Investigation of osteochondrosis in grazing beef cattle

Diagnosis and Prognosis of Common Disorders Involving the Proximal Limb

Claw diseases are the principal cause of lameness in cattle. They can be easily diagnosed by examining the feet while the animal is in the trimming chute. Lameness originating from the proximal limb is more challenging because it is less visible. The author describes a systematic approach to diagnose upper limb lameness. The most common causes of lameness are reviewed with special emphasis on physical examinations and appropriate diagnostic tools.

Response of cattle with clinical osteochondrosis to mineral supplementation

Since 1982, farmers in the North West province and other parts of South Africa have noticed an increase in the incidence of lameness in cattle. Macro- and microscopical lesions of joints resembled osteochondrosis. Pre-trial data indicated that cattle with osteochondrotic lesions recovered almost completely when fed a supplement containing bio-available micro- and macrominerals of high quality. In the present trial, 43 clinically affected cattle of varying ages (1-5 years) and sexes were randomly divided into three groups. Each group was fed the same commercial supplement base with differing micro- and macromineral concentrations to determine the effect of mineral concentrations on the recovery from osteochondrosis. Both supplements 1 and 2 contained 25% of the recommended National Research Council (NRC) mineral values. Additional phosphate was added to supplement 2. Supplement 3, containing 80% of the NRC mineral values, was used as the control. Results from all three groups indicated no recovery from osteochondrosis. Urine pH of a small sample of the test cattle showed aciduria (pH < 6). Supplement analysis revealed addition of ammonium sulphate that contributed sulphate and nitrogen to the supplement. Supplementary dietary cation anion difference (DCAD) values were negative at -411 mEq/kg, -466 mEq/kg and -467 mEq/kg for supplements 1, 2 and 3, respectively, whereas the pre-trial supplement was calculated at +19.87 mEq/kg. It was hypothesised that feeding a low (negative) DCAD diet will predispose growing cattle to the development of osteochondrosis or exacerbate subclinical or clinical osteochondrosis in cattle.

Growth Plate Lesions of Fattening Bulls

Lameness related to growth plate lesions is an important problem in the beef industry. This article describes the macroscopic and microscopic lesions in the distal metatarsal physis of bulls from an association of farmers in northeastern Italy. The metatarsal bones of 62 bulls (12 with severe lameness and 50 without lameness), average age 16.44 ± 1.72 months, were examined at the abattoir. The animals came from the same geographic area and shared intensive husbandry practices and a diet based on maize starch. A total of 124 metatarsal bones were sectioned, and the distal metaphyseal growth plate was grossly examined. Twenty-three cases, including 12 lame and 9 nonlame animals with visible lesions on macroscopic examination, and 2 controls (a total of 46 physes) were examined microscopically. Eight of 12 bulls with severe lameness had a chronic purulent physitis in at least 1 limb. Segmental thickening of the hypertrophic zone, consistent with osteochondrosis (OC), was present contralaterally ( n = 3 cases) and bilaterally ( n = 3 cases) in 6 of these animals. In the group of nonlame bulls, 19 of 50 (38%) had similar segmental thickening of the physis consistent with OC. In the remaining bulls, minor findings included partial closure of the physis and a variable degree of metaphyseal hyperemia. A high incidence of OC was found in both lame and nonlame fattening bulls. It is likely that lame animals were clinically more severe due to secondary hematogenous implantation of bacteria, resulting in a purulent physitis and severe lameness that required emergency slaughter in some cases.

