Skeletal deformities associated with nutritional congenital rickets in newborn lambs

Abstract

CASE HISTORY: A group of 545 pregnant rising 2-year-old Coopdale ewes on a Southland sheep farm were grazed over winter on a fodder beet (Beta vulgaris) crop. Subsequently, 45 out of approximately 750 lambs were born with a variety of skeletal deformities, including shortened limbs, varus and valgus angular limb deformities, palmar grade stance and cranial bowing of the carpus. Analysis of the crop showed the fodder beet contained a low percentage of phosphorus. In addition, 60 out of 460 rising 2-year-old ewes that had been grazed on the fodder beet crop as 1-year-olds had incisor abnormalities and malocclusion.

PATHOLOGICAL FINDINGS: Two affected lambs (1-day-old and 3-days-old) with representative clinical signs examined postmortem were found to have markedly enlarged costochondral junctions, and noticeably enlarged long bone metaphyses. In addition, one lamb had a dense band of metaphyseal sclerosis beneath the physes of all long bones examined. Histopathological findings included small islands and columns of chondrocytes and eosinophilic cartilage matrix present in the metaphysis. Metaphyseal trabeculae were disorganised and often lined by accumulations of pale pink osteoid; similar pale pink osteoid was also present in the cortices. Unerupted molar teeth in the affected lambs lacked a layer of enamel, and the dentine was irregular with globular basophilia.

DIAGNOSIS: The gross and histopathological lesions were consistent with a diagnosis of rickets.

CLINICAL RELEVANCE: Nutritional congenital rickets has not been previously diagnosed in sheep, but is a recognised disease of human infants with vitamin D deficient mothers. The rickets in affected lambs was most likely associated with phosphorus deficiency as a result of the pregnant ewes grazing fodder beet during gestation. While vitamin D deficiency was not definitively ruled out in these cases, practitioners are alerted to the possible effects of feeding phosphorus-deficient fodder beet to ewes for long periods during gestation and to 1-year-old sheep during important growth periods.     

Analysis of a survey of metabolic disorders

Extract

This survey was instigated in an endeavour to determine the overall incidence of metabolic disorders in dairying herds in the area covered by the Huntly District Veterinary Club. Response to treatment and mortality figures are also included.     

The impact of highly concentrated Mo and Cu dietary supplements,fed as a bolus,on the efficacy of chelated versus inorganic Cu in cattle on a low-Cu diet

AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.     

Blood sampling for inorganic phosphate analysis

Extract

It has been the, policy of this laboratory to request that blood samples for inorganic phosphate analysis be collected in potassium oxalatesodium fluoride anticoagulant but the origin of this recommendation is obscure. The recommendation is presumed to be based on the premise that fluoride ion inhibits a wide range of enzymes that hydrolyse phosphate esters and release phosphate ions.     

T cell rich,B cell lymphoma in the small colon of a yearling horse

A one‐year‐old, Thoroughbred colt presented for evaluation due to a one month history of fever of unknown origin and progressive weight loss. On initial presentation, the horse was febrile and showed signs localised to the respiratory tract. These included bilaterally increased bronchovesicular sounds and a moderate, diffuse interstitial pattern on thoracic radiographs. A transtracheal wash yielded mucopurulent debris, culture of which grew small numbers of Staphylococcus epidermidis and Aspergillus spp. The horse was discharged with a diagnosis of bronchointerstitial pneumonia and placed on antibiotic therapy. Ten days after initial presentation, he developed abdominal pain that was unresponsive to on‐farm treatment. The horse was febrile, displayed increased respiratory rate and effort, and showed moderate signs of abdominal pain. On rectal examination, a firm, 8–10 cm mass was palpated on midline. The colt was admitted to the hospital and scheduled for exploratory laparotomy, but died a short time later before surgery could be performed. This report describes the clinical, diagnostic and histopathological findings of a case of alimentary lymphoma in a yearling colt.     

