Role of dietary calcium and available phosphorus in the aetiology of tibial dyschondroplasia in growing turkeys

1. Large White male turkeys from a heavy commercial male-line were fed 16 diets containing 4 concentrations of calcium (6, 10, 14 and 18 g/kg) and available phosphorus (3, 5, 7 and 9 g/kg) in a 4 x 4 factorial experiment. There were three replicates (pens) of each treatment and the skeletal health, morphology and mineral status of 4 turkeys from each pen were assessed at 7, 10 and 13 weeks of age. 2. The prevalence of tibial dyschondroplasia increased after 7 weeks of age and was present in 50 and 71% of turkeys respectively at 10 and 13 weeks. The lesion was localised in the caudal aspect of the proximal tibiae. Dietary calcium and available phosphorus did not affect the prevalence of the lesion except in turkeys on the diet containing 6 g calcium/kg, where body weight and the incidence of tibial dyschondroplasia were low. 3. Histological investigation showed no evidence of rachitic changes. 4. Low dietary calcium was associated with lower tibial plateau angles at 10 and 13 weeks of age. Tibial torsion and the angle of rotation were not affected by dietary treatments or age. Tibial torsion and the angle of rotation were not affected by dietary treatments or age. 5. Increasing dietary calcium increased tibial radiodensity, cortical density and the widths of the cortex and proximal tibiotarsus. Radiodensities increased to 10 weeks and were significantly lower at 13 weeks of age. 6. Bone ash, calcium and phosphorus declined with age, particularly between 10 and 13 weeks, whereas bone calcium: phosphorus ratios were not affected by dietary treatment or age. 7. Dietary calcium was positively associated with blood calcium and calcium ion concentrations and was without effect on blood phosphorus. Available phosphorus was associated positively with increased blood phosphorus and lower calcium ion concentrations but had no effect on total calcium. Alkaline phosphatase activity was low at high concentrations of dietary calcium with low available phosphorus and there was higher activity on diets containing low calcium and high available phosphorus.     

Femoral fractures in a young male Turkey breeder flock

Twenty-two 32-to-35-wk-old male turkeys from a commercial breeding flock were presented to the California Veterinary Diagnostic Laboratory System, Fresno Branch, with a clinical complaint of lameness and increased mortality. Necropsy findings included a unilateral, closed oblique fracture involving the femur in 12 birds. Ten complete femoral fractures had periosteal new bone adjacent to and bridging the fracture. Periosteal callus formation, in this case, suggested that preexisting lesions preceded complete fracture of the femur. Factors such as selection for heavy body weight, lack of exercise, and handling might have contributed to the development and promotion of complete fractures.     

Relationships between leg disorders and changes in the behaviour of broiler chickens

The relationships between the severity of lameness, the presence of tibial dyschondroplasia, and the frequency of dustbathing behaviour and duration of tonic immobility were studied in 96 broiler chicks kept from day-old in groups of four in wire-floored cages. Dustbathing was observed when the birds were given access for one hour to a tray containing sand or straw. The duration of tonic immobility and the severity of lameness were scored during weeks 3, 4, 5 and 6. After slaughter at 41 or 45 days of age the birds were examined for tibial dyschondroplasia; 34 birds were classified as having tibial dyschondroplasia and 54 had detectable lameness problems. Birds with tibial dyschondroplasia had a higher lameness score (P < 0.001), dustbathed on fewer days (P < 0.0001), and had longer periods of tonic immobility (P < 0.03) at six weeks than birds which did not have the condition. However, almost all the chicks, including those with tibial dyschondroplasia dustbathed on day 27 after they had not been given access to the tray for three days, significantly more than on days when they had not been deprived of the tray (P < 0.0001). Furthermore, lame birds and birds with tibial dyschondroplasia also dustbathed less with age. Studies of the vertical wing-shaking element of dustbathing confirmed that tibial dyschondroplasia reduced dustbathing (P < 0.05) and also showed that during the one-hour tests, sand resulted in more dustbathing than straw (P < 0.01).     

Consequences of capital femoral dyschondroplasia in young adult and skeletally mature broilers

Radiographs revealed defective endochondral ossification in proximal femora of 52 lame broilers. Cartilage retention either involved epiphyseal cartilage close to the articular surface or growth plate cartilage (dyschondroplasia). In at least seven birds proximal femoral lesions were the only abnormalities detected which could have caused lameness. In cases of moderate or severe cartilage retention, fracture lines traversed necrotic cartilage to undermine part or all of the femoral head. Evidence of reparative fibrosis was seen with augmentation of metaphyseal trabeculae by woven bone apposition. Foveal blood vessels aided repair by re-establishing a new ossification centre but in many cases attempts at repair were inadequate.     

