Hoof Matters: Developing an Athletic Thoroughbred Hoof.

Conformation of the hooves and distal limbs of foals and factors influencing their morphological development have not been reported in detail for the Thoroughbred breed. In this paper we explore morphogenesis of the equine distal limb in Thoroughbred foals with emphasis on adaptations in response to weight bearing early in life that prepare the foal for an athletic career. Novel data from four studies are presented chronologically during key time periods to illustrate specific aspects of distal limb growth and adaptation. Dorsal epidermal thickness increased from 2.84 ± 0.41 mm in utero to 4.04 ± 1.10 mm by 4 months of age. The increase in thickness was accompanied by decreased tubular density, increased inter-tubular material, and an increase in number and size of tubules at the quarters, which provided a malleable hoof capsule to allow for skeletal growth. Between 4−6 months of age, the hoof widens, and higher loading on the medial side (>60%) vs. the lateral side (<40%) may be factors that influence mature asymmetric hoof shape. Shortly after 12 months-of-age, the dorsal hoof wall angle and dorsal parietal angle of the distal phalanx become parallel, thus optimizing the functional capacity of the hoof capsule in the weanling Thoroughbred.

Telehealth transformation: COVID-19 and the rise of virtual care.

The novel coronavirus disease-19 (COVID-19) pandemic has altered our economy, society, and healthcare system. While this crisis has presented the U.S. healthcare delivery system with unprecedented challenges, the pandemic has catalyzed rapid adoption of telehealth, or the entire spectrum of activities used to deliver care at a distance. Using examples reported by U.S. healthcare organizations, including ours, we describe the role that telehealth has played in transforming healthcare delivery during the 3 phases of the U.S. COVID-19 pandemic: (1) stay-at-home outpatient care, (2) initial COVID-19 hospital surge, and (3) postpandemic recovery. Within each of these 3 phases, we examine how people, process, and technology work together to support a successful telehealth transformation. Whether healthcare enterprises are ready or not, the new reality is that virtual care has arrived.

The role of hyperthermia in regional alkylating agent chemotherapy.

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanine mustard under conditions of normothermia, or l-phenylalanine mustard plus hyperthermia. Heat was administered locally using an in-line hot water circulation loop. Treatment with l-phenylalanine mustard at a concentration of 15 or 50 micrograms/mL was ineffective at producing tumor growth delay (P = 0.24 and 0.41, respectively). Furthermore, thermal enhancement of l-phenylalanine mustard activity was not seen at 15 micrograms/mL. However, administration of high-dose l-phenylalanine mustard, 50 micrograms/mL, with increasing amounts of heat yielded increasing tumor growth delay, increased regressions, and decreased proliferative index. Although l-phenylalanine mustard infusion under normothermia yielded a tumor growth delay of 7.1 days, combination l-phenylalanine mustard + hyperthermia treatment produced tumor growth delay of 27.0 days (P < 0.01; with two of five animals showing a complete response). Four hours after isolated limb infusion, 50.9% of cells in tumor treated with l-phenylalanine mustard + hyperthermia experienced apoptosis, whereas only 18.1, 16, and 4.4% of cells underwent apoptosis after treatment with l-phenylalanine mustard, saline + hyperthermia, or saline. The mean concentration of l-phenylalanine mustard within tumor relative to perfusate following isolated limb infusion was found to be similar among all groups at 0.023, 0.025, and 0.032 in animals undergoing isolated limb infusion with l-phenylalanine mustard, l-phenylalanine mustard + normothermia, and l-phenylalanine mustard + hyperthermia, respectively. These data indicate a synergistic cytotoxic effect of l-phenylalanine mustard + hyperthermia in isolated limb infusion, which is not attributable to enhanced tumor drug uptake.

Hoof renewal time from birth of Thoroughbred foals.

A circumferential ring in the hoof horn of foals occurs at birth and grows down to the distal border as the fetal hoof is replaced. Horn growth and complete hoof capsule renewal have not been measured in Thoroughbred foals but the determination of time of hoof renewal may allow accurate predictions of healing time to be made in cases of hoof lesions. The objective of this study was to measure the time taken for the fetal hoof of newborn foals to grow to the distal border and be replaced by hoof grown since birth. The age of the foal in days on the day that routine hoof trimming removed the hoof ring of the front hooves was recorded. The mean age at which the fetal hoof was removed was 145 ± 15 days (95% CI, 141.8-147.2), range 120-165 days. Thoroughbred foals replaced the fetal hoof in approximately half the time taken for mature horses (270-365 days).

Foot management in the foal and weanling.

Foot management and hoof care of foals, weanlings, and yearlings tends to be considered a specialist job. Many farriers and veterinary surgeons have little exposure to young and growing stock. Nevertheless, a variety of angular and flexural limb deformities can benefit from simple podiatry techniques, which can be performed provided that a few basic rules are followed. The combined skills of the farrier and veterinary surgeon offer many young horses with angular or flexural limb deformities a chance of a future athletic career.