as evaluated by determining serum ORF7-specific IgG and mucosal IgA responses, as well as Th1- and Th2-type cytokine production from antigen-stimulated T cells. The induced humoral responses were sustained for at least 12 weeks post-immunization. In particular, the immunized mice displayed immune responses to both the foreign ORF7 antigen and Salmonella itself. The results indicate the value of attenuated S. enterica serovar Typhimurium as an oral carrier of PRRSV antigenic proteins to induce effective systemic and mucosal immunity.     

Administration of RRR‐α‐tocopherol to pregnant mares stimulates maternal IgG and IgM production in colostrum and enhances vitamin E and IgM status in foals

This study assessed the effect of a vitamin E supplement given to pregnant mares on immunoglobulins (Ig) levels in foals. In addition, the fatty acid (FA) content and composition of the mares’ milk was assessed. Milk α‐tocopherol concentrations were compared between pregnant Danish Warmblood mares (n = 17) given a daily oral supplement of 2500 international units (IU) RRR‐α‐tocopherol in the last 4 weeks of pregnancy and a group of unsupplemented mares (n = 17) receiving 170–320 IU vitamin E daily originating from the feed. Milk α‐tocopherol was higher in supplemented mares (36.7, 12.4 and 9.8 μmol/l respectively) in relation to control mares (13.1, 6.4 and 5.8 μmol/l on days 1, 2 and 3 respectively; p < 0.001). Milk IgG was higher on days 2 and 3 post‐partum (PP) in supplemented mares (1.03 and 0.73 mg/ml respectively) in relation to control mares (0.79 and 0.56 mg/ml respectively; p < 0.05). Milk IgM was higher on days 2 and 3 post‐partum (PP) in supplemented mares (0.19 and 0.17 mg/ml) in relation to control mares (0.13 and 0.11 mg/ml respectively; p < 0.05). Plasma α‐tocopherol in foals was higher from supplemented mares on days 1, 2 and 3 (5.7, 14.8 and 19.2 μmol/l respectively) in relation to foals from control mares (3.6, 6.1 and 7.6 respectively; p < 0.001). Foal plasma IgM was higher from supplemented mares on day 3 (0.50 mg/ml) in relation to foals from control mares (0.32 mg/ml; p < 0.001). The total FA content in milk was highest on day 1 (21.6 g FA/kg milk) in relation to days 2 and 3 (13.6 and 13.5 g FA/kg milk respectively; p < 0.001). In conclusion, a daily oral supplement of 2500 IU RRR‐α‐tocopherol increased α‐tocopherol content in mare milk and foal plasma, IgG and IgM in mare milk and IgM in foal plasma.