Musculoskeletal problems associated with lameness and poor performance among horses used for barrel racing: 118 cases (2000-2003)

OBJECTIVE: To identify types of musculoskeletal problems associated with lameness or poor performance in horses used for barrel racing. DESIGN: Retrospective case series. ANIMALS: 118 horses. PROCEDURE: Medical records were reviewed for information on signalment, history, physical and lameness examination findings, diagnostic tests performed, diagnosis, and treatment. RESULTS: Most horses were examined because of lameness (n = 72 [61%]) rather than poor performance (46 [39%]), but owner complaint was not significantly associated with age or body weight of the horse. The most common performance change was refusal or failure to turn properly around the first barrel (19/46 [41%]). The right forelimb (n = 57 [48%]) was most commonly affected, followed by the left forelimb (51 [43%]), the left hind limb (31 [26%]), and the right hind limb (25 [21%]). In 31 horses (26%), both forelimbs were affected, and in 6 (5%), both hind limbs were affected. The most common musculoskeletal problems were forelimb foot pain only (n = 39 [33%]), osteoarthritis of the distal tarsal joints (17 [14%]), suspensory ligament desmitis (15 [13%]), forelimb foot pain with distal tarsal joint osteoarthritis (11 [9%]), and bruised feet (10 [8.5%]). In 81 (69%) horses, the affected joint was treated with intra-articular medications. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in horses used for barrel racing that are examined because of lameness or poor performance, the forelimbs are more likely to be affected than the hind limbs, with forelimb foot pain and osteoarthritis of the distal tarsal joints being the most common underlying abnormalities.     

Effects of supplementation of whole corn germ on reproductive performance, calf performance, and leptin concentration in primiparous and mature beef cows

A 2-yr study using primiparous and multiparous, spring-calving, crossbred beef cows was conducted to evaluate the effects of supplemental whole corn germ on reproductive performance, calf performance, and serum leptin concentrations. Each year, cows were blocked by age and BCS and assigned randomly to one of three treatments: PRE (n = 115) cows received 1.14 kg/d (DM basis) of whole corn germ for approximately 45 d before calving; POST (n = 109) cows were fed 1.14 kg/d of whole corn germ for approximately 45 d after calving; and control cows (n = 118) were fed similar energy and protein from dry-rolled corn (1.82 kg of DM/d) for 45 d before and after calving. Additionally, PRE cows were grouped with controls after calving, and POST cows were grouped with control cows before calving, so that corn germ-supplemented cows received the control supplement in the alternate feeding period. Cow BW (538 +/- 13 kg) and BCS (5.4 +/- 0.13) did not differ among treatments at any time during the experiment. Calf birth weight (39 +/- 2 kg), weaning weight (225 +/- 7 kg), and age-adjusted weaning weight (234 +/- 8 kg) did not differ because of dam supplementation regimen. Treatment did not affect the proportion of cows exhibiting ovarian luteal activity before the start of the breeding season (67%) or pregnancy rate (91%). The interval from exposure to bulls until subsequent calving did not differ (P = 0.16) among PRE (298 +/- 2.3 d), POST (303 +/- 2.6 d), and control (304 +/- 2.3 d) cows. Leptin concentrations did not differ among treatments and were 2.15 +/- 0.75, 1.88 +/- 0.76, and 1.91 +/- 0.75 ng/mL for control, POST, and PRE cows, respectively. Age and week relative to calving influenced leptin concentration. Primiparous cows had similar leptin concentrations to 3-yr-old and mature cows for wk -7 and -6 relative to calving, but lower (P < 0.10) concentrations than mature cows for wk -5, and lower (P < 0.05) concentrations than either 3-yr-old or mature cows for wk -4 to +7 relative to calving. Serum leptin was correlated with BCS (P < 0.0001; r = 0.35) at initiation of the feeding period and was correlated with BCS (P = 0.02; r = 0.12) and weight (P < 0.01; r = 0.14) at the completion of the supplement period, but it was not correlated with initial BW or interim BCS. Calving interval was not correlated (P > 0.12) with weekly measures of serum leptin concentration. Supplementing beef cows with whole corn germ had no effect on cow performance, calf performance, or serum leptin concentrations of cows.     

