Developmental comparisons of boars and barrows: II. Body composition and bone development

Differences in total carcass bone, muscle and fat, and linear measurements of the tibia and radius were evaluated in barrows at 105 kg and boars at 105, 118, 132 and 145 kg live body weight. The carcasses of five replicates were physically separated into skin, bone and soft tissues, and the linear measurements of the tibia and radius were obtained on seven replicates. At live weight of 105 kg, boars did not differ significantly in fat-free muscle, but they had 33.2% less fat, 11% greater bone weight and 14% greater skin weight than barrows. At 145 kg, boars had total carcass fat weight comparable with 105-kg barrows. Fat-free muscle, bone and skin weight of boars increased at linear rates of .41, .083 and .104 kg/kg of body weight increase from 105 to 145 kg, respectively. At 105 kg, density and length of the tibia and radius did not differ between boars and barrows. The tibia of boars were heavier than those of barrows at 105 kg, resulting in a greater ratio of tibia weight to length (indirect measure of bone thickness). As boars increased in live weight from 105 to 145 kg, total weight and length of the tibia and radius increased linearly. The ratio of weight to length of the tibia and radius increased during this 40-kg weight gain, indicating that weight of both bones increased at a greater rate than length. These results indicate that boars and barrows have the same weight of total carcass fat when boars are 40 kg heavier than the barrows. The greater bone weight of boar carcasses compared with barrows is due to greater bone thickness.     

Genetic correlation between boars, barrows and gilts for various carcass traits

Data from 11 generations of a selection study were analyzed to estimate genetic correlations between boars and gilts, boars and barrows, and gilts and barrows for carcass traits in the Lacombe and Yorkshire breeds of swine. Genetic correlations were estimated to determine if genotype X sex interactions existed and to assess the need for separate genetic parameters for boars and gilts in selection response equations. Genotype X sex interactions were found for total carcass fat/kg of cold carcass weight, area of lean in the ham face/kg of cold carcass weight and percent lean in the ham face/kg of cold carcass weight. Carcass length, longissimus muscle area/kg of cold carcass weight percent ham of side and percent lean in the ham face did not have genotype X sex interactions. Selection based on pooled genetic parameters over sex were favored over selection based on separate genetic parameters regardless of the presence or absence of genotype X sex interactions.     

Effects of Duroc, Meishan, Fengjing, and Minzhu boars on carcass traits of first-cross barrows.

Duroc, Meishan, Fengjing, and Minzhu boars were mated to crossbred gilts during two breeding seasons. From each sire breed group each season, six pens of approximately eight barrows each were slaughtered. A pen of pigs from each sire breed group was slaughtered at 7-d intervals from 168 to 203 d of age each season. Breed of sire effects were significant for all age-adjusted carcass traits except carcass length, fat thickness at the last rib, color score, and firmness score. At 184 d of age, Duroc crosses had the heaviest (P less than .05) slaughter and carcass weights; Minzhu crosses were lighter (P less than .05) than Meishan crosses but not lighter than Fengjing crosses. Differences among age-constant traits reflect differences in BW. After adjustment to a constant carcass weight of 78 kg, the three Chinese breeds had very similar carcass characteristics. Carcasses sired by Durocs had significantly less backfat and larger longissimus muscle area than carcasses sired by the Chinese breeds. Weight of each trimmed wholesale lean cut and their total weight were significantly higher for Duroc crosses than for Chinese crosses. Breed of sire means did not differ significantly for belly weight, but Duroc crosses had less (P less than .05) weight of leaf fat. Relative to Chinese crosses, longissimus muscles from Duroc crosses had more marbling (P less than .05). Sire breed groups did not differ significantly for color or firmness score. Pigs sired by Meishan, Fengjing, and Minzhu produced carcasses with significantly less lean content at a carcass weight of 78 kg than did pigs sired by Duroc.     

