Spanish Purebred Horses Research Articles

Age- and Sex-Related Modifications of Hematology in Spanish Purebred Horse

The purpose of this study was to test the hypothesis that age and sex significantly modulate the changes in hematological parameters of physiologically healthy Spanish Purebred horse, establishing the reference values. Blood samples were obtained on a total of 159 horses (n = 77 males and n = 82 females), classified in four age groups: group A (1–2 years; n = 39), group B (>2–3 years; n = 38), group C (>3–4 years; n = 41), and group D (>4–7 years; n = 41). By means ADVIA 2020i, red blood cell (RBC), hemoglobin concentration (HB), packed cell volume, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration, platelets (PLTs), as well as total and differential white blood cells (WBCs) were determined. Total plasma protein was determined by spectrophotometry. Results obtained showed that sex had a limited influence on these parameters, being the HB higher in males and WBC higher in females (P = .047). Age caused a reduction in RBC, with a compensatory increase of MCV and MCH, decrease in WBC, PLT, lymphocytes (LYMPs), as well as an increase of N/L ratio (P = .047). Interactions between age and sex showed higher RBC in males than in females of the group B, and higher HB and WBC in males than in females of the group D. According to hematological data, Spanish Purebred horse was classified as a warm- or cold-blooded horse. Decline of RBC, WBC, and PLT parameters is a natural condition of horse with the advance of age, indicating a decrease of the narrow bone response.

Procaine Induces Hyperactivated Motility in Stallion Spermatozoa by Inhibiting Sodium Influx

Equine piroplasmosis (EP) is a tick-borne disease caused by Babesia caballi and Theileria equi, which causes severe economic losses to the equine industry, represented by the Spanish Purebred (SP) horse in Spain. The seroprevalence of EP is known in certain regions of Spain, but till date, there are no data in SP horses. The aim of this study was to determine the seroprevalence of EP in the SP breeding horse population in central Spain and to evaluate risk factors associated with the occurrence of the infection. A total of 536 horse serum samples were tested for antibodies against T. equi and B. caballi by competitive inhibition enzyme-linked immunosorbent assay. Data on possible risk factors were examined using two logistic regression models with and without a random effect at the stud farm level. The true seroprevalence results were 21.8% for T. equi and 4.7% for B. caballi. Increasing horse age and increasing numbers of breeding stallions on the stud farm were identified as factors associated with EP seropositivity. The implementation of vaccination programs in the horses and disinfection measures in the premises were associated with a lower T. equi and B. caballi seroprevalence, respectively. A moderate exposure to EP was found in SP horses in central Spain. Further investigations are necessary to ensure appropriate preventive measures for stud farms and to facilitate the development of an EP surveillance program in the SP breeding horse population.

Epidemiological Situation of the Exposure to Agents Causing Equine Piroplasmosis in Spanish Purebred Horses in Spain: Seroprevalence and Associated Risk Factors

Equine piroplasmosis (EP) is a tick-borne disease caused by Babesia caballi and Theileria equi, which causes severe economic losses to the equine industry, represented by the Spanish Purebred (SP) horse in Spain. The seroprevalence of EP is known in certain regions of Spain, but till date, there are no data in SP horses. The aim of this study was to determine the seroprevalence of EP in the SP breeding horse population in central Spain and to evaluate risk factors associated with the occurrence of the infection. A total of 536 horse serum samples were tested for antibodies against T. equi and B. caballi by competitive inhibition enzyme-linked immunosorbent assay. Data on possible risk factors were examined using two logistic regression models with and without a random effect at the stud farm level. The true seroprevalence results were 21.8% for T. equi and 4.7% for B. caballi. Increasing horse age and increasing numbers of breeding stallions on the stud farm were identified as factors associated with EP seropositivity. The implementation of vaccination programs in the horses and disinfection measures in the premises were associated with a lower T. equi and B. caballi seroprevalence, respectively. A moderate exposure to EP was found in SP horses in central Spain. Further investigations are necessary to ensure appropriate preventive measures for stud farms and to facilitate the development of an EP surveillance program in the SP breeding horse population.

Seroprevalence and factors associated with seropositivity to equine arteritis virus in Spanish Purebred horses in Spain.

Equine viral arteritis (EVA), a disease caused by infection with the equine arteritis virus (EAV), is present in many European countries. In Spain, the last confirmed outbreak was reported in 1992 and there is a paucity of seroprevalence studies. The disease has a major impact on the equine breeding industry, which is mainly represented by Spanish Purebred (SP) horses in Spain. To estimate the seroprevalence of EAV in the breeding SP horse population in central Spain and identify potential horse and studfarm level factors associated with seropositivity to EAV. Cross-sectional study. Individual serum samples from 555 SP horses, collected between September 2011 and November 2013 at 35 studfarms, were tested using a commercially available EAV antibody ELISA and seroneutralisation as the World Organisation for Animal Health reference confirmation test for samples with positive and equivocal results. Data on factors putatively associated with seropositivity to EAV were collected via a questionnaire and examined using random effects logistic regression for analysis of clustered data. Equine arteritis virus seroprevalence in the SP breeding population in central Spain standardised for the sex distribution of the reference horse population, was estimated to be 16.8% (95% confidence interval 5.2-28.5%). Increasing numbers of breeding mares on the studfarm and increasing percentage of mares with reproductive problems during the last 12 months were identified as being positively associated with EAV seropositivity. Mares vaccinated against Equine herpesvirus-1 (EHV-1) and/or -4 (EHV-4) were also positively associated with EAV seropositivity. These findings are of importance to ensure appropriate biosecurity measures for studfarms are carried out and may help facilitate the development of an EVA surveillance programme in the SP breeding horse population.