A beef herd model for simulating feed intake, animal performance, and manure excretion in farm systems

A beef herd submodel was created for integration with other farm components to form a whole-farm model capable of simulating a wide range of beef production systems. This herd submodel determined the best available feed or feed mix to meet the fiber, energy, and protein requirements for each of up to six animal groups on the farm. The groups comprised any combination of cows, nursing calves, young heifers, yearling heifers, stockers, and finishing cattle. Protein, energy, and mineral requirements were determined for each group using the Cornell Net Carbohydrate and Protein System, Level 1. Diets were formulated to meet these requirements with available feeds, and the resulting feed intake, growth, and manure DM and nutrient (N, P, and K) excretions were predicted. Required feed characteristics included CP, ruminally degradable protein, acid detergent insoluble protein, NDF, P, and K concentrations. Feed intake was predicted by considering energy intake, potentially limited by fill, and exceeding a minimum roughage requirement. Fill and roughage limits were functions of feed NDF concentrations adjusted to consider particle size distribution and the relative rate of ruminal digestibility or the physical effectiveness of the fiber. The herd submodel was verified to predict feed intakes, nutrient requirements, diets, and manure excretions similar to those recommended or measured for beef animals. Incorporation of the beef herd submodel with other farm components, including crop growth (alfalfa, grass, corn, small grain, and soybean), harvest, storage, feeding, grazing, and manure handling, provided the Integrated Farm System Model. This comprehensive farm-simulation model is a useful research and teaching tool for evaluating and comparing the long-term performance, economics, and environmental impact of beef, dairy, and crop production systems.     

Grass Yields Under Clipping and Watering Explain Varied Efficacy of Management Intensive Grazing on Rangelands

Management intensive grazing (MIG) may not maximize plant productivity on rangelands because of morphophysiological traits of grassland vegetation. We examined defoliation and moisture effects on the biomass yield of rhizomatous and caespitose grass pairs that were either phylogenetically similar or of similar agroclimatic adaptation, including two agronomic grasses. From relatively low to high moisture regime adaptation, species pairs included western wheatgrass (Pascopyrum smithii [Rydb.] A. Love) and needle-and-thread (Hesperostipa comata [Trin. & Rupr.] Barkw.), northern wheatgrass (Elymus lanceolatus [Scribn. & J.G. Sm.]) and western porcupine grass (H. curtiseta [Hitchc.] Barkw.), plains and foothills rough fescue (Festuca hallii [Vasey] and F. campestris Rydb.), and smooth and meadow brome (Bromus inermis Leyss. and B. riparius Rehm). Response variables were shoot yield, root-shoot ratio, and water-use efficiency. We hypothesized that caespitose grasses, regardless of their origin or adaptation to agroclimate regime, would respond more determinately in biomass accumulation. Defoliation effects on shoot biomass were more pronounced under high moisture. Low intensity ? high frequency defoliation yielded similarly to deferred controls in all grasses, and the same was true for high-intensity ? low-frequency (HILF) defoliation in 1 rhizomatous grass. Three of the 4 rhizomatous grasses and 1 caespitose grass yielded greater under HILF defoliation compared with high-intensity ? high-frequency defoliation. Caespitose grasses allocated more biomass to roots under low moisture conditions. Water-use efficiency decreased under high moisture conditions and more intense and/or frequent defoliation and peaked in agronomic grasses. Overall, our results suggested that growth patterns corresponded more with phylogenetic similarity as opposed to growth form. A conceptual model from these results showed that across all species, only the introduced bromes generated greater biomass under HILF defoliation, and this may explain why past research consistently concludes that MIG does not enhance plant productivity on rangelands.     

Relationship between total transit time and faecal quality in adult dogs differing in body size

Fed the same diet, large and giant-breed dogs have higher faecal moisture and increased frequency of soft stools than small ones. This could be the result of physiological differences, such as a different gastrointestinal transit time. In this study, we have correlated mean total transit time (MTT) with body size and faecal consistency in dogs varying in body size. Fifty dogs from 13 different breeds were used, from a Dachshund to a Great Dane. The MTT was determined using coloured plastic beads [Cummings and Wiggins, Gut, Vol. 17 (1976), p. 219], and faecal consistency was scored daily during the study. We confirmed the strong correlation between height at the shoulder (body size) and faecal score (r = 0.76; p < 0.0001). The MTT increased with body size, from 22 h for a Miniature Poodle to 59 h for a Giant Schnauzer. We found significant positive correlations (p < 0.0001) between MTT and body size as well as faecal scores (r = 0.71 and 0.70 respectively). In the present study, we observed an effect of body size on MTT. In our 50 healthy dogs a longer MTT was related to a poorer faecal quality. Previous studies reported no relationship between body size and the upper gastrointestinal transit time in healthy dogs. So, we hypothesized that body size would mainly affect colonic transit time and that a longer colonic residence time would be related to a poorer faecal quality by promoting fermentation activity.     

