An osteodystrophy apparently caused by vitamin D deficiency in growing pigs

An osteodystrophy with features of both rickets and fibrous osteodystrophy was diagnosed in growing pigs housed indoors and fed on a diet deficient in vitamin D. Affected pigs were severely lame and preferred to remain recumbent. At necropsy, the long bones had reduced breaking strength and in one tive-month- old pig the articular surfaces of both proximal humeri were indented due to collapse of subchondral bone.

Microscopic changes in the bones included prominent osteoclastic activity in the proximal metaphyses, variable myelofibrosis, trabecular microfractures, and focal thickening of the hypertrophic zone in some growth plates.

Treatment consisted of an injection of Vitamin D₃, addition of dicalcium phosphate to the diet for 18 days and long-term supplementation of the diet with fat-soluble vitamins. This is the first report of an osteodystrophic disease in pigs in New Zealand.     

Osteodystrophia fibrosa in two guinea pigs.

Two adult guinea pigs were examined because they were lethargic and reluctant to walk. Additionally, I guinea pig had otitis media, and the other had dental malocclusion. Both guinea pigs had been fed a commercially available diet of cereals and pellets enriched with vitamin C and formulated for this species. Radiographically, the guinea pigs had coarse trabecular bone patterns, skeletal deformations, pathologic fractures, and polyarthritic degenerative joint disease. A double cortical line was also evident on several long bones, the pelvis, and the vertebrae. A diagnosis of osteopenia was confirmed by use of dual-energy x-ray absorptiometry. Analysis of a food sample fed to 1 guinea pig revealed calcium and phosphorus contents of 0.524 and 0.425%, respectively (Ca:P ratio, 1.23:1). Microscopic examination of bone tissue from both guinea pigs revealed severe fibrous osteodystrophy. Nutritional secondary hyperparathyroidism caused by calcium-phosphorus imbalance was considered to be the underlying cause of osteodystrophia fibrosa in both guinea pigs.     

Fibrous osteodystrophy in dromedary camels (Camelus dromedarius).

Fibrous osteodystrophy of the facial and long bones was diagnosed in four dromedary camels (Camelus dromedarius). None of the animals responded to treatment with antiinflammatory medications or calcium supplements. The lesions were probably caused by multiple factors, including inappropriate diet and gastrointestinal parasitism. A critical factor in lesion formation may have been vitamin D deficiency secondary to gastrointestinal malabsorption and inadequate winter exposure to ultraviolet light.     

Changes in gastric contents in pigs fed a finely ground and pelleted or coarsely ground meal diet.

The objective was to characterize the change in stomach contents in relation to time after feeding between pigs consuming a restricted amount of a finely ground and pelleted (FGP) or coarsely ground meal (CGM) diet. Particular interest was placed on the concentration of organic acids and ammonia, the products of microbial fermentation. Thirty barrows were ranked by weight and assigned to a postfeeding time of 2, 4, 6, 8, or 12 h and either the FGP or CGM diet. Initiation and termination of the experiment were staggered over a 2-wk period. The treatment period was 42 d. Percentage of dry matter was higher (P<.01) in the stomach contents of pigs on the CGM diet. Concentrations of pepsin and protein were higher (P<.05) and ammonia tended to be higher (P = .10) in the proximal stomach of pigs fed the FGP diet. In contrast, concentrations of acetate and L-lactate were higher (P<.05) in the proximal stomach of pigs fed the CGM diet. All pigs on the CGM diet had stomachs that graded as normal on visual inspection. There was variable damage to the stomachs of pigs on the FGP diet. Measurement of chromium concentration in the stomach after an oral dose of Cr-EDTA clearly demonstrated the mixing that occurs between the proximal and distal stomach by 2 h after feeding in pigs consuming the FGP diet, whereas a gradient was maintained in pigs consuming the CGM diet. Thus, components normally secreted in the distal stomach return to the proximal stomach. These data show that components secreted in the distal region, such as acid and pepsin, may play a role in initiating damage to the stratified squamous mucosa. High concentrations of organic acids in the stomach of pigs on the CGM diet were not associated with damage to the stratified squamous mucosa in the esophageal region.     