Genetic and environmental effects on carcass characteristics of Southdown x Romney lambs: I. Growth rate, sex, and rearing effects

Carcass data from more than 4,400 Southdown x Romney ewe and wether lambs collected over a 16-yr period were analyzed for the effects of sex, rearing status, and growth rate. Ewe lambs grew more slowly than wethers and had .78 kg less carcass weight at the same age. The carcass weight advantage for wethers was nearly all caused by heavier fat-free weight. Based on fat depths, the fat on ewe lambs was distributed in more anterior and ventral parts of the carcass relative to wether lambs. Lambs reared as twins had 1.73 kg less carcass weight and correspondingly reduced carcass measurements compared with lambs reared as singles. Sex and rearing status interacted for some traits. However, in no case was a significant sex difference reversed in single- and twin-related lambs. Growth rate effects were determined by regressing average change in carcass measurements on average carcass weight gain over a 5-wk period. When carcass weight remained constant over a 5-wk period, fat weight increased by .12 kg, fat-free weight and muscle measurements decreased, and bone lengths increased. For each kilogram of increase in 5-wk carcass weight gain, the marginal increase in fat weight was .41 kg and that of fat-free weight was .59 kg. At the average 5-wk carcass weight gain of 1.4 kg, fat and fat-free gains were As carcass weight gain increased above 1.4 kg, fat-free gain exceeded fat gain.     

Growth and metabolism in somatotropin-treated steers: I. Growth, serum chemistry and carcass weights

Growth, feed conversion, serum chemistry and gross slaughter characteristics were determined in 20 steers (initially 9 mo of age, 231 +/- 18 kg) receiving daily injections of either saline (S) or recombinantly derived bovine somatotropin (rBST, 20.6 mg/d) for 112 d. Live weight gains were 15% greater for steers treated with rBST than for those treated with S. Feed intake was not different between S- and rBST-treated steers; thus, feed conversion was 12% more efficient in rBST steers. Scanogram backfat measurements were not affected by treatments. Serum electrolytes, protein, glucose and most enzyme activities were similar in S and rBST steers. Serum urea, creatinine and cholesterol (toward the end of treatment) concentrations, however, were lower (P less than .05) in rBST steers, suggesting that nitrogen retention was increased and lipid turnover was decreased by rBST. Total (P less than .1) and conjugated (P less than .05) bilirubin concentrations and glutamate-pyruvate transaminase activity (P less than .05) were lower in rBST steers. Carcass weights were not altered, but dressing percentages were lower (P less than .05) in rBST steers. This indicated that weight gain response to rBST was primarily in noncarcass components; further examination showed that this gain was predominantly in gut fill (approximately 2/3 of the greater live weight gain in rBST steers). Alternative protocols, such as administering the hormone to younger animals and (or) for a longer duration, may be necessary in order to achieve desirable responses in carcass growth.     

Prediction of carcass characteristics by real-time ultrasound in barrows and gilts slaughtered at three weights.

The carcass characteristics of 27 market barrows and 27 market gilts were evaluated at various times (n = 8) with real-time ultrasound (Aloka 210 DX) from approximately 20 kg until slaughter at three end points. The pigs were randomly assigned to slaughter weight groups of 91, 104.5, and 118 kg at weaning time. Correlations were determined over slaughter weight group and sex, and the accuracies of ultrasound measurements were also evaluated. The regressions of ultrasound 10th-rib fat and ultrasound longissimus muscle area on live weight were also developed. Correlations between actual and ultrasound-measured last-rib fat, 10th-rib fat, and longissimus muscle area were high (r = .91, .63, and .53, respectively; P less than .01). The accuracy of ultrasound longissimus muscle area prediction was lower for 118-kg pigs than for the two lighter groups, whereas the accuracy for prediction of last-rib fat was lower for 91-kg pigs than for the two heavier groups, as indicated by higher absolute differences (P less than .05). Last-rib fat and longissimus muscle area tended to be overestimated and 10th-rib fat tended to be underestimated by real-time ultrasound. Prediction of last-rib fat by ultrasound was more accurate for gilts than for barrows, as indicated by a lower absolute difference (P less than .05).     

