l-carnitine enhances the kinematics and protects the sperm membranes of chilled and frozen-thawed Peruvian Paso horse spermatozoa.

l-carnitine (LC) transports fatty acids to the mitochondria for energy production, reducing lipid availability for peroxidation through ß-oxidation. This research examines the effect of LC supplementation to two skimmed milk-based extenders on the cryosurvival of chilled (5°C) and frozen-thawed Peruvian Paso horse spermatozoa .An initial experiment determined the optimal LC concentration (0, 1, 5, 10, 25, and 50 mM) when added to INRA-96® and UHT (skimmed milk + 6% egg yolk) extenders, using nine ejaculates from three stallions chilled for up to 96 h. Subsequently, the effect of 25 mM LC supplementation (the optimal concentration) on chilling (INRA-96) and freezing (INRA-Freeze®) extenders was evaluated using eight pooled samples from sixteen ejaculates (2 ejaculates/pool) from four stallions. Results indicated that all LC concentrations produced significantly higher values (P<0.05) for kinematic variables (total [TM] and progressive motilities, curvilinear [VCL] and straight-line [VSL] velocity, and beat-cross frequency [BCF]), and the integrity of plasma/acrosome membranes (IPIA) compared to non-supplemented chilled sperm samples for up to 96 h with both extenders. Moreover, the use of 25 mM LC was more efficient (P<0.05) in preserving the post-chilled values of velocity, BCF, and IPIA for the long term than lower LC concentrations (1-10 mM). Post-thaw values of total motility, the amplitude of lateral head displacement (ALH), and IPIA were significantly improved (P<0.05) when INRA-Freeze extender was supplemented with 25 mM LC. In conclusion, supplementation of l-carnitine to skimmed milk-based extenders enhanced kinematic variables and protected the membrane integrity in chilled and frozen-thawed Peruvian Paso horse spermatozoa.

Effect of Melatonin and Caffeine Supplementation to Freezing Medium on Cryosurvival of Peruvian Paso Horse Sperm Using a Two-Step Accelerating Cooling Rate.

This research examined the antioxidant and cryoprotective effects of melatonin (ME) and caffeine (CAF) supplementation in freezing medium on the cryosurvival of Peruvian Paso horse sperm using a two-step accelerating cooling rate. Twenty ejaculates from four adult and fertile stallions were recovered, initially diluted with INRA-96®, and finally frozen with INRA-Freeze® with either no supplementation (as control), 1 µM ME, or 2 mM CAF using a two-ramp freezing system content inside a cryogenic-box and liquid nitrogen vapors. The sperm kinematic parameters and integrity of the plasma and acrosomal membranes of fresh semen and cryopreserved samples were evaluated using the CASA system (SCA-Evolution® 2018) and PI/fluorescein isothiocyanate-conjugated peanut (Arachis hypogaea) agglutinin double fluorescent test, respectively. The oxidative stress of post-thaw sperm samples was also assessed using the CellRox Deep Red fluorescence test. The results showed that curvilinear velocity and average-path velocity were greater (p < 0.05) after freezing with CAF than the control group. In addition, there were significance differences (p < 0.01) between stallions (1-4) in post-thaw kinematic parameters regardless of ME or CAF addition. Both ME and CAF improved (p < 0.05) the proportion of sperm with intact plasma membranes and intact acrosomes. Nevertheless, neither CAF nor ME improved the oxidative stress after the cryopreservation process.

Determination of Positional Parameters of the Distal Phalanx Within the Hoof Capsule in Sound Colombian Paso Horses.

The economic relevance, populational importance and expansion of the Colombian Paso Horse to other latitudes calls for a growth in studies based on this type of horse. Lack of written reports about the relationship of the distal phalanx (DP) within the hoof in this gaited horse makes it important to establish a baseline to determine hoof health and possible alterations. The purpose of this study was to report, for the first time, the positional parameters of the distal phalanx, and its relationship within the hoof in sound Colombian Paso Horses. A latero-medial radiographic image of each digit was taken in 45 horses between 3 and 5 years old, distributed into groups according to the gaits determined by FEDEQUINAS. Three angles and three distances were measured. The dorsal wall thickness (W-T) was measured proximally and distally, and the sole depth (P-S) was measured dorsally and palmarly/plantarly. As expected, these distances showed moderate to strong positive correlations in front (W-Tp/W-Td r = 0.53; P-Sd/P-Sp r = 0.72) and hind feet (W-Tp/W-Td r = 0.61; P-Sd/P-Sp r = 0.71). The palmar/plantar angle of the distal phalanx (PA) and sole depth (P-S) showed that the distal phalanx of the hind feet is flatter compared to the front. The results of this study show differences in the positional parameters of distal phalanx compared to other breeds of horses and provides information for veterinarians and farriers working with Colombian Paso Horses.

