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The value of precise dual energy X-ray absorptiometry (DEXA) cut weight predictions to lamb allocation to cut plans is unknown. Lambs (n = 191) varying in carcase weight (HSCW) and GR (tissue depth over the 12th rib) were DEXA scanned and boned out to weigh retail cuts. Cut weights were predicted using HSCW; HSCW + GR; HSCW + DEXA and HSCW + DEXA image components in GLM models. DEXA improved cut weight predictions in most cuts (P < 0.05). A dataset of 10,000 carcases was then simulated using the associations between HSCW, GR and cut weights, before being truncated to 4500 lambs representing onel day's HSCW distribution. A lamb Carcase Optimisation Tool scenario was developed with 2-3 cut options per carcase section and cut weight thresholds applied to several cuts. Processing costs, market values and actual cut weights were input into the Optimiser to determine carcase allocation to cut options for optimised profits. This scenario was repeated using the predicted cut weights to determine the cut misallocations caused. DEXA-predicted cut weights produced 16.7% and 8.0% less misallocations than HSCW and GR. DEXA produced 20.8% and 14.3% less misallocations than HSCW and GR in shortloins, and 25.5% and 12.9% less in hindquarters. While cut misallocations have little direct impact on total profits, as product is over and under-valued when misallocated, reducing cut misallocations will improve processor compliance when sorting carcases into cut plans- reducing their need to retrim, downgrade and repackage product or the erosion of customer confidence caused by supplying product not meeting market specifications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Dual energy x-ray absorptiometry (DXA) devices were installed at two Australian abattoirs to predict computed tomography (CT) determined fat % and lean % of lamb carcasses. This study tested three algorithms developed for these devices, termed β1, β2 and β3, and assessed their accuracy and precision in predicting CT composition. Algorithm β3 included the use of a plastic phantom calibration block scanned by both DXA devices to adjust prediction equations, resulting in superior accuracy to the algorithms without phantom calibration (β1 and β2). When compared to the gold-standard CT composition, the bias of the DXA predictions was lowest when using algorithm β3 at the two sites (-1.17%, -0.49% for fat %, 0.11%, -0.37% for lean %). The difference of DXA composition predictions between sites was lowest when using algorithm β3, which demonstrated between site differences of 0.59 CT fat %, and 0.46 CT lean%. In contrast, algorithm β1 and β2 produced differences of 23.7% and 30.8% for CT fat, and 17.3% and 21.9% for CT lean between the two DXA devices. There was a small difference of 0.78% between the fat predictions of the first DXA image compared to the second DXA image for each carcass. The precision of predictions improved slightly using algorithm β3. This work demonstrates that the in-line DXA systems can produce comparable results across sites., Competing Interests: Declaration of competing interest There is no conflict of interest involved in this work, (Copyright © 2024. Published by Elsevier Ltd.)

Skeleton bones, distinguished by trabecular and cortical bone tissue content, exhibit varied growth and composition, in response to modified dietary calcium and phosphorus levels. The study investigated how gilts adapt their individual bone and bone region mineralisation kinetics in response to changing intake of Ca and P. A total of 24 gilts were fed according to a two-phase (Depletion (D) 60-95 and Repletion (R) 95-140 kg BW, respectively). During the D phase, gilts were fed either 60% (D60) or 100% (D100) of the estimated P requirement. Subsequently, during the R phase, half of the gilts from each D diet were fed either 100% (R100) or 160% (R160) of the estimated P requirement according to a 2 × 2 factorial arrangement. Bone mineral content (BMC) was assessed in the whole body, individual bones (femur and lumbar spine L2-L4), and bone regions (head, front legs, trunk, pelvis, femur, and hind legs) every 2 weeks using dual-energy X-ray absorptiometry (DXA). At 95 kg BW, gilts fed D60 showed reduced BMC and BMC/BW ratio in all studied sites compared to those fed D100 (P < 0.001). During the depletion phase, the allometric BW-dependent regressions slopes for BMC of D100 gilts remained close to 1 for all sites and did not differ from each other. In contrast, the slopes were lower in D60 gilts (P < 0.05), with an 18% reduction in the whole body, except for the front and hind legs, femur, and pelvis, which exhibited higher reductions (P < 0.05). At 140 kg BW, BMC and BMC/BW ratio of all studied sites were similar in gilts previously fed D60 and D100, but higher in R160 than in R100 gilts (P < 0.05), except for front and hind legs. During the repletion phase, the allometric BW dependent regressions slopes for BMC were lower (P < 0.05) in R100 than in R160 gilts (for whole body -10%; P < 0.01) except for front and hind legs, femur, and pelvis. In conclusion, bone demineralisation and recovery followed similar trends for all measured body sites. However, the lumbar spine region was most sensitive whereas the hind legs were least sensitive. These data suggest that using bone regions such as the head and forelegs that can be collected easily at the slaughterhouse may be a viable alternative to whole body DXA measurement., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

A prototype, on-line Dual Energy X-ray Absorptiometer (DXA) has shown high precision of the prediction of carcass composition for the purpose of improved sheep meat grading in the Australian lamb supply chain, albeit with small inaccuracies over time. These inaccuracies were present across hours, and more significantly across days, which were unacceptable for any accreditation of this device as an objective carcass measurement tool in Australia. This inaccuracy demanded the creation of a novel image-processing algorithm for the prototype DXA. This DXA was tested for repeatability of predictions of lamb carcass composition over minutes, hours, and days, using two developed image processing algorithms. There was high immediate repeatability for both algorithms when predicting lean muscle % in 40 lamb carcasses, with a maximum CV of 0.65% over five repeated scans. There was a decrease in the CV of the prediction of lean muscle % of 30 lambs scanned three times over a 48-h period from 5.93 to 1.19% when the superior algorithm was used. The inaccuracies of lean muscle % predictions were associated with increases in the unattenuated space pixel values in DXA images. Improvements of the current algorithm are required to demonstrate repeatability over time for the purpose of accreditation within the Australian sheep meat industry, and for possible expansion of this technology into international supply chains., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