Response to dietary phosphorus deficiency is affected by genetic background in growing pigs

Concern over the environmental effect of P excretion from pig production has led to reduced dietary P supplementation. To examine how genetics influence P utilization, 94 gilts sired by 2 genetic lines (PIC337 and PIC280) were housed individually and fed either a P-adequate diet (PA) or a 20% P-deficient diet (PD) for 14 wk. Initially and monthly, blood samples were collected and BW recorded after an overnight fast. Growth performance and plasma indicators of P status were determined monthly. At the end of the trial, carcass traits, meat quality, bone strength, and ash percentage were determined. Pigs fed the PD diet had decreased (P < 0.05) plasma P concentrations and poorer G:F (P < 0.05) over the length of the trial. After 4 wk on trial, pigs fed the PD diet had increased (P < 0.05) plasma 1,25(OH)(2)D(3) and decreased (P < 0.05) plasma parathyroid hormone compared with those fed the PA diet. At the end of the trial, pigs fed the PD diet had decreased (P < 0.05) BW, HCW, and percentage fat-free lean and tended to have decreased LM area (P = 0.06) and marbling (P = 0.09) and greater (P = 0.12) 10th-rib backfat than pigs fed the PA diet. Additionally, animals fed the PD diet had weaker bones and also decreased (P < 0.05) ash percentage and increased (P < 0.05) concentrations of 1alpha-hydroxylase and parathyroid hormone receptor mRNA in kidney tissue. Regardless of dietary treatment, PIC337-sired pigs consumed more feed and gained more BW than their PIC280-sired counterparts (P < 0.05) during the study. The PIC337-sired pigs also had greater (P < 0.05) HCW, larger (P < 0.01) LM area, and tended to have (P = 0.07) greater dressing percentage. Meat from the PIC337-sired pigs also tended to have greater (P = 0.12) concentrations of lactate but decreased (P = 0.07) concentrations of total glucose units 24 h postslaughter. Although plasma 1,25(OH)(2)D(3) concentrations were elevated (P < 0.05) in all the animals fed the PD diet, this elevation due to P deficiency tended (P = 0.09) to be greater in the PIC337-sired pigs after 12 wk on the treatment. The PIC337-sired pigs had stronger (P < 0.01) bones with greater ash percentage than the PIC280-sired pigs. The difference in the strength of the radii between the PIC337-sired pigs fed the PA and PD diets was greater than their PIC280-sired counterparts, which resulted in sire line x treatment interactions (P < 0.05). These data indicate differing mechanisms of P utilization between these genetic lines. Elucidating these mechanisms may lead to strategies to increase efficiency of growth in a more environmentally friendly manner.     

Performance,carcass and technological meat quality of pigs in indoor and outdoor production systems

Abstract

This study aimed to compare different production systems, i.e., the combined effect of outdoor and indoor rearing of pigs and organic diets fed ad libitum or restrictively. Furthermore, the suitability of two breed crosses for outdoor rearing was studied. The effects on performance, carcass and technological quality traits were investigated. During two years, 240 pigs of Duroc x Large White (D*LW) and Swedish Landrace x Large White (L*LW) were allocated to three production systems: 1) Pigs kept outdoors, fed an organic diluted diet (20% alfalfa roughage) ad libitum; 2) Pigs kept outdoors, strategically fed a diluted organic diet up to a live weight of approximately 80 kg and thereafter an undiluted organic diet ad libitum; 3) Pigs kept indoors, fed an undiluted organic diet restrictively. For outdoor pigs, strategic feeding increased daily weight gain and backfat thickness, compared with feeding a diluted diet throughout (p≤0.01). L*LW pigs in both outdoor systems grew slower than in the indoor system (p≤0.001), whereas for D*LW pigs only outdoor pigs fed the diluted diet had a slower growth rate. Outdoor pigs had lower dressing percentage than indoor pigs. Glycogen content and L* values in M. longissimus dorsi were higher, whereas b* values were lower in meat from pigs in the indoor system. D*LW pigs had higher water-holding capacity (lower drip, thawing and cooking losses), lower shear force and higher intramuscular fat content compared with L*LW pigs.     

