Chilled Carcass Weight Research Articles

Evaluation of columbia, USMARC-Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: III. Prefabrication carcass traits and organ weights1,2

To evaluate terminal-sire breeds, harvest BW, prefabrication carcass measurements, and organ weights were evaluated over 3 yr for 518 crossbred wether lambs (ovis aries). Lambs were produced by single-sire matings of 22 Columbia, 22 USMARC-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouillet ewes. Lambs were raised to weaning under an extensive western rangeland production system and finished in a feedlot on a high-energy finishing diet. Wethers were randomly assigned to be harvested at an average BW of 54.4, 61.2, or 68.0 kg and then transported to The Ohio State University abattoir for harvest. Wether BW was recorded before transport (off-test BW) and before harvest. Prefabrication carcass measurements and organ weights were recorded either after harvest or after an approximate 24-h chill. At comparable numbers of days on feed, Suffolk-sired lambs had heavier (P < 0.01) off-test BW, harvest BW, HCW, chilled carcass weight (CCW), and kidney weights than lambs sired by the other breeds. Suffolk-sired lambs had more (P < 0.01) kidney-pelvic fat than did Columbia-sired lambs; Composite- and Texel-sired lambs were intermediate and did not differ (P > 0.06) from the other crossbred lambs. Texel- and suffolk-sired lambs had larger lm area and greater conformation scores than Columbia-sired lambs (P < 0.03). Texel-sired lambs had greater (P < 0.01) body wall thickness, quality grades, and leg scores than Columbia-sired lambs. Composite- and Suffolk-sired lambs did not differ from each other or from lambs sired by any other breed for body wall thickness (P > 0.18) and were intermediate for quality grades and leg scores. Sire breed did not affect (P > 0.05) shipping shrink, dressing percentage, pelt weight, liver weight, and fat depth. Adjusting data to a comparable off-test BW or CCW modified sire breed rankings for some measurements. Texel-sired lambs were equal or superior to lambs sired by other breeds for HCW, CCW, dressing percentage, pelt weight, LM area, quality grade, and leg and conformation scores. However, Texel-sired lambs also had values for kidney-pelvic fat weight, fat depth, and body wall thickness that were equal to or greater than those of lambs sired by the other breeds, indicating increased fatness at comparable BW. Producers can use these results to select terminal-sire sheep breeds that will complement their production system and improve market lamb value.

Carcass traits and meat quality of two different rabbit genotypes

To evaluate the effect of genotype on carcass traits and meat quality, sixty-four rabbits belonging to two genotypes (slow growing local population, LP; commercial hybrids, HY) were used. Rabbits were weaned at 35 days of age and slaughtered when they reached 2500 g of live weight, corresponding to 103 and 87 days of age for LP and HY, respectively. Comparing the slaughter traits of two genotypes, LP provided higher dressing out (59.4 vs 56.2%, P<0.01) and skin percentage (16.0 vs 14.2%, P<0.05), lower incidence of full gastrointestinal tract (18.5 vs 22.3%, P<0.01) and higher incidence of head (9.5 vs 8,9%, P<0.05) and kidneys (0.99 vs 0.86%, P<0.05) than HY. Reference carcasses from LP had greater incidence of perirenal fat (2.04 vs 1.12%; P<0.01), loin (21.5 vs 19.2%; P<0.01) and hind leg (34.4 vs 31.6%; P<0.01) than HY. Hind leg meat-to-bone ratio was significantly higher in HY than LP (4.7 vs 3.8%; P<0.01). The comparison between the variances of slaughter weight, chilled carcass weight, kidneys percentage, reference carcass weight, perirenal fat and hind leg percentage showed the greatest variability in the LP. Meat derived from LP showed lower L*, higher a*, b* and C* colour values than HY (P<0.01). In conclusion, LP showed good slaughter traits and favourable meat quality. The great variability observed in the LP could allow to improve the productive performances, however maintaining animal rusticity.