An on-line Dual Energy X-ray Absorptiometry (DXA) scanner's tissue composition prediction precision and accuracy was tested across the entire height of the unit's detector, and the hardware was assessed for robustness by measuring X-ray photon intensity throughout production days. There was good precision when predicting the tissue composition of 5 different lamb fat and lean muscle mixtures across 3 different thicknesses (R 2  = 0.93 to 0.98, RMSE = 3.18% to 5.83%), however was less precise at the greatest thickness of 200 mm (R 2  = 0.59, RMSE = 11.4%). There was no significant difference in the prediction of tissue composition at 8 of the 9 detector positions, however the position at the perpendicular of the X-ray photon beam was significantly different, with a fat prediction error of -4%, although no lamb carcass is detected in this position during normal production. A significant upwards drift in X-ray photon intensity was found over the course of production, especially immediately after restarting the DXA scanner following a period of inactivity. This upwards drift may affect tissue composition predictions over the span of a production day if uncorrected., Competing Interests: Declaration of competing interest There is no conflict of interest involved in this work., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Despite the acknowledged significance of nutrition in bone development, effects of methionine (Met) and cysteine (Cys) on bone quality remain under-researched, particularly during Eimeria challenge. We investigated the effects of different supplemental Met to Cys ratios (MCR) on bone quality of broilers under Eimeria challenge. A total of 720 fourteen-day old Cobb500 broilers were allocated into a 5 × 2 factorial arrangement. Five diets with Met and Cys supplemented at MCR of 100:0, 75:25, 50:50, 25:75, and 0:100 were fed to the birds with or without Eimeria challenge. Body composition was measured by dual energy x-ray absorptiometry, and the femur bone characteristics were assessed by microtomography. Data were analyzed by two-way ANOVA and orthogonal polynomial contrast. The results reaffirmed the detrimental effects of Eimeria challenge on bone quality. On 9 d post inoculation (DPI), significant interaction effects were found for whole body bone mineral content (BMC), lean tissue weight, and body weight (P < 0.05); in the nonchallenged group (NCG), these parameters linearly decreased as MCR decreased (P < 0.05). In the challenged group (CG), body weight and lean tissue weight were unaffected by MCR, and BMC linearly increased as MCR decreased (P < 0.05). For the cortical bone of femoral metaphysis on 6 DPI, bone mineral density (BMD) linearly increased as MCR decreased (P < 0.05). Bone volume to tissue volume ratio (BV/TV) in the CG linearly increased as MCR decreased (P < 0.05). On 9 DPI, BMC and TV linearly increased as MCR decreased (P < 0.05) in the NCG. BMD and BV/TV changed quadratically as MCR decreased (P < 0.05). For the trabecular bone of femoral metaphysis on 9 DPI, BV/TV, and trabecular number linearly increased as MCR decreased (P < 0.05) in the NCG. For the femoral diaphysis, BV, TV, BMC on 6 DPI, and BMD on 9 DPI linearly increased as MCR decreased (P < 0.05). In conclusion, this study showed that both Eimeria challenge and varying supplemental MCR could influence bone quality of broilers., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Assessment of body composition is an essential aspect of veterinary canine care, particularly as prevalence of overweight and obesity in dogs is increasing. Few quantitative objective methods for body composition measurement are available for routine clinical use. Bioelectrical impedance analysis is widely used in human medicine and nutritional assessment and although it has shown promise in production animals it has not yet been adopted for companion animals. The present study validated bioimpedance spectroscopy (BIS) against the reference method of dual-energy X-ray absorptiometry. Resistivity coefficients for use in BIS were determined: ρe = 444.8 and ρi = 1477.8 ohm.cm and used to predict fat-free mass (FFM) in a cohort of 35 mixed breed dogs. Overall, FFM was predicted to within 3.5% of reference values. At an individual level, FFM was predicted within 2 standard deviations (95% confidence) of 10%. BIS provides an objective quantitative alternative to the widely used semi-quantitative body condition scoring. In addition, BIS provides estimates of body water volumes (total, extra-and intracellular), information that can be useful in fluid management. BIS is inexpensive, and simple to perform but does require brief (<5 min) sedation of the animal., Competing Interests: Conflict of interest statement Author Ward consults to ImpediMed Ltd. ImpediMed had no involvement in the execution of this study or in the preparation of this manuscript. None of the authors has any other financial or personal relationships that could inappropriately influence or bias the content of the paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Two trials were carried out to develop and validate linear regression equations for body composition prediction using Dual-energy X-ray absorptiometry (DEXA). In Trial 1, 300 Cobb500 male chickens raised from 1 to 42 d of age were scanned in DEXA to estimate total weight, fat mass, soft lean tissue (SLT) mass, bone mineral content (BMC), and fat percentage. DEXA estimates were compared to body ash, crude fat, SLT (sum of protein and water) and scale body weight. The dataset was split, with 70% used for prediction equations development and 30% for testing, and the 5k-fold cross-validation analysis was used to optimize the equations. The R 2 , mean absolute error (MAE), and root-mean-squared error (RMSE) were used as precision and accuracy indicators. A negative correlation (ρ = -0.27) was observed for ash content, while no correlation was observed for protein content (P > 0.05). Predictive linear equations were developed to assess broiler weight (R 2 = 0.999, MAE = 25.12, RMSE = 38.99), fat mass (R 2 = 0.981, MAE = 13.87, RMSE = 21.28), ash mass (R 2 = 0.956, MAE = 3.98, RMSE = 5.61), SLT mass (R 2 = 0.997, MAE = 35.73, RMSE = 52.45), water mass (R 2 = 0.997, MAE = 29.56, RMSE = 43.94), protein mass (R 2 = 0.989, MAE = 12.94, RMSE = 19.05), fat content (R 2 = 0.855, MAE = 0.81, RMSE = 1.05), SLT content (R 2 = 0.658, MAE = 1.01, RMSE = 1.28), and water content (R 2 = 0.678, MAE = 0.99, RMSE = 1.27). All equations passed the test. In Trial 2, 395 Cobb500 male chickens were raised from 1 to 42 d of age and used for validation of prediction equations. The equations developed for weight, fat mass, ash mass, SLT mass, water mass, and protein mass were validated. In conclusion, DEXA was found to be an effective approach for measuring the body composition of broilers when using predictive equations validated in this study for estimate calibration., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of the present study was to estimate the chemical composition (water, lipid, protein, mineral, and energy contents) of carcasses measured postmortem using dual-energy X-ray absorptiometry (DXA) scans of cold half-carcass or 11th rib cut. One hundred and twenty beef-on-dairy (dam: Swiss Brown, sire: Angus, Limousin, or Simmental) bulls (n = 66), heifers (n = 42), and steers (n = 12) were included in the study. The reference carcass composition measured after grinding, homogenization, and chemical analyses was estimated from DXA variables using simple or multiple linear regressions with model training on 70% (n = 84) and validation on 30% (n = 36) of the observations. In the validation step, the estimates of water and protein masses from the half-carcass (R2 = 0.998 and 0.997; root mean square error of prediction [RMSEP], 1.0 and 0.5 kg, respectively) and 11th rib DXA scans (R2 = 0.997 and 0.996; RMSEP, 1.5 and 0.5 kg, respectively) were precise. Lipid mass was estimated precisely from the half-carcass DXA scan (R2 = 0.990; RMSEP = 1.0 kg) with a slightly lower precision from the 11th rib DXA scan (R2 = 0.968; RMSEP = 1.7 kg). Mineral mass was estimated from half-carcass (R² = 0.975 and RMSEP = 0.3 kg) and 11th rib DXA scans (R2 = 0.947 and RMSEP = 0.4 kg). For the energy content, the R2 values ranged from 0.989 (11th rib DXA scan) to 0.996 (half-carcass DXA scan), and the RMSEP ranged from 36 (half-carcass) to 55 MJ (11th rib). The proportions of water, lipids, and energy in the carcasses were also precisely estimated (R2 ≥ 0.882) using either the half-carcass (RMSEP ≤ 1.0%) or 11th rib-cut DXA scans (RMSEP ≤ 1.3%). Precision was lower for the protein and mineral proportions (R2 ≤ 0.794, RMSEP ≤ 0.5%). The cattle category (sex and breed of sire) effect was observed only in some estimative models for proportions from the 11th rib cut. In conclusion, DXA imaging of either a cold half-carcass or 11th rib cut is a precise method for estimating the chemical composition of carcasses from beef-on-dairy cattle., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Egyptian fruit bats ( Rousettus aegyptiacus ) are commonly held within zoos and research facilities. Despite this popularity, there have been no publications regarding normal bone density or bone mineral concentration and few publications regarding the normal dietary requirements of calcium, phosphorus, and vitamin D (25-hydrox-vitamin D 3 [25(OH)D 3 ]) for the species. A clinical investigation into frequent fractures in a zoo population of 23 adult male Egyptian fruit bats used dual-energy X-ray absorptiometry (DXA) to evaluate bone mineral density (BMD) and bone mineral content (BMC) prior to and after dietary adjustment of calcium and phosphorus. This study documents BMD, BMC, serum trace minerals, and serum levels of 25(OH)D 3 within this population and includes postmortem bone density and bone ash from a subset of bats that died during the study period. A handheld point-of-care analyzer was utilized to assess ionized calcium and electrolytes (sodium, potassium, chloride, total CO 2 ), glucose, blood urea nitrogen, and creatinine at each DXA time point to contribute to published reference ranges for this species. This study identified a significant ( P < 0.001) increase in BMC over 15 mon (4.71-8.26 g) following additional calcium and phosphorus supplementation in the diet. The BMD also trended toward a significant increase (0.124-0.274 g/cm 2 , P < 0.053). Additional studies documenting normal bone density that include both sexes and possibly free-ranging bats consuming a natural diet are recommended to determine normal values for R. aegyptiacus .

Background: Monitoring changes in appendicular skeletal muscle mass is frequently used as a surrogate marker for limb function. The primary objective of this study was to review scientific information related to the assessment of appendicular skeletal muscle mass in dogs. The secondary objective was to develop practical recommendations for serial evaluation of muscle mass., Methods: A scoping review was conducted with a systematic search of PubMed, Web of Science, CAB abstract, and Cochrane from inception to June 2021. The following modalities were included in the search: limb circumference, diagnostic ultrasound, computed tomography, magnetic resonance imaging, and dual-energy x-ray absorptiometry., Results: A total of 62 articles that measured appendicular skeletal muscle mass in dogs were identified. Limb circumference (55 articles) was the most commonly used modality. Its reliability was investigated in five studies. Several factors, including measuring tape type, body position, joint angles, and the presence of hair coat, were reported as variables that can affect measurements. Diagnostic ultrasound (five articles) was validated in three articles, but there is scarce information about observer reliability and variables affecting the measurement. Computed tomography (four articles) and magnetic resonance imaging (one article) have been used to validate other modalities at a single time point rather than as a clinical tool for serial muscle mass monitoring. Dual-energy x-ray absorptiometry (two articles) has been used to quantify specific skeletal muscle mass but was mainly used to evaluate body composition in dogs., Conclusion: Limb circumference and ultrasound are likely the main modalities that will continue to be used for serial muscle mass measurement in the clinical setting unless a new technology is developed. The reliability of limb circumference is questionable. Several key factors, including measuring tape type, body position, joint angles, and coat clipping, need to be controlled to improve the reliability of limb circumference measurements. Ultrasound may provide a reasonable alternative, but further studies are required to evaluate the reliability of this modality and identify factors that influence ultrasound measurements., (© 2022. The Author(s).)