Prevalence and characteristics of osteochondrosis in 309 Spanish Purebred horses

Articular osteochondrosis (OC) is commonly reported in horses but there are no reports of its prevalence in the Spanish Purebred (SP). The objective of this study was to assess the prevalence and characteristics of OC of the tarsocrural, dorsal metacarpo-metatarsophalangeal and femoropatellar joints in the SP in a retrospective study. The data were obtained from the radiographs of 309 SP horses and the prevalence and characteristics of lesions were calculated.Osteochondral lesions at predilected sites were diagnosed in 48.8% of the horses. It was more common to find the presence of fragments (28.8%) than flattening of the subchondral bone contour (20.1%). The percentage with abnormal articular margins was 1.3% for the femoropatellar joint, 33.3% for the tarsocrural and 25% for the dorsal fetlock region, where flattening was more common than the presence of fragments; in the tarsus and stifle, fragments were more common. The severity of the disease in the dorsal fetlock area was higher in hindlimbs than in forelimbs. Femoropatellar lesions were rare. Osteochondrosis is a common disease in the SP and this study provides information about the prevalence of osteochondrosis lesions in the breed and the interrelationships between the joints.

Sire × stud interaction for body measurement traits in Spanish Purebred horses1

The mating policy for Spanish Purebred horses encourages the same or closely related stallions to be used for reproduction across studs differing in environments. Stallions may perform differently across studs, and if so, adjustment for the sire x stud (ss) interaction is recommended. However, there are no studies available that analyzed the influence of ss interaction on estimation of genetic parameters in horses. This research is aimed at assessing the implications of including ss interaction in models fitted for the estimation of genetic parameters for traits under selection using 8 body measurements in Spanish Purebred (Andalusian) horses: height at withers, height at chest, leg length, body length, width of chest, heart girth circumference, knee perimeter, and cannon bone circumference. Body measurements were available for 11,894 horses. Genetic parameters and EBV were estimated using animal models by REML. The inclusion of the ss interaction gives reduced estimates of heritability. Generally, the genetic correlations estimated using the models including the ss interaction were greater than those obtained using the simpler model. Estimates for the ss variance as a proportion of the total phenotypic variance ranged from 0.02 (height at withers) to 0.11 (width of chest). Estimates between the ss interaction correlations associated with each body measurement were positive, significant, and from moderate to low. The range of EBV estimated using the model including the ss interaction decreased with respect to those estimated using the simpler model, and the EBV ranking order was affected. The models including ss interaction fitted significantly better. Therefore, the genetic parameters estimated using the ss interaction may be more realistic, and the obtained (co)variances may be assumed to be closer to the true population parameters. This interaction may result from selective decisions or preferential management practices causing greater similarity between the progeny of a sire in the same stud. It is therefore advisable to include it in genetic models used in horse breeding schemes.

Assessment of inbreeding depression for body measurements in Spanish Purebred (Andalusian) horses

Our aim was to ascertain inbreeding depression in the Spanish Purebred horses for eight body measurements. A total of 16,472 individuals were measured for height at withers, height at chest, leg length, body length, width of chest, heart girth circumference, knee perimeter and cannon bone circumference. Three different multivariate animal models including, respectively, no measure of inbreeding, individual inbreeding coefficients ( F i ) or individual increase in inbreeding coefficients (Δ F i ) as linear covariates were used. Significant inbreeding depression was assessed. Even though the models including measures of inbreeding fitted better with data, no effect on estimates of genetic parameters was assessed. However, the inclusion of inbreeding measures affected the ranking order according to the Expected Breeding Values (EBV). Due to the better fit with data and nice properties (the adjustment of individual inbreeding coefficients with the pedigree depth and linear behaviour) the use of Δ F i in the evaluation models can be recommended for morphological traits in horses.

Multiple generalized follicular cysts in a stallion

This case report describes a case of multiple follicular cysts in a 4-year-old Spanish purebred stallion. The lesions ranged in size from 0.5 to 3 cm in diameter, and were firm, well circumscribed and nonpruritic. They developed over a 2-year period with a generalized distribution affecting all body regions. Five nodules were removed and histopathologically corresponded to simple epidermal cysts (infundibular and isthmus-catagen) with squamous epithelium and a keratin filled cavity. Lesions were not evident at birth but their number, early age of detection, slow growth and lack of previous trauma suggested that they were congenital. To the authors' knowledge, this condition has not previously been reported either in young horses or in Spanish purebred horses.

Genetic parameters of biokinematic variables of the trot in Spanish Purebred horses under experimental treadmill conditions

The purpose of this study was to estimate the genetic parameters of biokinematic variables in Spanish Purebred (SPB) horses in order to select those of sufficient interest to be measured in the pre-selection of the animals for possible inclusion in the breeding programme. Kinematic analysis of 130 SPB horses 4.6 ± 1.5 years old were recorded at the trot (4 m/s) on a treadmill. Genetic parameters were estimated using VCE software and a bivariate mixed animal model including age and stud as fixed effects and animal additive genetic effect and residual error as random effects. In general, heritabilities were high (0.33–0.88). The angular variables presented the lowest heritabilities, whereas the maximum height of the fore-hoof and the duration of swing phase in the hindlimb gave the highest scores. Genetic correlations were also very high, so it was possible to reduce the number of breeding programme characteristics to stride duration, hindlimb swing phase duration, range of stifle and elbow angles, minimal angle of carpus, and minimal retraction-protraction angle of the hindlimb.