Supplemental fat in the diet of horses...is it advantageous?

Feeding fat-supplemented diets to horses has drawn considerable interest. One of the advantages of such diets is that the energy density is increased, so that less feed is needed to meet energy requirements. In addition, adding fat to the diet enhances the contribution of fat oxidation to energy production, thus sparing muscle glycogen. The 'spared' glycogen is available for energy metabolism when the acutely exercising horse reaches a point of oxygen deficit and must rely on anaerobic metabolism. This appears to be beneficial for both aerobic and anaerobic performance. Fats are readily digested by the horse. Vegetable oils are more palatable to horses than animal fats, but the palatability of fat-rich diets may decrease in the long term.     

Fragmented coronoid process in the dog: is there a role for incongruency?

Fragmented coronoid process in the dog is a common yet frustrating and poorly understood condition. Elbow joint incongruency, which refers to malalignment of the joint surfaces of the elbow, has been proposed as a key factor in the pathogenesis of fragmented coronoid process, and various surgical procedures have been devised to treat the proposed incongruency. However, precise characterisation of incongruency present in cases of fragmented coronoid process has not been reported consistently. In this article, the literature relating to the pathogenesis of fragmented coronoid process, the role of incongruency and its implications are reviewed.     

Pathophysiology of abomasal parasitism: is the host or parasite responsible?

Nematode larvae developing within the glands cause local loss of parietal cells and mucous cell hyperplasia whereas reduced acid secretion, increased serum gastrin and pepsinogen concentrations and generalized histological changes are associated with parasites in the abomasal lumen. Parietal cells with dilated canaliculi and/or degenerative changes typical of necrosis are present soon after the transplantation of adult worms, and abomasal secretion is also affected. Anaerobic bacteria survive in greater numbers as the pH rises, with bacterial densities becoming similar to ruminal populations at an abomasal pH of 4 and above. Failure to lyse bacteria may affect adversely the nutrition of the host. The parasites may initiate the pathophysiology through the release of excretory/secretory (ES) products which either act directly on parietal cells or indirectly through enterochromaffin-like (ECL) cells by provoking inflammation or by disrupting the protective mucosal defence system.Parietal cell dysfunction is proposed as a key event which leads to loss of mature chief cells and mucous cell hyperplasia, as well as hypergastrinaemia. Inflammation increases circulating pepsinogen concentrations and may also contribute to increased gastrin secretion. Stimulation of mucosal proliferation and differentiation of parietal cells in the isthmus by the raised serum gastrin levels will be beneficial by generating a new population of active parietal cells and adequate acid secretion.     

Trends in the management of horses referred for evaluation of colic: 2004–2017

The financial crisis of 2008 had effects on veterinary practice, with falling turnovers associated with reluctance of owners to spend money on veterinary care. There were anecdotal reports that fewer horses were undergoing colic surgery. The aims of this study were to document the numbers of horses with colic being referred to, and undergoing surgery and/or euthanasia, at two equine hospitals (a university based equine hospital in the United States [NC State] and a private equine hospital in the UK [Bell Equine]) over a 14-year period (2004–2017). There was a trend of declining total yearly equine accessions at NC State starting in 2009, followed by an increase starting in 2012. At Bell Equine, total accessions showed an increasing trend from 2004 to 2015, followed by a slight decline in 2016 and 2017. The proportion of equine accessions that were colics varied from around 15% to 20% at both hospitals and did not show any notable variations over the time period studied. Both practices showed a trend of decreasing colic admissions undergoing and recovering from surgery starting from 2007 to 2008. The numbers and percentages of colic admissions that were subjected to euthanasia increased from 2004/2005 to 2014/2015 in both hospitals; there was a greater increase in numbers being subjected to euthanasia at surgery at NC State, compared to a greater increase in numbers being subjected to euthanasia without surgery at Bell Equine. At both hospitals, there was a trend of increasing mean invoice totals over the study period. The results show that there has been a trend of decreasing numbers of horses undergoing surgical treatment for colic since 2004/2005. This is likely to be, at least partly, due to the financial crisis of 2008, although other factors, including the high costs of surgery and the ageing equine population may also be important.     

Changes in eggshell structure and predisposition of broilers to health problems: is there a common pathophysiology?

1. A study of broiler breeder eggs differing in eggshell matrix optical density was conducted to determine the association of eggshell structural quality and the risk of disease in broilers.

2. A total of 10 000 eggs from a broiler breeder flock were examined according to the pre-established criteria, and allocated to groups classified as having a high or low density shell matrix.

3. The eggs from respective groups were incubated and hatched in a commercial hatchery. Samples of unhatched eggs from each group were subjected to detailed examination to establish the cause of reproductive failure. First, quality chicks from each group were raised as separate flocks in a commercial broiler barn. Group performance, morbidity, and mortality were monitored throughout the growth period. All birds were processed in a commercial plant, and condemnation data were compiled.

4. There were significantly more unhatched eggs, and fewer quality chicks in the group classified as having a low density eggshell matrix, in comparison to the high-density group.

5. Embryo pathology accounted for a large proportion of the overall reproductive failure in both groups, with a large proportion of embryos showing anatomical anomalies. The eggs and embryos from the low-density eggshell matrix group were three times more likely to be infected.

6. Significantly higher production losses associated with mortality/morbidity, and condemnations of carcasses at processing were observed in broilers from the low-density eggshell group compared with the high-density eggshell group.