Effect of nutritional status of rabbit kits on their productive performance, carcass and meat quality traits

The effect of nutrient supply at foetal, suckling and growing ages on productive, carcass and meat quality traits of rabbits was studied. New-born rabbits were divided into three groups according to their birth weight (low/L/: 35–50 g, medium/M/: 58–62 g and high/H/: 70–88 g). Half of the litters were nursed by one doe (O) and the other half by two does (T). The kits were weaned at 3 weeks. From the age of 4 weeks, half of the rabbits were fed ad libitum (A), or on a restricted regime (R) (85–90% of the ad libitum feed intake level). Rabbits were slaughtered at 11 weeks of age. Difference in average feed intake between groups L and H, groups O and T and between R and A was 11.2%, 7.8% and 11.7%, respectively; in all cases, the latter groups had the highest intakes. Body weight gain between 3 and 11 weeks was significantly affected by birth weight and feeding regime. Body weight at slaughter of L rabbits was 124 g lower than that of M rabbits and 255 g lower than that of H rabbits (P < 0.05). Group L had the highest dressing out percentage (58.0%), whereas M rabbits had the lowest dressing out percentage (57.3%) (P < 0.05). Ratio of hind part of the reference carcass was higher in group H (39.0%) than in group L (38.1%) (P < 0.05). Percentage of perirenal fat was the highest in L rabbits (2.10%) and the lowest in group H (1.64%) (P < 0.05). Slaughter weight of T rabbits was 198 g higher (P < 0.001) than that of group O. Chilled carcass weight and dressing out percentage were 16 g (P = 0.006) and 0.7% (P = 0.002) lower, respectively, in T rabbits. In consequence of feed restriction slaughter weight, chilled carcass weight and dressing out percentage decreased by 141 g (P < 0.001), 22 g (P < 0.001) and 0.8% (P = 0.001), respectively, while the ratio of liver and kidneys to liveweight increased by 0.57% (P < 0.001) and 0.05% (P < 0.001). Cooking loss of musculus longissimus dorsi (MLD) was 1.8% lower (P < 0.05) in H rabbits compared with L and M animals. Cooking loss was 1.6% lower (P = 0.003) in group T than in group O. Due to the restriction, slaughter weight and dressing out percentage decreased by 141 g (P < 0.001) and 0.8% (P = 0.001), respectively. Feeding regime influenced all meat quality parameters except the b* value of meat colour. Rabbits in R group had 0.08 (P < 0.001) lower pH, while 1.1 (P < 0.001) higher L* and 0.7 (P = 0.008) lower a* values resulted lighter colour of MLD. The cooking loss of MLD of R rabbits was 1.2% higher (P = 0.028). Results show that the foetal and suckling nutrient supply exert a long-term effect, affecting also carcass traits and meat quality.

Slaughter and carcass characteristics of Gokceada, Maltese and Turkish Saanen suckling kids

Abstract. Aim of the study was to investigate comparatively the slaughter and carcass characteristics of Gokceada, Maltese and Turkish Saanen suckling kids. Eight suckling male kids at 80–90 days of age from each genotype were used in the study. The kids were collected from dairy goat farms and slaughtered after lairage of an overnight period. Although the kids were at similar age and sex, the slaughter weight and chilled carcass weight of indigenous Gokceada kids were lower than those of Maltese and Turkish Saanen kids (P&lt;0.001). Chilled dressing percentage calculated according to empty body weight was 48.97 % in Gokceada, 51.32 % in Maltese and 52.35 % in Turkish Saanen kids (P&lt;0.001). There were not statistically significant differences among the breeds in terms of neck, shoulder, ribs and long leg percentages, musculus longissimus dorsi (MLD) section area and back fat thickness (P&gt;0.05). While there were significant differences between breeds in terms of muscle, bone and fat weights in half carcass on the side of Turkish Saanen and Maltese kids, the differences between the genotypes were not significant for percentages of muscle, bone and fat. The carcass structure of suckling kids was small and meat production was low, however, they had very little fat in the carcass. It was concluded that Maltese and Turkish Saanen kids were favourable than Gokceada kids in terms of suckling kid meat production.

