Body Cavity Fat Research Articles

Carcass and Primal Composition Predictions Using Camera Vision Systems (CVS) and Dual-Energy X-ray Absorptiometry (DXA) Technologies on Mature Cows

This study determined the potential of computer vision systems, namely the whole-side carcass camera (HCC) compared to the rib-eye camera (CCC) and dual energy X-ray absorptiometry (DXA) technology to predict primal and carcass composition of cull cows. The predictability (R2) of the HCC was similar to the CCC for total fat, but higher for lean (24.0%) and bone (61.6%). Subcutaneous fat (SQ), body cavity fat, and retail cut yield (RCY) estimations showed a difference of 6.2% between both CVS. The total lean meat yield (LMY) estimate was 22.4% better for CCC than for HCC. The combination of HCC and CCC resulted in a similar prediction of total fat, SQ, and intermuscular fat, and improved predictions of total lean and bone compared to HCC/CCC. Furthermore, a 25.3% improvement was observed for LMY and RCY estimations. DXA predictions showed improvements in R2 values of 26.0% and 25.6% compared to the HCC alone or the HCC + CCC combined, respectively. These results suggest the feasibility of using HCC for predicting primal and carcass composition. This is an important finding for slaughter systems, such as those used for mature cattle in North America that do not routinely knife rib carcasses, which prevents the use of CCC.

Alewife and Blueback Herring Captured by Intertidal Weirs of the Inner Bay of Fundy, Canada, Display Seasonal Demographics that Suggest Multiple Migrating Stocks

AbstractLittle information is available concerning the seasonal demographics of marine migrating Alewife Alosa pseudoharengus and Blueback Herring A. aestivalis, reported in commercial fisheries as “gaspereau” in Canada and “river herring” in the USA. Once adults and age‐0 juveniles depart from coastal spawning rivers, they migrate along the North American Atlantic coast and are difficult to access for scientific analysis. During June–October 1985, a total of 3,785 Alewife and 2,343 Blueback Herring were examined for length, sex, and gonadal stage from commercial intertidal fishing weirs in Minas Basin and Cobequid Bay, Bay of Fundy, Nova Scotia. Of these, 999 adults were subsampled for total weight and body cavity fat deposits. Both species first appeared in the weirs during June, when Blueback Herring generally dominated catches. By July, catches were evenly divided between the two species, and Alewife dominated after mid‐August. Most adults were mature, and there was no discernable sex ratio pattern during the sampling period. Sampled fish exhibited abrupt changes in length, gonadal stage, condition factor, and abdominal wall and visceral mesentery fat deposits in relation to season (week), moon phase, and time of low tide. Sudden shifts in average lengths and fat deposits suggested that migrating Alewife were from different stocks. For Blueback Herring, the condition and status of fat deposits during June suggested that they were probably long‐distance adult migrators. Blueback Herring in Cobequid Bay weirs during July were probably from local stocks. Results from a total of 12,422 tagged adults that were released in Minas Basin and Cobequid Bay during 1985 supported these findings. We propose that shifts in condition and fat deposits can be used to estimate migration distance, discriminating among local, regional, and long‐distance movements.

Adaptation of cultured salmon Salmo salar (Salmonidae) yearlings to natural environments

The process of adaptation of the yearling Atlantic salmon Salmo salar cultured under the farming conditions in the Umba fish hatchery to the natural environments has been studied during a 1-year period after releasing them into the river. The significant differences in a range of the morphophysiological parameters between the hatchery-reared juveniles and their wild-origin peers, which were revealed immediately before the release into the river and 1 month later, are gradually reduced. The index of body condition, the liver index, and the body cavity fat content are normalized 4 months later; 13 months later, the other analyzed parameters (the hemoglobin concentration and the indices of heart, gills, and pectoral fins) are brought back into the normal ranges. The behavioral patterns of the hatchery-reared and wild-origin juveniles remain different during the whole observation period, since the behavioral habits acquired under the farming conditions, when compared to the developmental abnormalities, more commonly affect the juvenile fish survival in the natural environments.