7. It is concluded that common metabolic/physiological changes in breeder hens associated with eggshell pathology may be also risk factors linked with predisposition of broiler chicks to some health problems.

     

Cartilage matrix changes in the developing epiphysis: early events on the pathway to equine osteochondrosis?

REASONS FOR PERFORMING STUDY: The earliest osteochondrosis (OC) microscopic lesion reported in the literature was present in the femorotibial joint of a 2-day-old foal suggesting that OC lesions and factors initiating them may arise prior to birth. OBJECTIVE: To examine the developing equine epiphysis to detect histological changes that could be precursors to OC lesions. METHODS: Osteochondral samples from 21 equine fetuses and 13 foals were harvested from selected sites in the scapulohumeral, humeroradial, metacarpophalangeal, femoropatellar, femorotibial, tarsocrural and metatarsophalangeal joints. Sections were stained with safranin O and picrosiruis red to assess cartilage changes and structural arrangement of the collagen matrix. RESULTS: Extracellular matrix changes observed included perivascular areas of paleness of the proteoglycan matrix associated with hypocellularity and, sometimes, necrotic chondrocytes. These changes were most abundant in the youngest fetuses and in the femoropatellar/femorotibial (FP/FT) joints. Indentations of the ossification front were also observed in most specimens, but, most frequently, in scapulohumeral and FP/FT joints. A cartilage canal was almost always present in these indentations. The vascular density of the cartilage was higher in the youngest fetuses. In these fetuses, the most vascularised joints were the metacarpo- and metatarsophalangeal joints but their cartilage canals regressed quickly. After birth, the most vascularised cartilage was present in the FP/FT joint. Articular cartilage differentiated into 4 zones early in fetal life and the epiphyseal cartilage also had a distinct zonal cartilage structure. A striking difference was observed in the collagen structure at the junction of the proliferative and hypertrophic zones where OCD lesions occur. CONCLUSION: Matrix and ossification front changes were frequently observed and significantly associated with cartilage canals suggesting that they may be physiological changes associated with matrix remodelling and development. The collagen structure was variable through the growing epiphysis and a differential in biomechanical properties at focal sites may predispose them to injury.     

What is the Evidence of Hyaluronic Acid and Polyacrylamide Hydrogel in Intra-articular Therapy in Equines? Systematic Literature Review

A systematic review was conducted to investigate evidence to support or refute the use of hyaluronic acid and polyacrylamide hydrogel as intra-articular therapy in equines, which are frequent treatment options in the routine of veterinarians of equines in cases of osteoarthritis. In total, 19 studies were included, among clinical and in vitro studies, as well as a retrospective series of cases. The outcomes of the included studies provided fragile evidence supporting the recommendation for intra-articular use of hyaluronic acid. No study was included showing any clinical outcome in diseased synovial tissues of the polyacrylamide hydrogel. There is no concrete evidence of benefits, treatment protocols, and mechanisms of action of hyaluronic acid in the joint therapy in equines.     

Validation of noninvasive blood pressure equipment: which peripheral artery is best for comparison studies in dogs?

Objectives

1) To determine which peripheral artery commonly used for invasive arterial blood pressure (IBP) monitoring yields the least bias when compared with noninvasive blood pressure (NIBP) values obtained at the antebrachium of the dog, and 2) to identify and describe differences in systolic (SAP), mean (MAP) and diastolic arterial pressures (DAP) among different anatomical locations.

Quantitative assessment of gait parameters in horses: Useful for aiding clinical decision making?

Gait analysis in horses has moved from the laboratory into the outside world enabling researchers and clinicians to make use of quantitative measurements to provide evidence aiding clinical decision making. In this article we explain how the two major visual signs of lameness – head nod and hip hike –are linked to the mechanics of lameness. These parameters should be regarded as well suited for incorporation into clinical decision making being easily measurable e.g. with inertial sensors under nonlaboratory conditions and representative of the underlying mechanical changes. A brief overview of the results of validation studies of the use of inertial sensors for quantification of movement symmetry shows that accuracy, precision and repeatability with current sensor generations are in the order of 3–7 mm; this is below the reported detection threshold for movement symmetries ‘by eye’. Recent studies with inertial sensors have investigated conditions relevant to the clinical lameness examination: lungeing, flexion tests and diagnostic analgesia. Lungeing introduces kinematic adaptations rendering head and pelvic movement asymmetrical, even in sound horses. First guideline values are available for changes after flexion tests and diagnostic analgesia, and we understand which parameters show consistent changes. This is crucial for investigating the effects in horses with different orthopaedic deficits. In conclusion, the current inertial sensor systems, while not quantifying all the gait adaptations seen in lame horses, characterise the major mechanical changes affecting fore‐ and hindlimb lame horses. In order to avoid misinterpretation of the generated data, users should have a thorough understanding of the gait parameters and be aware of sensor limitations in terms of accuracy, precision and repeatability.     

Coughing in dogs: what is the evidence for and against a cardiac cough?

Cough has been historically reported as a major clinical sign of cardiogenic pulmonary oedema in dogs. However, recent evidence appears to contradict the traditional dogmatic approach that linked cough to congestive heart failure in dogs. Here we use a question‐based format to introduce and discuss the modern evidence regarding “cardiac cough” and the interpretation of this important but often misleading clinical sign.