Quantities of ash,Ca, and P in metacarpals,metatarsals, and tibia are better correlated with total body bone ash in growing pigs than ash,Ca, and P in other bones

The objective was to determine correlations between individual bones and total body bone ash to identify the bone that is most representative of total body bone ash in growing pigs. Twenty growing pigs were allotted to 1 of 2 diets that were formulated to contain 60% or 100% of the requirement for standardized total tract digestible (STTD) P. Both diets had an STTD Ca to STTD P ratio of 1.90:1. Growth performance and carcass weights were determined. Metacarpals, metatarsals, femur, tibia, fibula, 3rd and 4th ribs, and 10th and 11th ribs, and all other bones from the left half of the carcass were collected separately. Each bone was defatted and ashed. Pigs fed the diet containing 100% of required Ca and P had greater (P < 0.05) average daily gain, gain to feed, and ash concentration (%) in total and all individual bones except femur and fibula compared with pigs fed the diet containing 60% of required Ca and P. Calcium and P concentrations in bone ash were not affected by dietary treatments. Weights (g) of bone ash, bone Ca, and bone P were greater (P < 0.05) or tended to be greater (P < 0.10) for pigs fed the diet containing 100% of required Ca and P. Correlation coefficients between the weight of ashed metacarpals, metatarsals, and tibia and the weight of total bone ash were >0.95. In conclusion, metacarpals, metatarsals, and tibia were more representative of total body bone ash compared with other bones.     

Effect of dietary inclusion of distillers dried grains with solubles, soybean hulls, or a polyclonal antibody product on the ability of growing pigs to resist a Lawsonia intracellularis challenge

An experiment was conducted to determine if dietary inclusion of distillers dried grains with solubles (DDGS), soybean hulls, or soybean hulls sprayed with an egg-based, polyclonal antibody product would reduce the incidence or severity of infection, or both, in growing pigs after a Lawsonia intracellularis challenge. One hundred 17-d-old weaned pigs were blocked by sex, ancestry, and BW, and randomly allotted to 1 of 5 treatment groups: negative control, unchallenged, corn-soy diet; positive control, challenged, corn-soy diet; 20% DDGS diet (D), challenged; 5% soybean hulls diet (SH), challenged; and SH sprayed with a polyclonal antibody product diet, challenged. Challenged pigs were orally inoculated with 6.4 x 10(8) L. intracellularis organisms after a 4-wk prechallenge feeding period. On d 21 postchallenge, pigs were euthanized, lesions of intestinal mucosa were evaluated, and ileal tissue samples were analyzed by immunohistochemistry to determine the presence and proliferation rate of L. intracellularis. Challenging pigs with L. intracellularis reduced growth rate, feed intake, and efficiency of gain (P < 0.02) and increased the proportion of internal organ weights relative to BW (P < 0.01). Dietary treatment did not affect growth performance pre- or postchallenge (P > 0.10). Heart, empty stomach, and liver weights were similar among dietary treatments (P > 0.10). Weight of the large intestine as a percentage of BW was increased in D and SH pigs compared with positive control pigs (P < 0.05). Lesion length, prevalence, and severity, and fecal shedding of L. intracellularis were primarily unaffected by dietary treatment (P > 0.10), although ileal lesion length and severity observed tended to be greater in the SH sprayed with polyclonal antibody product diet vs. the D pigs (P < 0.10). Results from a previous study indicated that diet composition may affect length, severity, and prevalence of lesions caused by L. intracellularis in growing pigs subjected to a moderate challenge. However, beneficial results were not observed by feeding the dietary treatments used in this study.     

Nutrition in relation to skeletal growth deformities

The pathophysiology of alimentary hyperparathyroidism and its pathological fractures and growth deformities are described. Renal hyperparathyroidism with hyperostotic osteodystrophy in young animals and isostotic osteodystrophy in old animals is briefly mentioned. Hypercalcitoninism caused by excessive prolonged calcium intake in growing dogs will go together with disturbances in skeletal remodelling and disturbed enchrondral ossification, leading to such entities as canine wobbler syndrome, enostosis, osteochrondrosis dissecans, and radius curvus syndrome. Dogs, who are dependent upon dietary vitamin D sources, can develop rickets with skeletal growth deformities when a diet deficient in vitamin D is fed under controlled conditions. Growth plates and mineralisation grade normalised when commercial dog food was given. As a sole therapy normalisation of the diet will not be sufficient in all skeletal growth deformities as described above. Prevention by feeding diets with optimal contents will be of benefit to veterinarians and their patients.     