Using Dual Energy X-Ray Absorptiometry (DXA) For A Rapid, Non-Invasive Carcass Fat and Lean Prediction in Beef

ObjectivesThe objective of this study was to evaluate the potential use of the dual energy X-ray absorptiometry (DXA) for estimating total lean, fat and bone content of beef carcasses and main primal cuts. Materials and MethodsTo represent the majority of commercial cattle, the animal population used (n = 316) to develop and validate the prediction models was selected within a grid based on live weight at slaughter and grade fat. Following normal commercial slaughter and chilling, left carcass sides were fabricated using the Institutional Meat Purchase Specifications (IMPS) for Fresh Beef Products, Series 100. The primals collected included the chuck (IMPS #113), rib (IMPS #103), brisket (IMPS #118), flank (IMPS #193, non-trimmed), foreshank (IMPS #117), loin (IMPS #172A), round (IMPS #158A) and plate (IMPS #121). Each primal cut was scanned with a Lunar iDXA unit (GE Lunar Lunar Prodigy Advance, General Electric, Madison, WI, USA) using the whole body scan option on standard mode to estimate DXA fat, lean and bone tissues. After scanning, all left primal cuts were fully dissected into subcutaneous fat, intermuscular fat, body cavity fat, lean, and bone and then weighed. ResultsRegression and partial least square regression (PLSR) were used to evaluate the relationship of DXA lean, fat and bone values from primal cut scans to cut-out values from manual dissection. Using linear regression, R² (i.e., the % of variation accounted for by the model) for total carcass lean, fat and bone were 0.88, 0.95 and 0.53, respectively. Within individual primals, R² for lean, fat and bone ranged from 0.26 to R² = 0.90, with the highest R² generally for fat, and the lowest predictions generally for bone. Industry applications of this technology for total lean, fat and bone would be expected to achieve these levels of prediction robustness. Using PLSR analyses, which consider all the DXA scan information from all primals as independent variables, overall R² for total carcass lean and fat were both 0.98. PLSR improved the lean prediction for most of primal cuts yielding R² over 0.94 for the brisket, foreshank and flank. The highest R² were observed for the chuck (R² = 0.99), round (R² = 0.98) and loin (R² = 0.97). Similar to lean, PLSR increased the R² for fat predictions; with all being higher than 0.91, excluding the foreshank (R² = 0.77). The highest R² for fat were observed for the flank (R² = 0.98), rib, plate and loin (R² = 0.97). ConclusionDXA was able to be used to develop robust equations for estimating total lean and fat in carcasses normally encountered in the market. Both linear and PLSR equations will provide realistic estimations of the potential utility of DXA within an industry environment, to improve estimations of lean meat yield. In research, DXA coupled with PLSR will also be able to replace manual cut-outs which are destructive, time consuming and costly.

Using Dual Energy X-Ray Absorptiometry (DXA) For A Rapid, Non-Invasive Carcass Fat and Lean Prediction in Beef