Responses of swamp bay,Persea palustris,and avocado,Persea americana,to various concentrations of the laurel wilt pathogen,Raffaelea lauricola

Laurel wilt, caused by the fungus Raffaelea lauricola and transmitted by the exotic ambrosia beetle Xyleborus glabratus, has killed members of the Lauraceae plant family throughout the southeast United States. A series of experiments were conducted to examine the effects of inoculum concentration on the development of laurel wilt in swamp bay, Persea palustris, and avocado, Persea americana. In each experiment, host plants were inoculated with aqueous suspensions of 10², 10³, 10⁴ or 10⁵ conidia of R. lauricola, and plants were rated periodically for external symptom development (wilting and foliar dieback). At the end of experiments, plants were rated for internal symptoms of the disease (discoloration of sapwood) and assayed for R. lauricola on a semi‐selective medium. Symptom severity in swamp bay was significantly lower for the 10² treatment than at higher (10³–10⁵) concentrations, whereas 10² and 10³ conidia caused less disease than 10⁴ and 10⁵ conidia in avocado. At the lowest inoculum concentration, 67% of the swamp bay plants and 20% of the avocados died by the time the respective experiments were terminated. The pathogen was recovered from a high proportion of the symptomatic sapwood of swamp bay (100%) and avocado (94%), and sapwood discoloration and recovery of R. lauricola from inoculated stems of swamp bay were highly correlated with recovery of the pathogen and symptom development in roots. Clearly, swamp bay and avocado are very sensitive to R. lauricola. The ability of only 100 conidia of this pathogen to kill these hosts suggests that few individuals of X. glabratus or other ambrosia beetles that carry low levels of the pathogen would be sufficient to transmit conidia that infect and lead to disease development. The results are also relevant to the development of disease‐tolerant host selections, as they indicate levels of the pathogen appropriate for use in screening plants for disease resistance.     

Uptake and nutrient balance of nitrogen,sulfur, and boron for optimal canola production in eastern Canada

Balanced plant nutrition is essential to achieve high yields of canola (Brassica napus L.) and get the best economic return from applied fertilizers. A field study was conducted at nine site‐years across eastern Canada to investigate the effects of nitrogen (N), sulfur (S) and boron (B) fertilization on canola nutrient uptake, nutrient balance, and their relationship to canola yields. The factorial experiment consisted of four N rates of 0 (N0), 50 (N50), 100 (N100), and 150 (N150) kg ha^?1, two S rates of 0 (S0) and 20 (S20) kg ha^?1, and three B treatments of 0 (B0), 2 kg ha^?1 at preplant (B2.0P), and 0.5 kg B ha^?1 foliar‐applied at early flowering stage (B0.5F). Each site‐year used the same experimental design and assigned treatments in a randomized complete block design with four replications. Fertilizer S application greatly improved seed yields at six out of nine site‐years, and the highest N use efficiency was in the N150+S20 treatment. Sulfur application generally increased seed S concentration, seed S removal, and plant total S uptake, while B fertilization mainly elevated straw B concentration and content, with minimal effect on seed yields. At the early flowering stage, plant tissue S ranged from 2.2 to 6.6 mg S g^?1, but the N : S ratio was over or close to the critical value of 12 in the N150+S0 combination at five site‐years. On average across nine site‐years, canola reached a plateau yield of 3580 kg ha^?1 when plants contained 197 kg N ha^?1, 33 kg S ha^?1 and 200 g B ha^?1, with a seed B content of 60 g B ha^?1. The critical N, S, and B values identified in this work and their potential for a posteriori nutrient diagnosis of canola should be useful to validate fertilizer requirements for canola production in eastern Canada.     

Effects of postharvest preparation on organophosphate insecticide residues in apples

Apples were sampled directly from orchard trees at 96, 45, and 21 days postapplication with one of three organophosphate insecticides (azinphos methyl, phosalone, or phosmet, respectively). Individual apples were prepared for analysis following one of three postharvest preparations: no preparation, rinsed with deionized water for 10-15 s, or rinsed and peeled. Azinphos methyl, phosalone, and phosmet concentrations ranged from below the level of detection to 5.26 ng/g, 94.7 to 5720 ng/g, and 0.011 to 663 ng/g in the apples that received no postharvest preparation, respectively. Although rinsed apples had lower maximum concentrations than observed in apples with no preparation, levels were not significantly lower. Concentrations of all three OP insecticides in apples that were rinsed followed by peeling, however, were much lower (below detection limits to 0.733 ng/g, azinphos methyl; 0.322-219 ng/g, phosalone; and below detection limits to 44.0 ng/g, phosmet) than observed in apples that had been rinsed alone. Rinsing and peeling of apples resulted in a 74.5-97.9% reduction in OP residues, while rinsing alone lowered mean concentrations by 13.5-28.7% relative to apples that received no postharvest preparation.