Reproductive and health traits among Boer, Kiko, and Spanish meat goat does under humid, subtropical pasture conditions of the southeastern United States

Boer (n = 132), Kiko (n = 92), and Spanish (n = 79) straightbred does were studied across 6 yr to assess doe fitness on southeastern US pastures. Does were exposed to Boer, Kiko, and Spanish bucks in a complete 3-breed diallel mating scheme each fall for spring kidding in March or May. A total of 1,041 doe-yr units were observed with does (ranging from 2 to 8 yr of age) managed together in a semi-intensive manner. The proportion of buck-exposed does delivering at least 1 live kid was less (P < 0.01) for Boer does (80%) than for Kiko (96%) and Spanish does (94%). Litter size and litter weight at birth were not affected (P > 0.15) by breed of dam. By weaning at 3 mo, the proportion of available does weaning at least 1 kid was less (P < 0.01) for Boer does (53%) than for Kiko (84%) and Spanish does (82%). For does weaning kids, litter size at weaning was greater (P = 0.01) for Spanish does (1.74 kids) than for Kiko (1.59 kids) and Boer does (1.47 kids). Litter weaning weight was lighter (P < 0.01) for Boer dams (23.0 kg) than for Kiko (27.2 kg) and Spanish dams (26.5 kg). The efficiency ratio of litter weight to dam weight at weaning differed (P < 0.05) among all 3 dam breeds: Boer = 51%; Kiko = 62%; Spanish = 68%. Annual rates of lameness, endoparasitism, and attrition, respectively, were greater (P < 0.01) for Boer does (69, 53, and 28%) than for Kiko (32, 24, and 10%) and Spanish does (42, 22, and 11%). Postpartum fecal egg counts for endoparasite loads were less (P < 0.05) for Spanish dams (346 eggs/g) than for Kiko (524 eggs/g) and Boer does (675 eggs/g). Whole-herd annual doe productivity based on all available does was less (P < 0.01) for Boer does (11.7 kg weaned/doe) compared with Kiko (22.0 kg weaned/doe) and Spanish does (21.1 kg weaned/doe). Boer does expressed substantially decreased levels of fitness compared with Kiko and Spanish does when semi-intensively managed on humid, subtropical pasture. Kiko and Spanish should be preferred as maternal breeds in meat goat production systems under conditions reflective of this study.     

Carcass yield traits of kids from a complete diallel of Boer, Kiko, and Spanish meat goat breeds semi-intensively managed on humid subtropical pasture

Bucklings (n = 275) from a complete diallel of Boer, Kiko, and Spanish meat goats were slaughtered at 7 mo of age (4 mo postweaning) to evaluate genetic effects on carcass yield. Breed of sire did not affect (P > 0.05) live, carcass, and primal weights. Conversely, breed of dam was a consistently significant source of variation for carcass weight traits. Kiko dams produced kids with heavier (P < 0.05) live, carcass, and primal weights than Boer dams. Weights from Spanish dams were intermediate to Boer and Kiko with the significance of differences varying by trait. Cold carcass dressing percent was affected (P < 0.01) by breeds of sire and dam. Boer sires decreased (P < 0.05) dressing percent compared with Kiko and Spanish sires. Dressing percent was also less (P < 0.01) from Boer dams than from Kiko dams; Spanish dams were intermediate and did not differ (P > 0.05) from Boer or Kiko. Subjective conformation scores for muscularity were affected (P < 0.01) by breeds of sire and dam. Boer-sired kids had better (P < 0.01) live scores than Kiko-sired kids. Progeny of Boer dams had better (P < 0.05) live scores than progeny of Spanish dams. Boer-sired kids also had better carcass scores (P < 0.05) than Kiko-sired and Spanish-sired kids. Breed differences for primal cut proportions were negligible. Proportional boneless meat yields did not vary (P > 0.05) by breeds of sire or dam. Direct effects of Boer were negative for carcass weight, dressing percent, and shoulder weight and positive for proportional leg weight. Direct effects of Kiko were positive for carcass weight and shoulder weight and negative for proportional leg weight. Direct effects of Spanish did not differ (P > 0.10) from 0 for any trait tested. Heterosis levels were similar among breed pairings. Heterosis was substantial (P ≤ 0.05) for live, carcass, and primal weights (5 to 9%) but not for dressing percent, proportional boneless meat yield, or primal weight proportions (<2%). Significant genetic variation was observed among goat breeds for carcass yield traits. Dam breed was more influential than sire breed. Boer germplasm was not superior to Kiko or Spanish germplasm for carcass yield when semi-intensively managed on humid, subtropical pasture. Results emphasize the importance of comparative breed evaluations to provide industry with reliable information on carcass yield among goat genotypes.     