Effects of winter stocker growth rate and finishing system on: I. Animal performance and carcass characteristics

Angus-crossbred steers (n = 216) were used in a 3-yr study to assess the effects of winter stocker growth rate and finishing system on finishing performance and carcass characteristics. During winter months (December to April) steers were randomly allotted to 3 stocker growth rates: low (0.23 kg x d(-1)), medium (0.45 kg x d(-1)), or high (0.68 kg x d(-1)). Upon completion of the winter phase, steers were randomly allotted within each stocker treatment to a corn silage-concentrate or pasture finishing system. All steers regardless of finishing treatment were finished to an equal-time endpoint to eliminate confounding of treatments with animal age or seasonal factors. Upon completion of the finishing period, steers were slaughtered in 2 groups (one-half of pasture and one-half of feedlot cattle each time) and carcass data were collected. Winter data were analyzed as a completely randomized design, with winter treatment, pen replicate, year, and the winter x year interaction in the model. Finishing performance and carcass data were analyzed in a split-plot design with finishing system in the whole plot, and winter growth rate and winter x finish in the split-plot. Winter treatment mean within finishing replication was the experimental unit, and year was considered a random effect. Winter stocker phase treatments resulted in differences (P < 0.001) in final BW, ADG, and ultrasound LM area between all treatments for that phase. Pasture-finished cattle had lower (P < 0.001) final BW, ADG, HCW, LM area, fat thickness, KPH, dressing percent, USDA yield grade, and USDA quality grade. Winter stocker treatment influenced (P < 0.05) final BW and HCW, with low and medium being less than high. Steers with low stocker gain had greater (P < 0.05) finishing ADG. Dressing percent was greater (P < 0.001) for high than low, and USDA quality grade was greater (P < 0.05) for high than low and medium. Carcass LM area, fat thickness, KPH, and USDA yield grade were not influenced (P > 0.05) by winter rate of gain. Cattle on low during winter exhibited compensatory gain during finishing but were unable to catch the high group regarding BW or HCW. The USDA quality grade was greater for high than low or medium. Animal performance during the winter stocker period clearly impacts finishing performance, carcass quality and beef production in both pasture- and feedlot-finishing systems, when cattle were finished to an equal-time endpoint.     

Growth, carcass characteristics, and lipid composition of adipose tissue and muscle of pigs fed canola

Sixty-one finishing pigs (53.4 kg) were fed a control diet (containing soybean meal) or diets containing 20% intact canola (IC) or 20% ground canola (GC) for 8 wk. Diets were not isocaloric. Daily gain and feed efficiency were not affected by dietary treatment, but pigs fed GC ate less than pigs fed either IC or the control diet. Carcass measurements, obtained on 43 of the pigs, were not affected by diet. For 27 pigs, fatty acid composition of perirenal adipose tissue (PRF), subcutaneous adipose tissue (SCF), and longissimus muscle (LDM) was analyzed. Nine pigs (three per treatment) were randomly selected for fatty acid composition analysis of intramuscular adipose tissue (IMF) and for cholesterol analysis of several tissues. Pigs fed canola had greater (P less than .05) proportions of mono- and polyunsaturated fatty acids and less (P less than .05) saturated fatty acids in PRF and SCF. The differences were more pronounced for PRF than for SCF. In the LDM, pigs fed canola tended to have elevated levels of unsaturated fatty acids at the expense of the saturated fatty acids, but this effect was significant for linolenic acid only. The fatty acid composition of IMF was not affected by diet (P greater than .05). Diet did not alter the cholesterol content of the tissues, but cholesterol in IMF was higher (P less than .05) than in PRF, SCF, and LDM. In conclusion, 20% IC or GC did not alter growth performance or carcass characteristics of pigs. Feeding of canola increased the degree of unsaturation of PRF and SCF, but it had less effect on IMF and LDM.     

Effects of ractopamine, genotype, and growth phase on finishing performance and carcass value in swine: I. Growth performance and carcass merit