Effect of target slaughter weight on production efficiency, carcass traits and behaviour of restrictively-fed gilts and intact male finisher pigs

The effect of 3 slaughter weights (85, 95 or 105 kg) on performance and carcass traits of 481 pigs in single-gender groups of 13 (18 groups of gilts and 19 groups of intact males) was evaluated. Pigs (39.5 ± 3.3 kg) were fed a liquid diet 3 times daily in a long trough. The behaviour of pigs slaughtered at 105 kg was recorded at 50, 60 and 70 days after the start of the experiment (5 groups of gilts and 4 groups of intact males). Behaviour (active, inactive, feeding) and posture (standing, lying, dog-sitting) of all pigs was recorded at 5-min intervals for 30 min prior to and 1 h after each feeding event. Slaughtering pigs at 95 kg and 105 kg delayed production by 7 and 16 days, respectively, compared to slaughtering at 85 kg ( P < 0.0001). Gilts needed 4 days more than males to reach each slaughter weight ( P < 0.01), and chilled carcass weights increased with increasing slaughter weight ( P < 0.0001). Daily feed intake and gain were not affected by slaughter weight; however, gain-to-feed ratio increased in males with increasing slaughter weight while the inverse was observed in gilts ( P < 0.01). The kill-out percentage was greater at the heavier weights ( P < 0.05). Backfat depth increased in males with increasing slaughter weight ( P < 0.01) but there was no change in females ( P > 0.05). Muscle depth increased with increasing slaughter weight ( P < 0.05) and therefore lean meat yield did not change. Behaviour did not differ between genders on the 3 days of observation, but the proportion of time spent active and standing before feeding increased as pigs grew from day 50 to 70 ( P < 0.05). The proportion of posture changes was greater before than after feeding ( P < 0.001). Results of this study indicate that slaughtering intact male pigs at heavier weights improved growth performance but increased fat depth. Conversely, gilts were less efficient at converting feed into body weight at the heavier weights but carcass traits were not modified as slaughter weight increased. In the latter part of the finishing period, competition for access to the trough probably increased as trough space allowance decreased, and the increase found in standing before feeding could reflect an attempt by the pigs to gain immediate access to the feed.

Carcass quality characteristics of Hair Goat and Saanen × Hair Goat crossbred kids from intensive production system

The aim of this study was to investigate the effects of crossbreeding indigenous Hair Goat with Saanen on carcass quality characteristics of kids under an intensive production system. Twenty four male kids from purebred Hair Goat and Saanen × Hair Goat (F 1 and B 1 ) crossbred genotypes were weaned at 75-80 days of age and fattened for 56 days. Slaughter weights were 17.42, 18.22 and 16.79 kg and chilled carcass weights were 6.49, 7.29 and 6.69 kg for Hair Goat, F 1 and B 1 , respectively. The organ weights, dressing percentages, M. longissimus dorsi area, fatness parameters, carcass measurements, subcutaneous fat colour, carcass joint weights and percentages and dissected leg compositions of kids were similar (P>0.05) in genotype groups. It is concluded that crossbreeding indigenous Hair Goat with Saanen at F 1 and B 1 levels did not result in any improvement in quality carcass production of kids under an intensive production system.

Effect of cage density on growth and carcass performance of fattening rabbits under tropical heat stress conditions.

Three hundred crossbred New Zealand, California, Butterfl y, Dutch, and Satin rabbits, weaned at 30 d and weighing 535±8 g (standard error) were assigned randomly to four treatments: 6, 12, 18 and 24 rabbits/m2 (3, 6, 9 and 12 rabbits/cage, respectively, each cage measuring 0.5 m2) resulting in 10 cages/treatment. During the experimental period (from weaning to 2.2 kg body weight) weekly individual live weight, cage feed intake, incidence of diarrhoea, ringworm, and injured rabbit data was recorded. The maximum temperature-humidity index ranged from 31 to 35, and so indicating severe heat stress. At the end of the experimental period 10, 20, 30 and 30 rabbits under densities of 6, 12, 18 and 24 rabbits/m2, respectively, were slaughtered and carcass performance recorded. Average daily gain and feed intake from weaning to the end of the experimental period decreased by 0.31±0.070 and 1.20±0.25 g, respectively, for each unit that the density increased at the beginning of the experiment (P=0.001). The length of the fattening period increased by 0.91±0.16 d (P=0.001) for each unit of increment of density. However, rabbit production (expressed in kg/m2) increased linearly and quadratically with density (P<0.008). Cage density did not affect feed effi ciency, which on average was 0.214 g/g (P=0.37). Animals housed at the highest density, compared to the average of those caged at lower densities, tended to show higher incidence of ringworm (68.9 vs 39.4%; P=0.075) and injury (16.8 vs 3.03%; P=0.12), and showed higher mortality (20.5 vs 9.63%; P=0.043). Density did not alter the dressing out percentage nor chilled carcass weight. The proportion of scapular fat (P=0.042) increased linearly with increasing levels of density, but perirrenal fat was unaffected (P=0.22). Increasing density reduced dorsal length linearly (P=0.001), and reduced drip loss percentage linearly and quadratically (P=0.097 and 0.018, respectively).Based on these results, under our heat stress conditions, avoiding densities higher than 18 rabbits/m2 or 34 kg/m2 at the end of fattening is recommended.

