Intra-flock variability in the body reserve dynamics of meat sheep by analyzing BW and body condition score variations over multiple production cycles

Breeding for resilience requires a better understanding of intra-flock variability and the related mechanisms responsible for robustness traits. Among such traits, the animals’ ability to cope with feed fluctuations by mobilizing or restoring body reserves (BR) is a key mechanism in ruminants. The objective of this work was to characterize individual variability in BR dynamics in productive Romane ewes reared in extensive conditions. The BR dynamics profiles were characterized by combining individual longitudinal measurements of BW and body condition scores (BCS) over several production cycles. Historical data, including up to 2628 records per trait distributed in 1146 ewes, underwent cluster analysis. Two to four trajectories were observed for BW depending on the cycle, while three trajectories were found for BCS, whatever the cycle. Most trajectories suggested that BR dynamics were similar but the level of BR may differ between ewes. Nevertheless, some trajectories suggested that both BR dynamics and levels were different for a proportion of ewes. Clustering on BW and BCS profiles adjusted for individual level trends, resulted in differences only in the level of BW or BCS, rather than differences in trajectories. Thus, the overall shape of trajectories was not changed considering or not the individual level trend across cycles. In addition to individual variability, the ewe’s age at first lambing and litter size contributed to the distribution of the ewes between the trajectories. Regarding the entire productive life, three trajectories were observed for BW and BCS changes over three productive cycles. Increase in BW at each cycle suggested that ewes kept growing up until 3 to 4 years old in our conditions. Similar alternation of BCS gains and losses across cycles suggested BR dynamics might be repeatable. Many individual trajectories remained the same throughout a ewe’s life, whatever the age at first lambing, parity or litter size. Our results demonstrate the relevance of using BW and BCS changes for characterizing the diversity of BR mobilization–accretion profiles in sheep in a long timespan perspective.     

The ability of video image analysis to predict lean meat yield and EUROP score of lamb carcasses

A total of 862 lamb carcasses that were evaluated by both the VIAscan® and the current EUROP classification system were deboned and the actual yield was measured. Models were derived for predicting lean meat yield of the legs (Leg%), loin (Loin%) and shoulder (Shldr%) using the best VIAscan® variables selected by stepwise regression analysis of a calibration data set (n=603). The equations were tested on validation data set (n=259). The results showed that the VIAscan® predicted lean meat yield in the leg, loin and shoulder with an R² of 0.60, 0.31 and 0.47, respectively, whereas the current EUROP system predicted lean yield with an R² of 0.57, 0.32 and 0.37, respectively, for the three carcass parts. The VIAscan® also predicted the EUROP score of the trial carcasses, using a model derived from an earlier trial. The EUROP classification from VIAscan® and the current system were compared for their ability to explain the variation in lean yield of the whole carcass (LMY%) and trimmed fat (FAT%). The predicted EUROP scores from the VIAscan® explained 36% of the variation in LMY% and 60% of the variation in FAT%, compared with the current EUROP system that explained 49% and 72%, respectively. The EUROP classification obtained by the VIAscan® was tested against a panel of three expert classifiers (n=696). The VIAscan® classification agreed with 82% of conformation and 73% of the fat classes assigned by a panel of expert classifiers. It was concluded that VIAscan® provides a technology that can directly predict LMY% of lamb carcasses with more accuracy than the current EUROP classification system. The VIAscan® is also capable of classifying lamb carcasses into EUROP classes with an accuracy that fulfils minimum demands for the Icelandic sheep industry. Although the VIAscan® prediction of the Loin% is low, it is comparable to the current EUROP system, and should not hinder the adoption of the technology to estimate the yield of Icelandic lambs as it delivered a more accurate prediction for the Leg%, Shldr% and overall LMY% with negligible prediction bias.     