A replicated factorial experiment using 183 individually fed crossbred barrows was conducted. Pigs were fed an 18.5% CP (.95% lysine) diet with 3,594 kcal of ME/kg. The effects of five genotypes (GT): 1) Hampshire (H) x (H x Duroc [D]), 2) synthetic terminal sire line, 3) (H x D) x (Landrace [L] x [Yorkshire (Y) x D]), 4) L x (Y x D), and 5) Y x L; two levels of ractopamine (RAC) treatment: 0 and 20 ppm; and three treatment weight periods (WT): 1) 59 to 100, 2) 73 to 114, and 3) 86 to 127 kg live weight on growth performance and carcass traits were evaluated. Ractopamine increased (P less than .0001) amount (FSL) and percentage (PFSL) of carcass lean standardized to 10% fat content, loin eye area (LEA), and dressing percentage (PDRES) and reduced (P less than .01) amount (DF) and percentage (PDF) of dissected fat. Magnitudes of RAC effects were smaller than those reported by other researchers. Effects of GT and WT on all growth and carcass traits were highly significant (P less than .001) except for those of WT on ADG (P less than .05) and GT on average feed intake (AFI) and backfat thickness at the last rib (BFLR; P less than .05). Genotype 3 performed better for most economically important traits than did GT 1 and 4, suggesting that heterosis existed in GT 3, which essentially was obtained by crossing GT 1 and 4. Among the three treatment periods, WT 2 had the highest ADG. As BW increased from WT 1 to 3, AFI and AFI/ADG ratio (FCR) increased and lean percentage decreased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Response time of broiler chickens to cimaterol: meat tenderness, muscle composition fiber size, and carcass characteristics.

The response time to cimaterol (CIM), a beta-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were conducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet containing 1 ppm of CIM. Trial 1 consisted of 55, 31-d-old broiler chickens individually fed for up to 48 h. At 0, 6, 12, 18, 24, and 48 h, five CON and five CIM-fed chickens were killed. Trial 2 consisted of 160, 33-d-old broiler chickens group-fed for up to 14 d. At 2, 4, 6, 8, 10, 12, and 14 d, 10 CON and 10 CIM-fed chickens were killed. The breast muscle (BM) and leg muscle (LM) weight, cathepsin B and L activities, DNA, RNA, and protein concentration, and BM shear force value (SFV) were measured in both trials. Thigh muscle (TM) SFV were measured in Trial 2 only. Fiber size of BM was measured (five birds per treatment) at d 2, 6, 10, and 14. In Trial 1, BM weight and SFV were lower in CIM-fed birds at 6 h (P less than .05). In Trial 2 BM SFV were higher at d 8 (P = .06) and d 10 (P less than .05) in CIM-fed chickens. The SFV of CIM-fed chickens were higher at d 4, 8, 10, 12, and 14 (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of diet and exercise on performance, carcass traits and plasma components of growing-finishing barrows

Twenty-four barrows (approximately 25 kg initial wt) were used in each of three 2 X 2 factorially arranged trials to study effects of exercise (not exercised vs walking 30 min/d, 6 d/wk on a treadmill) and diet (low energy vs high energy) on performance during the growing-finishing period. Average daily gain (ADG) of barrows not exercised was greater (P less than .07) than that of those exercised. Barrows fed the high-energy diet had greater (P less than .05) ADG, lower (P less than .01) feed intake and lower (P less than .01) feed-to-gain ratio than barrows fed low-energy diets. In trials 1 and 2, pigs were slaughtered when removed from test and selected carcass measurements and internal organ weights were obtained. Exercise did not significantly affect carcass length, backfat thickness, loin muscle area or lean cuts (as a percentage of off-test weight). Pigs fed the high-energy diet had more (P less than .01) backfat than those fed the low-energy diet. Neither the exercise program nor the diet had a significant effect on organ weights. Pigs not exercised had a higher (P less than .05) plasma albumin-to-globulin ratio and lower (P less than .05) plasma creatinine concentration than did pigs that were exercised. Also, pigs not exercised had slightly higher (P less than .08) plasma albumin and glucose, but lower (P less than .06) plasma globulin levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

The provision of solid feeds to veal calves: I. Growth performance, forestomach development, and carcass and meat quality