Genetic selection of pigs over recent decades has sought to reduce carcass fat content to meet consumer demands for lean meat in many countries (e.g., Australia). Due to the impacts of genetic changes, it is unknown whether the carcass fat measures are still responsive to energy intake. Thus, the present experiment aimed to quantify the relationship between tissue composition and dietary energy intake in finisher pigs selected for low carcass backfat. Intact male and female pigs (n = 56 for each sex; Primegro Genetics, Corowa, NSW, Australia) were fed seven different amounts of an amino acid adequate wheat-based diet containing 14.3 MJ digestible energy (DE)/kg to provide the following daily DE intakes- 25.8, 29.0, 32.6, 35.3, 38.5, 41.5, and 44.2 (ad libitum) MJ DE/d for males, and 25.8, 28.9, 32.0, 35.6, 38.3, 40.9, and 44.5 (ad libitum) MJ DE/d for females between 60 and 108 kg live weight. Body composition of anesthetized pigs was measured using the dual energy X-ray absorptiometry (DXA) method when individual pigs reached 108 kg, and protein, fat, and ash deposition rates were calculated. Pigs were slaughtered on the second day post-DXA scan for carcass backfat measurement. The results showed that the carcass backfat thickness (standardized at 83.7 kg carcass) increased by 0.125 mm for every MJ increase in daily DE intake in male pigs (P = 0.004; R2 = 0.130), but carcass backfat of female pigs (standardized at 85.1 kg carcass) was not responsive to daily DE intake. Whole-body fat composition and fat deposition rate increased linearly (both P < 0.01) in male pigs but quadratically (both P < 0.01) in female pigs in response to DE intake. Every MJ increase of daily DE intake increased the rate of daily protein deposition by 3.8 g in intact male pigs (P < 0.001; R2 = 0.781) and by 2.5 g in female pigs (P < 0.001; R2 = 0.643). In conclusion, the selection for low backfat thickness over the last two decades has altered the response of fat deposition and backfat thickness to energy intake, particularly in female pigs. Despite this change, the linear relationship between DE intake and protein deposition rate was maintained in these modern genetics., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A 4-month-old male Old English Sheepdog was presented for evaluation of a raw meat-based homemade diet after a 1-month history of progressive lameness. Marked dietary deficiencies were detected, which included calcium, phosphorus and vitamin D. Hypovitaminosis D and hypocalcaemia were diagnosed by serum analysis. Evidence of severe diffuse osteopenia was noted on survey radiographs. Dual-energy X-ray absorptiometry (DEXA) was used to quantify bone mineral content and density and compare to published reference ranges. The puppy's initial bone mineralization was markedly subnormal, with bone mineral density 66% lower than expected, and bone mineral content 40% lower than expected. Subsequent DEXA scans were performed at intervals during the puppy's recovery to document the rate of bone re-mineralization and guide therapeutic recommendations. Marked improvement was achieved within 4 months through exercise control and feeding of a diet appropriately formulated for large breed puppy growth and development. This report reinforces the necessity of thorough dietary history and highlights the potential for malnutrition in pets fed homemade and raw meat-based diets. Use of DEXA has rarely been reported in clinical cases, yet can be a valuable tool for diagnosing and monitoring cases with abnormal bone mineralization. Further studies using DEXA to track bone mineralization in healthy puppies are encouraged to develop a more robust reference range of bone mineralization in growing dogs of varying sizes, weights and ages., (© 2019 Blackwell Verlag GmbH.)

An on-line Dual Energy X-ray Absorptiometry (DXA) scanner was used in an Australian abattoir to predict computed tomography (CT) determined composition % of fat, lean muscle and bone in lamb carcasses at chain speed. This study assessed the effect of spray-chilling on these estimates, as well as their repeatability over a 10-min period, and over a 72 h period. There was no prediction bias between the 15 spray-chilled and 15 non-spray-chilled carcasses. When repeat DEXA scans were undertaken across a 10-min period, there was a high level of repeatability for the prediction of CT Fat %. When repeat scans were conducted at 6 time points across a 72 h period the precision of the DXA prediction of CT Fat % of 30 carcasses remained high (R 2  = 0.94, RMSEP = 1.20%), although small biases existed between time points (P < 0.01). These biases were minimised when the DXA scanner had been operational prior to experimentation, suggesting a 'warm-up' effect., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Data were obtained from 120 lambs which were slaughtered, scanned using dual energy X-ray absorptiometry (DEXA) and underwent eating quality assessment. DEXA images were used to determine R values, reflecting atomic mass, to predict carcass lean %. Additionally, bone regions (humerus, lumbar, femur and "all carcass bone") were isolated from images to determine bone specific R values (DEXA R Mean and SDev). Prediction of overall liking of cuts across the carcass (scored between 0 and 100) using lean % and bone DEXA was variable. Loin grill overall liking demonstrated significant associations with lumbar DEXA R Mean and SDev, decreasing by 8.6 and 7.6 units across the increasing range of these bone DEXA measures. This association is somewhat independent of carcass lean % and intramuscular fat % of the loin. Given the association of DEXA with eating quality, there are potential benefits for the lamb industry with respect to carcass sorting and marketing during routine processing and DEXA scanning., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Studies in animal science assessing nutrient and energy efficiency or determining nutrient requirements benefit from gathering exact measurements of body composition or body nutrient contents. Those are acquired by standardized dissection or by grinding the body followed by wet chemical analysis, respectively. The two methods do not result in the same type of information, but both are destructive. Harnessing human medical imaging techniques for animal science can enable repeated measurements of individuals over time and reduce the number of individuals required for research. Among imaging techniques, dual-energy X-ray absorptiometry (DXA) is particularly promising. However, the measurements obtained with DXA do not perfectly match dissections or chemical analyses, requiring the adjustment of the DXA via calibration equations. Several calibration regressions have been published, but comparative studies of those regression equations and whether they are applicable to different data sets are pending. Thus, it is currently not clear whether existing regression equations can be directly used to convert DXA measurements into chemical values or whether each individual DXA device will require its own calibration. Our study builds prediction equations that relate body composition to the content of single nutrients in growing entire male pigs (BW range 20-100 kg) as determined by both DXA and chemical analyses, with R 2 ranging between 0.89 for ash and 0.99 for water and CP. Moreover, we show that the chemical composition of the empty body can be satisfactorily determined by DXA scans of carcasses, with the prediction error ranging between 4.3% for CP and 12.6% for ash. Finally, we compare existing prediction equations for pigs of a similar range of BWs with the equations derived from our DXA measurements and evaluate their fit with our chemical analysis data. We found that existing equations for absolute contents that were built using the same DXA beam technology predicted our data more precisely than equations based on different technologies and percentages of fat and lean mass. This indicates that the creation of generic regression equations that yield reliable estimates of body composition in pigs of different growth stages, sexes and genetic breeds could be achievable in the near future. DXA may be a promising tool for high-throughput phenotyping for genetic studies, because it efficiently measures body composition in a large number and wide array of animals., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

This experiment assessed the ability of an on-line dual energy x-ray absorptiometer (DEXA) installed at a commercial abattoir to determine commercial cut weights in lamb carcases at abattoir chain-speed. 200 lamb carcases were scanned using a DEXA that was trained to predict the computed tomography determined proportions of fat, lean, and bone. Models were then trained using hot carcase weight and, DEXA fat% value or GR tissue depth to predict cut weight. Results from validation tests of DEXA models demonstrated excellent precision for predicting cut weight, in most cases describing more than 85% of the variation, and RMSE values that represented between 5 and 13% of the average weight of each cut. For most cuts these weight predictions were superior to those informed by GR tissue depth. This precision was maintained upon validation. Additional analyses utilised pixel information from the fore, saddle, and hind sections of DEXA images. This further enhanced the predictive power of cut weight models., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The development of a novel rapid dual energy X-ray absorptiometry (DEXA) system provides the opportunity to improve measurement of beef carcase composition. A prototype rapid DEXA system was built in a shipping container to scan 51 beef carcases selected for a wide range in weight and fatness. One side of each carcase was spray chilled and the other conventionally chilled overnight before being quartered for DEXA scanning and then being cut into 16 pieces for CT scanning to determine carcase composition. Spray chilling did not impact DEXA prediction of CT composition, with the DEXA system describing 89%, 95%, and 87% of the variation in beef carcase CT lean %, fat % and bone %, with a root mean square error of prediction of 2.31 lean %, 2.15 fat %, and 1.12 bone % units. These results demonstrate that the novel rapid DEXA system has excellent capacity to predict CT composition in beef carcases., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Dual energy X-ray absorptiometry (DEXA) is an imaging modality that has been used to predict the computed tomography (CT)-determined carcass composition of multiple species, including sheep and pigs, with minimal inaccuracies, using medical grade DEXA scanners. An online DEXA scanner in an Australian abattoir has shown that a high level of precision can be achieved when predicting lamb carcass composition in real time. This study investigated the accuracy of that same online DEXA when predicting fat and lean percentages as determined by CT over a wide range of phenotypic and genotypic variables across 454 lambs over 6 kill groups and contrasted these results against the current Australian industry standard of grade-rule (GR) measurements to grade carcasses. Lamb carcasses were DEXA scanned and then CT scanned to determine CT Fat % and CT Lean %. All phenotypic traits and genotypic information, including Australian Sheep Breeding Values, were recorded for each carcass. Residuals of the DEXA predicted CT Fat % and Lean %, and the actual CT Fat % and Lean % were calculated and tested against all phenotypic and genotypic variables. Excellent overall precision was recorded when predicting CT Fat % (R2 = 0.91, RMSE = 1.19%). Small biases present for sire breed, sire type, dam breed, hot carcass weight and c-site eye muscle area could be explained by a regression paradox; however, biases among kill group (-0.73% to 1.01% for CT Fat %, -1.48% to 0.76% for CT Lean %) and the Merino sire type (0.36% for CT Fat %, -0.73% for CT Lean %) could not be explained by this effect. Over the large range of phenotypic and genotypic variation, there was excellent precision when predicting CT Fat % and CT Lean % by an online DEXA, with only minor biases, showing superiority to the existing Australian standard of GR measurements.