ObjectivesThe objective of this study was to evaluate the potential use of the dual energy X-ray absorptiometry (DXA) for estimating total lean, fat and bone content of beef carcasses and main primal cuts. Materials and MethodsTo represent the majority of commercial cattle, the animal population used (n = 316) to develop and validate the prediction models was selected within a grid based on live weight at slaughter and grade fat. Following normal commercial slaughter and chilling, left carcass sides were fabricated using the Institutional Meat Purchase Specifications (IMPS) for Fresh Beef Products, Series 100. The primals collected included the chuck (IMPS #113), rib (IMPS #103), brisket (IMPS #118), flank (IMPS #193, non-trimmed), foreshank (IMPS #117), loin (IMPS #172A), round (IMPS #158A) and plate (IMPS #121). Each primal cut was scanned with a Lunar iDXA unit (GE Lunar Lunar Prodigy Advance, General Electric, Madison, WI, USA) using the whole body scan option on standard mode to estimate DXA fat, lean and bone tissues. After scanning, all left primal cuts were fully dissected into subcutaneous fat, intermuscular fat, body cavity fat, lean, and bone and then weighed. ResultsRegression and partial least square regression (PLSR) were used to evaluate the relationship of DXA lean, fat and bone values from primal cut scans to cut-out values from manual dissection. Using linear regression, R² (i.e., the % of variation accounted for by the model) for total carcass lean, fat and bone were 0.88, 0.95 and 0.53, respectively. Within individual primals, R² for lean, fat and bone ranged from 0.26 to R² = 0.90, with the highest R² generally for fat, and the lowest predictions generally for bone. Industry applications of this technology for total lean, fat and bone would be expected to achieve these levels of prediction robustness. Using PLSR analyses, which consider all the DXA scan information from all primals as independent variables, overall R² for total carcass lean and fat were both 0.98. PLSR improved the lean prediction for most of primal cuts yielding R² over 0.94 for the brisket, foreshank and flank. The highest R² were observed for the chuck (R² = 0.99), round (R² = 0.98) and loin (R² = 0.97). Similar to lean, PLSR increased the R² for fat predictions; with all being higher than 0.91, excluding the foreshank (R² = 0.77). The highest R² for fat were observed for the flank (R² = 0.98), rib, plate and loin (R² = 0.97). ConclusionDXA was able to be used to develop robust equations for estimating total lean and fat in carcasses normally encountered in the market. Both linear and PLSR equations will provide realistic estimations of the potential utility of DXA within an industry environment, to improve estimations of lean meat yield. In research, DXA coupled with PLSR will also be able to replace manual cut-outs which are destructive, time consuming and costly.

Patterns of energy allocation to reproduction in three Amazonian fish species

The study considered the influence of the hydrological cycle and gonadal development on the accumulation and use of energy in three fish species from an Amazonian flooded area. Fishes were sampled over a 24 hour period at monthly intervals between July 2004 and June 2005 using gillnets of different mesh sizes. Body cavity fat and gonadosomatic indices were determined, as well as energy content of gonads and muscles. Amongst the studied species, different means of energy allocation for reproduction were found: Acestrorhynchus falcirostris allocate energy from body cavity fat to its gonads; Pygocentrus nattereri uses mainly energy accumulated in the muscles for the process of gonadal maturation; and Hoplosternum littorale uses energy accumulated in their muscles and body cavity fat for reproductive processes. It is quite clear that the flood pulse regulates the gain and use of the energy reserves in fishes from the Amazonian floodplain.

Genetic evaluation of retail product percentage in Simmental cattle

The objective of this study was to estimate genetic parameters required for genetic evaluation of retail product percentage (RPP) in Simmental cattle. Carcass weight (HCW), subcutaneous fat thickness (FAT), longissimus muscle area (REA) and kidney, pelvic, and heart fat (KPH) records were available to compute RPP on steers (n = 5171) and heifers (n = 1400) from the American Simmental Association database; animals were sired by 561 Simmental bulls and out of 5886 crossbred dams. Genetic parameters were estimated using residual maximal likelihood and a four trait animal model for the components of RPP including fixed harvest contemporary group effects, random animal genetic effects, and a linear covariate for age at harvest. Heritability estimates were 0.51 +/- 0.05, 0.36 +/- 0.05, 0.46 +/- 0.05, and 0.18 +/- 0.05 for HCW, FAT, REA and KPH respectively. Non-zero genetic correlations were estimated between HCW and REA (rg = 0.51 +/- 0.06) and between REA and FAT (rg = -0.43 +/- 0.08), but other genetic correlation estimates among the component traits were low. As a linear function of its components, heritability and genetic correlations involving RPP were estimated using index methods. The heritability estimate for RPP was 0.41, and genetic correlations were -0.17, -0.83, 0.67, and 0.01 with HCW, FAT, REA and KPH respectively. Therefore, RPP was strongly associated with muscle and fat deposition, but essentially independent of carcass weight and internal body cavity fat. Genetic evaluation of RPP would be straightforward using multiple trait index methods and genetic regression, although the inclusion of KPH would be of marginal value.

