In dieser Arbeit wurde das Signalement, die Jahreszeit bei Klinikeinweisung, die Diagnose, die Operationstechnik, die Operationskomplikationen und der Therapieerfolg von laparotomierten Fohlen im Alter bis zu einem Jahr ausgewertet. Grundlage war das Patientengut der Chirurgischen Tierklinik der Universität Leipzig in den Jahren 2001 bis 2011. Neben intestinalen Erkrankungen wurden auch extraintestinale Erkrankungen involviert.

While forage plays an important role in equine nutrition, little research has been conducted evaluating fiber utilization by young horses. Therefore, studies were conducted to compare in vivo digestibility and digesta passage in weanlings and mature horses (Exp 1) and yearlings and mature horses (Exp 2). All horses were fed forage-based diets at the same rate (on a metabolic BW basis; Exp 1: 67% alfalfa cubes, 33% concentrate; Exp 2: 75% timothy cubes, 25% concentrate). Ytterbium labeled hay and cobalt-ethylenediaminetetraacetic acid were used to estimate digesta mean retention time (MRT), while in vivo digestibility (DM, OM, and NDF) was measured using a total fecal collection method. Feed and water intake was similar between young and mature horses in both experiments. In Exp 1, there were no differences in digestibility or MRT due to age. The results suggested that weanling horses are capable of digesting a relatively high quality diet as efficiently as mature horses and that most of the development of the gastrointestinal tract occurs before 6 mo of age. In Exp 2, digestibility estimates were greater (P < 0.0311) for the yearlings than for the geldings. The increased digestive capacity of the yearlings was likely due to the longer MRT observed for the particulate phase in the yearlings (P = 0.0190). A third study was conducted to compare the microbial profiles of the feces of mares and foals. Fecal samples were collected from mare-foal pairs as the foal matured. The profiles of each pair, obtained using polymerase chain reaction-denaturing gradient gel electrophoresis, were compared and used to describe bacterial colonization in the foal. Mean similarity between mares and their foals on the day of parturition was low, but rapidly increased. Within 2 wk of parturition, similarity among mares and their foals was higher than among mature mares, suggesting that by 2 wk of age the bacterial species found in the foals’ gut are similar to those found in the mature horse. Collectively, the results from this series of experiments describe the early development of the foal’s digestive capacity.

Evaluation of movement mechanics of warmblood foals in gait and trot. Czech warmblood in comparison with dutch warmblood