Early lesions of osteochondrosis (OC) are exhibited by regions of cartilage retention along the growth plate and articular cartilage. Progression of OC lesions may impair locomotion and necessitate euthanasia in adherence to animal welfare guides. Little is known about the role of nutrition in the initiation and early stages of OC. However, dietary components are commonly implicated as predisposing factors. In this study, diets were altered as an attempt to induce early stage OC lesions under controlled conditions. At 8 wk of age, 96 crossbred gilts (body weight [BW] = 17.4 ± 0.18 kg) were randomly assigned to one of four corn-soybean meal-based diets (four pens per diet, six pigs per pen) to assess diet effects on the number and volume of OC lesions in the distal femur. Diets included a non-pelleted control diet (Ctl); Ctl plus 20% glucose (Glc); the Ctl with increased concentrations of lysine, Ca, and P (+CaP); and the +CaP diet in a pelleted form (PEL). Femurs were collected from pigs euthanized at either 14-wk (Wk 14) or 24-wk (Wk 14) of age for assessments of OC lesions. Based on a mixed model analysis with pen as the experimental unit, dietary treatments did not affect final BW (129.3 ± 3.8 kg) or average daily gain (ADG) (1.00 ± 0.03 kg/d) over the trial. As expected, pigs fed PEL and Glc diets were more efficient (P < 0.05) in feed conversion compared with Ctl and +CaP. Using femurs as the experimental unit at Wk 14 (collected from two of the six pigs per pen), bone mineral content, determined by dual-energy x-ray absorptiometry scans, was greater (P < 0.05) in pigs fed +CaP and PEL than Ctl or Glc diets; however, only +CaP group differed (P < 0.05) at Wk 24 (collected from four pigs per pen). Computed tomography (CT) scans of femurs were reconstructed as three-dimensional images to allow detection of the number, volume, and surface area of lesions in distal growth plates. At Wk 14, pigs fed Ctl had fewer number of lesions (P < 0.05); however, no differences were detected among dietary treatments in lesion volume or lesion surface area. Pigs had fewer lesions at Wk 24 than Wk 14; however, differences were not detected among dietary treatments. At Wk 24, pigs fed Ctl diets had the greatest lesion volume among dietary treatments (P < 0.05). In conclusion, none of the pigs exhibited symptoms of lameness regardless of dietary treatment or OC lesion traits. Diet modifications due to pelleting or inclusion of rapidly digestible ingredients, such as glucose, did not increase prevalence or size of OC lesions. Image analysis of CT scans was a reliable method to quantify the number, size, and location of OC lesions., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Diagnostic imaging relies on interpretation of interactions between the body tissue and various energies, such as x-rays, ultrasound, and magnetic or nuclear energies, to differentiate normal from abnormal tissues. Major technological improvements regarding emission and detection of the energetic waves, as well as reconstruction and interpretation of the images, have occurred. These advances made possible visualization of smaller structures, quantitative evaluation of functional processes, and development of unique imaging-guided procedures. This article reviews the technological advances that allowed development of cone beam computed tomography, dual-energy x-ray absorptiometry, and contrast-enhanced ultrasonography, which all could have applications in exotic pet medicine., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Musculoskeletal problems are one of the top five causes of disease in elephants. However, recent blood chemistry analysis is the only routine protocol for bone mineral status evaluation, with no assessment method currently available for the direct measurement of elephant bone mineral density (BMD). This work applied the the dual-energy X-ray technique (DXA) technique for bone density assessment. The elephant's tail was chosen for the analysis to avoid the radiation harm. Twelve live Asian elephants ( Elephas maximus ) comprising eight males and four females with ages in the range of 4-77 yr were investigated. The BMD was calculated based on radiographic images acquired using the DXA technique carried out at 40 kVp 2 mAs and 50 kVp 2 mAs. Blood serum analysis of total calcium (Ca), phosphorus (Phos) and alkaline phosphatase (ALP) content was conducted in parallel with the physical examination to correlate age and BMD. Analyses produced an overall mean BMD value in the range of 0.54-1.39 g/cm 2 , with that of the males higher than that of the females. The BMD was found to be negatively correlated with age, Ca, and Phos, but not with ALP. In summary, the BMD analysis of an elephant's tail might be used with blood serum Ca and Phos to predict the overall bone mineral status of the animal., (Copyright 2019 by American Association of Zoo Veterinarians.)

In this study, a Lunar Prodigy dual-energy X-ray absorptiometry (DEXA) scanner was validated as a technique to estimate chicken body composition in a non-invasive way. Former research has emphasized the importance of validation of every scanner and software version. In a first trial, DEXA estimated body composition for broilers was correlated with chemical carcass analysis to develop prediction equations. As such, those equations can be used in later experiments with chickens to correct DEXA estimations to estimate body composition accurately by DEXA. DEXA estimated fat mass, lean tissue mass, bone mineral content (BMC) and total body mass, which is the sum of fat, lean mass and BMC, were compared to chemically analyzed crude fat, lean mass as the sum of protein and water and body ash content and scale body weight, respectively. Those regression equations were then used in a second trial to determine body composition based upon DEXA for breeders at different ages. In this experiment, fat and lean tissue determined by DEXA, were compared to dissection parameters commonly used for assessing carcass quality, namely breast muscle and abdominal fat. The first trial showed that DEXA provides high correlations for body mass (ρ = 1) and the individual tissue masses separately (ρ ranging between 0.98 and 1). These high correlations allow for accurate prediction of those components with the developed regression equations. Proportional fat and lean tissue were correlated with their chemical counterparts, however, to a lower extent than absolute values due to lower variation between the proportional weights. BMC percentage was not significantly correlated with ash percentage. Furthermore, in trial 2 high correlations were observed between dissection parameters and DEXA-corrected estimations. These correlations show that DEXA can assess carcass quality in breeders without sacrificing the birds. In conclusion, DEXA is a reliable technique to estimate breeder and broiler body composition in a non-invasive way, hence allowing for longitudinal studies over longer periods of time while avoiding sacrificing of birds., (© 2019 Poultry Science Association Inc.)

Objectives: The objectives for this study were to compare the body composition of adult indoor neutered domestic cats with outdoor intact cats with an ideal body condition score using dual-energy x-ray absorptiometry, and to report the body composition findings of free-roaming cats, as this has not been previously reported. Most domestic house cats differ from free-roaming cats as they are confined indoors and neutered. Indoor neutered cats have reduced activity and hormonal alterations that may result in lower muscle mass and higher body fat percentages vs outdoor intact cats, despite similar body condition scores., Methods: Twenty-one outdoor intact cats (10 male, 11 female) were selected from a trap-neuter-return program and 16 indoor neutered domestic cats (10 male, six female) were client-owned. Inclusion criteria included an estimated age between 1 and 6 years, complete blood count, biochemistry panel, urinalysis, total thyroxine, feline leukemia virus/feline immunodeficiency virus screening and a body condition score of 4-5/9., Results: Indoor neutered cats had a higher body fat percentage (22.1% [range 17.3-28.2%]) than outdoor intact cats (17.3% [range 10.0-33.6%]; P = 0.002). Indoor neutered male cats had a higher body fat percentage ( P <0.001) than outdoor intact cats. No difference in body fat percentage was observed in female cats ( P = 0.159). Indoor neutered domestic cats had a higher bone mineral density than outdoor intact cats ( P = 0.023)., Conclusions and Relevance: The results of this study suggest indoor confinement and neutering increase body fat percentage and bone mineral density in cats with an ideal body condition score.