Relationship of parity and body condition score to pregnancy rates in Florida beef cattle

Pregnancy rates, determined by per rectum palpation, were analyzed with respect to cow parity (range 1 to >8 calvings) and body condition score (BCS, 1=thin to 9=fat) at pregnancy examination for 3734 beef cattle females on 3 commercial beef operations (8 herds) in 3 Florida counties in 1989 and 1990. The means and standard deviations for the herds were the following: pregnancy rate, 81.3 +/- 39% (range 62.1 to 91.5%); BCS, 4.7 +/- 0.6 (range 4.3 to 4.9); and parity, 3.9 +/- 2.3 (range 2.8 to 4.8). Significant associations were found between pregnancy rate, parity, BCS and herd (P < 0.001); and between the variable interactions, parity with BCS, herd with BCS, and herd with parity (P < 0.001). Cows with a BCS /=5 had a pregnancy rate of 90%. Cows having a parity of <4 had a PR of 80%, while cows having a parity >/=4 had a PR of 85%. The interaction of parity with BCS was significant, resulting in pregnancy rates as follows; parity <4 and BCS /= 5 was 88%; parity >/=4 and BCS /=5 and BCS >/= 5 was 93%. Body condition, parity, and the interaction of body condition and parity play important roles in the reproductive performance of commercial beef cows in Florida.     

Relationship of body condition score and blood urea and ammonia to pregnancy in Italian Mediterranean buffaloes

The relationship of body condition score (BCS) and blood urea and ammonia to pregnancy outcome was examined in Italian Mediterranean Buffalo cows mated by AI. The study was conducted on 150 buffaloes at 145 +/- 83 days in milk that were fed a diet comprising 14.8% crude protein, 0.9 milk forage units.kg-1 dry matter and a non-structural carbohydrate/crude protein ratio of 2.14. The stage of the oestrous cycle was synchronised by the Ovsynch-TAI programme and blood urea and ammonia levels were assessed on the day of AI. Energy corrected milk (ECM) production and BCS were recorded bi-weekly. The pregnancy risk was 46.7% and was slightly lower in buffaloes with BCS < 6.0 and BCS > 7.5. There were no significant differences in ECM, urea and ammonia between pregnant and non-pregnant buffaloes. However, pregnancy outcome was higher (P = 0.02) in buffaloes with blood urea < 6.83 mmol.L-1. The likelihood of pregnancy for buffaloes with low urea blood level was 2.6 greater than for high urea level and exposure to a high urea level lowered the probability of pregnancy by about 0.25. The findings indicate that buffaloes are similar to cattle and increased blood levels of urea are associated with reduced fertility when animals are mated by AI.     

Short communication: Differences in genetic merit for visually-assessed body condition score materialises as phenotypic differences in tactile-based body condition score in commercial dairy cows

Body condition score (BCS) is a known risk factor for cow health and well-being. Many different BCS scales and systems for assessment exist;while the scales used for assessing BCS vary, differences in how BCS is assessed (i.e., visual versus visual plus tactile) and the extent of training and experience of the assessor (i.e., professional linear classifiers versus producers) also contributes to the underlying variability. Registered dairy cows globally are routinely assessed for linear type traits which describe biological extremes in the morphological attributes; BCS and a correlated trait angularity are within this suite of traits assessed. These linear-type data are used to generate estimates of genetic merit (predicted transmitting ability), but how these estimates manifest themselves as phenotypic differences when assessed by producers on commercial multiparous cows has never been quantified. To evaluate this, 58 440 phenotypic BCS records from 48 823 lactations in 38 608 cows were used. Associations were undertaken using linear mixed models relating phenotypic BCS to genetic merit after accounting for nuisance factors. Differences in genetic merit for either BCS or angularity (assessed visually by professionals on a 1 to 9 scale just once during lactation in primiparous registered cows) translated to phenotypic difference in BCS (assessed by producers using both tactile and visual assessment on a 1 to 5 scale across lactation in commercial dairy cows). The partial correlation between test phenotypic BCS and genetic merit for either BCS or angularity was 0.13 and  0.10, respectively. Based on the model coefficients estimated in the present study, the mean expected difference in phenotypic BCS on a 1 to 5 scale between the top and bottom 10% on genetic merit for BCS or angularity was 0.28 and 0.31 units, respectively. Results from the present study clearly provide confidence that genetic merit for BCS or angularity based on a single visual assessment in primiparous cows is useful to breed for cows of better body condition, irrespective of stage of lactation or parity.     