Growth performance, forestomach development, and carcass and meat quality of veal calves fed a milk replacer diet (Control) were compared to those obtained from calves fed the same liquid diet plus 250 g x calf(-1) x d(-1) of dried beet pulp or wheat straw. Three groups of 46 Polish Friesian calves, balanced according to initial BW, were assigned to the three dietary treatments in a fattening trial, which lasted 160 d. The provision of either solid feed did not affect the milk replacer intake. However, calves' ADG was increased (P < 0.01) only by feeding the beet pulp diet. The administration of both solid feeds improved calves' health status; calves fed solid feeds required fewer iron treatments for low hemoglobin and needed less medical treatments for respiratory or gastrointestinal diseases. In comparison to the Control calves, the provision of wheat straw and beet pulp increased iron intake throughout the fattening period by 41 and 130%, respectively. However, only calves fed beet pulp showed higher levels of hemoglobin and plasma iron concentrations (P < 0.05), whereas the same blood parameters were similar between Control calves and those fed wheat straw. At slaughter, both solid feeds led to empty forestomach weights heavier than those of Controls without reducing dressing percentage. The reticulorumen was heaviest in calves fed beet pulp, whereas wheat straw promoted omasal development. The administration of beet pulp resulted in a better carcass conformation than did the Control diet or wheat straw, but it had a detrimental effect on carcass color, which was graded as the darkest (P < 0.001). Consistent with this result, meat color of calves fed beet pulp was darker than that of Control calves and those fed wheat straw, because of the higher hematin concentration measured at the muscle level. No differences in carcass and meat color were observed between Control calves and calves fed wheat straw. The administration of solid feeds for welfare purposes does not always prevent the production of veal meat fulfilling the color standards required by the market. There is not a straight-forward relationship between a solid feed's iron content and the "redness" of veal meat, which should be related to the capability of the calves to use the iron provided by the roughage.     

Growth and carcass characteristics of cull cows after different times-on-feed

Cull cows (N = 48) of similar age from Angus and Hereford breed types were assigned to one of four feeding periods (0, 28, 56 or 84 d) and subdivided into two groups, one implanted with Synovex-H and a non-implanted control. Cows were fed a high energy diet and slaughtered at the end of each feeding period. Average daily gain and feed efficiency were evaluated on each animal during the trial. The following carcass traits were evaluated: USDA yield and quality grade characteristics, boning yield, muscle weights, bone weights, pH and Warner-Bratzler shear force of the longissimus muscle. The left side of each carcass was boned and proximate analysis was determined. No significant implant effects were encountered for any of the traits evaluated; therefore, data were pooled and evaluated by feeding period only. Carcass weight and boneless forequarter and hindquarter tissue weights increased significantly between each feeding period; percent kidney, pelvic and heart fat (KPH) and yield grade did not differ (P greater than .05) until d 56 and 84, respectively. Quality grade and marbling scores improved (P less than .05) between 28 and 56 d of feeding. Biceps femoris weight changed during the 84-d experiment from 4.1 kg on d 0 to 5.3 kg on d 84 (P less than .05). Proximate analysis of the boneless tissue indicated an increase (P less than .05) in extractable fat of approximately 6% for each feeding period (6.3% fat on d 0 to 25.4% on d 84).(ABSTRACT TRUNCATED AT 250 WORDS)     

Genetic (co)variances and breeding value estimation of Gompertz growth curve parameters in Finnish Yorkshire boars, gilts and barrows.

This paper's objectives were to estimate the genetic (co)variance components of the Gompertz growth curve parameters and to evaluate the relationship of estimated breeding values (EBV) based on average daily gain (ADG) and Gompertz growth curves. Finnish Yorkshire central test station performance data was obtained from the Faba Breeding (Vantaa, Finland). The final data set included 121,488 weight records from 10,111 pigs. Heritability estimates for the Gompertz growth parameters mature weight (alpha), logarithm of mature weight to birth weight ratio (beta) and maturation rate (kappa) were 0.44, 0.55 and 0.31, respectively. Genotypic and phenotypic correlations between the growth curve parameters were high and mainly negative. The only positive relationship was found between alpha and beta. Pearson and Spearman rank correlation coefficients between EBV for ADG and daily gain calculated from Gompertz growth curves were 0.79. The Spearman rank correlation between the sire EBV for ADG and Gompertz growth curve parameter-based ADG for all sires with at least 15 progeny was 0.86. Growth curves differ significantly between individuals and this information could be utilized for selection purposes when improving growth rate in pigs.     

Characterization of muscles from boars, barrows, and gilts slaughtered at 100 or 110 kilograms: differences in fat, moisture, color, water-holding capacity, and collagen.