Effect of substituting soybean meal with mycelium of Penicillium chrysogenum in lamb diets on performance and carcass quality

Thirty-two intact male Pelibuey lambs with an average weight of 21.2 kg were randomly assigned to four treatment rations in a completely random design. The four experimental rations contained incremental levels of dry waste mycelium: 0, 2.7, 5.4 and 8.1%. The study was 75 days long, with 15 days for adaptation of lambs to their pens and a 60-day experimental period in which dry matter (DM) intake, daily weight gain, and feed efficiency were determined. At the end of the study, lambs were slaughtered, and their carcasses weighed and marbling scores determined. Results show a quadratic effect on DM intake ( P = 0.035) and ADG ( P = 0.006). Both DM intake and ADG first increased before declining as mycelium level increased in the diet. Gain:feed decreased linearly ( P < 0.001) with an increase in waste mycelium in the diet. Carcass characteristics, such as hot and chilled carcass weight and hot and chilled dressing percent, and carcass marbling score, were not affected ( P > 0.10). Marbling score of the carcasses ranged from traces to modest marbling.

Carcass conformation and cut composition of Creole goat from Guadeloupe

Carcass data base of 164 Creole male goats was used in order to provide factual data on the carcass conformation. Standardised procedures of carcass measuring and cutting were followed. The European official grid of light lamb is implemented for meat goat in the French West Indies and included five levels. Weights of carcass, cuts and tissues, quality scores and linear measurements were analysed. Feeding system, age at slaughter and weight were taken into account for statistical analysis. There were significant differences among carcass conformation classes (CC) for many traits except for the fat score, leg length and compactness ratio (carcass width on length): 2.2, 34.5 cm and 0.30 on average, respectively. The values of chilled carcass weight and yield and the carcass linear measurements steadily increased until conformation class 4 or 5: 6.7 to 11.2 kg, 49% to 55% and 52.4 to 58.0 cm carcass length. For the weights of carcass cuts, significant differences appeared between two groups: classes 1 and 2 vs. classes 3, 4 and 5. Regardless of the carcass weight, the distribution of prime cuts remained similar. The indices calculated on a weight basis (kg/cm), either for the carcass or the leg, increased significantly (P<0.01): with 54% and 63% difference between the two extreme classes, respectively. The muscle, bone and fat proportions in the shoulder did not vary between CC with 0.72, 0.22 and 0.06, respectively. Corresponding traits in leg were 0.74, 0.23 and 0.03; the last two were different (P<0.05) from class 1 to class 5. The muscle/bone ratios calculated either in shoulder or in leg ranged from 3.1 to 3.6 (P>0.05).

A survey of beef carcass quality and quantity attributes in Mexico1

The objective of the present study was to evaluate quality and yield attributes of Mexican beef carcasses to serve as a benchmark for production in the Mexican beef cattle industry. Seven packing plants were surveyed nationwide. Carcass yield and quality traits were assessed in the cooler at approximately 24 h postmortem. Results indicated that around 90% of the beef slaughter population in Mexico has a strong Bos indicus genetic background. Moreover, 71.6% of the surveyed cattle are presented for slaughter at a BW between 400 and 500 kg. Chilled carcass weight was between 220 and 340 kg in 88.9% of the surveyed population. According to European beef carcass grading standards, carcass conformation varied from poor to good in 82% of the carcasses, whereas in 17.8% the conformation was very good or excellent. In 60.7% of the surveyed carcasses the KPH was 2% or less. The subcutaneous fat depth was 1 cm or less in 90% of the carcasses. In 71.8% of the carcasses the LMA was of 80 cm(2) or less, whereas only 8.6% had LMA values of 90 cm(2) or greater. Carcass maturity score USDA B(100) or less was found in 92.4% of the evaluated carcasses, whereas 28.5% were graded as USDA A(100)/B(00). A total of 93.6% of the sample had marbling scores of 300 or less, corresponding to the categories slight, practically devoid, or traces. Only 12.9% of the carcasses exhibited a yellow fat cover. In the remaining 87.1% the fat cover was white or beige. The backfat layer was uniform in 43.2% of the carcasses, whereas 55.9% had an uneven fat cover. Information from this survey provided data that could serve as a means to develop a yield and quality evaluation program that can be further developed into a value system for Mexican beef carcasses and live cattle.