This study was conducted to evaluate the effects of sequential feeding technique in two genetic lines (GL; Line A [cross having a greater proportion of Pietrain] and Line B [cross having a lower proportion of Pietrain]) of growing-finishing pigs reared under daily cyclic high ambient temperature conditions. Seventy-eight castrated male pigs (22 ± 2.5 kg BW) were housed in a single group and were allocated to one of the three feeding programs: control (CON, 24 h control diet), high-fat/low-crude protein (HF/LP, 24 h high-fat/low-crude protein diet), and sequential feeding (SEQ, control diet from 1800 to 1000 h and HF/LP diet from 1001 to 1759 h). Cyclic high ambient temperature was induced by exposing the pigs to 22ºC ambient temperature from 1800 to 1000 h (time-period 22ºC, TP22) and to 30ºC from 1001 to 1759 h (TP30). The experimental period lasted 84 days and was divided into 3 growth phases, growing 1 (from day 0 to 20), growing 2 (from day 21 to 48) and finishing (from day 49 to 83). Feed intake was recorded in real time using an automatic feeder system. Pigs were weighed at the beginning and end of each experimental phase. Animal body composition was measured through dual-energy X-ray absorptiometry on days 0, 35, and 70. The ambient temperature averaged 22.3 ± 0.4ºC during TP22 and 30.2 ± 0.5ºC during TP30, characterizing the condition of daily ambient temperature variation that which pigs are usually exposed in tropical climate areas. During growing phase 1, the feeding programs had negligible effects on pig performance (P > 0.05), whereas during growing phase 2, ADG was greater in SEQ than in CON pigs (7%; P = 0.04). During the finishing phase, HF/LP pigs had greater ADFI (+ 10%) and ADG (+ 8%) than CON pigs. Lean mass and gain did not differ among feeding programs (P > 0.05). Overall, fat mass and gain were similar between SEQ and HF/LP pigs (P > 0.05), and both were greater than those of CON pigs (P < 0.05). On the basis of pig performance per phase, the supply of high-fat/low-crude protein diets (SEQ and HF/LP feeding) improved the performance of pigs under daily cyclic high ambient temperature. However, the use of these techniques resulted in fatter carcasses and in higher energy cost of gain. Finally, pigs with greater proportion of Pietrain genes had decreased growth performance in our experimental conditions., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Calcium and vitamin D are critical in attenuating metabolic Ca insufficiency often observed in older hens. We investigated interactive effects of dietary Ca and top-dressed 25-hydroxy vitamin D3 (25OHD3) on egg production, eggshell quality (thickness, EST, and breaking strength, ESBS), serum Ca, kidney, liver, and bones attributes in 74-wk old Lohmann LSL-lite layers. A total of 4 levels of Ca (3.0, 3.5, 4.0, and 4.5%) and 3 levels of 25OHD3 (0, 69, and 138 μg/kg) were tested. All diets had basal level of 3,300 IU of vitamin D3/kg, were allocated to 84 individually housed hens (n = 7), and fed to 81 wk of age. Dual-energy X-ray absorptiometry was used to measure bone mineral content (BMC) and density (BMD) in left ulna, femur, and tibia at week 74 (13 spare birds, baseline) and week 81. Birds fed diets containing 3.0, 3.5, 4.0, and 4.5% Ca consumed 3.4, 4.1, 4.2, and 4.8 Ca g/b/d. Interaction (P < 0.05) between Ca and 25OHD3 was such that 25OHD3 linearly increased egg weight and percentage of eggs graded as jumbo (≥70 g) at 3.0, 3.5, and 4.5% Ca levels. There was no interaction (P > 0.05) between Ca and 25OHD3 on the rest of the parameters. Calcium increased EST and ESBS quadratically (P < 0.05), EST increased with Ca intake up to 4.1 g of Ca/b/d whereas Ca intakes (3.4 and 4.8 g of Ca/b/d) had poor ESBS relative to intermediate Ca intakes. Kidney ash concentration increased linearly (P = 009) with Ca intake. However, BMC and BMD in ulna, tibia, and femur declined (P < 0.05) at week 81 relative to baseline. In conclusion, top dressed 25OHD3 linearly increased egg weight at various Ca intakes with no negative effect on eggshell quality or bone attributes. Feeding 4.1 to 4.2 g of Ca/b/d improved eggshell quality, however, higher intake deteriorated eggshell quality and increased renal ash accumulation with no benefit on skeletal integrity., (© 2018 Poultry Science Association Inc.)

A study was conducted to determine the effect of different feeding programs and energy intakes on the body composition of broiler breeders (BB) from 22 wk of age to 65 wk of age. Cobb 500 BB that had been reared using three growth curves: (1) the control group followed Cobb 500 guidelines (SBW) for target body weights (BW), (2) the second group target BW was 20% heavier (HBW) than the SBW group, and (3) the third group target BW was 20% lighter (LBW) than the SBW group. At 21 wk of age, pullets from each growth curve were assigned to be fed one of six treatments. Diets were formulated and allocated to provide 330, 360, 390, 420, 450, or 480 kcal ME/hen/d and 24 g protein/hen/d, at peak intake. Body composition (lean mass, fat mass, and mineral content) was measured by dual-energy x-ray absorptiometry throughout the production period. Significantly, greater (P < 0.05) amounts of fat mass and lower amounts of lean mass were evident at the beginning of the production period for HBW hens compared with SBW and LBW hens. Higher levels of energy intake also affected body composition. Namely, fat deposition was greatest throughout the production period in hens consuming 480 kcal/d at peak intake (P < 0.05). Critically, fluctuations to lean and fat mass throughout the production period are suggestive of underlying regulatory processes. Specifically, hens appears to maintain consistent lean mass throughout the production period with a coefficient of variation of <12% across all birds. The results of this study provide important BB body composition information from management and nutrition studies that showed the dynamics of body composition change during the production period., (© 2018 Poultry Science Association Inc.)

Background: Computed tomography (CT) has been used to estimate body composition and determine tissue distribution in dogs, despite limited validation. This may introduce error into estimates of body composition studies and its effect on health in dogs. Further, the modality has not been validated against dual-energy X-ray absorptiometry (DXA) or over a wide range of dog breeds, ages and sexes. The objective of this study was to validate the use of semi-automated, abdominal volume CT for estimating total body composition of dogs relative to DXA. Twenty-two staff-owned dogs (weighing between 5.1-60 kg) were sedated and underwent full body DXA scan and abdominal CT. Abdominal tissue composition was estimated by CT using semi-automated volume segmentation, over predetermined tissue Hounsfield threshold values. Abdominal tissue composition determined by the various CT threshold ranges was compared to total body composition determined by DXA., Results: Abdominal tissue composition estimated by CT strongly correlated with the estimates derived from DXA with a small Bland-Altman mean percentage differences in values: total body mass (- 250/2000HU: r 2  = 0.985; - 1.10%); total fat mass (- 250/-25HU: r 2  = 0.981; - 1.90%); total lean tissue mass (- 25/150HU: r 2  = 0.972; 3.47%); and total bone mineral content (150/2000HU: r 2  = 0.900; - 0.87%). Although averaged CT values compared well to DXA analysis, there was moderate variation in the individual predicted values. There was near perfect inter- and intra-observer agreement in segmentation volumes for abdominal fat., Conclusions: Abdominal volume computed tomography (CT) accurately and reliably estimates total body composition in dogs, but greater variations may be observed in dogs weighing less than 10 kg.

This study evaluated the responses of individual daily precision (IPF) and conventional 2-phase (CON) feeding systems (FS) in terms of pig growth performance, nutrient balance, serum parameters, and meal patterns of growing pigs reared under thermoneutral (TN: 23 °C) and heat stress (high temperature [HT]: 30 °C) conditions. The animals in each treatment were assigned on the basis of equal BW to the experimental treatments (12 animals per treatment at 41.0 ± 4.87 kg of BW). The experiment lasted 55 d (phase 1 from days 0 to 27 and phase 2 from days 28 to 55). Pigs fed CON received within each phase a constant blend of diets with high and low nutrient density supplying the estimated nutrient requirements of the group, whereas the IPF pigs received daily a personalized blend providing the estimated amount of nutrients according to individual feed intake and body weight information. Body mineral content, and lean and fat masses were assessed through dual-energy X-ray absorptiometry at the beginning and end of each phase. Data were analyzed using a linear mixed-effect model, with fixed effects of the FS, temperature (AT), and the 2-way interaction between FS and AT and random effects of blocks. In relation to CON pigs, IPF pigs reduced (P < 0.05) Lys (19%), protein (16%), and P (14%) intake without impairing (P > 0.05) body composition. Nitrogen excretion was 24% lower (P < 0.05) in IPF pigs than in CON pigs; however, both groups had similar N retention efficiency thoroughly the trial. Amount of time feeding, feed intake rate, and feed intake per meal were 15% lower (P < 0.05) in pigs raised under HT than under TN conditions. During the phase 2, only amount of time feeding, feed intake rate, and feed intake per meal were decreased (P < 0.05) in pigs under HT conditions during nocturnal (2000 to 0500 h) and diurnal (0501 to 1959 h) periods. Haptoglobin levels were affected by the AT, showing an increase of 70% and 43% in HT at 28 and 55 d of the experiment, respectively. Pigs raised under HT conditions had 10% lower (P < 0.05) serum albumin concentration at day 55 than those under TN conditions. For serum urea concentrations, IPF pigs had 28% lower (P < 0.01) levels than CON pigs. Even though HT conditions considerably reduced growth performance and activated inflammatory responses in growing pigs, IPF was not able to rescue performance during HT; however, it was equally effective at improving nutrient utilization and maintaining body composition in HT and TN conditions.

This experiment assessed the ability of an on-line dual energy x-ray absorptiometer (DEXA) installed at a commercial abattoir to determine carcase composition at abattoir chain-speed. 607 lamb carcases from 7 slaughter groups were DEXA scanned and then scanned using computed tomography to determine the proportions of fat (CT fat%), lean (CT lean%), and bone (CT bone%). Data between slaughter groups were standardised relative to a synthetic phantom consisting of Nylon-6. Models were then trained within each dataset using hot carcase weight and DEXA value to predict CT composition, and then validated in the remaining datasets. Results from across-dataset validation tests demonstrated excellent precision for predicting CT fat%, with RMSE and R 2 values of 1.32 and 0.89, compared to values of 1.69 and 0.69 for CT lean%, and 0.81 and 0.68 for CT bone% which had less precision. Accuracy across datasets was also robust, with average bias values of 0.66, 0.83, and 0.51 for CT fat%, lean%, and bone%., (Copyright © 2018. Published by Elsevier Ltd.)