For characterization of ether-extractable fat content (EE), L*, a*, and b* color, and water-holding capacity (WHC), 12 muscles or muscle groups were dissected from 48 pork carcasses of boars, barrows, or gilts that were fed diets either at minimum (LO) or 1% above (HI) their protein requirements and slaughtered in two separate trials at 100 or 110 kg. In both trials across muscles, gilts and boars had lower (P < .05) EE than barrows. In the 110-kg trial, boars had lower (P < .001) EE than gilts. In the 100-kg trial, boars on LO diets had lower (P < .001) WHC than all other groups, and both boar groups had lower (P < .05) WHC than gilts. No differences (P > .05) in WHC were seen in the 110-kg trial. In the 100-kg trial, gilts had lower L* (P < .05) than boars and barrows, but in the 110-kg trial boars had lower L* (P < .05) than barrows and gilts. The lowest (P < .05) a* values were for boars in the 100-kg trial and for boars on LO diets in the 110-kg trial. In both trials, the serratus ventralis had more (P < .001) EE than all other muscles. In both trials, the semitendinosus had higher (P < .001) L* and the longissimus had lower (P < .01) a* and b* than all other muscles. The numerous differences observed among muscles may help identify optimal uses for the entire pork carcass.     

Effect of chromium picolinate and chromium propionate on glucose and insulin kinetics of growing barrows and on growth and carcass traits of growing-finishing barrows

Two experiments were conducted to determine the effects of dietary Cr tripicolinate (CrPic) or Cr propionate (CrProp) on growth, carcass traits, plasma metabolites, glucose tolerance, and insulin sensitivity in pigs. In Exp. 1, 36 barrows (12 per treatment; initial and final BW were 20 and 38 kg) were allotted to the following treatments: 1) corn-soybean meal basal diet (control), 2) as 1 + 200 ppb Cr as CrPic, or 3) as 1 + 200 ppb Cr as CrProp. Growth performance data were collected for 28 d, and then 23 pigs (seven, eight, and eight pigs for treatments 1, 2, and 3, respectively) were fitted with jugular catheters and a glucose tolerance test (500 mg glucose/kg BW) and an insulin challenge test (0.1 IU of porcine insulin/kg BW) were conducted. Both CrPic and CrProp decreased (P < 0.05) ADG and ADFI but did not affect gain:feed (P > 0.10). Fasting plasma glucose, total cholesterol, urea N, insulin, and high-density lipoprotein cholesterol:total cholesterol concentrations were not affected (P > 0.10) by either Cr source. Pigs fed CrPic had lower (P < 0.02) fasting plasma NEFA concentrations than control pigs, but plasma NEFA concentrations of pigs fed CrProp were not affected (P > 0.10). During the glucose tolerance test, glucose and insulin kinetics were not affected by treatment (P > 0.10). During the insulin challenge test, glucose clearance was increased (P < 0.01) in pigs fed CrProp but not affected (P > 0.10) in pigs fed CrPic. Glucose half-life was decreased (P < 0.03) in pigs fed CrPic or CrProp, but insulin kinetics were not affected (P > 0.10). In Exp. 2, 48 barrows (four replicates of four pigs per replicate; initial and final BW were 23 and 115 kg) were allotted to the same dietary treatments in a growing-finishing study. Average daily gain, ADFI, and gain:feed were not affected (P > 0.10) by treatments. Carcass length tended (P = 0.10) to be greater in pigs fed CrPic than in pigs fed CrProp, but other carcass measurements were not affected (P > 0.10). Glucose kinetics from the insulin challenge test indicate that both CrPic and CrProp increase insulin sensitivity and that both Cr sources are bioavailable.     

Pruteen,a new source of protein for growing pigs. II. Feeding trial: Growth rate,feed utilization and carcass and meat quality

Pruteen, a bacterial protein (Imperial Chemical Industries, Billingham, Cleveland, Great Britain) was tested as a sole protein supplement in diets for growing pigs based on barley and fine wheat offal replacing white fish meal.The protein supplements were tested at a ‘standard’ and a ‘marginal’ level of supplementation, fed throughout the growing periods of either pork pigs (20–58 kg live weight) or bacon pigs (20–87 kg live weight).The growth rate and the feed:gain ratio were similar in pigs which received either the Pruteen or the white fish meal diets.Carcass dissection and extensive meat quality studies (raw and cooked) revealed no differences between pigs fed Pruteen or white fish meal.     