O trabalho teve como objetivo compreender o relacionamento entre a égua e o potro e a influência deste sobre o comportamento social e temperamento do potro, a partir do décimo primeiro dia de vida até após o processo de desmama do potro. Oito díades de éguas e potros da raça Mangalarga Marchador provenientes de um criatório situado na cidade de Amparo/SP foram avaliadas durante três etapas distintas. A primeira foi realizada para caracterizar o comportamento social do grupo de equinos e o relacionamento entre égua e potro durante os três períodos de desenvolvimento do potro (dependência, socialização e independência). Nessa etapa foram registradas: as interações agonísticas das éguas; episódios de mamada dos potros (tentativas e mamadas) e para o par égua e potro foram anotados os comportamentos afiliativos e a relação espacial. Ao final dessa etapa os potros foram classificados em dependentes e independentes e as éguas foram divididas de acordo com sua hierarquia. A segunda etapa constitui-se da avaliação das atividades e relação espacial dos potros durante o processo de desmama, para a caracterização do estresse dos potros. Na terceira etapa a relação social dos potros foi observada na ausência de suas mães, através do registro das interações e da relação espacial dos potros. Durante as três etapas foram aplicados quatro testes de avaliação dos aspectos do temperamento dos animais: teste de reatividade durante o manejo de escovação para a avaliação da reatividade ao manejo; teste de arena para avaliar a emotividade ao isolamento; teste de reatividade perante humano desconhecido e ativo para avaliar a reatividade ao humano; e teste da presença de estímulo sonoro desconhecido para avaliação da emotividade ao estímulo desconhecido. A hierarquia e a experiência da mãe interferiam no cuidado materno de aleitamento (P&LT;0,05), entretanto, não influenciaram o cuidado de proteção (P&GT;0,05). A frequência de permanência dos potros com sua mãe na distância de até 1 metro diminuiu ao longo dos períodos (P&LT;0,05). As éguas não modificaram a frequência dos comportamentos afiliativos com seus potros ao longo dos períodos (P&GT;0,05). As maiores frequências de comportamentos afiliativos dos potros com suas mães foram durante os períodos iniciais do desenvolvimento do potro (dependência e socialização, P&LT;0,05). Potros dependentes apresentaram maior frequência e menor duração das mamadas quando comparado à frequência e duração dos potros independentes (P&LT;0,05). A reatividade ao manejo e a emotividade ao isolamento dos potros foram maiores nos períodos da dependência, da socialização e durante a desmama (P&LT;0,05). A reatividade ao humano e emotividade ao desconhecido apresentaram a tendência de diminuir ao longo dos períodos observados (P&LT;0,05). Os potros dependentes apresentaram maior emotividade ao desconhecido e ao isolamento (P&LT;0,05), além de maior estresse durante a desmama, quando comparado aos potros independentes. Todos os potros normalizaram suas atividades no decorrer do processo da desmama. Na ausência das mães os potros independentes foram os que iniciaram a maioria das interações entre os animais (P&LT;0,05). O relacionamento entre a égua e o potro foi modificado devido às características maternas de hierarquia e experiência, além do nível de independência do potro e do seu temperamento. / The study aimed to understand the relationship between the mare and the foal and the influence of this on the social behavior and foal\'s temperament from the eleventh day of life until after the foal weaning process. Eight dyads of mares and foals Mangalarga Marchador from a farm situated in the city of Amparo/Brazil were evaluated during three different stages. The first stage was performed to characterize the social behavior of horses group and the relationship between mare and foal during the three foal developmental periods (dependency, socialization and independence). At the first stage the aggressive interactions of the mares were registered; episodes of sucking of foals (attempt and bout of sucking); and the pair mare and foal were noted the affiliative behaviors and spatial relationship. At the end of this stage the foals were classified as dependent and independent and mares were divided according to their hierarchy. In the second step we evaluated the activities and spatial relationship of foals during the weaning process, to characterize the stress of foals during this process. In the third stage the social relationship of foals was observed in the absence of their mothers, through the recording of interactions and the spatial relationship of the foals. During the three stages were applied four tests for assessing aspects of animal temper: reactivity test during brushing for evaluation of reactivity handling; arena test to evaluate the emotionality isolation; human reactivity test unknown and active to assess the reactivity to human; and test for the presence of unknown sound stimulus to evaluate the emotionality of the unknown stimulus. The hierarchy and the mother\'s experience interferes with maternal care of lactation (P&LT;0.05), but did not influence the protective care (P&GT;0.05). The frequency of stay of foals with mother at a distance of up to 1 meter decreased over the period (P&LT;0.05). The mares do not change the frequency of affiliative behaviors with their foals (P&GT;0.05). The highest frequency of affiliative behaviors foals with their mothers were during the early periods foal development (dependency and socialization; P&LT;0.05). The dependent foals presented a higher frequency and shorter duration of sucking bouts when compared to the frequency and duration of foals independent (P&LT;0.05). The reactivity handling and emotionality isolation of foals were higher in dependency periods, socialization and during weaning (P&LT;0.05). The reactivity of human and emotionality of the unknown showed a tendency to decrease over the observed periods (P&LT;0.05). The dependent foals showed larger emotionality to the unknown and isolation (P&LT;0.05). The dependent foals showed greater emotionality to the unknown and isolation (P&LT;0.05) as well as increased stress during weaning when compared to independent foals. All foals normalized its activities during the weaning process. After separation independent foals were those who started most interactions between animals (P&LT;0.05). The relationship between the mare and the foal was modified due to maternal characteristics hierarchy and experience, beyond the temperament of foal and independence level of the foal.

The prevalence of carriers of three genetic disorders, severe combined immunodeficiency, lavender foal syndrome and cerebellar abiotrophy, in registered, purebred Arabians in South Africa was assessed. Genotyping for the three disorders was performed on individuals randomly selected from two populations: purebred Arabian horses born in South Africa during the intervals 1 August 2004 to 31 July 2005 and 1 August 2009 to 31 July 2010, in line with physiological breeding seasons. This permitted an estimation of the change in prevalence of each disorder between 2004 and 2009, during which time compulsory testing for SCID, and selective breeding based on the results thereof, was performed. The prevalence of lavender foal syndrome and cerebellar abiotrophy for the 2009 breeding season was found to be 11.7% (95% confidence interval [CI] 7.80 – 16.37) and 5.1% (95% CI 2.56 – 8.69) respectively, with no statistically significant change in the prevalence of these disorders between 2004 and 2009. Utilizing a larger sample size, the prevalence of severe combined immunodeficiency was found to have decreased significantly from 6.4% (95% CI 6.05 – 6.78) in 2004 to 3.4% (95% CI 2.67 – 4.23) in 2009 (P < 0.0001). These results will encourage the genetic screening of Arabian horses intended for breeding purposes in order to prevent the birth of clinically affected individuals. This study also highlights the usefulness of genetic testing as a tool to decrease the prevalence of specific genetic disorders within animal populations. / Dissertation (MSc)--University of Pretoria, 2012. / Production Animal Studies / unrestricted