AIMS To develop an equation that accurately estimates fat-free mass (FFM) and the ratio of FFM to skeletal size or mass, using morphometric measurements in lean working farm dogs, and to examine the association between FFM derived from body condition score (BCS) and FFM measured using isotope dilution. METHODS Thirteen Huntaway and seven Heading working dogs from sheep and beef farms in the Waikato region of New Zealand were recruited based on BCS (BCS < 3, 3-4, > 4) using a nine-point scale. Bodyweight, BCS, and morphometric measurements (head length and circumference, body length, thoracic girth, and fore and hind limb length) were recorded for each dog, and body composition was measured using an isotopic dilution technique. A new variable using morphometric measurements, termed skeletal size, was created using principal component analysis. Models for predicting FFM, leanST (FFM minus skeletal mass) and ratios of FFM and leanST to skeletal size or mass were generated using multiple linear regression analysis. RESULTS Mean FFM of the 20 dogs, measured by isotope dilution, was 22.1 (SD 4.4) kg and the percentage FFM of bodyweight was 87.0 (SD 5.0)%. Median BCS was 3.0 (min 1, max 6). Bodyweight, breed, age and skeletal size or mass were associated with measured FFM (p<0.001). There was a good correlation between predicted FFM and measured FFM (R 2 =0.96), and for the ratio of predicted FFM to skeletal size and measured values (R 2 =0.99). Correlation coefficients were higher for the ratio FFM and leanST to skeletal size than for ratios using skeletal mass. There was a positive correlation between BCS-derived fat mass as a percentage of bodyweight and fat mass percentage determined using isotope dilution (R 2 =0.65). CONCLUSIONS AND CLINICAL RELEVANCE As expected, the predictive equation was accurate in estimating FFM when tested on the same group of dogs used to develop the equation. The significance of breed, independent of skeletal size, in predicting FFM indicates that individual breed formulae may be required. Future studies that apply these equations on a greater population of working Huntaway and Heading dogs are needed to establish the utility of these equations on a large scale. Such studies could ascertain if there is a ratio for lean mass to skeletal size below which the risk of injury or disease increases. If these equations prove useful they would provide an objective and non-invasive measure to determine when welfare in individual dogs is compromised by underfeeding.

The precision of a dual-energy X-ray absorptiometry (DXA) device in terms of repeatability and reproducibility was evaluated on nine left half-carcasses from pigs with large variability in body weight and fat content. Repeatability was assessed by scanning each carcass 10 times sequentially in the same position. Reproducibility was assessed by scanning each carcass in 10 different positions. Images were analyzed with DXA software using a custom region of interest (ROI) and the standard head, trunk, arm, and leg ROI. Predicted values from the DEXA for bone mineral content (BMC), bone area, bone mineral density (BMD), total weight, soft-tissue weight, fat-tissue weight, and lean-tissue weight were considered. Repeatability was associated with the variance between measurements on the same carcass in the same position (repeatability conditions). An average variance value was obtained with all the carcasses combined, and the SD was calculated as the square root of this combined variance. The CV was the ratio between the SD of the measurements and its average value. Reproducibility was calculated for each carcass as the difference between the variance obtained under the reproducibility conditions and that obtained under the repeatability conditions. The effects of the ROI and conditions were evaluated by ANOVA and Tukey's test. Means of BMC, bone area, BMD, fat tissue, and lean tissue differed among the ROI (P < 0.05) in both the repeatability and reproducibility conditions. The CV of DXA measurements under repeatability condition obtained in the head, arm, and leg ROI was lesser than 1%. Only the repeatability errors of fat tissue differed (P < 0.05) among the ROI, with the lowest precision found for the trunk ROI. The reproducibility errors of BMC, bone area, fat tissue, and lean tissue differed (P < 0.05) among the ROI. The custom ROI had reproducibility errors greater than 2% for fat tissue and greater than 3.5% for BMC and bone area. In addition, the trunk ROI had the highest reproducibility errors for fat tissue (20.7%) and lean tissue (6.2%) when compared to the other ROI. In conclusion, repeatability and reproducibility results obtained for most of the studied ROI indicate that DXA is a valuable tool for carcass evaluation. From a methodological viewpoint and considering the variations observed in this study, the ROI should be chosen based on the item to be evaluated or on the conditions in which the DXA measurements are to be taken.

Consumption of a high-fat diet, rich in SFA, causes deterioration of bone properties. Some studies suggest that feeding inulin to animals may increase mineral absorption and positively affect bone quality; however, these studies have been carried out only on rodents fed a standard diet. The primary objective of this study was to determine the effect of inulin on bone health of pigs (using it as an animal model for humans) fed a high-fat diet rich in SFA, having an unbalanced ratio of lysine:metabolisable energy. It was hypothesised that inulin reduces the negative effects of such a diet on bone health. At 50 d of age, twenty-one pigs were randomly allotted to three groups: the control (C) group fed a standard diet, and two experimental (T and TI) groups fed a high-fat diet rich in SFA. Moreover, TI pigs consumed an extra inulin supply (7 % of daily feed intake). After 10 weeks, whole-body bone mineral content (P=0·0054) and bone mineral density (P=0·0322) were higher in pigs of groups TI and C compared with those of group T. Femur bone mineral density was highest in pigs in group C, lower in group TI and lowest in group T (P=0·001). Femurs of pigs in groups TI and C had similar, but higher, maximum strength compared with femurs of pigs in group T (P=0·0082). In conclusion, consumption of a high-fat diet rich in SFA adversely affected bone health, but inulin supplementation in such a diet diminishes this negative effect.

This study aimed to demonstrate the higher accuracy and reproducibility of quantitative computed tomography (QCT) compared with dual-energy X-ray absorptiometry (DXA) as a gold standard for measuring canine bone mineral density (BMD). Seven middle-aged beagle dogs underwent lumbar vertebral and bilateral femoral DXA and QCT scans. BMD (mg/cm 2 ) was measured at the vertebral body from L2 to L6, femoral neck, and proximal and distal femoral diaphyses. The BMD values were measured 3 times and compared. The BMD value on QCT was higher than that on DXA for femoral BMD but not for vertebral BMD. The correlation was strong for the lumbar vertebrae (r=0.66) and was strongest for L3 (r=0.85). No correlation was found for the femoral neck (P=0.35), and only moderate correlations were found for the proximal and distal femoral diaphyses (r=0.43 and r=0.40, respectively). The limits of agreement were narrower for vertebral BMD than for femoral BMD, and L3 had the narrowest limits of agreement. The intraclass correlation (ICC) was higher for DXA than for QCT at all lumbar and femoral sites measured, but the ICC of QCT was higher than 0.7. In conclusion, L3 can be used to monitor changes in BMD, and relative values and sequential monitoring of femoral BMD can also be useful because of the high reproducibility of QCT measurements. QCT would be a useful technique for evaluation of BMD in veterinary practice.

Locomotion problems in meat poultry have multifactorial etiology. A better understanding of normal gait and its influences on biomechanical aspects of leg bones among turkey genetic lines is important to prevent skeletal disorders and locomotion issues. The objective of this experiment was to determine the possible differences in gait kinetic and kinematic parameters of turkey strains and their effects on bone biomechanical properties. Four genetic lines, named A, B, C, and D, were obtained and raised in 48 floor pens with new pine shavings. Leg health issues were classified at 16 and 33 d of age. Fifteen turkeys from each strain with apparent normal legs and gait at 33 d of age were selected for gait analysis. These 15 turkeys were trained to walk on a pressure sensitive walkway and video was recorded to calculate articulation movements. These data also were analyzed to obtain kinetic and kinematic parameters of the gait cycle collected at 47, 84, 107, and 145 d of age. At 20 wk all turkeys were sacrificed, and legs were collected and frozen for analysis. Weights and morphologic measurements of the femur, tibia, and shank were recorded. Bone mineral density (BMD) and content (BMC) were obtained using DEXA. Femur and tibia strength were evaluated by a 4-point bending test and torsion test, respectively. Gait parameters changed as toms aged and some differences were observed among lines. Genetic lines differed on BMD, but not on BMC. Strain D had a higher BMD and smaller diaphyseal angle than strain C, characteristics that were correlated with stronger bones. Strain D also had the lowest incidence of leg problems while strain C had the highest. Furthermore, the D strain had a smaller vertical motion of the toe than strains C and B at 47 d and strain A at 145 d, indicating that the D strain had a more efficient gait. In summary, genetic strains differ significantly on gait parameters, which in turn impacts bone biomechanics., (© 2017 Poultry Science Association Inc.)

Background: Aseptic loosening due to bone remodelling processes after total hip replacement is one common cause for revision surgery. In human medicine, dual-energy X-ray absorptiometry (DEXA) is the gold standard for quantitative evaluation of bone mineral density, whereas in veterinary medicine conventional radiography is used for follow-up studies. Recently, a method has been described using digital X-ray images for quantitative assessment of grey scale values of bone contrast. Therefore, the aim of the present study was to evaluate the correlation of bone mineral density (BMD) measured by DEXA with grey scale values (GV) measured in digital X-ray images (RX50, RX66) ex vivo., Results: The measured GV in the chosen X-ray settings showed on average a good correlation (r = 0.61) to the measured BMD with DEXA. Correlation between the two X-ray settings was very good (r = 0.81). For comparisons among regions of interests (ROIs) a difference of 8.2% was found to be statistically significant, whereas in the case of RX50 and RX66 differences of 5.3% and 4.1% were found to be statistically significant., Conclusions: Results indicate that measuring absolute changes in bone mineral density might be possible using digital radiography. Not all significant differences between ROIs detectable with DEXA can be displayed in the X-ray images because of the lower sensitivity of the radiographs. However, direct comparison of grey scale values of the periprosthetic femur in one individual patient during the follow-up period, in order to predict bone remodelling processes, should be possible, but with a lesser sensitivity than with DEXA. It is important that the same X-ray settings are chosen for each patient for follow-up studies.