Effect of dietary phosphorus levels on porcine renal 25-hydroxyvitamin D-1 alpha- and 24R-hydroxylase activities and plasma 1,25-dihydroxyvitamin D3 concentration

Results of studies on the effect of dietary P deprivation on pig renal 1 alpha- and 24-hydroxylase activities and on concentrations of plasma alkaline phosphatase, Ca, P and vitamin D metabolites are presented. Renal 1 alpha-hydroxylase activity was increased six- to eightfold and plasma 1,25-dihydroxyvitamin D3 concentration increased two- to threefold in pigs fed a low P diet (.085% P) compared with pigs fed a control diet (.6% P). In contrast, renal 24-hydroxylase activity and plasma 25-hydroxyvitamin D concentration did not differ between diet groups. Plasma alkaline phosphatase activity was two to four times higher in pigs fed the low P diet compared with pigs fed the control diet. The rate of gain by pigs fed the low P diet was less than pigs fed the control diet. The low P diet was associated with a prolonged elevation of renal 1 alpha-hydroxylase activity in spite of the presence of a pronounced hypercalcemia.     

Relative bioavailability of phosphorus in inorganic phosphorus sources fed to growing pigs

The relative bioavailability of P in 5 sources of inorganic P was determined using growing pigs. The 5 sources of inorganic P were dicalcium phosphate (DCP), monocalcium phosphate (MCP) containing 50% MCP (MCP50), MCP containing 70% MCP (MCP70), MCP containing 100% MCP (MCP100), and monosodium phosphate (MSP). A total of 11 diets were formulated. The basal diet was formulated to contain 0.10% P, and 10 additional diets were formulated by adding 0.07 or 0.14% P from each of the 5 P sources to the basal diet. Growing pigs (n = 44; initial BW: 16.8 ± 4.3 kg) were individually housed and randomly allotted to the 11 experimental diets. Feed was provided on an ad libitum basis throughout the 28-d experimental period. At the conclusion of the experiment, all pigs were killed, and 4 bones (i.e., the third and fourth metacarpals on both front feet) were harvested. Bone-breaking strength, bone ash, and Ca and P concentrations were determined. The concentration of bone ash increased (P < 0.05) as MCP50, MCP70, MCP100, or MSP were added to the basal diet, and the concentration of bone P also increased (P < 0.05) as MCP70, MCP100, or MSP were added to the basal diet. The relative bioavailability of P in each of the feed phosphates was determined using slope ratio methodologies based on breaking strength, and expressed relative to MSP. The slope of the regression line for diets containing MSP or MCP100 was steeper (P < 0.05) than the slope for pigs fed the diet containing DCP, but not different (P > 0.05) from that of pigs fed diets supplemented with MCP50 or MCP70. In conclusion, P in MSP and MCP100 is more bioavailable than P in DCP, but there were no differences within MCP sources.     

Feed physical form and formic acid addition to the feed affect the gastrointestinal ecology and growth performance of growing pigs

The effect of feeding a coarsely ground meal (COARSE) and a finely ground pelleted diet with 1.8% (as-fed basis) added formic acid (ACID) was compared with feeding a standard finely ground pelleted diet (STD) on the gastrointestinal ecology of growing pigs at different intervals after feeding. One hundred five castrated male growing-finishing pigs (initial BW 27 kg) were used. At a BW of 63 kg, 60 pigs were killed 0.5, 2.5, 4.5, 6.5, and 8.5 h after feeding, and samples from the gastrointestinal tract (GIT) were obtained. The remaining 45 pigs were kept on the experimental diets to a BW of 99 kg. Feeding the three diets resulted in a similar pattern of gastric pH with time, (i.e., highest pH values 0.5 h after feeding and decreasing values at the following sampling times, to reach a value of 2.12 at 8.5 h after feeding). The pH of the gastric digesta of pigs fed the ACID diet was below 4 at all sampling times, whereas the digesta from the other two dietary groups had values above pH 4 at the first sampling times. Feeding the ACID diet decreased the counts of total anaerobes in the proximal GIT (P < or = 0.007), and of lactic acid bacteria (P < or = 0.001), enterobacteria (P < or = 0.02), and yeasts (P < or = 0.01) along the GIT compared with feeding the other two diets. Feeding the COARSE diet stimulated the growth of total anaerobes and lactic acid bacteria in the stomach and distal small intestine increased the microbial diversity mainly in the stomach (P = 0.001), compared with feeding the other two diets (P < or = 0.09), and decreased the number of enterobacteria in the cecum compared with the STD diet (P = 0.03), with the same tendency in the mid-colon (P = 0.07). The concentration of lactic acid in the stomach was highest in the pigs fed the COARSE diet compared with the other two groups (P < 0.05). The concentration of formic acid was highest in the stomach and all segments of the small intestine of the pigs fed the ACID diet compared with those fed the STD and COARSE diets (P < 0.05). The results from this study suggest that feeding a coarsely ground diet and a finely ground diet with added formic acid affect the gastrointestinal ecology of pigs mainly by changing the environment in the proximal GIT. The presence of organic acids in the proximal GIT is a crucial factor contributing to the decrease in the number of enterobacteria along the GIT. The time after feeding at which samples are taken to measure characteristics describing the gastrointestinal ecology affects the results from the stomach and small intestine.     