Insulin sensitivity decreases during pregnancy, presumably an adaptation ensuring sufficient glucose supply to feto-placental tissues. Feeds high in non-structural carbohydrates are also linked to diminished insulin sensitivity in horses. Because the equine fetus is highly glucose reliant, maternal glucose and insulin dynamics during pregnancy may have implications for optimal fetal development in horses. Mismanagement of maternal nutrition during gestation could predispose the offspring to metabolic disorders (e.g. insulin resistance) later in life. In horses, insulin resistance is associated with increased risk for development of laminitis. These studies measured insulin sensitivity and glucose dynamics in pregnant and non-pregnant mares fed high sugar and starch (SS) or high fat and fiber (FF) feeds, as well as neonatal foals born from pregnant mares fed SS and FF feed. Insulin modified frequently sampled intravenous glucose tolerance tests (FSIGT) were applied to pregnant Thoroughbred mares (n = 22) at 28 ± 3 wks (Period 1) and 47 wks (Period 2) gestation, as well as non-pregnant mares (n=10) measured simultaneously. Following the first FSIGT mares were fed SS or FF feed for the remainder of the study. After 11 wks adaptation to feeding, a subset of mares were evaluated with hourly blood samples for 24 h to assess glycemic and insulinemic response to three times daily feeding while on pasture. Neonatal foal FSIGTs (n=20) were conducted at 5 ± 1 d of age. The minimal model of glucose and insulin dynamics was used to determine insulin sensitivity (SI), glucose effectiveness (Sg), acute insulin response to glucose (AIRg) and disposition index (DI). Pregnant mares during Period 1 exhibited lowered SI, Sg and elevated AIRg relative to non-pregnant mares. Pregnant mares demonstrated greater glycemic and insulinemic responses to feeding of both SS and FF meals than non-pregnant mares consuming the same feeds. Also, SS feed elicited greater glycemic and insulinemic areas under the curve following feeding than FF feed in pregnant mares. These data support that pregnancy in mares in associated with lowered SI by 28 wks gestation and that altered SI, Sg and AIRg are associated with different responses to consuming SS and FF feeds. Foals exhibited high basal glucose, basal insulin, SI and Sg relative to mature horses, indicating a large capacity for glucose uptake with or without insulin. Basal glucose concentrations were higher and basal insulin concentrations tended to be higher in SS than FF foals (P = 0.016 and P = 0.071, respectively). Glucose and insulin dynamics in late gestation mares and neonatal foals exemplify the adaptive nature of energy metabolism in horses. Furthermore, dietary energy composition affects glucose and insulin responses to feeding in late gestation mares, which in turn was associated with different basal blood concentrations of these variables in the resulting neonatal foals. / Master of Science

Although Rhodococcus equi (R. equi), previously known as Corynebacterium equi, was first isolated from pneumonic foals almost a century ago, it remains the most common cause of subacute or chronic granulomatous bronchopneumonia in foals. While the majority of foals exposed to R. equi develop a protective immune response (regressors), others exhibit a unique susceptibility to infection (progressors). The determinants for either outcome are not completely understood. Therefore, current diagnostic and preventive measures are suboptimal and require betterment. In light of this current need, we hypothesized that immunoglobulin G subisotype T [IgG(T)] against the virulence-associated protein A (VapA) of R. equi, and whole blood cytokine expression profile of foals predict the outcome of infection and can be used as diagnostic markers of clinical disease. Further, we hypothesized that the use of R. equi hyperimmune plasma (HIP) decreases severity of disease in naturally infected foals, playing an important role in disease prevention in the field. Lastly, we hypothesized that specific anti-Rhodococcus equi pili antibodies passively acquired by foals via colostrum after immunization of pregnant mares with a Rhodococcus equi pili-based candidate vaccine will confer protection against induced disease, and therefore have an immediate impact on R. equi pneumonia prophylaxis. The objectives of this study were: (1) to describe the humoral immune response of progressor and regressor foals to R. equi following experimental challenge and natural infection, (2) to compare the cytokine and cell-marker expression profile in whole blood of progressor and regressor foals after challenge, (3) to evaluate the Vap-A specific IgG profile of a commercially available HIP product and its value as a prophylactic tool on an endemic farm, and (4) to evaluate the efficacy of a vaccine based on the Rhodococcus equi pili (Rpl). Although the IgG(T) response of progressor foals after challenge or following natural infection tended to be more pronounced than that observed in regressor foals, its performance as a diagnostic test for predicting disease outcome was poor. Likewise, whole blood cell-marker and cytokine expression profiles of progressor and regressor foals were not significantly different, undermining its reliability as a diagnostic tool. Evaluation of the association of HIP VapA specific IgG profile and rhodococcal disease outcome in the field resulted in the conclusion that progressor foals received significantly less VapA specific IgG, suggesting that HIP may have provided some protection to regressor foals. Although HIP appeared to have provided some protection against clinical pneumonia, Rpl maternally-derived IgG failed to confer any advantage to foals born from vaccinated mares. The Rpl candidate vaccine failed to confer protection to foals after challenge, and did not decrease disease severity in comparison to a control group. In summary, the results of this study do not support the use of VapA specific IgG(T) or whole blood cytokine expression profile as predictors of disease outcome. Further, our results suggest a positive effect of HIP on disease outcome. Lastly, the presence of systemic and local Rpl antibodies was not protective in foals.