The effect of caponization on the mechanical properties of Polbar chicken bones was the subject of investigation. The biomechanical strength of bones and the risk of their deformation or fracture were determined on the basis of their geometric, structural, material, and densitometric properties. Eight-week-old cockerels of Polbar breed were surgically castrated and then fattened until the 24th week of life. It was observed that caponization did not influence the weight and length of either of the long bones. It did however significantly reduce their ash content and the Ca and P contents in their femur, and P content in their tibia. Dual energy x-ray absorptiometry densitometry revealed that bone mineral content of the mid-diaphyseal part of both bones were reduced. Similarly, the bone tissue density of bones decreased. Caponization influenced the bone's geometric structure increasing the internal and external diameters of the bones. The bone cross-sectional area was greater in capons, and, consequently, the cross-sectional moment of inertia and the radius of gyration significantly increased. However, the relative wall thickness and cortical index were not altered. The three-point bending tests revealed the negative effect of caponization on the mechanical endurance of bones. Yield strength, Young modulus, and yield stress, characterizing the strength of the bone's material, decreased in capons. That suggests a higher risk of permanent deformation as capon bones become less elastic. Concluding, caponization negatively influenced the quality characteristics of Polbar chicken long bones., (© 2016 Poultry Science Association Inc.)

The aim of this study was to assess the measurement of bone mineral density (BMD) by quantitative computed tomography (QCT), comparing the relationships of BMD between QCT and dual-energy X-ray absorptiometry (DXA) and between QCT and radiographic absorptiometry (RA) in the metacarpal bone of Holstein dairy cows (n=27). A significant positive correlation was found between QCT and DXA measurements (r=0.70, P<0.01), and a significant correlation was found between QCT and RA measurements (r=0.50, P<0.01). We conclude that QCT provides quantitative evaluation of BMD in dairy cows, because BMD measured by QCT showed positive correlations with BMD measured by the two conventional methods: DXA and RA.

It is expensive and laborious to evaluate carcass composition in beef cattle. The objective of this study was to evaluate a method to predict the 9th to 11th rib section (rib) composition through empirical equations using dual energy X-ray absorptiometry (DXA). Dual energy X-ray absorptiometry is a validated method used to describe tissue composition in humans and other animals, but few studies have evaluated this technique in beef cattle, and especially in the Zebu genotype. A total of 116 rib were used to evaluate published prediction equations for rib composition and to develop new regression models using a cross-validation procedure. For the proposed models, 93 ribs were randomly selected to calculate the new regression equations, and 23 different ribs were randomly selected to validate the regressions. The rib from left carcasses were taken from Nellore and Nellore × Angus bulls from 3 different studies and scanned using DXA equipment (GE Healthcare, Madison, WI) in the Health Division at Universidade Federal de Viçosa (Viçosa, Brazil). The outputs of the DXA report were DXA lean (g), DXA fat free mass (g), DXA fat mass (g), and DXA bone mineral content (BMC; g). After being scanned, the rib were dissected, ground, and chemically analyzed for total ether extract (EE), CP, water, and ash content. The predictions of rib fat and protein from previous published equations were different ( < 0.01) from the observed composition. New equations were established through leave-one-out cross-validation using the REG procedure in SAS. The equations were as follows: lean (g) = 37.082 + 0.907× DXA lean ( = 0.95); fat free mass (g) = 103.224 + 0.869 × DXA fat free mass ( = 0.93); EE mass (g) = 122.404 + 1.119 × DXA fat mass ( = 0.86); and ash mass (g) = 18.722 + 1.016 × DXA BMC ( = 0.39). The equations were validated using Mayer's test, the concordance correlation coefficient, and the mean square error of prediction for decomposition. For both equations, Mayer's test indicated that if the intercept and the slope were equal to 0 and 1 ( > 0.05), respectively, then the equation correctly estimated the rib composition. Comparing observed and predicted values using the new equations, Mayer's test was not significant for lean mass ( = 0.26), fat free mass ( = 0.67), EE mass ( = 0.054), and ash mass ( = 0.14). We concluded that the rib composition of Nellore and Nellore × Angus bulls can be estimated from DXA using the proposed equations.

Thirty-five healthy, neutered, mixed breed dogs were used to determine the ability of multifrequency bioelectrical impedance analysis (MFBIA) to predict accurately fat-free mass (FFM) in dogs using dual energy X-ray absorptiometry (DXA)-measured FFM as reference. A second aim was to compare MFBIA predictions with morphometric predictions. MFBIA-based predictors provided an accurate measure of FFM, within 1.5% when compared to DXA-derived FFM, in normal weight dogs. FFM estimates were most highly correlated with DXA-measured FFM when the prediction equation included resistance quotient, bodyweight, and body condition score. At the population level, the inclusion of impedance as a predictor variable did not add substantially to the predictive power achieved with morphometric variables alone; in individual dogs, impedance predictors were more valuable than morphometric predictors. These results indicate that, following further validation, MFBIA could provide a useful tool in clinical practice to objectively measure FFM in canine patients and help improve compliance with prevention and treatment programs for obesity in dogs., (Copyright © 2016. Published by Elsevier Ltd.)

While osteopenia (OPE) and osteoporosis (OPO) have been studied in various species of aging nonhuman primates and extensively in ovariectomized rhesus and cynomolgus macaques, there is virtually no information on the effects of castration on the skeleton of male nonhuman primates. Most information on castrated male primates comes from a few studies on the skeletons of eunuchs. This report used a subset of the Caribbean Primate Research Center's (CPRC) Cayo Santiago (CS) rhesus macaque skeletal collection to qualitatively and quantitatively compare the bone mineral density (BMD) of castrated and age-matched intact males and, thereby, determine the long-term effects of castration (orchidectomy) on bone. Lumbar vertebrae, femora, and crania were evaluated using dual-energy X-ray absorptiometry (DEXA or DXA) and digital radiography augmented, when fresh tissues were available, with autoradiography and histology. Results confirmed physical examinations of long bones that castration causes changes in the skeleton of male rhesus macaques similar to those found in eunuchs, including OPE and OPO of the vertebrae and femora, thinning of the skull, and vertebral fractures and kyphosis of the spine more severe than that caused by normal aging alone. Also like eunuchs, some castrated CS male rhesus monkeys had a longer life span than intact males or females. Based on these results and the effects of castration on other tissues and organs of eunuchs, on behavior, hormone profiles and possibly on cognition and visual perception of human and nonhuman primates, and other mammals, castrated male rhesus macaques should be used with caution for laboratory studies and should be considered a separate category from intact males. Despite these caveats, the castrated male rhesus macaque should make an excellent animal model in which to test hormone replacement therapies for boys and men orchidectomized for testicular and prostate cancer., (© 2016 Wiley Periodicals, Inc.)

We aimed to examine the early effects of prepubertal ovariohysterectomy (P-OHE) on bone loss and proximal physeal closure in cats. Fourteen kittens randomly underwent P-OHE or sham operations (S-OP) at three months (mo) of age and were allocated to group I and group II. Each mo between four and nine mo of age, dual-energy X-ray absorptiometry (DEXA) scans were performed to determine the total body bone mineral density (BMD) and bone mineral content (BMC). Proximal radial physeal closure and radial length were determined by radiography. Bone-specific alkaline phosphatase (BAP), carboxy-terminal collagen teleopeptide (CTX), 17-β estradiol, progesterone, calcium (Ca) and phosphorus (P) were measured in the serum samples. No significant differences were observed between the groups in terms of BMD, BMC, BAP, BAP/CTX, P, progesterone and body weight (BW) (between 4 and 9mo) and for Ca (between 5 and 9mo) and for CTX levels (between 4 and 8mo). The 17-β estradiol was significantly higher at 6, 8 and 9mo of age in the S-OP group due to puberty (P=0.02, P=0.03 and P=0.02 respectively). Although there was a significant difference (P=0.0002) between the P-OHE and S-OP groups in terms of the proximal radial physeal closure times (7.43±0.20mo and 6.14±0.14mo, respectively), no significant difference was observed for the mean radius length (10.59±0.10cm and 10.06±0.27cm, respectively) at the last evaluation time. In conclusion, prepubertal ovariohysterectomized cats do not have any osteoporotic risks until nine mo of age and exhibit a delayed physeal closure time without a change in radius length., (Copyright © 2015. Published by Elsevier B.V.)

Objective: To determine the effect of feeding a food with coconut oil and supplemental L-carnitine, lysine, leucine, and fiber on weight loss and maintenance in cats., Design: Prospective clinical study., Animals: 50 overweight cats., Procedures: The study consisted of 2 trials. During trial 1, 30 cats were allocated to 3 groups (10 cats/group) to be fed a dry maintenance cat food to maintain body weight (group 1) or a dry test food at the same amount on a mass (group 2) or energy (group 3) basis as group 1. During trial 2, each of 20 cats was fed the test food and caloric intake was adjusted to maintain a weight loss rate of 1%/wk (weight loss phase). Next, each cat was fed the test food in an amount calculated to maintain the body weight achieved at the end of the weight loss phase (weight maintenance phase). Cats were weighed and underwent dual-energy x-ray absorptiometry monthly. Metabolomic data were determined before (baseline) and after each phase., Results: During trial 1, cats in groups 2 and 3 lost significantly more weight than did those in group 1. During trial 2, cats lost a significant amount of body weight and fat mass but retained lean body mass during the weight loss phase and continued to lose body weight and fat mass but gained lean body mass during the weight maintenance phase. Evaluation of metabolomic data suggested that fat metabolism was improved from baseline for cats fed the test food., Conclusions and Clinical Relevance: Results suggested that feeding overweight cats the test food caused weight loss and improvements in body condition during the weight maintenance phase, possibly because the food composition improved energy metabolism.