Carcass traits of improved and indigenous lamb breeds of North-Western Turkey under an intensive production system

The aim of study was to investigate the carcass quality of Turkish Merino, Ramlic, Kivircik, Chios and Imroz breeds in north-western Turkey under an intensive production system. After weaning at approximately 85 days of age, 46 lambs from Turkish Merino, Ramlic, Kivircik, Chios and Imroz breeds were fattened for 56 days. Slaughter weights were 47.39, 45.68, 47.27, 31.08 and 29.82 kg and chilled carcass weights were 23.35, 22.33, 23.51, 14.33 and 13.75 kg, respectively (P<0.001). Improved Turkish Merino and Ramlic and indigenous Kivircik lambs had higher carcass measurements than indigenous Chios and Imroz lambs. Chios lamb carcasses had the highest tail root fat yellowness and tail percentage while having the lowest fatness score, omental and mesenteric fat percentage and kidney knob and channel fat percentage. Turkish Merino lambs had higher shoulder percentage, lean percentage and lean/total fat ratio in the hind leg and produced less total fat in the hind leg than Ramlic and Kivircik lambs. These results indicate that improved Turkish Merino might be used to produce high quality lamb carcasses in north-western Turkey. Among indigenous breeds Kivircik showed an outstanding carcass production performance.

Comparison of carcass and meat characteristics of Brahman grade cattle (Bos indicus) and crossbred water buffalo (Bubalus bubalis)

ABSTRACTThis study was conducted to determine and compare the live traits, carcass yield and the physical, chemical, processing and sensory properties of meat from 20 Brahman grade cattle (crossbred cattle) and crossbred water buffalo (Philippine carabao × Murrah, Bulgarian or Indian) with an average age and weight of 29 months and 434 kg, respectively. The animals were fed a similar diet for 180 days before slaughter. A survey was performed to establish consumer meat preference between the two species. Live weights before slaughter of the two species were found to be different (P &lt; 0.05) with the crossbred water buffalo showing higher bodyweight. However, the crossbred water buffalo had a lower (P &lt; 0.05) dressing yield based on hot carcass weight and chilled carcass weight. The lower dressing yield of crossbred water buffalo can be attributed to its higher (P &lt; 0.05) weights of edible and non‐edible slaughter by‐products. The chilled carcass yield of the forequarters and hindquarters from crossbred cattle and crossbred water buffalo were comparable when expressed as percent of live weight and chilled carcass weight. The estimated lean yield was higher in crossbred cattle than crossbred water buffalo. Crude protein, ash, fat, cholesterol, myofibrillar, sarcoplasmic and insoluble protein contents of the beef and carabao meat were all similar. Water holding capacity, pH, muscle fiber diameter, tenderness, firmness and marbling score in carabeef were all comparable to the beef. Redness was found to be higher (P &lt; 0.05) in carabeef than the beef as measured with a color meter. The consumer meat preference survey showed that 55.9% selected the beef while 44.1% preferred carabeef. The color and amount of fat on the outside of the beef sample were primary in buyer selection.

Effect of Delayed Bleeding on Carcass and Eating Qualities of Rabbit Meat

A total of forty eight matured New Zealand rabbits with an average weight of 2.06±0.45 kg were used to evaluate the effect of delayed bleeding on carcass and organoleptic characteristics of rabbit meat. The rabbits were fed concentrate diet containing 19.11% Crude Protein (CP) and 2514.3 Kcal/kg Metabolizable Energy (ME) for a period of thirty five days. The rabbits were randomly assigned to fou r treatment groups in a completely randomized design. Each treatment was replicated thrice with each replicate consisting of four rabbits. Treatment one served as control where the 12 rabbits were bled immediately after stunning while treatments 2, 3 and 4 comprised of rabbits that were bled 5, 10 15 minutes after stunning. After proper bleeding, the rabbits were skinned, washed and eviscerated and cut into primal cuts. Samples for sensory evaluations were taken from the thigh muscle and the remaining carcasses were aged at 4°C for 24 and 72 hours. The result showed that the dressing percentage, chilled carcass weight and the pH were not affected (p>0.05) by delayed bleeding while the volume of blood drained decreased (p 0.05) by delayed bleeding.