Growth performance, carcass characteristics and pork quality of pigs fed diets containing meal from conventional or glyphosate-tolerant canola

Growth performance, carcass characteristics and pork quality were evaluated for pigs fed barley and wheat-based diets, which included meal from conventional or transgenic glyphosate-tolerant (Roundup-Ready®) canola. One hundred and forty-four pigs (72 gilts and 72 barrows) weighing 30 ± 3 kg were assigned, three to a pen, on the basis of gender and weight to receive one of four dietary treatments formulated using canola meal from two commercial sources (COM1 and COM2), non-transgenic parental control (PCC) or transgenic (RRC) canola. Pigs were fed a grower diet (75 g kg-1 canola meal) until 60.5 ± 4.0 kg and then a finishing diet (150 g kg-1 canola meal) to 108.6 ± 7.3 kg at slaughter. Pigs receiving the COM1 and COM2 diets had an overall higher (P < 0.0001) daily feed intake (DFI) compared with pigs fed the PCC and RRC diets. Corresponding average daily gain (ADG) was also increased (P = 0.02) for COM1-fed pigs, although feed conversion efficiencies (FCE) of the pigs were similar (P > 0.05) among diets. Gilts had lower overall DFI (P < 0.0001), ADG (P < 0.0001) and FCE (P = 0.04) compared with barrows. Pigs receiving the PCC and RRC diets had heavier (P = 0.002) liver weights than those pigs fed the COM1 and COM2 diets (2.06 and 2.05 kg vs. 1.95 and 1.96 kg, respectively). Postmortem decline in pH and temperature of the longissimus thoracis (LT) muscle from pigs were not different (P > 0.05) among the dietary treatments. Characteristics of pork quality for the LT muscle, which included objective colour and shear force were also not affected (P > 0.05) by dietary source of canola meal. Gross composition of commercial pork cuts were similar (P > 0.05) among the dietary treatments with the exception of small differences for intermuscular (P = 0.04) and body cavity (P = 0.02) fat in the picnic cut and body cavity (P = 0.02) fat in the loin cut. Differences in DFI, ADG and liver weights of the pigs may be related to higher content of antinutritional glucosinolates (µmoles g-1) in the PCC (20.20) and RRC (15.04) varieties compared with COM1 (7.55) and COM2 (7.46) sources of canola meal. Key words: Transgenic canola, growth, pork quality, pigs

Genetic correlations between live yearling bull and steer carcass traits adjusted to different slaughter end points. 2. Carcass fat partitioning1,2

Partial carcass dissection data from 1,031 finished crossbred beef steers were used to calculate heritabilities and genetic correlations among subcutaneous, intermuscular, and body cavity fat percentage and marbling score adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant endpoints. Genetic correlations were also calculated among these fat partitions with live growth and ultrasound traits evaluated in yearling beef bulls (n = 2,172) and steer carcass measurements. Heritabilities of the different fat partitions ranged from 0.22 (marbling score-constant body cavity fat) to 0.46 (HCW-constant marbling score). Genetic correlations between subcutaneous fat and intermuscular fat (rg = 0.16 to 0.32) and between intermuscular fat and body cavity fat (rg = 0.38 to 0.50) were more highly associated than subcutaneous fat and body cavity fat (rg = -0.08 to 0.05), indicating that fat depots are not under identical genetic control. Adjusting fat depots to different end points affected the magnitude but usually not the sign of the genetic correlations. Bull postweaning gain was associated with intermuscular (-0.24 to -0.35), body cavity (-0.24 to -0.29), and marbling fat (-0.24 to -0.39) in steers. Bull hip height was associated with body cavity (-0.20 to -0.29) and marbling fat (-0.20 to -0.47) in steers. Bull ultrasound fat depth was associated with subcutaneous (0.11 to 0.29), intermuscular (0.05 to 0.36), body cavity (0.27 to 0.49), and marbling fat (0.27 to 0.73) in steers. Bull ultrasound intramuscular fat percentage was associated with subcutaneous (-0.22 to -0.44) and intermuscular fat (-0.06 to 0.31) in steers. Bull ultrasound LM area was associated with body cavity (-0.25 to -0.31) and marbling fat (-0.25 to -0.30) in steers. Ultrasound LM width measurements were negatively correlated with subcutaneous fat (rg = -0.09 to -0.18), intermuscular fat (rg = -0.53 to -0.61), body cavity fat (rg = -0.63 to -0.69), and marbling score (rg = -0.75 to -0.87) at slaughter age-, HCW-, and fat depth-constant endpoints; correlations were generally lower at a marbling score-constant end point (rg = 0.07 to -0.49). Ultrasound indicator traits measured in seedstock may be useful in altering fat partitioning in commercial beef carcasses.