Effect of microbial phytase addition with or without the trace mineral premix in nursery, growing, and finishing pig diets

Two experiments were conducted to determine the interactive effects of phytase with and without a trace mineral premix (TMP) in diets for nursery, growing, and finishing pigs on growth performance, bone responses, and tissue mineral concentrations. Pigs (initial and final BW of 5.5 and 111.6 kg [Exp. 1] or 5.4 and 22.6 kg [Exp. 2]) were allotted to treatments on the basis of BW with eight (Exp. 1) or six (Exp. 2) replications of six or seven pigs per replicate pen. Pigs were started on the diets the day of weaning (average of 18 d). In both experiments, the treatments were with or without 500 phytase units/kg of diet and with or without the TMP in a 2 x 2 factorial arrangement. The Ca and available P concentrations were decreased by 0.10% in diets with phytase. The nursery phase consisted of Phase I (7 d), Phase II (14 d), and Phase III (13 d) periods. In Exp. 1, 26 of 52 pigs fed the diet without the TMP and without phytase had severe skin lesions and decreased growth performance; therefore, pigs fed this diet were switched to the positive control diet. In Exp. 2, the treatment without the TMP and without phytase had 12 replications instead of six. At the end of Phase III, half these replications were switched to the positive control diet and half were switched to the diet without the TMP but with phytase. In Exp. 1 during Phases II and III and in the overall data, pigs fed the diet without the TMP had decreased ADG and ADFI, but the addition of phytase prevented these responses (phytase x TMP; P < 0.02). Growth performance was not affected by diet during the growing-finishing period. Coccygeal bone Zn and Na concentrations were decreased (P < 0.09) in pigs fed the diet without the TMP, and adding phytase increased (P < 0.03) Zn and Fe concentrations. In Exp. 2 during Phases I and II, pigs fed the diet without the TMP had decreased ADG, but the addition of phytase prevented this response (phytase x TMP; P < 0.10). Pigs fed the diet without the TMP had decreased (P < 0.10) ADG (Phase II and overall), ADFI (Phases II and III and in the overall data), and G:F (Phase III). Coccygeal bone Zn and Cu concentrations were decreased (P < 0.09) in pigs fed the diet without the TMP, and adding phytase increased (P < 0.03) Zn concentration in the bones. These data indicate that removing the TMP in diets for nursery pigs decreases growth performance and bone mineral content, and that phytase addition to the diet without the TMP prevented the decreased growth performance.     

Effect of spray-dried plasma and lipopolysaccharide exposure on weaned pigs: II. Effects on the hypothalamic-pituitary-adrenal axis of weaned pigs