Evaluation of TRICAL-336 Triticale, Maton Rye and Kentucky-31 Fescue as Winter Pasture for Meat Goats

ABSTRACT Because of their cold tolerance and double-cropping potential, small grains such as triticale (× Triticosecale Wittmack) and rye (Secale cereale) can play an important role in sustainable agriculture in Tennessee. A grazing trial was conducted to evaluate TRICAL-336 (triticale), Maton (rye) and Kentucky-31 fescue (control) for meat goats. Maton and TRICAL-336 were 78 and 74% higher in crude protein, 33 and 44% lower in acid-detergent fiber, and 49 and 51% lower in neutral-detergent fiber, respectively, than Kentucky-31. Net energy, total digestible nutrient, relative feed value, Ca, Mg, K and P contents were also significantly higher (P < 0.01) for Maton and TRICAL-336. Average daily gain and live weight gain per ha of does grazing Maton (74.0 g d−1 and 12.38 kg ha−1) and TRICAL-336 (78.9 g d−1 and 11.77 kg ha−1, respectively) were significantly higher (P < 0.05) than that of Kentucky-31 does which lost weight (−19.4 g d−1 and −2.6 kg ha−1, respectively) during the same period. Boneless major retail cut yield was 23 and 37% higher in favor of Maton and TRICAL-336, respectively, while boneless shoulder, boneless leg, loin and rack weight were 30, 35, 69 and 37% higher for TRICAL-336 and 17, 19, 22 and 61% higher, respectively, for Maton than for Kentucky-31. Hot carcass weights and chilled carcass weights were higher for Maton by 28 and 20% and for TRICAL-336 by 32 and 30%, respectively, than Kentucky-31. Slaughter weight, height to the cross, carcass length, kidney, pelvic and heart fat, thoracic circumference, blood concentration of creatine kinase, glucose, albumin, globulin, blood urea nitrogen, Ca, Na, K, monocyte, red blood cell, hematocrit and hemoglobin were significantly higher (P < 0.05) for TRICAL-336 and Maton.

Ability of physico‐chemical measure‐ments to discriminate rabbit meat from three different productive processes

AbstractBACKGROUND: To fulfil consumers' requirements for food traceability, it is necessary to have effective tools to differentiate food products according to their origin. The aim of the study was to identify a limited number of physico‐chemical measurements that could differentiate rabbit meat from three different rearing systems: standard production system or a high quality norm system or a very low growth breeding system.RESULTS: The stepwise linear discriminant analysis (LDA) provided 14 physico‐chemical variables, then combined into two discriminant factors. Most of them (n = 8) were related to bone traits, and especially (n = 5) to mechanical femur assessments. Mechanical characteristics of meat were also relevant in this analysis. Decision tree analysis (DTA) selected two variables only (femur stiffness, and ratio of femur weight to chilled carcass weight) to discriminate the three groups. A total of 96% and 90% of rabbits were correctly assigned to their original group according to LDA and DTA, respectively.CONCLUSION: This work demonstrated that simple physico‐chemical traits recorded in carcasses and meat were efficient to discriminate rabbits from three different rearing systems using LDA or DTA procedures. These systems could have further implications for future traceability of breeding origin. Copyright © 2007 Society of Chemical Industry

Evaluation of associations between prion haplotypes and growth, carcass, and meat quality traits in a Dorset × Romanov sheep population1,2