Background: Almost all foals develop transient diarrhoea within the first weeks of life. Studies indicated different viral, bacterial, and parasitic causes, such as rotavirus, Clostridium perfringens, Escherichia coli, and Cryptosporidium are discussed. But little is known about the development of intestinal microflora in foals. The present study investigated whether the supplementation with Bacillus cereus var. toyoi would modify the developing intestinal microflora and consequently reduce diarrhoea in foals. From birth, the foals were randomly assigned to three treatment groups: placebo (10 mL isotonic NaCl, n = 8), low dosage (LD; 5 × 108 cfu B. cereus var. toyoi, n = 7) and high dosage (HD; 2 × 109 cfu B. cereus var. toyoi, n = 10). Treatment groups were supplemented orally once a day for 58 days. Faeces scoring and sampling were performed within the first 24 h after birth and on day 9, 16, 23, 30, 44, 58 of the foal’s life and also on the first day of diarrhoea. Culture-plate methods were used to analyse the bacterial microflora. Results: Eighty-eight per cent of the foals developed diarrhoea (placebo 7/8, LD 5/7, HD 10/10) during the first 58 days of life. Bacillus cereus var. toyoi supplementation had no effect on bacterial microflora. Clostridium perfringens and enterobacteria were equally prevalent in foals with diarrhoea and those who were not afflicted. Conclusions: We conclude that the supplementation of B. cereus var. toyoi had no effect on the occurrence of diarrhoea and health status in the foals.

In dieser Arbeit wurde das Signalement, die Jahreszeit bei Klinikeinweisung, die Diagnose, die Operationstechnik, die Operationskomplikationen und der Therapieerfolg von laparotomierten Fohlen im Alter bis zu einem Jahr ausgewertet. Grundlage war das Patientengut der Chirurgischen Tierklinik der Universität Leipzig in den Jahren 2001 bis 2011. Neben intestinalen Erkrankungen wurden auch extraintestinale Erkrankungen involviert.

Kentucky 31 tall fescue (KY31) infected with the common toxic endophyte strains of Epichloё coenophiala produces toxic alkaloids that improve plant vigor, but cause numerous adverse effects in grazing animals. Researchers developed a variety of KY31 containing an alternative strain of E. coenophiala, termed novel endophyte (NE). Adverse health effects in mares have not been evaluated. Experiments in this thesis tested the hypothesis that the NE pasture does not cause adverse effects typically associated with KY31. Specific aims were to: 1) compare forage ergovaline concentrations between KY31 vs NE pastures; 2) evaluate palmar artery diameters in mares grazing KY31, NE, or orchardgrass-bluegrass (OGBG) pastures; 3) determine mare serum prolactin, estradiol, and progesterone concentrations associated with ingesting each pasture type over time; and 4) measure foaling outcomes, including percentage of live foals, foal birth weights, and foal growth rates. In 2015, six nonpregnant mares grazed KY31, six pregnant mares grazed NE and six pregnant mares grazed OGBG pastures. In 2016, eighteen mares were used; six mares grazed each pasture type. Study results showed that ergovaline did not appear to be produced by NE. Novel endophyte pasture did not have negative effects on palmar artery diameter, reproductive hormones, or foaling outcomes.