A study was conducted with 20 weaned barrows (14 d, 4.98 +/- 0.21 kg) to determine the effect of feeding spray-dried plasma (SDP) after weaning on the pig's stress response to a lipopolysaccharide (LPS) challenge. After weaning, pigs were fed a diet containing 0 or 7% SDP for 7 d. On d 6 after weaning, all pigs were nonsurgically fitted with a jugular catheter. On d 7 after weaning, the pigs were given i.p. injections of either saline or LPS (150 microg/kg BW) followed by serial blood collection every 15 min for a 3-h period. Following the 3-h blood collection, all pigs were killed and tissue was collected for mRNA analysis. Pig weight on d 7 after weaning was not affected by dietary treatment (P > 0.21). Pigs fed the diet with SDP had lower (P < 0.05) levels of hypothalamic corticotropin-releasing hormone (CRH) mRNA, pituitary gland CRH receptor mRNA, and adrenal gland adrenocorticotropin-releasing hormone (ACTH) receptor mRNA. Dietary treatment did not affect pituitary gland proopiomelanocortin (POMC) mRNA. No effect of LPS treatment was observed in any of the mRNA levels examined. For both serum ACTH and cortisol, there was a significant diet x LPS treatment interaction (P < 0.01) such that both the ACTH and cortisol responses to the LPS challenge were greater in the pigs fed the diet with SDP than in the pigs fed the diet without SDP. For pigs given the saline injection, diet did not affect basal serum cortisol concentration; however, basal serum ACTH concentration was lower in those pigs fed the diet with SDP (P < 0.0001). A diet x LPS treatment interaction (P < 0.024) was observed for adrenal gland mRNA expression for steroidogenic acute regulatory (StAR) protein such that the LPS-induced increase in StAR mRNA was greater in the pigs fed SDP than in pigs fed the diet without SDP. These results demonstrate that pigs fed a diet with SDP have an increased activation of the pituitary-adrenal axis following an LPS challenge compared to pigs fed a diet without SDP.     

Hypertrophic osteodystrophy of the proximal humerus in two dogs

Two dogs, 3 and 6 months of age, were presented with painful, swollen shoulder and carpal joints; reluctance to stand; and pyrexia. Radiographs in both cases revealed an irregular lucent zone in the metaphysis of the proximal humerus, parallel and adjacent to the physis. The same lucent zone was also evident in the physes of the distal radial and ulnar metaphyses. Clinical signs and radiographs were consistent with hypertrophic osteodystrophy. Clinical signs resolved in both dogs with administration of carprofen, tramadol, and intravenous fluids. No signs of recurrence were reported at 3-month follow-ups.     

Fecal microbiome of growing pigs fed a cereal based diet including chicory(Cichorium intybus L.) or ribwort(Plantago lanceolata L.) forage

Background: The purpose of this study was to investigate how inclusion of chicory forage or ribwort forage in a cereal-based diet influenced the fecal microbial community(microbiome) in newly weaned(35 days of age) piglets.The piglets were fed a cereal-based diet without(B) and with inclusion(80 and 160 g/kg air-dry forage) of vegetative shoots of chicory(C) and leaves of ribwort(R) forage in a 35-day growth trial. Fecal samples were collected at the start(D0), 17(D17) and 35(D35) days after weaning and profiles of the microbial consortia were generated using terminal restriction fragment length polymorphism(T-RFLP). 454-FLX pyrosequencing of 16 S r RNA gene amplicons was used to analyze the microbial composition in a subset of the samples already analyzed with T-RFLP.Results: The microbial clustering pattern was primarily dependent on age of the pigs, but diet effects could also be observed. Lactobacilli and enterobacteria were more abundant at D0, whereas the genera Streptococcus, Treponema,Clostridium, Clostridiaceae1 and Coprococcus were present in higher abundances at D35. Pigs fed ribwort had an increased abundance of sequences classified as Treponema and a reduction in lactobacilli. However, the abundance of Prevotellaceae increased with age in on both the chicory and the ribwort diet. Moreover, there were significant correlations between the abundance of Bacteroides and the digested amount of galactose, uronic acids and total non-starch polysaccharides, and between the abundance of Bacteroidales and the digested amount of xylose.Conclusion: This study demonstrated that both chicory and ribwort inclusion in the diet of newly weaned pigs influenced the composition of the fecal microbiota and that digestion of specific dietary components was correlated with species composition of the microbiota. Moreover, this study showed that the gut will be exposed to a dramatic shift in the microbial community structure several weeks after weaning.     