Objective: To determine the effect of feeding a food with coconut oil and supplemental L-carnitine, lipoic acid, lysine, leucine, and fiber on weight loss and maintenance in dogs., Design: Prospective clinical study., Animals: 50 overweight dogs., Procedures: The study consisted of 2 trials. During trial 1, 30 dogs were allocated to 3 groups (10 dogs/group) to be fed a dry maintenance dog food to maintain body weight (group 1) or a dry test food at the same amount on a mass (group 2) or energy (group 3) basis as group 1. During trial 2, each of 20 dogs was fed the test food and caloric intake was adjusted to maintain a weight loss rate of 1% to 2%/wk (weight loss phase). Next, each dog was fed the test food in an amount calculated to maintain the body weight achieved at the end of the weight loss phase (weight maintenance phase). Dogs were weighed and underwent dual-energy x-ray absorptiometry monthly. Metabolomic data were determined before (baseline) and after each phase., Results: During trial 1, dogs in groups 2 and 3 lost significantly more weight than did those in group 1. During trial 2, dogs lost a significant amount of body weight and fat mass but retained lean body mass (LBM) during the weight loss phase and continued to lose body fat but gained LBM during the weight maintenance phase. Evaluation of metabolomic data suggested that fat metabolism and LBM retention were improved from baseline for dogs fed the test food., Conclusions and Clinical Relevance: Results suggested that feeding overweight dogs the test food caused weight loss and improvements in body condition during the weight-maintenance phase, possibly because the food composition improved energy metabolism.

The ability to accurately measure body or carcass composition is important for performance testing, grading and finally selection or payment of meat-producing animals. Advances especially in non-invasive techniques are mainly based on the development of electronic and computer-driven methods in order to provide objective phenotypic data. The preference for a specific technique depends on the target animal species or carcass, combined with technical and practical aspects such as accuracy, reliability, cost, portability, speed, ease of use, safety and for in vivo measurements the need for fixation or sedation. The techniques rely on specific device-driven signals, which interact with tissues in the body or carcass at the atomic or molecular level, resulting in secondary or attenuated signals detected by the instruments and analyzed quantitatively. The electromagnetic signal produced by the instrument may originate from mechanical energy such as sound waves (ultrasound - US), 'photon' radiation (X-ray-computed tomography - CT, dual-energy X-ray absorptiometry - DXA) or radio frequency waves (magnetic resonance imaging - MRI). The signals detected by the corresponding instruments are processed to measure, for example, tissue depths, areas, volumes or distributions of fat, muscle (water, protein) and partly bone or bone mineral. Among the above techniques, CT is the most accurate one followed by MRI and DXA, whereas US can be used for all sizes of farm animal species even under field conditions. CT, MRI and US can provide volume data, whereas only DXA delivers immediate whole-body composition results without (2D) image manipulation. A combination of simple US and more expensive CT, MRI or DXA might be applied for farm animal selection programs in a stepwise approach.

Sixteen female piglets (58 d of age, 16.8 ± 0.8 kg body weight [BW]) were assigned to two groups (n = 8) and received until day 100 of age (50.3 ± 1.2 kg BW) ad libitum either a diet with a standard (diet C) or low (diet L) total phosphorus (P) content (5.38 and 4.23 g/kg, respectively). Diet C was supplemented with mineral P (1.15 g/kg) and did not contain microbial phytase. Diet L did not contain any inorganic P but 750 FTU/kg of microbial phytase. Despite these treatments, both diets were composed with the same ingredients. Body mineralisation of each gilt was assessed by determining the bone mineral content (BMC), area bone mineral density (BMD) by the dual-energy X-ray absorptiometry (DXA) at days 58, 72, 86 and 100 of age. Feeding diet L caused a higher P digestibility (p = 0.008) measured from days 72 to 86 of age and at 100 days of age a higher BMC and BMD (p ≤ 0.01). Furthermore, the gilts of group L deposited more minerals in the body than control pigs (by 2.4 g/d, p = 0.008). It was found that BMD and BMC were positively correlated with body lean mass and digestible P intake. The results indicated that, even for very young pigs, the addition of microbial phytase instead of inorganic P increases the amount of digestible P covering the requirements of piglets for proper bone mineralisation. Furthermore, it was proved that the DXA method can be successfully applied to measure body fat and lean mass contents as well as bone mineralisation of growing pigs using the same animals.

Objectives: To compare optical values in the osteotomy gap created after a tibial tuberosity advancement (TTA) treated with autogenous cancellous bone graft, extracorporeal shock wave therapy, a combination of autogenous cancellous bone graft and extracorporeal shock wave therapy, and absence of both autogenous cancellous bone graft and extracorporeal shock wave therapy using densitometry., Methods: Dogs that were presented for surgical repair of a cranial cruciate ligament rupture were randomly assigned to one of four groups: TTA with autogenous cancellous bone graft (TTA-G), TTA with autogenous cancellous bone graft and extracorporeal shock wave therapy (TTA-GS), TTA with extracorporeal shock wave therapy (TTA-S), and TTA with no additional therapy (TTA-O). Mediolateral radiographs at zero, four and eight weeks after surgery were evaluated to compare healing of the osteotomy gap via densitometry. An analysis of variance was used to compare the densitometric values between groups., Results: At four weeks after surgery, a significant difference in osteotomy gap density was noted between TTA-GS (8.4 millimetres of aluminium equivalent [mmAleq]) and TTA-S (6.1 mmAleq), and between TTA-GS (8.4 mmAleq) and TTA-O (6.4 mmAleq). There were no significant differences noted between any groups at the eight week re-evaluation., Clinical Significance: There were no significant differences in the osteotomy gap density at eight weeks after surgery regardless of the treatment modality used. The combination of autogenous cancellous bone graft and extracorporeal shock wave therapy may lead to increased radiographic density of the osteotomy gap in the first four weeks after surgery. Densitometry using an aluminium step wedge is a feasible method for comparison of bone density after TTA in dogs.

A study was conducted to examine the effects of 25-hydroxyvitamin D3 (25-(OH)D3) on fecal Ca and P excretion, bone mineralization, performance and the mRNA expression of intestinal transporter genes in growing female pigs. Sixty-day old gilts (n = 24) with an average initial BW of 23.13 ± 1.49 kg were randomly allocated to a control diet (diet 1) containing wheat/corn/soybean meal and 150 IU kg(-1) of Vitamin D3, diet 1 + 50 μg of 25-(OH)D3 kg(-1) (diet 2) and diet 1 + 100 μg of 25-(OH)D3 kg(-1) (diet 3). The pigs were housed in an individual pen and had ad libitum access to feed and water for 42 days, and BWG and feed intake were measured weekly. Measures of bone mineralization and expression of Ca and P transporters mRNA were analyzed using Dual Energy X-Ray Absortiometry (DEXA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Data were analyzed using GLM procedure of the Statistical Analysis System (SAS Institute version 9.2). Fecal Ca and P concentration were significantly reduced (P ≤ 0.05) in pigs fed diets 2 and 3 compared with the control diet. Supplementation of 25-(OH)D3 did not significantly improve bone mineralization, animal performance and intestinal transporters mRNA expression except for SLC34A1, a sodium-dependent phosphate transporter 1. In conclusion, supplementation of 25-(OH)D3 in swine nutrition may not improve animal performance but has the potential to reduce environmental pollution by increasing dietary Ca and P retention while reducing their excretion.

Body condition scoring (BCS) provides a readily available technique that can be used by both veterinary professionals and owners to assess the body condition of cats, and diagnose overweight or underweight conditions. The objective of this study was to evaluate a five-point BCS system with half-point delineations using dual-energy x-ray absorptiometry (DXA). Four evaluators (a veterinarian, veterinary technician, trained scorer and untrained scorer) assessed 133 neutered adult cats. For all scorers, BCS score was more strongly correlated with percent body fat than with body weight. Percent body fat increased by approximately 7% within each step increase in BCS. The veterinarian had the strongest correlation coefficient between BCS and percent fat (r = 0.80). Mean body fat in cats classified as being in ideal body condition was 12 and 19%, for 3.0 and 3.5 BCS, respectively. Within BCS category, male cats were significantly heavier in body weight than females within the same assigned BCS category. However, DXA-measured percent body fat did not differ significantly between male and female cats within BCS category, as assigned by the veterinarian (P >0.13). Conversely, when assessed by others, mean percent body fat within BCS category was lower in males than females for cats classified as being overweight (BCS >4.0). The results of this study show that using a BCS system that has been validated within a range of normal weight to moderately overweight cats can help to differentiate between lean cats and cats that may not be excessively overweight, but that still carry a higher proportion of body fat., (© ISFM and AAFP 2014.)