Effects of body condition score and score change on the reproductive performance of dairy cows: a meta-analysis

A meta-analysis was conducted to evaluate the effects of body condition score (BCS) at parturition and at first AI, and of body condition change during the early lactation period on the variables pregnancy rate at first AI and number of days open in dairy cattle. Inclusion criteria for the publications were: comparison of at least two groups of animals of different categories of BCS or change (independent variables) and consideration of pregnancy rate at first AI or number of days open (dependent variables). Fifteen papers were selected and 23 excluded. Data corresponding to 7733 cows from 11 studies described in 10 papers were included in the analysis of pregnancy rate at first AI, and those derived from 4529 cows from 11 studies described in 10 papers were used to analyze effects on the number of days open. Analyses were stratified according to study design and milk production characteristics. We defined low, intermediate and high categories of BCS for values lower than 2.5, from 2.5 to 3.5, or higher than 3.5, respectively. The categories of body condition change were increase (gain in score), slight loss (0-0.5 point loss), moderate loss (0.6-1 point loss), and severe loss (over 1 unit loss). Intermediate body condition at parturition and at first AI, and a slight loss during the early lactation period were used as reference categories. The effects of body condition on the variable pregnancy rate at first AI were highly heterogeneous, while all the studies considering the number of days open presented homogeneous results. A clear association between body condition category and pregnancy rate at first AI was detected only when the effect of a low score at parturition was analyzed: pregnancy rate at first AI significantly decreased by about 10% in cows delivering in poor condition. Animals with a high BCS at parturition showed a significant reduction in the number of days open of 5.8 or 11.7 when compared with animals with an intermediate or low body condition, respectively. In animals in the high body condition category at first AI, the variable days open showed a significant drop of 11.9 or 24.1, compared to animals in the intermediate or low categories, respectively. A severe loss in score during early lactation was related to a significant (10.6) increase in the number of days open, while a slight or moderate body condition change, either loss or gain in score, was not significantly related to the variable days open. We found that the number of days open was a good indicator of the effects of BCS or change in score on reproductive performance in dairy cattle. The variable pregnancy rate at first AI, however, yielded heterogeneous results among studies.     

Use of magnetic resonance imaging to predict the body composition of pigs in vivo

The objective of the study was to evaluate whether magnetic resonance imaging (MRI) offers the opportunity to reliably analyze body composition of pigs in vivo. Therefore, the relation between areas of loin eye muscle and its back fat based on MRI images were used to predict body composition values measured by dual energy X-ray absorptiometry (DXA). During the study, a total of 77 pigs were studied by MRI and DXA, with a BW ranging between 42 and 102 kg. The pigs originated from different extensive or conventional breeds or crossbreds such as Cerdo Iberico, Duroc, German Landrace, German Large White, Hampshire and Pietrain. A Siemens Magnetom Open was used for MRI in the thorax region between 13th and 14th vertebrae in order to measure the loin eye area (MRI-LA) and the above back fat area (MRI-FA) of both body sides, whereas a whole body scan was performed by DXA with a GE Lunar DPX-IQ in order to measure the amount and percentage of fat tissue (DXA-FM; DXA-%FM) and lean tissue mass (DXA-LM; DXA-%LM). A linear single regression analysis was performed to quantify the linear relationships between MRI- and DXA-derived traits. In addition, a stepwise regression procedure was carried out to calculate (multiple) regression equations between MRI and DXA variables (including BW). Single regression analyses showed high relationships between DXA-%FM and MRI-FA (R² = 0.89, √MSE = 2.39%), DXA-FM and MRI-FA (R² = 0.82, √MSE = 2757 g) and DXA-LM and MRI-LA (R² = 0.82, √MSE = 4018 g). Only DXA-%LM and MRI-LA did not show any relationship (R² = 0). As a result of the multiple regression analysis, DXA-LM and DXA-FM were both highly related to MRI-LA, MRI-FA and BW (R² = 0.96; √MSE = 1784 g, and R² = 0.95, √MSE = 1496 g). Therefore, it can be concluded that the use of MRI-derived images provides exact information about important ‘carcass-traits’ in pigs and may be used to reliably predict the body composition in vivo.     