Preliminary report on osteochondrosis in cattle in the north-western parts of South Africa

The north-western part of South Africa, in particular, is well known for mineral imbalances. Aphosphorosis, resulting in rickets and osteomalacia, received a lot of attention at the turn of the nineteenth century (1882–1912). This was followed in 1997 by research on Vryburg hepatosis, another area-specific mineral imbalance–related disease in young calves reared on manganese-rich soil derived from the weathering of dolomitic (carbonate) rock formations. In 1982, a totally new syndrome (osteochondrosis) manifested in, amongst others, areas in South Africa where aphosphorosis was rife. Osteochondrosis was also identified in the south-western parts of Namibia as well as southern Botswana and other areas in South Africa. Osteochondrosis has a multifactorial aetiology and this study focused on the role of minerals, particularly phosphorus, in the development of the disease. A significant improvement in the clinical signs in experimental animals and a reduction of osteochondrosis occurred on farms where animals received bioavailable trace minerals and phosphorus as part of a balanced lick. An increase in the occurrence of the disease on farms during severe drought conditions in 2012–2013 prompted researchers to investigate the possible role of chronic metabolic acidosis in the pathogenesis of the disease.

Joint disorder; a contributory cause to reproductive failure in beef bulls?

The lame sire, unsound for breeding, can cause substantial economic loss due to reduced pregnancies in the beef-producing herd. To test the hypothesis that joint disorder is a possible cause of infertility in beef sires, right and left hind limb bones from 34 beef sires were examined postmortem to identify lesions in the femorotibial, femoropatellar (stifle), tarsocrural, talocalcaneus, and proximal intertarsal (tarsal) joints. The bulls were slaughtered during or after the breeding season due to poor fertility results. Aliquots of the cauda epididymal contents taken postmortem from 26 bulls were used for sperm morphology evaluation. As a control, hind limbs (but no semen samples) from 11 beef bulls with good fertility results were included. Almost all infertile bulls (30/34) had lesions in at least one joint. Twenty-eight bulls (28/30, 93%) had lesions in the stifle joint, and 24 (24/28, 86%) of these were bilateral. Fourteen bulls (14/30, 47%) had lesions in the tarsal joint, and 10 (10/14, 71%) of these were bilateral. Four bulls (4/34, 12%) had no lesions, three bulls (3/34, 9%) had mild osteoarthritis (OA), 5 (5/34, 15%) moderate OA, 17 (17/34, 50%) severe OA and 5 (5/34, 15%) deformed OA. Almost all OA lesions (97%) were characterized as lesions secondary to osteochondrosis dissecans. All the bulls with satisfactory sperm morphology (n = 12/34) had joint lesions, with mostly severe or deformed bilateral lesions (83%). Consequently, the most likely cause of infertility in these 12 bulls was joint disease. Almost all control bulls (10/11) had OA lesions, but most of them were graded as mild (55%) or moderate (36%). None of the control bulls had severe lesions or deformed OA. We suggest that joint lesions should be taken into consideration as a contributory cause of reproductive failure in beef sires without symptoms of lameness.

Consequences of hazardous dietary calcium deficiency for fattening bulls

Background

Deficient mineral supplementation on a feedlot farm resulted in severe clinical manifestations in fattening bulls. Animals mistakenly received only 60–70% of the recommended calcium intake, while simultaneously receiving twice the amount of phosphorus recommended. Thus, the dietary Ca/P ratio was severely distorted. After approximately six months on such a diet, four fattening bulls were euthanized because of severe lameness and 15% of other animals on the farm were having clinical leg problems. Veterinary consultation revealed the mistake in mineral supplementation.

Methods

Fattening bulls were divided into three groups depending on the time of their arrival to the farm. This enabled the effect of mineral imbalance at different growth phases to be examined. After slaughtering, the bones of both front and hind limbs were macroscopically evaluated.

Results

Over 80% of the animals with a calcium-deficient diet had at least one severe osteoarthritic lesion. The economic impact of the calcium deficiency was statistically significant.

Conclusion

Calcium deficiency with distorted Ca/P ratio yielded a severe outbreak of osteoarthritis in fattening bulls. Calcium deficiency caused a more serious lesions in age group 5–12 months than age group 12–18 months. Besides causing obvious economic losses osteoarthritis is also a welfare issue for feedlot animals.