Association of a single nucleotide polymorphism in the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition

Leptin is a 16-kDa-hormone product of the obese gene synthesized and expressed predominantly by adipose tissues, which has been shown to play major roles in the regulation of body weight, feed intake, energy balance, fertility, and immune system functions. We report an investigation into the association of a previously identified cytosine to thymine missense mutation in exon 2 of the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition in five genetic selection lines of a commercial population of beef cattle. Differences among genotypes in growth, feed intake and feed efficiency were not significant (P > 0.10) though steers homozygous for the thymine allele had positive residual feed intake (i.e., consumed more feed than expected) (+ 0.19 kg d-1) whilst steers homozygous for the cytosine allele had negative residual feed intake (-0.18 kg d-1). Steers carrying the thymine allele had a higher rate of gain in ultrasound backfat (P = 0.02), ultrasound backfat thickness (P = 0. 06), higher carcass grade fat (backfat) (P = 0.005), lower yield grade (P = 0.01) and lower lean meat yield (P = 0.007). The thymine allele also tended to be associated with higher loin subcutaneous fat (P = 0.07) and was associated with higher brisket subcutaneous fat (P = 0.01), and brisket body cavity fat (P = 0.0001). No associations were found among the different genotypes and real-time ultrasound marbling, ultrasound longissimus thoracis area, carcass marbling and carcass longissimus thoracis area (P > 0.10). Our results show that animals carrying the thymine allele versus the cytosine allele may produce carcasses with poorer grades and lower lean meat yields but do not differ in carcass marbling or other fat depots. Key words: Beef cattle, leptin, feed intake, carcass merit

Residual feed intake and body composition in young growing cattle

Crossbred steers (n = 176), 7–8 mo of age and from the five BeefBooster strains (M1, M2, M3, M4 and TX), were used to determine the relationships between residual feed intake (RFI) and growth rate, body composition and heat production (HP), and to quantify differences in RFI independent of differences in body composition. Animals with different RFI levels were also characterized for growth, carcass and body compositional traits. Steers from each genetic strain were selected at random and serially slaughtered on 5 pre-selected days of the finishing period. Steers grew at 1.52 (SD = 0.22) kg d-1 and had dry matter intake (DMI) of 8.5 (SD = 1.0) kg d-1 during the last 71 to 183 d before slaughter. Metabolic mid-point weight, average daily gain (ADG), gain in empty body fat and gain in empty body water accounted for 67.9, 8.6, 3.9 and 1.1%, respectively, of the variation in actual feed intake. Similarly, metabolic mid-point weight (68.5%), ADG (8.2%), gain in ultrasound backfat thickness (1.8%), gain in ultrasound marbling score (1.1%) and year (1.3%) accounted for 80.9% of the variation in actual feed intake. Residual feed intake adjusted for differences in estimated composition of gain (estimated gain in empty body fat and water; RFIII) ranged from -2.06 kg d-1 to +1.61 kg d-1 (SD = 0.60 kg d-1). Residual feed intake adjusted for live animal measures of body composition (gain in ultrasound backfat thickness and marbling score; RFIIII) ranged from -2.11 kg d-1 to +1.88 kg d-1 (SD = 0.62 kg d-1). Low RFIIII animals (efficient) had 6.0% lower metabolizable energy intake (MEI), retained 9.3% less energy and had 4.5% lower HP than medium RFIIII animals (P < 0.01). Low RFIIII animals also had 10.2% lower MEI, retained 12.0% less energy and produced 9.3% less heat than high RFIIII animals (P < 0.01). Liver (P <0.01), small and large intestine (P = 0.09) and stomach and intestine (P < 0.01) weights were less in low and medium RFIIII steers compared to high RFIIII steers. There was a trend for low RFIIII steers to have less dissectible carcass fat (P = 0.08), intermuscular fat (P = 0.06), body cavity fat in the butt and loin (P = 0.01), faster accretion rate of empty body water (P = 0.04) and a slower accretion rate of empty body fat (P < 0.01) than medium and high RFIIII steers. A portion of the greater MEI by high RFIIII steer was accounted for by differences in the chemical composition of gain. However, a greater proportion was due to a disproportionate increase in the energy required for maintenance and heat increment of feeding in high RFIIII steers. An attempt should be made to adjust RFI for changes in the chemical composition of gain, possibly by the inclusion of ultrasound backfat thickness and marbling score into the equation for determining RFI. Key words: Cattle, feed efficiency, residual feed intake, remote sensing, GrowSafe System