Key role of Chlamydophila psittaci on Belgian turkey farms in association with other respiratory pathogens

Two hundred turkey sera from eight Belgian and two French farms were tested for the presence of antibodies against avian pneumovirus (APV), Ornithobacterium rhinotracheale (ORT), Mycoplasma gallisepticum, Mycoplasma meleagridis and Chlamydophila psittaci. At slaughter, C. psittaci, APV and ORT antibodies were detected in 94, 34 and 6.5% of the turkeys, respectively. No antibodies against M. gallisepticum or M. meleagridis were present. Additionally, turkeys on three Belgian farms were examined from production onset until slaughter using both serology and antigen or gene detection. All farms experienced two C. psittaci infection waves, at 3-6 and 8-12 weeks of age. Each first infection wave was closely followed by an ORT infection starting at the age of 6-8 weeks, which was still detectable when the second C. psittaci infection waves started. Animals on farm A were not vaccinated against APV leading to an APV subtype B outbreak accompanying the first C. psittaci infection wave. Despite subtype A APV vaccination on farms B and C, the second C. psittaci infection waves were accompanied (farm B) or followed (farm C) by a subtype B APV infection. On all farms respiratory signs always appeared together with a proven C. psittaci, APV and/or ORT infection. This study suggests an association between C. psittaci, APV and ORT, and indicates the multi-factorial aetiology of respiratory infections in commercial turkeys. All three pathogens should be considered when developing prevention strategies for respiratory disease.     

Treatment of dog thelaziosis caused by Thelazia callipaeda (Spirurida, Thelaziidae) using a topical formulation of imidacloprid 10% and moxidectin 2.5%

Canine thelaziosis caused by Thelazia callipaeda infects dogs, cats, foxes, rabbits, and humans resulting in conjunctivitis, pain and excessive lacrimation. T. callipaeda live in the eyes under the nictitating membrane and females release first stage larvae which are ingested by flies which act as intermediate hosts. Control of canine thelaziosis is currently based on the removal of nematodes directly from the eyes of affected dogs or on the local instillation of antiparasitic drugs. With the aim of evaluating the efficacy against T. callipaeda of an association of imidacloprid 10% and moxidectin 2.5% by spot-on formulation administered via dermal application, three groups of naturally infected animals were selected: i.e. group A (21 dogs) received a single dose of imidacloprid 10% and moxidectin 2.5% by spot-on; group B (21 dogs) received a single dose of imidacloprid 10% by spot-on and group C (20 dogs) were left untreated. The efficacy of treatments was established by eye inspection and parasite viability and vitality after 1, 5 and 9 days after animal treatments (groups A and B) and after 9 days only in untreated animals (group C). Imidacloprid 10% and moxidectin 2.5% in spot-on formulation showed to be effective with regards the control of dog thelaziosis within 5 (90.47%) to 9 (95.23%) days after treatment. Only one dog from group A presented nematodes after treatment. The presence of parasites in the eyes of dogs from groups B (imidacloprid 10%) and C confirm that the anthelmintic efficacy against T. callipaeda in animal from group A (imidacloprid 10% and moxidectin 2.5%) was most likely attributable to moxidectin 2.5%. The spot-on formulation containing imidacloprid 10% and moxidectin 2.5% is very easy to apply and helps overcome problems linked to the mechanical removal of parasites or to the restraining of the animals for the local instillation of drugs in the eyes.     

Eversion of the Urinary Bladder: A Sequel to Third-Degree Perineal Laceration in the Mare

Two cases of urinary bladder eversion are described in association with third-degree perineal lacerations in the mare. One case of eversion followed surgical repair of the perineal defect. The other occurred spontaneously in a 5-month postpartum mare awaiting repair of a third-degree perineal laceration. Both everted bladders contained the pelvic flexure of the large colon, and in 1 case a bladder rent allowed evisceration. Surgical intervention was required, and was successful in one case.