There is concern about potential antagonistic correlated responses due to intensive selection for scrapie-resistant haplotypes of the prion (PRNP) gene in sheep. The objective of the present research was to test for associations of PRNP haplotypes for codons 136, 154, and 171 with growth, carcass, and meat quality traits in an F2 Dorset x Romanov population (n = 415) segregating the 2 callipyge alleles. Haplotypes of the 3 PRNP codons were determined for each sheep, and breed of origin of each gamete was predicted by genotyping 6 microsatellite markers flanking the PRNP locus. Twenty-five growth, carcass, and meat quality traits were evaluated. Data were analyzed using a basic model consisting of fixed effects of year, sex, and callipyge genotype, the random effect of sire, and 7 covariates corresponding to the probability that a lamb inherited a specific PRNP haplotype of either Dorset or Romanov origin. A fixed effect of litter size was added to the model for growth traits. The model for carcass traits contained the linear and quadratic effects of chilled carcass weight and the interactions among callipyge genotype and linear and quadratic terms. For meat quality traits, the model contained chilled carcass weight as a covariate and the interaction between callipyge genotype and chilled carcass weight. A contrast between the resistant ARR haplotype and the average effect of other PRNP haplotypes was tested to investigate the effects of potential selection for ARR within each breed of origin (Dorset, ARR vs. ARQ, VRQ, and AHQ; Romanov, ARR vs. ARQ and VRQ). There was limited evidence that selecting for scrapie resistance would cause correlated responses due to linkage disequilibrium. Associations of only 3 traits with PRNP haplotypes were detected in either breed of origin. In Romanov, the ARR haplotype was associated with longer carcasses (P < 0.013), narrower rumps (P = 0.038), and less marbling (P = 0.022) than the average of ARQ and VRQ haplotypes. No significant contrasts were detected for Dorset. This study is the first to account for breed of origin while investigating haplotype associations in an F2 population. This study provided limited evidence of associations between PRNP haplotypes and growth, carcass, and meat quality traits.

Effects of Size and Rate of Maturing on Carcass Composition of Pasture- or Feedlot- Developed Steers

Steers (n = 335) of known genetic backgrounds from four fundamentally different growth types were subjected to two production systems to study the main effects and possible interactive effects on carcass composition. Growth types were animals with genetic potential for large mature weight (LL), intermediate mature weight-late maturing (IL), intermediate mature weight-early maturing (IE), and small mature weight-early maturing (SE). Each year, in a nine year study, calves of each growth type were weaned and five steers of each growth type were developed on pasture or feedlot and harvested at approximately 20 and 14 mo of age, respectively. Data recorded were chilled carcass weight and percentages of forequarter, foreshank, chuck, rib, plate, brisket, hindquarter, round, rump, shortloin, sirloin, flank, lean, fat, bone, and retail cuts. The growth type×production system interaction was an important source of variation in chilled carcass weight (p = 0.0395) and percentage retail cuts (p = 0.001), lean (p = 0.001), fat (p = 0.001), rump (p = 0.0454), shortloin (p = 0.0487), and flank (p = 0.001). The ranking of the growth type x production system means for percentage lean was LL-pasture>IL-pasture = IE-pasture = SE-pasture>LL-feedlot, IL-feedlot>IE-feedlot = SE-feedlot. The growth type× production system interaction was non-significant (p>0.05) for forequarter, foreshank, chuck, rib, plate, brisket, hindquarter, round and bone. Growth types of IE and SE yielded greater (p<0.05) mean forequarter than did growth types of IL and LL (51.6±0.3 and 51.5±0.3 vs. 51.1±0.3 and 50.8±0.3%). Mean bone was highest (p<0.05) for the LL growth type and lowest (p<0.05) for the SE growth type (19.5±0.5 vs. 16.8±0.5%). Mean bone was greater (p<0.05) for the pastured steers than for the feedlot steers (21.8±0.8 vs. 14.5±0.6%). These data indicate that growth type responded differently in the two production systems and that these results should be helpful in the match of genetics to production resources. (Asian-Aust. J. Anim. Sci. 2006. Vol 19, No. 5 : 661-671)

The effects of high levels of supplemental copper on the serum lipid profile, carcass traits, and carcass composition of goat kids