Cartilage lesions associated with shaky-leg lameness in turkeys

Shaky-leg lameness is a poorly defined, mild to very severe, painful lameness occurring mainly in 10-to-18-week-old fast-growing male turkeys. Since there are no significant gross or microscopic lesions in early or uncomplicated cases, the cause of the lameness is likely soft-tissue (muscle or tendon) pain. A case history of a flock problem of shaky-leg lameness is described, and it is suggested that stiffness and inactivity secondary to footpad dermatitis in these turkeys was responsible for the severe shaky-leg lameness in the flock. The cartilage lesion described is an avascular lesion and appeared to be the result of inactivity rather than the cause of lameness in these turkeys.     

Effect of the analgesic butorphanol on activity behaviour in turkeys (Meleagris gallopavo)

During fattening, the bodyweight of modern broad-breasted turkeys increases considerably within a very short space of time. In particular, the breast muscles increase disproportionately. This leads to a disadvantageous distribution in weight, and as a consequence, to a disturbed leg position and skeletal deformations like antitrochanteric degeneration, tibial dyschondroplasia, bending, twisting and rotation of the tibia, osteochondrosis, osteomyelitis, rickets, and epiphyseolysis of the femoral head increases. This cases of degenerative joint disease cause severe pain in humans and there are indications that this is also true for turkeys. The purpose of this study was to determine if behaviour indicative of such pain in turkeys of the B.U.T. Big 6 breeding line could be attenuated by administering a quick-acting analgesic, butorphanol. Twelve pairs of turkeys were tested at the ages of 7 and 12 weeks. One bird in each pair received an analgesic opioid injection, while the other one received a control injection of physiologically balanced saline solution. The time the birds spent putting weight on their legs, i.e., 'walking' and 'standing' and the distance covered by the birds were recorded during the 30 min periods before and after the application of the drug. At week seven the treated birds spent significantly more time putting weight on their legs than control birds. At week 12, the same tendency was observed. No significant differences were found in the distances covered by the animals. It is concluded that fattening turkeys reduce the time they are putting weight on their legs because these behaviours may be associated with pain.     

Evaluation of foot pain in the standing horse by magnetic resonance imaging

The records of 41 horses with previously undiagnosed foot pain that had been examined by standing magnetic resonance imaging were reviewed and follow-up information was obtained from their owners two years after the examination. A range of soft tissue and osseous abnormalities were identified, with multiple lesions frequently occurring. Deep digital flexor tendonitis was recorded in 12 of the horses, and distension of the distal interphalangeal joint was identified in 15, but it was not always associated with lameness; in contrast, distension of the navicular bursa was always associated with lameness in the seven affected horses. Navicular bone lesions were identified in 13 of the horses, often in the absence of radiographic changes. Follow-up information was obtained for 35 of the horses, 27 of which were alive; of these, 16 had returned to their previous level of performance. Of the five horses with navicular bursal changes, four had been euthanased owing to lameness and the other had returned to work at a reduced level.     

Bone marrow lesions of the distal condyles of the third metacarpal bone are common and not always related to lameness in sports and pleasure horses

The metacarpophalangeal joint is a common site of pain in horses. Little information is available about bone marrow lesions in the distal condyles of the third metacarpal bone in sports and pleasure horses. Aims of this prospective, retrospective, observational study were to evaluate the prevalence of bone marrow lesions in the distal condyles of the third metacarpal bone, to describe their anatomic distribution and to correlate lesions with the presence of lameness and the level and type of activity. All sports and pleasure horses undergoing standing low‐field MRI of the front fetlock region between 2009 and 2016 were included and divided into three lameness groups according to the results of diagnostic analgesia. Bone marrow lesions were analyzed and graded by one reader. Grades were compared between anatomical locations and between lameness groups. A total of 166 horses were sampled. The prevalence of bone marrow lesions was 76.5% (127/166). The dorsal aspects of the medial condyle (31%, 39/127) and of the sagittal ridge (28%, 36/127) were the most commonly affected locations. There was no significant difference between both forelimbs (lame limb and non‐lame limb) of the same horse. Lesion severity was neither significantly associated with the lameness group nor with the type or level of activity. The prevalence of bone marrow lesions in the distal condyles of the third metacarpal bone is high in this population and the clinical significance is not always clear. Further studies are required to elucidate the clinical significance of this finding in sports and pleasure horses.     