Relationships between body condition score and ultrasound skin-associated subcutaneous fat depth in equids

Background

In equids, health and welfare depend on body composition. A growing number of equids are now used as leisure and companion animals, and often found overfeed. The need for a close monitoring of body fatness led to the search for tools allowing a rapid and non-invasive estimation of fatness. This study intends to assess real-time ultrasonography (RTU) usefulness in establishing a relationship between ultrasound measures of subcutaneous fat–plus–skin thickness (SF-Skin) and body condition score (BCS) in horses and donkeys. Forty-three healthy animals (16 donkeys and 27 horses) were used in this study to generate 95 records (RTU and BCS pairs), in multiple RTU sessions for 2 years. Using visual appraisal and palpation, BCS was graded in a 1–9 points scale. Real-time ultrasonography images were taken using a 7.5 MHz linear transducer, placed perpendicular to the backbone, over the 3rd lumbar vertebra. ImageJ was used to measure the SF-Skin on RTU images. The relation between BCS and SF-Skin measurements was tested by linear and polynomial regression analysis.

Results

The BCS values were similar in horses (5.50; from 3 to 8 points) and donkeys (5.14; from 3 to 7 points). The SF-Skin measures show a similar trend (a mean of 7.1 and 7.7 mm in horses and donkeys, respectively). A polynomial regression among BCS and SF-Skin explained 92 and 77 % of the variation in donkeys and horses respectively. The coefficient of determination was considerably higher for the regression developed for donkeys compared with that of horses (R2 = 0.92 vs. 0.77, respectively), which reduced the accuracy of the method in horses. Both the linear and polynomial models tested show a strong relationship among BCS and SF-Skin for donkeys (R2 > 0.91; P < 0.01) and horses (R2 > 0.74; P < 0.01), despite that the extremes for BCS did not existed in our sample.

Conclusions

Our results showed the potential RTU usefulness to monitor body fat in equids. Using a high-frequency transducer and RTU together with image analysis allowed the identification of small SF-skin variations. This report will support further studies on the relationships between SF-Skin and BCS, particularly in extreme BCS scores.

     

Relationships between administration of GnRH, body condition score and fertility in Holstein dairy cattle

The objective of this study was to determine the effect of GnRH treatment in dairy cows differing in body condition score. A total of 2437 primiparous and multiparous cows was allocated randomly to receive either GnRH (100 mug) or placebo at the post partum exam (25 to 35 d) and at the first breeding. Complete records were available from 1906 cows: Group 1 (n = 535) placebo and placebo; Group 2 (n = 489) GnRH and placebo; Group 3 (n = 438) placebo and GnRH; and Group 4 (n = 444) GnRH and GnRH. The change of body condition score during early lactation was determined on a 1 to 5 scale (1 = emaciated to 5 = obese). Cows with a high body condition score (>/=3.0) at the first breeding had 8.8 fewer days to first service and 6.4 fewer days open but more services per conception (0.16) than cows with low body condition score (<3.0). Conception rate improved when GnRH was administered at the first breeding to cows with a body condition score of <3.0 at the first breeding regardless of parity. The administration of GnRH at the post partum exam decreased the conception rate in first lactation cows but was beneficial for cows in second and greater lactations. Thus the efficacy of GnRH may not be consistent in all parities and body condition groups.     

Effect of avoparcin on performance,body composition and meat quality of finishing bulls

Three experiments were carried out with Belgian white-blue bulls housed in tie stalls. They received maize silage in the first trial and maize silage supplemented with a restricted amount of potatoes in two other trials. Besides the basal feed an appropriate concentrate was given at 7.5 g per kg liveweight per day. In Experiments I and II half the animals received 150 mg avoparcin per kg concentrate. In Experiment III, three concentrates were administered, containing 0, 75 and 150 mg avoparcin per kg.For the three trials, daily gain amounted to 1.07 and 1.08 kg; 1.11 and 1.07 kg; and 1.11, 1.14 and 1.13 kg, respectively, for the control and avoparcin-fed animals. Treatment differences were not significant. Daily feed intake was depressed from 75.6 to 73.3 g; 75.9 to 71.9 g; and from 75.3 to 72.9 and 71.4 g dry matter per kg W^0.75, respectively. Avoparcin improved dry matter consumption per kg gain by 4% in Experiment I, 3% in Experiment II and 6 and 7% in Experiment III. Differences in intake were significant only in Experiment III (P<0.05). Carcass parameters did not differ significantly and meat quality characteristics were mostly very similar.     