This experiment was conducted to determine the effect of high levels of supplemental Cu (as (CuSO4).5H2O) on the serum lipid profile and carcass traits of goat kids. Fifteen Boer x Spanish wether goat kids (BW = 21.3 +/- 0.7 kg) were housed in individual pens and were assigned randomly to 1 of 3 treatments. Treatments consisted of 1) control (no additional supplemental Cu), 2) 100 mg of Cu/d, and 3) 200 mg of Cu/d. Copper sulfate was placed in gelatin capsules and inserted into the esophagus via a balling gun before the morning feeding. Animals were fed a high-concentrate (70:30 grain:hay) diet for 112 d. Serum lipid profile was determined on d 14 and 112, and BW was recorded after 4-h withdrawals from feed and water. After 112 d, animals were slaughtered, and carcass traits were measured. The left half of 12 carcasses and 9th to 11th rib sections from the right side of 15 carcasses were dissected into separable soft tissue and bone portions. The soft tissue portion was analyzed for moisture, ether extract, CP, and ash. Average daily feed intake decreased (linear; P = 0.05), and G:F increased (quadratic; P = 0.02) in the 100 mg of Cu/d group. Serum cholesterol and triglycerides did not change (P > 0.10); however, NEFA decreased (linear; P = 0.01) as supplemental Cu increased. No differences were observed (P > 0.10) in HCW, chilled carcass weight, or kidney and pelvic fat; however, 12th rib fat (linear; P = 0.01) and adjusted fat thickness (linear; P = 0.03) decreased as Cu supplementation increased. No differences (P > 0.10) in LM area were observed; however, percentage of boneless closely trimmed retail cuts increased (linear; P = 0.04) as Cu supplementation increased. The moisture (%) of the 9th to 11th rib sections increased (linear; P = 0.03), ether extract (%) decreased (linear; P = 0.02), and CP and ash (%) tended to increase (linear; P = 0.09 and 0.06, respectively) as Cu supplementation increased. Carcass composition measured using the left half of the carcass confirmed the values obtained through the 9th to 11th rib sections. Results of this study indicate that supplemental Cu can alter the serum lipid profile, carcass characteristics, and carcass composition of goat kids.

Dietary tryptophan need of broiler males from forty-two to fifty-six days of age

Tryptophan requirements of broiler males from 42 to 56 d of age were studied. Ross x Ross 308 chicks were placed in an open-sided house, and provided common starter and grower diets from 0 to 42 d of age. Subsequently, a corn, soybean meal, corn gluten meal, and gelatin combination of feedstuffs provided 0.12% Trp to which 0.04% increments of L-Trp were supplemented at the expense of an isonitrogenous amount of L-Glu to 0.24%. Birds that received diets containing 0.12% Trp exhibited aberrant behavior based on the spillage of considerable amounts of feed from the trough and contamination of adjacent waterers with floor litter. There were reductions in body weight gain, feed conversion, and carcass and breast fillets weights and yields with dietary Trp at 0.12%, but these were not affected at Trp levels at or above 0.16%. Exponential regression analyses showed that body weight gain improved as Trp increased, with maximum overall performance being attained at 0.17%, whereas chilled carcass weight maximized at 0.16% dietary Trp. Nitrogen retention measured using the same experimental feeds and sample birds at 48 to 49 d of age was unaffected by dietary Trp. Plasma uric acid, albumin, total protein, and aspartate-transferase measured concurrently with nitrogen retention were not altered; however, blood glucose was reduced in broilers fed 0.12% dietary Trp. Overall results suggest that broiler males need approximately 0.17% dietary Trp between 42 and 56 d of age, which closely agrees with the NRC (1994) recommendation of 0.16% Trp estimated from modeling for this feeding period.

Effect of Dietary Acidification on Mortality Rates, General Performance, Carcass Characteristics, and Serum Chemistry of Broilers Exposed to Cycling High Ambient Temperature Stress

A 2-phase (starter and grower) experiment was conducted to evaluate efficacy of a commercial phosphoric and citric acid based dietary acidifier (Lucta’cid) on broiler performance, survivability, serum chemistry, and carcass characteristics during cycling high ambient temperature stress. Starter phase acidifier supplementation (0 and 0.2% of diet) had no impact (P > 0.1) on broiler performance. The grower phase examined the 2 starter phase acidifier exposure histories along with 5 acidifier inclusion levels (0, 0.05, 0.10, 0.20, 0.30%) under cycling high ambient temperatures. A significant starter phase acidifier history × grower phase acidifier inclusion level interaction was noted on final BW, BW gain, and mortality. Mortality for birds lacking starter phase acidifier exposure declined quadratically (P < 0.05) with acidifier level, whereas no such response was noted for chicks consuming acidifier during the starter period. Broiler performance and survivability data, combined to estimate productivity per bird placed, indicated a continued mortality-driven acidifier history × inclusion level interaction (P < 0.10) on hot carcass weight, chilled carcass weight, breast yield, and leg quarter weight. Birds lacking starter phase acidifier and consuming acidifier during grower phase exhibited increased carcass, leg quarters, and breast yield per bird placed. In conclusion, data suggest that grower acidifier supplementation has the potential to reduce economic losses attributable to heat stress.