Use of standing low‐field magnetic resonance imaging to diagnose middle phalanx bone marrow lesions in horses

Bone marrow lesions (BMLs) (also known as ‘bone bruises’, ‘bone oedema’, ‘bone contusions’ and ‘occult fractures’) within the middle phalanx were diagnosed by standing low field magnetic resonance imaging (MRI) in 7 horses. The lesions were characterised by low signal intensity on T1‐ and T2*‐weighted gradient echo sequences, mildly increased signal intensity on T2 fast spin echo sequences, and high signal intensity on short tau inversion recovery (STIR) sequences. Four distinct patterns of abnormal signal were identified: BML associated with osteoarthritis of either the proximal or distal interphalangeal joints; BML associated with soft tissue injury; BML associated with acute trauma; and BML unassociated with any other injury or lameness (assumed to represent bone response to biomechanical stress). Repeat MRI was undertaken in 4 cases. In most cases the BML resolved with rest and time, although lameness was persistent in 2 horses (one of which had an associated osteoarthritis of the proximal interphalangeal joint).     

Musculo-skeletal lesions in adult male broiler breeder fowls and their relationships with body weight and fertility at 60 weeks of age

1. Males from three broiler breeder experiments were examined to determine the incidence of musculo-skeletal lesions (destructive cartilage loss, dyschondroplasia and its sequelae, ruptured tendons and ligaments) in birds culled for low fertility and in males surviving to the end of the breeding period. Relationships with body weight and fertility were studied. 2. The incidence of musculo-skeletal lesions in males culled for low fertility was high. 3. In two experiments, high body weights at termination of the breeding period were associated with a raised incidence of musculo-skeletal lesions and lowered fertility. 4. The results support the hypothesis that lack of control of male body weight gain per se is an important cause of declining fertility with age in broiler breeder flocks. There was no evidence that males were obese.     

Articular aspergillosis of hip joints in turkeys

Aspergillosis is an important cause of morbidity and mortality in birds. Turkey poults are known to be particularly susceptible to fungal infection. Although the respiratory tract is the most commonly affected, dissemination can occur into virtually any organ. Here, we report an unusual outbreak of articular aspergillosis in a flock of meat turkeys with clinical signs of lameness. Between 7 and 11 weeks of age, turkeys had severe granulomatous osteoarthritis of the hip joints with necrosis of the femur head. Fungal morphology and PCR amplification and sequencing of the first ITS1-5.8S-ITS2 rDNA region identified Aspergillus fumigatus as the infectious agent. Concurrently, Staphylococcus spp. was isolated from the hip joints, which may have promoted the tropism of the fungus. Mild respiratory tract aspergillosis was observed in only one case. The findings suggest that fungal arthritis may present a specific disease entity in turkeys and should be considered as further cause of lameness in turkeys.     

Immunization of turkey breeder hens against fowl cholera by combined oral and wing-web administration of attenuated (CU) pasteurella multocida

Turkey breeder candidates were exposed to attenuated Pasteurella multocida (Clemson University strain) via both mouth (one or three times) and wing-web stick (one or two times). Significant protection lasting to 25-30 weeks post-vaccination was conferred under such immunization programs. The best protection with the fewest adverse effects of vaccination was established when orally vaccinated turkeys were subsequently vaccinated via wing-web at 20 and 25 weeks of age. High doses of attenuated P. multocida via wing-web produced lameness (synovitis and osteomyelitis) and severe wing lesions in growing turkeys.     

Characteristics of Actinomyces pyogenes involved in lameness of male turkeys in north-central United States

A new condition of clinical lameness in 20 male turkey flocks of North-Central United States, associated with isolation of gram-positive rod bacteria from lesions of osteomyelitis, is characterized. The characterization confirmed the randomly selected isolates as Actinomyces pyogenes based on macroscopic and microscopic observations and 17 biochemical tests. The disease was reproduced within 3 weeks in all male turkeys, following an intravenous challenge at 15 weeks of age. The agar gel precipitin test and immunoblotting confirmed the antigenic similarity of the isolates recovered from the osteomyelitis lesions of lame birds.     

RESOLUTION OF LESIONS ON STIR IMAGES IS ASSOCIATED WITH IMPROVED LAMENESS STATUS IN HORSES

Magnetic resonance (MR) imaging is important in diagnosing musculoskeletal injuries in horses. However, there is still much to learn regarding the significance of lesions identified in equine MR images. Of particular importance is the clinical significance of signal change as a function of pulse sequence. We hypothesized that a resolution of tendon, ligament, and bone marrow lesions on short‐tau inversion recovery (STIR) images would be associated with a return to soundness, and that a persistence of tendon and ligament lesions on only T1‐weighted (T1w) gradient recalled echo (GRE) images would not be associated with persistent lameness. The medical records and MR images of 27 horses that had a hyperintense lesion in initial STIR MR images followed by a subsequent follow‐up MR imaging examination were reviewed. Horses whose tendon or ligament lesions had resolved on STIR images at the time of the recheck examination were significantly more likely to be sound than horses whose lesions persisted on STIR images (P=0.039). This association did not exist in horses with bone marrow lesions (P=1.00). Horses whose tendon or ligament lesions persisted only on T1w GRE images were no more likely to be sound than horses whose lesion persisted on at least one other sequence type (P=0.26). However, the low number of horses included in this analysis may have precluded identification of a significant difference in lameness status. Tendon or ligament lesions visualized on STIR images may represent active lesions that may contribute to lameness in the horse.     