Can tritiated water-dilution space accurately predict total body water in chukar partridges?

Total body water (TBW) volumes determined from the dilution space of injected tritiated water have consistently overestimated actual water volumes (determined by desiccation to constant mass) in reptiles and mammals, but results for birds are controversial. We investigated potential errors in both the dilution method and the desiccation method in an attempt to resolve this controversy. Tritiated water dilution yielded an accurate measurement of water mass in vitro. However, in vivo, this method yielded a 4.6% overestimate of the amount of water (3.1% of live body mass) in chukar partridges, apparently largely because of loss of tritium from body water to sites of dissociable hydrogens on body solids. An additional source of overestimation (approximately 2% of body mass) was loss of tritium to the solids in blood samples during distillation of blood to obtain pure water for tritium analysis. Measuring tritium activity in plasma samples avoided this problem but required measurement of, and correction for, the dry matter content in plasma. Desiccation to constant mass by lyophilization or oven-drying also overestimated the amount of water actually in the bodies of chukar partridges by 1.4% of body mass, because these values included water adsorbed onto the outside of feathers. When desiccating defeathered carcasses, oven-drying at 70 degrees C yielded TBW values identical to those obtained from lyophilization, but TBW was overestimated (0.5% of body mass) by drying at 100 degrees C due to loss of organic substances as well as water.(ABSTRACT TRUNCATED AT 250 WORDS)     

Using body size to predict perceptual range

We examined the relationship between body size and perceptual range (the distance at which an animal can perceive landscape elements) for a group of forest-dwelling rodents. We used previously published data on orientation ability at various distances for three sciurid species (gray squirrel, fox squirrel and chipmunk) and one murid species (white-footed mouse) to build a predictive model. We found a significant positive relationship between perceptual range and body mass. Although this model was built using a 15.5 m high horizon, we used this relation to predict the perceptual range of root voles (3.9–4.3 m) orienting towards a 0.5 m high horizon which was consistent with other empirical work suggesting a value of something less than 5 m. This model illustrates a relationship between perceptual range and body size and can be used to develop starting points for future investigations of perceptual range for similar organisms.     

Anthropometric variables accurately predict dual energy x-ray absorptiometric-derived body composition and can be used to screen for diabetes

The current world-wide epidemic of obesity has stimulated interest in developing simple screening methods to identify individuals with undiagnosed diabetes mellitus type 2 (DM2) or metabolic syndrome (MS). Prior work utilizing body composition obtained by sophisticated technology has shown that the ratio of abdominal fat to total fat is a good predictor for DM2 or MS. The goals of this study were to determine how well simple anthropometric variables predict the fat mass distribution as determined by dual energy x-ray absorptometry (DXA), and whether these are useful to screen for DM2 or MS within a population. To accomplish this, the body composition of 341 females spanning a wide range of body mass indices and with a 23% prevalence of DM2 and MS was determined using DXA. Stepwise linear regression models incorporating age, weight, height, waistline, and hipline predicted DXA body composition (i.e., fat mass, trunk fat, fat free mass, and total mass) with good accuracy. Using body composition as independent variables, nominal logistic regression was then performed to estimate the probability of DM2. The results show good discrimination with the receiver operating characteristic (ROC) having an area under the curve (AUC) of 0.78. The anthropometrically-derived body composition equations derived from the full DXA study group were then applied to a group of 1153 female patients selected from a general endocrinology practice. Similar to the smaller study group, the ROC from logistical regression using body composition had an AUC of 0.81 for the detection of DM2. These results are superior to screening based on questionnaires and compare favorably with published data derived from invasive testing, e.g., hemoglobin A1c. This anthropometric approach offers promise for the development of simple, inexpensive, non-invasive screening to identify individuals with metabolic dysfunction within large populations.     