Body fat evaluation in Colombian Paso horses: body condition score and morphometric and ultrasound measurements / Avaliação da gordura corporal em equinos Paso colombianos: escore de condição corporal e medidas morfométricas e ultrassonográficas

The body condition score (BCS) is insufficient in determining the amount of body fat in horses, thus defining obesity. Measurement of the subcutaneous fat thickness (SFT) by ultrasonography should be considered as an appropriate method in the definition of fat distribution at different body locations in horses. Therefore, this study aimed to 1) characterize the SFT in three different anatomical locations (i.e. neck, lumbar region, and gluteal region); 2) evaluate the relationship between BCS and SFT; 3) determine the influence of gender, weight, age, and gait on BCS and SFT measurements, and 4) explore the agreement between the morphometric measurements [i.e. body mass index (BMI), girth circumference: height at withers ratio (GC: HW), neck circumference: height at withers ratio (NC: HW)], and BCS and SFT in a population of Colombian Paso Horses (CPHs). The Henneke's body condition scoring was applied to 69 adult CPHs, selected using a convenience sampling. Additionally, BMI, GC: HW, and NC: HW were calculated. Body fat percentage (BF%) was calculated by ultrasound measurement of the SFT in the neck, lumbar region, and gluteal region. The BF% in the CPHs was 6.4 ± 1.1. The GC: HW, NC: HW, and BMI were not predictors of the BF% or BCS, and neither gender nor gait was decisive in the definition of fattening in the study animals, although age and weight were determining variables. According to our results, ultrasound is an adequate tool to calculate the BF% of the CPHs. However, it must be accompanied by Henneke's BCS assessment.(AU)

O escore de condição corporal (ECC) é insuficiente para a determinação da quantidade de gordura corporal em cavalos e para a definição da obesidade. A mensuração da espessura da gordura subcutânea (EGS) por ultrassonografia pode ser considerada um método apropriado para a definição da distribuição de gordura em diferentes locais do corpo em cavalos. Portanto, este estudo teve como objetivo 1) caracterizar a EGS em três diferentes localizações anatômicas (pescoço, região lombar e região glútea), 2) avaliar a relação entre ECC e EGS, 3) determinar a influência de gênero, peso, idade e marcha nas medidas ECC e EGS e, 4) explorar a concordância entre as medidas morfométricas [i.e. índice de massa corporal (IMC), razão da circunferência da cintura:altura da cernelha (CC:AC), razão da circunferência do pescoço:altura da cernelha (CP:AC)], ECC e EGS em uma população de Cavalos Paso colombiano (CPCs). A pontuação da condição corporal de Henneke foi aplicada a 69 CPCs adultas, selecionadas por amostragem de conveniência. Além disso, IMC, CC:AC e CP:AC foram calculados. O percentual de gordura corporal (%GC) foi calculado por meio da ultrassonografia da EGS no pescoço, região lombar e região glútea. A %GC nas CPCs foi de 6,4 ± 1,1. O CC:AC, CP:AC e IMC não foram preditores da %GC ou ECC, e nem o gênero nem a marcha foram decisivos na definição de obesidade nos animais do estudo, embora a idade e o peso fossem variáveis determinantes. De acordo com nossos resultados, o ultrassom é um recurso adequado para calcular a %GC das CPCs. No entanto, deve ser acompanhado pela avaliação do ECC do Henneke.

Cryopreservation of Peruvian Paso horse spermatozoa: dimethylacetamide preserved an optimal sperm function compared to dimethyl sulfoxide, ethylene glycol and glycerol.

The objective was to evaluate the effect of different cryoprotectant agents in the cryopreservation of Peruvian Paso horse semen. Twenty semen samples were collected from five Peruvian Paso horse stallions. Each sample was divided into 12 parts to form the groups: dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol (GLY), at 3%, 4% and 5%. Samples were frozen using a rate-controlled freezer. Sperm parameters evaluated were motility and viability/acrosomal status. After thawing, progressive motility in DMA group was higher (p < .05) than in DMSO, EG and GLY groups. Similarly, viable acrosome-intact spermatozoa were higher (p < .05) using DMA in comparison with DMSO. No differences were found when comparing concentrations for any of the cryoprotectant agents. In conclusion, DMA seems to be a good cryoprotectant agent for the cryopreservation of Peruvian Paso horse stallion semen.