Annulus formation on scales and seasonal growth of the Central Amazonian anostomid Schizodon fasciatus

Annulus formation on the scales of the Central Amazonian anastomid fish Schizodon fasciatus was studied with respect to periodic variations in growth rates caused by seasonal inundation or associated biological processes. Monthly samples from fish markets were analysed with regard to marginal scale increment, feeding index, condition factor, gonadosomatic index, and body cavity fat content. There was a significant variation in all indices which was related to seasonal change in water level. Fat storage was related to energy requirements especially during gonad maturation. Fastest growth was observed during the period of falling water level. The formation of scale growth marks corresponded to the period of gonad maturation between January and February. The results indicate the formation of only one single growth mark on scales per year.

Relationships of fat-tail weight with fat-tail measurements and carcass characteristics of Mehraban and Ghezel rams

The relationships between fat-tail weight (FTW) and measurements (circumference, depth, thickness at the widest part and at the base of tail), carcass characteristics (chemical composition, trimmed meat, separable fat and bone), and body cavity fat were studied in 17–18-month-old rams of two Iranian breeds of sheep; Mehraban ( n = 34) and Ghezel ( n = 29). FTW varied from 2.9 to 9.6 kg in Mehraban rams, and from 3.8 to 8.1 kg in Ghezel rams. In Mehraban rams, fat-tail lower width accounted for 75% of variation in FTW, but in Ghezel rams lower circumference accounted for 70% of the variation in FTW. FTW was correlated with carcass chemical fat ( r = 0.50; P < 0.05) in Ghezel rams, but not in Mehraban rams. The correlation coefficient of FTW with total carcass fat was 0.75 in Mehraban rams ( P < 0.01) and 0.27 in Ghezel rams ( P > 0.05). Results showed that FTW in live sheep can be estimated by external measurement of the tail; however, the prediction equations contained different predictor variables for each breed.

The effects of plane of nutrition and slaughter weight on the performance and carcass composition of continental beef bulls given high forage diets

AbstractBulls (½ Blonde d'Aquitaine ⅜ Charolais) were used in a 2 × 3 factorial design experiment with two planes of nutrition in the finishing period and three slaughter weights. High and low planes of nutrition were based on diets with similar forage to concentrate ratio (0·40 of dry matter (DM)) offered ad libitum or at 0·78 of ad libitum DM intake at equal live weight respectively. The target slaughter live weights were 550, 625 and 700 kg. Twelve bulls were taken to each slaughter point and an additional five animals were killed as a pre-experimental slaughter group. Mean initial live weight was 412 (s.e. 5·3) kg at a mean age of 342 (s.e. 2·5) days. No significant interactions were found between the main factors. For the high and low planes, live-weight and estimated carcass gains were 1251 and 989 (s.e. 47·7), and 816 and 668 (s.e. 35·3) g/day respectively, the reduction in gains being similar to the proportional degree of nutritional restriction. Plane of nutrition had no effect on live-weight or carcass gain per unit of energy intake. The low plane of nutrition produced significant decreases in body cavity fat depots, subcutaneous fat in the sample joint and increased the proportions of both saleable beef and high-priced joints in the carcass.With increase in slaughter weight, energy intake per unit of live weight0·75 and rates of both live-weight and carcass gain tended to decline. The dressing proportions were 583,579 and 609 (s.e. 9·1) g/kg for the slaughter live weights of 550, 625 and 700 kg. Carcass conformation improved while fat depots in the body cavity and estimated concentration of separable fat in the carcass increased with increase in slaughter weight, and both estimated lean and bone concentrations decreased. Forequarter as a proportion of total side tended to increase with increase in slaughter weight. Slaughter weight had no effect on concentration of saleable meat or ultimate pH of carcass muscle. It is concluded that bulls of this genotype can be taken to high slaughter weights on diets having a relatively high proportion of forage as grass silage, with high rates of growth and acceptable carcass leanness.