Effects of body condition score on direct and indirect measurements of insulin sensitivity in periparturient dairy cows

Reductions in insulin sensitivity in periparturient dairy cows develop as a means to support lactation; however, excessive mobilization of fatty acids (FA) increases the risk for peripartal metabolic disorders. Our objectives were to investigate the effect of prepartum body condition score (BCS) on systemic glucose and insulin tolerance, and to compare direct and indirect measurements of insulin sensitivity in peripartal lean and overweight dairy cows. Fourteen multiparous Holstein cows were allocated into two groups according to their BCS at day −28 prepartum: lean (n = 7; BCS ≤ 3.0) or overweight; (n = 7; BCS ≥ 4.0). Liver biopsies were performed on day −27, −14 and 4, relative to expected parturition. Intravenous insulin or glucose tolerances tests were performed following each liver biopsy. Relative to lean cows, overweight cows exhibited lower dry matter intake, lost more BCS and displayed increased plasma FA and β-hydroxybutyrate concentrations and elevated liver lipid content during peripartum. Glucose clearance rate was lower for all cows postpartum. Prepartum BCS had minimal effects on insulin and glucose tolerance; however, the ability of the cow to restore blood glucose levels following an insulin challenge was suppressed by increased BCS. Glucose-dependent parameters of insulin and glucose tolerance were not correlated with surrogate indices of insulin sensitivity. We conclude that prepartum BCS had minimal effect on systemic insulin sensitivity following parturition. The observed inconsistency between surrogate indices of insulin sensitivity and direct measurements of insulin and glucose tolerance adds support to growing concerns regarding their usefulness as tools to estimate systemic insulin action in periparturient cows.     

Influences of landscape composition on hunter-harvested mallard body mass and condition in eastern Arkansas

Waterfowl with more body mass and a greater body condition during the non-breeding season are thought to be more likely to survive and have increased productivity during the following breeding season. Body mass and body condition in waterfowl should reflect the resources available to them locally. We analyzed the relationship of landscape composition on mallard (Anas platyrhynchos) body mass and body condition (mass-wing length index) among age and sex groups. We calculated these variables from hunter-harvested mallards during the 2019–2020 and 2020–2021 duck hunting seasons in the Lower Mississippi Alluvial Valley of Arkansas, USA. We used linear mixed-effects models to analyze changes in body mass and body condition with changes in the percent landscape composition of water cover, woody wetlands, herbaceous wetlands, rice, soybeans, and disturbance. We found that body mass and condition of harvested mallards were positively associated with greater proportions of water cover and woody wetlands but negatively associated with greater proportions of herbaceous wetlands and human disturbance from human infrastructure. Management actions focused on providing flooded and woody wetland areas on the landscape that allow waterfowl to access food resources, while decreasing the disturbance around wetlands in the form of road density and human infrastructure, should increase body mass and body condition in mallards spending the non-breeding season in the Lower Mississippi Alluvial Valley.     

Body condition score,morphometric measurements and estimation of body weight in mature Icelandic horses in Denmark

Background

Obesity is related to the development of several diseases like insulin resistance and laminitis in horses. The prevalence of obesity among mature Icelandic horses in Denmark has not been investigated previously. This study aimed to find the prevalence of obesity, to compare body condition score (BCS) based on owner perception with that of an experienced person and to correlate the BCS to body weight (BW) and morphometric measures in a group of mature Icelandic horses in Denmark. A total of 254 Icelandic horses (≥4 years; 140 geldings, 105 mares, 9 stallions) from 46 different farms were included. All horses were assigned a BCS on a scale from 1 to 9 (1 is poor, 5 is moderate and 9 is extremely fat) by their owner and by an experienced person. Two weight tapes were used to assess BW. Girth circumference (GC), neck circumference (NC) and height at withers (HW) were measured, and the GC:HW and NC:HW ratios were calculated.

Results

Categorising the horses into four groups, 5.9 % were underweight (BCS 3–4), 70.1 % were optimal (BCS 5–6), 13.8 % were overweight (BCS 7) and 10.2 % were obese (BCS 8–9). The GC:HW and NC:HW ratios increased with increasing BCS, as did the BW estimated with the weight tapes. A GC:HW ratio >1.21 might indicate overweight or obesity in Icelandic horses. Horse owners underestimated the BCS of their horses compared to an experienced person.

Conclusions

The results from this study show that 24.0 % of mature Icelandic horses in Denmark are overweight or obese, and that owners tend to underestimate the BCS of their Icelandic horses. The GC:HW ratio might indicate overweight or obesity, however, the ratio for Icelandic horses is different than reported for horses and ponies of other breeds.