Association between findings on palmarodorsal radiographic images and detection of a fracture in the proximal sesamoid bones of forelimbs obtained from cadavers of racing Thoroughbreds

OBJECTIVE: To determine the distribution for limbs and bones in horses with fractures of the proximal sesamoid bones and relationships with findings on palmarodorsal radiographic images. SAMPLE POPULATION: Proximal sesamoid bones obtained from both forelimbs of cadavers of 328 racing Thoroughbreds. PROCEDURE: Osteophytes; large vascular channels; and fracture location, orientation, configuration, and margin distinctness were categorized by use of high-detail contact palmarodorsal radiographs. Distributions of findings were determined. Relationships between radiographic findings and fracture characteristics were examined by use of chi2 and logistic regression techniques. RESULTS: Fractures were detected in 136 (41.5%) horses. Biaxial fractures were evident in 109 (80%) horses with a fracture. Osteophytes and large vascular channels were evident in 266 (81%) and 325 (99%) horses, respectively. Medial bones typically had complete transverse or split transverse simple fractures, indistinct fracture margins, > 1 vascular channel that was > 1 mm in width, and osteophytes in abaxial wing and basilar middle or basilar abaxial locations. Lateral bones typically had an oblique fracture and distinct fracture margins. Odds of proximal sesamoid bone fracture were approximately 2 to 5 times higher in bones without radiographic evidence of osteophytes or large vascular channels, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Biaxial fractures of proximal sesamoid bones were common in cadavers of racing Thoroughbreds. Differences between medial and lateral bones for characteristics associated with fracture may relate to differences in fracture pathogeneses for these bones. Osteophytes and vascular channels were common findings; however, fractures were less likely to occur in bones with these features.     

Improving pork quality by feeding supranutritional concentrations of vitamin D3

Duroc-cross pigs (n = 25) were assigned to one of three experimental finishing diets containing 0 (control), 40,000 (40), or 80,000 (80) IU of supplemental vitamin D3/kg of feed (as-fed basis)to test the effects of vitamin D3 on pork quality traits. Experimental diets were fed for 44 or 51 d before slaughter, and days on feed were blocked in the experimental design. A trend existed for pigs receiving the highest concentration of vitamin D3 supplementation to have a lower (P = 0.08) ADG (0.77 kg/d) compared with pigs fed either the 40-diet (0.88 kg/d) or control (0.92 kg/d). Diet did not (P > 0.10) affect backfat thickness measured along the midline, 10th-rib fat depth, longissimus muscle area, muscle score, or hot carcass weights. Longissimus pH, measured at 0.5, 1, 2, 3, 4, and 24 h postmortem, was higher (P < 0.05) for pigs on the 80-diet than those fed the control diet. Longissimus muscle color, measured at 24 h postmortem, from pigs fed either the 40- or 80-diet were darker (lower L* values; P < 0.05) than those fed the control diet. Objective longissimus color scores were higher (P < 0.01), and firmness/wetness scores lower (P < 0.05), for pigs on the 80-diet as compared to those on the 40-diet or control diet. The diet had no (P > 0.10) effect on Warner-Bratzler shear force values; percentage of cook loss; or trained sensory panel evaluations for tenderness, juiciness, and flavor. Feeding the 80-diet increased (P < 0.05) plasma vitamin D3 and calcium after 2, 4, and 6 wk on feed compared with the control diet. Vitamin D3 and 25-hydroxy vitamin D3 concentrations in the longissimus muscle increased (P = 0.001) with increasing vitamin D3 levels in the diet; however, muscle calcium concentrations and fiber type were not (P > 0.30) affected by diet. These results indicate that feeding supranutritional levels of vitamin D3 for at least 44 d improves pork color and increases pH, but may retard growth if fed at 80,000 IU/kg of feed.     

Vitamin A toxicity: comparative changes in bone of the broiler and leghorn chicks

Severe skeletal lesions were produced in both broilers and leghorns orally administered toxic levels of vitamin A (330 or 660 IU vit. A/g body weight X day) for 21 consecutive days. Hypervitaminosis A in broilers produced an osteodystrophy characterized by abnormal thickening of the proliferative-maturation zone, metaphyseal sclerosis, hyperosteoidosis, decreased number of osteoclasts, and parathyroid gland hyperplasia. In leghorns, the osteodystrophic lesions were characterized by a thin proliferative-maturation zone, a relatively thickened hypertrophy zone, flattened spindle-shaped osteoblasts, and osteoporosis. In both broilers and leghorns given excessive vitamin A, the osteogenic layer of periosteum in all bones was thin.