Some Methods for Assessing the Quality of Striped Bass for Use in Laboratory Studies

Abstract Techniques are described for assessing the quality of cultured striped bass (Morone saxatilis) for use in laboratory studies. Larval striped bass can be screened for swim bladder inflation by their responses to anesthesia with tricaine (MS-222) or benzocaine. Typical values for blood chemistry, condition factor, and responses to a saltwater challenge were established for normal fish larger than 90 mm. Neither blood chemistry measurements, nor liver anatomy, nor body cavity fat correlated well with the incidence of uninflated swim bladders. Extremely low plasma chlorides were found in some fish without inflated swim bladders. Blood characteristics of normal fish fell within reported ranges for hematocrit and total plasma proteins.

Direct, maternal and heterosis effects for slaughter and carcass characteristics in three breeds of fat tailed sheep

Direct, maternal and heterosis effects for slaughter and carcass characteristics of 162 lambs of three fat-tailed Iranian breeds of sheep, Karakul (K), Mehraban (M) and Baluchi (B), and their reciprocal crosses were estimated. The lambs were kept in a feedlot for 120 days after weaning and were slaughtered at 195 days of age. Offals, internal fat, and carcass cuts were individually weighed, and testicular weight, volume and dimensions, backfat thickness, and rib-eye muscle area and dimensions were measured. The large-size M was superior to the small-size B for maternal environment effects on weight and percentage of omental and mesenteric (OM) fat and tail-fat, whereas B ranked highest among the breeds for maternal effects on proportion of offals and prime cuts. Baluchi, which are adapted to the desert conditions, had a higher direct genetic effect compared with other breeds for fat production, as is indicated by its thicker ( P < 0.05) backfat and higher weight and percentage of tail fat and body-cavity fat ( P > 0.10). For K direct genetic effects resulted in leaner carcasses of their progeny. A small degree of positive overall heterosis was observed for weight or size of each trait measured, but heterosis virtually disappeared when the traits were expressed as a percentage of slaughter or carcass weight. Exceptions were significant heterosis exhibited by testis weight (6.6%) and volume (7.9%) as a percentage of slaughter weight, and by percentage of OM fat (10.1%) which showed largest estimates of overall heterosis. It was concluded that the magnitude of heterosis depends, in part, on the rate of development of a tissue. Tissues that had their greatest growth at a specific point in the developmental process showed the highest heterosis at that point.

Influence of Sustained-Release Estradiol-17-Beta in Pellet Form on Performance of Growing-Finishing Steers

Three trials, utilizing a total of 490 growing-finishing steers, were conducted (202-260 d) in different geographical regions (Missouri, Indiana, Kansas) under different feeding and management regimens to evaluate the efficacy of a sustained-release estradiol-17-beta implant. The implant formulation consisted of a copolymer pellet (5mm long, 2.4mm in diameter, and 27mg in total weight) impregnated with 19mg estradiol and dusted with oxytetracycline-HCl. Treatments were 1) nonimplanted control, 2) positive implanted control, and 3) 19mg, 4) 38mg, or 5) 57mg of estradiol in the test formulation. Implanted steers grazing native range (Kansas) gained faster (P<.05) compared to nonimplanted control steers. However, non-significant improvements were observed for cattle pastured on endophyte-infested tall fescue-red clover (Missouri) or backgrounded on a relatively high energy (75% corn silage:25% high moisture corn) program (Indiana). A treatment X experiment interaction (P<.05) indicated that steers severely restricted in the growing phase (Missouri) had no daily gain response to anabolic implants during the finishing phase. Implanting with 57mg estradiol increased warm carcass weight by 15.4kg (P<.05). Implanted steers had less (P<.05) body cavity fat, and tended to have less backfat, lower yield grades and larger ribeye areas.Pooled data indicate that total experiment weight gains were greater (P<.05) for all implant groups compared to the nonimplanted controls. The experimental implant was efficacious for a period of at least 200 d, but the magnitude of response to any anabolic implant may be affected by feeding and management regimen.