Growth performance and carcass characteristics of indigenous Mukota pigs of Zimbabwe

Carcass quality characteristics are essential in affecting grading and revenue that pig producers realize. No information is available on the grading of carcasses in indigenous Mukota pigs of Zimbabwe. The objective of this study was to determine the influence of genotype (Mukota and Large White × Mukota) and sex on post-weaning growth performance and carcass traits of pigs fed maize cob-based diets. All pigs were weighed at 2-week intervals to estimate average daily gain, dressing percentage (DP), and carcass lengths. Backfat thickness was also measured. Males had higher body weight gains than females (P < 0.05). Growth rates for Mukota (0.31 ± 0.010) and crossbred (0.41 ± 0.030) pigs were lower in the cool season than the other seasons (P < 0.05). Body weights were consistently higher in the crossbred than in the Mukota pigs (P < 0.05). Mukota pigs showed a peak growth between 12 and 14 weeks post-weaning (P < 0.05). The DPs were 0.70 and 0.73 for the Mukota and crossbred pigs, respectively (P < 0.05). Crossbred pigs had longer (P < 0.05) carcasses than Mukota (655.5 ± 1.68 versus 507.2 ± 0.92 mm). Although there were no differences in the backfat thickness between males and females of the crossbred pigs, Mukota males had thicker backfat than the females (P < 0.05). Crossbreeding is, therefore, significant in improving carcass grades of Mukota pigs.     

Growth, puberty, and carcass characteristics of Brahman-, Senepol-, and Tuli-sired F1 Angus bulls

Postweaning growth, sexual development, libido, and carcass data were collected from two consecutive calf crops using 31 Brahman x Angus (B x A), 41 Senepol x Angus (S x A), and 38 Tuli x Angus (T x A) F1 bulls. Following weaning (by mid-September) and preconditioning, at the start of the study (late September) bulls were fed concentrate (three times each week at a rate equivalent to 4.5 kg/d) on bahiagrass pasture for approximately 250 d. At the start of the study and at 28-d intervals, BW, hip height, and scrotal circumference (SC) were measured. Concurrently at 28-d intervals, when the SC of a bull was > or = 23 cm, semen collection was attempted using electroejaculation. Ejaculates were evaluated for presence of first spermatozoa (FS), 50 x 10(6) sperm with at least 10% motility (PU), and 500 x 10(6) sperm with at least 50% motility (PP). After all bulls reached PP they were subjected to two libido tests. Carcass data were collected on all bulls (n = 110) and Warner-Bratzler shear (WBS) force values were assessed on a subset (n = 80). For both years, B x A bulls were heavier (P < 0.05) and taller (P < 0.05) than S x A and T x A bulls at the start and end of the study. However, breed type did not influence (P > 0.10) gain in BW or hip height during the study. Scrotal circumference of T x A bulls was larger (P < 0.05) than that of B x A or S x A bulls at the start of the study, but there was no effect (P > 0.10) of breed type by the end of the study. At PU and PP, B x A bulls were older (P < 0.05), heavier (P < 0.05), and taller (P < 0.05) and had larger (P < 0.05) SC than S x A and T x A bulls. Tuli x Angus bulls were younger (P < 0.05) than S x A bulls at PU and PP but had similar SC. Libido scores tended (P < 0.10) to be lower for B x A than for S x A and T x A bulls. Breed type affected (P < 0.05) carcass traits; B x A bulls had the heaviest (P < 0.05) hot carcass weight, greatest (P < 0.05) dressing percentage, larger (P < 0.05) longissimus muscle area than S x A bulls, and higher (P < 0.05) USDA yield grade than T x A bulls but greatest (P < 0.05) WBS force values. Breed type did not affect (P > 0.10) USDA quality grade. In conclusion, tropically adapted F1 bulls produced from Senepol (Bos taurus) and Tuli (Sanga) sires bred to Angus cows in Florida had lighter BW, shorter hip heights, and smaller carcasses than those from Brahman sires but reached puberty earlier and had higher libido scores and lower WBS force values.