Fluorosis as a probable cause of chronic lameness in free ranging eastern grey kangaroos (Macropus giganteus).

A population of eastern grey kangaroos (Macropus giganteus) inhabiting heathland and farmland surrounding an aluminum smelter at Portland, Victoria, Australia, exhibited clinical signs of lameness. An investigation was undertaken to determine the cause of this lameness. Hematology, necropsy, histopathology, fecal egg count, total worm count, reproductive status, and the population age range were examined and failed to reveal any additional underlying disease state. The specific problem of lameness was addressed with bone histopathology, radiography, quantitative ultrasonography, microradiography, and multielement analysis of bone ash samples. The significant lesions observed were: osteophytosis of the distal tibia and fibula, tarsal bones, metatarsus IV, and proximal coccygeal vertebrae; osteopenia of the femur, tibia, and metatarsus IV; incisor enamel hypoplasia; stained, uneven, and abnormal teeth wear; abnormal bone matrix mineralization and mottling; increased bone density; and elevated bone fluoride levels. Microradiography of affected kangaroos exhibited "black osteons," which are a known manifestation of fluorosis. Collectively, these lesions were consistent with a diagnosis of fluorosis.     

Magnetic resonance imaging changes of the navicular bursa following navicular bursoscopy in seven horses

Navicular syndrome is a multifactorial disease process in horses with multiple structures in the foot contributing to lameness. Surgical debridement is a treatment option for lesions of the navicular bursa and deep digital flexor tendon. This retrospective case series describes the magnetic resonance imaging (MRI) appearance of the navicular bursa following bursoscopy. Seven horses (three being bilaterally affected) with forelimb lameness isolated to the foot, and pre- and post-operative MRI were included. All limbs had concurrent lesions associated with the deep digital flexor tendon, navicular bone, impar ligament, collateral sesamoidean ligament and/or distal interphalangeal joint. All bursae developed or had progression of proliferative bursal tissue following surgery. At recheck MRI, following rehabilitation protocols, almost all horses had improved to resolved lameness with relatively unchanged concurrent lesions despite the navicular bursa appearance worsening. Outcomes for return to work were poor with only two horses going back to the previous level of work.     

Inflammation of the nasal gland in domestic turkeys.

A prominent swelling above the eye of range-reared tom turkeys was found to be due to severe inflammation and hyperplasia of the nasal or salt gland. The incidence of affected turkeys was sporadic, and no mortality or other lesions were associated with the condition.     

Relationship of high intensity step-up lighting to bone ash and growth plate closure of the tarso-metatarsus in turkeys

The reduced lameness observed in turkeys reared in a high intensity step-up (HISU) lighting programme as compared to a low intensity step-down (LISD) lighting regimen cannot be explained by differences in the inorganic matrix of the bone, because the proportions of bone ash, bone ash calcium, and bone ash phosphorus did not differ between lighting programmes. At 17 weeks of age, there was a significant difference in the proportion of closed growth plates in males reared on the HISU programme rather than on LISD lighting. These results support the hypothesis that HISU lighting reduces lameness by promoting earlier growth plate closure of long bones.     

Foot pad dermatitis develops at an early age in commercial turkeys

1. A field experiment was conducted to identify the macroscopic and histological changes associated with the development of foot pad dermatitis (FPD) in growing turkeys. Two affected and two unaffected turkeys were sampled weekly from 1 to 8 and at 10 and 21 weeks of age. 2. At one week old, birds with external signs of FPD (surface skin discolouration) showed abnormal cellular changes of the foot pad integument. As the flock aged the reactions intensified, with one sample exhibiting a fully developed macroscopic lesion at 3 weeks. 3. Major pathological changes had occurred by 6 weeks and all turkeys with external signs of lesions had fully developed microscopic inflammatory cellular lesions. From 6 weeks of age onwards lesions were increasingly numerous and became more overtly necrotic. 4. Externally normal foot pads showed microscopic evidence of lesions after the turkeys reached 4 weeks. 5. We conclude that FPD lesions become severe over a short period of time and at a very early age.