Performance, Yield, and Body Composition of Fingerling Channel Catfish Fed a Dried Waste Egg Product

Abstract Fingerling channel catfish (Ictalurus punctatus) were fed diets for 85 d in which 50 and 100% of the fish meal and fish oil had been replaced with a spray-dried waste egg product. There were no significant differences (P > 0.05) among the fish fed the five diets in weight gain, final length, percent mortality, feed conversion, or proximate composition, though fish fed the egg diets tended to have lower moisture and higher fat values than fish fed the control diet. The fish fed the 100% replacement diets had significantly more (P < 0.05) body cavity fat than fish fed the 50% replacement diets; both groups had more body cavity fat than the control. No biotin deficiency symptoms were observed in the fish.

Use of Mononuclear Leukocyte Insulin Receptor Characteristics as Predictors of Carcass Composition in Heifers and Steers

Total insulin specific binding (IB) and the number and affinity of insulin receptors on mononuclear leukocytes (MNL) were used to predict carcass composition of heifers and steers. Dependent variables were kidney fat, body cavity fat, s.c. fat, intermuscular fat, lean and bone. Independent variables were parameters that could be measured on the live animal, including insulin receptor characteristics, age, shrunk weight, breed and carcass s.c. rib fat thickness (SUB). All carcass fat characteristics and IB were greater for heifers than for steers, but the ability to predict either heifer or steer carcass fat characteristics was not improved by inclusion of IB in prediction equations. However, the number of low-affinity insulin receptors on MNL contributed significantly to the prediction of all heifer carcass characteristics except bone. Carcass s.c. rib fat thickness also entered the prediction equations for all heifer carcass characteristics except kidney fat. In the prediction of heifer kidney fat, the only significant independent variable was the number of low-affinity insulin receptors on MNL (R2 = .38). Carcass characteristics of steers were better predicted by SUB than were heifer carcass characteristics, and insulin receptor characteristics, when added to steer equations that contained SUB, improved R2 by .10 or less. Our results suggest that insulin receptor characteristics will be most useful in the prediction of carcass characteristics of heifers where there is a poor relationship between quantity of s.c. fat and other carcass fat depots.

PATTERNS OF MUSCLE, BONE, AND FAT ACCRETION IN THREE BIOLOGICAL TYPES OF FEEDLOT BULLS FED THREE DIETARY ENERGY LEVELS

The effect of three types of diet on the carcass composition of 71 feedlot bulls of three biological types (Dairy Cross (DX), Hereford Cross (HX), and Beef Cross (BX)) was studied over a 2-yr period. Diets consisted of pelleted alfalfa with 0, 35 or 85% grain. Serial slaughter and carcass dissection into eight wholesale cuts and component tissues were carried out over an age range of 392–636 days. Interactions of biological type with diet-year were generally not significant for actual weight of muscle, bone and fat, or for weight of these tissues at a constant side subcutaneous fat weight of 16 kg. There were few significant effects of biological type or diet-year on the ratio of actual weight of subcutaneous to intermusclar plus body cavity fat. HX bulls had significantly less muscle and less bone than BX or DX, based on actual weights, but the rate of tissue accretion relative to side subcutaneous fat was the same for the three biological types. Animals on the lowest level of dietary energy had less weight of fat than did those on an 85% grain diet, but diet-year growth coefficients of tissue weights relative to side subcutaneous fat weight were generally homogeneous. It was concluded that effects of dietary energy were consistent over the biological types studied and for most of the wholesale cuts. Key words: Feedlot bulls, diet, biological types, tissue growth