Abstract: This study examined relative influences of predominant collagen fiber orientation (CFO), mineralization (% ash), and other microstructural characteristics on the mechanical properties of equine cortical bone. Using strain-mode-specific (S-M-S) testing (compression testing of bone habitually loaded in compression; tension testing of bone habitually loaded in tension), the relative mechanical importance of CFO and other material characteristics were examined in equine third metacarpals (MC3s). This model was chosen since it had a consistent non-uniform strain distribution estimated by finite element analysis (FEA) near mid-diaphysis of a thoroughbred horse, net tension in the dorsal/lateral cortices and net compression in the palmar/medial cortices. Bone specimens from regions habitually loaded in tension or compression were: (1) tested to failure in both axial compression and tension in order to contrast S-M-S vs non-S-M-S behavior, and (2) analyzed for CFO, % ash, porosity, fractional area of secondary osteonal bone, osteon cross-sectional area, and population densities of secondary osteons and osteocyte lacunae. Multivariate multiple regression analyses revealed that in S-M-S compression testing, CFO most strongly influenced total energy (pre-yield elastic energy plus post-yield plastic energy); in S-M-S tension testing CFO most strongly influenced post-yield energy and total energy. CFO was less important in explaining S-M-S elastic modulus, and yield and ultimate stress. Therefore, in S-M-S loading CFO appears to be important in influencing energy absorption, whereas the other characteristics have a more dominant influence in elastic modulus, pre-yield behavior and strength. These data generally support the hypothesis that differentially affecting S-M-S energy absorption may be an important consequence of regional histocompositional heterogeneity in the equine MC3. Data inconsistent with the hypothesis, including the lack of highly longitudinal collagen in the dorsal-lateral ;tension' region, paradoxical histologic organization in some locations, and lack of significantly improved S-M-S properties in some locations, might reflect the absence of a similar habitual strain distribution in all bones. An alternative strain distribution based on in vivo strain measurements, without FEA, on non-Thoroughbreds showing net compression along the dorsal-palmar axis might be more characteristic of the habitual loading of some of the bones that we examined. In turn, some inconsistencies might also reflect the complex torsion/bending loading regime that the MC3 sustains when the animal undergoes a variety of gaits and activities, which may be representative of only a portion of our animals, again reflecting the possibility that not all of the bones examined had similar habitual loading histories.

Abstract: The quality of husbandry of Franches-Montagnes horses (FM) in Switzerland is evaluated on the basis of an investigation carried out in 2002 by the Swiss FM breeding federation. Questionnaires were sent to 3500 of its members and the results include data from 968 breeding enterprises, housing a total of 3965 FM: 46.1% were breeding mares (61.0% with foal at foot), 26.5% young stock, 1.3% stallions and 26.0% non breeding stock (74.6% of which were pleasure horses and 25.4% working horses). 57.6% of the FM were housed in individual boxes with or without permanent outdoor access, 25.4% were hold in groups with or without permanent outdoor access, the remaining 17.0% were kept in standing stalls. 95.0% of the FM had at least visual contact with other equines and 99.2% had sufficient light in their stable. 88.1% were stabled on long stalk straw, while only 4.3% were bedded on other materials other than straw. The average time spent at pasture per horse and per week ranged from 96.5 +/- 51.6 hours in summer to 27.2 +/- 26.7 hours in winter. On average, a FM is used for 8.3 +/- 6.5 hours per week. Horses with an paddock at their disposal spend an average of 39.8 +/- 45.9 hours there per week.

Abstract: In North America, there are few representative data about the effects of management practices on equine welfare. In a randomized survey of 312 nonracing horses in Prince Edward Island (response rate 68.4%), owners completed a pretested questionnaire and a veterinarian examined each horse. Regression analyses identified factors affecting 2 welfare markers: body condition score (BCS) and stereotypic behavior. Horses' BCSs were high (mean 5.7, on a 9-point scale) and were associated with sex (males had lower BCSs than females; P < 0.001) and examination date (P = 0.052). Prevalences of crib biting, wind sucking, and weaving were 3.8%, 3.8%, and 4.8%, respectively. Age (OR = 1.07, P = 0.08) and hours worked weekly (OR = 1.12, P = 0.03) were risk factors for weaving. Straw bedding (OR = 0.3, P = 0.03), daily hours at pasture (OR = 0.94, P = 0.02), and horse type (drafts and miniatures had a lower risk than light horses; P = 0.12) reduced the risk of horses showing oral stereotypies. Some of these results contradict those of other studies perhaps because of populations concerned.

Abstract: OBJECTIVE: To confirm that the midshaft dorsal cortex of the third metacarpal bone experienced higher compressive strains during fast exercise than the medial or lateral cortices, and that the strain peak occurred earlier in the hoof-down phase of the stride on the dorsal cortex than the medial or lateral cortices. DESIGN: Observations of a single horse. PROCEDURE: Strains were collected from a single, sound, 3-year-old Thoroughbred mare during treadmill exercise from rosette strain gauges implanted onto the medial, lateral and dorsal surfaces of the midshaft of the right cannon bone, simultaneously with data from a hoof switch that showed when the hoof was in the stance phase. RESULTS: Peak compressive strains on the dorsal surface of the third metacarpal bone were proportional to exercise speed and occurred at about 30% of stance. Peak compressive strains on the medial surface of the non-lead limb reached a maximum at a speed around 10 m/s and occurred at mid-stance. Peak compressive strains on the lateral surface varied in timing and size between strides at all exercise speeds, but remained less than -2000 microstrains. CONCLUSIONS: The timing of peak compressive strains on the dorsal cortex suggests a relationship to deceleration of the limb following hoof impact, so the main determinants of their size would be exercise speed and turning (as shown in previous experiments). This experiment confirms data from other laboratories that were published but not discussed, that peak compressive strains on the medial surface occur at mid-stance. This suggests that they are related to the support of body weight. The strains on the lateral cortex occurred at variable times so may be associated with the maintenance of balance as well as the support of body weight. Understanding the loading of the third metacarpal bone will help to determine causes of damage to it and ways in which the bone might be conditioned to prevent such damage.

Abstract: The guidelines of the Federal Ministry of User Protection, Nutrition and Agriculture (BMVEL) regarding “horse keeping with respect to animal welfare” are from 1995 (BMELF, 1995). Therefore, they are not suitable for modern horse keeping. The Veterinary Association for Animal Welfare (TVT) held it to be necessary to rework the guide-lines in light of 1) many subsequent investigations concerning horse keeping, and 2) the species-specific needs of horses in practice. Each chapter of the BMELF (1995) guide-lines was revised such that the literature and practical experiences were updated. Several chapters (recumbency resting behaviour, fences, underground outdoor and in stables, litter) were added in the position paper of the TVT to reflect the increasing use of boxes with paddocks, loose housing systems with open yards, pasture and winter yards as housing conditions. Keeping horses outdoors permanently during winter is possible because horses have very good thermoregulatory capabilities so that they are able to adapt themselves to cold conditions. However, in light of animal welfare, the holding system must include adequate shelter (natural or artificial). Shelters should protect against wetness, heat, cold and wind, and must be sufficiently large and high, with a dry and clean underground. In keeping horses outdoors permanently, the paths to the feeding and watering areas and to the shelter must be dry. The food must also be protected against mould and soiling. Keeping horses permanently without adequate shelter or in deep marsh without any dry places is against the Animal Protection Act.