Additive and heterosis effects on preweaning traits, maternal ability and reproduction from crossing of the Angus and brown Swiss breeds in Florida

Angus (A), Brown Swiss (S) and A X S reciprocal F1 (AS) dams were mated to A, S and AS (also reciprocal F1) sires resulting in nine breed groups of progeny with varying proportions of Angus and Brown Swiss breeding. Breed group of dam and of sire significantly influenced birth weight, preweaning daily gain, weaning weight, 205-d weight, condition score and frame size. The means for birth weight and weaning weight were 33 and 213 kg, respectively. Brown Swiss bulls sired calves with the heaviest birth and weaning weights. Calves produced by S dams likewise were heavier at birth and weaning. Pregnancy rates were influenced significantly by year, age and breed of dam and averaged 79, 95 and 92% for S, AS and A cows, respectively. Survival rate averaged 97% and was not influenced significantly by any of the effects examined. Because survival rates were similar for all breed groups, the results for weaning rate paralleled those for pregnancy rate. Genetic influences on preweaning growth traits and survival rate were partitioned into additive breed differences (B) and heterosis (H) effects for direct (d) and maternal (m) components. Pregnancy and weaning rates were examined using similar analyses except that genotype of service sire of dam replaced that of the offspring for the direct additive breed and direct heterosis components. The Bd values indicated that the Angus breed was inferior (P less than .01) to the Brown Swiss breed for all preweaning growth traits except for condition score, in which the Angus breed surpassed (P less than .01) the Brown Swiss. The Bm values also showed an advantage for the Brown Swiss breed for all preweaning growth traits. The additive maternal effect (the genotype of the females exposed), Bm, was important for pregnancy rate and weaning rate (P less than .001 and P less than .05) but not for survival rate (P greater than .10). The direct additive breed effect was not important for any reproductive trait. Direct heterosis did not affect any of the preweaning or reproduction traits; however, maternal heterosis (Hm) significantly affected all traits except birth weight, frame score and survival rate. The Hm estimates were 12.0 and 8.4 kg for weaning weight and 205-d weight, respectively. The Hm estimates for pregnancy rate, survival rate and weaning rate were 10, 2 and 13%, respectively.     

Biological type effects on gestation length, calving traits and calf growth rate

Gestation length, birth weight calving difficulty, calf mortality rate at birth, calf mortality rate from birth to weaning, preweaning calf growth rate and calf 200-d weight were evaluated in a biological type study in which four sire breeds were bred by AI to Hereford dams. Angus and Red Poll sires represented breeds of medium size, and Pinzgauer and Simmental sires represented large breeds. Angus and Pinzgauer represented breeds with medium milk production, and Red Poll and Simmental represented breeds with high milk production. Dams mated to large sire breeds had longer (P less than .01) gestation lengths (.95 d) and higher calving difficulty scores than dams mated to medium-sized sire breeds. Calves from large sire breeds had heavier birth weight (P less than .01) and 200-d wt (6.1 kg; P less than .01) than calves from medium-sized sire breeds. Calf death loss and ADG to weaning were similar (P greater than .10) for all breeds of sire. Calves from the higher milk level sire breeds exceeded the medium-milk breeds in birth weight (1.3 kg; P less than .01) but did not (P greater than .10) in other traits. Calves from the higher milk level sire breeds exceeded the medium-milk breeds in birth weight (1.3 kg; P less than .01) but not (P greater than .10) in other traits. Interaction between size and milk production of sire breed existed for gestation length, birth weight, ADG from birth to weaning and 200-d calf weight (P less than .01). In general, mature size of sire breed was a good indication of expected performance traits not easily influenced by environment. Not all differences, however, could be explained by size and milk production of the size breed.     

Effect of tropically adapted sire breeds on preweaning growth of F1 Angus calves and reproductive performance of their Angus dams

The objective of this study was to determine the effect of tropically adapted sire breeds on preweaning growth performance of F1 calves and on reproductive performance of their Angus dams. Angus (A) cows were bred in two consecutive years (1992 and 1993) by AI using semen from Brahman (B; Bos indicus; n = 10), Senepol (S; Bos taurus; n = 10), and Tuli (T; Sanga; n = 9) bulls. A total of 82 B x A, 85 S x A, and 91 T x A calves were born. The statistical model included the fixed effects of year, sire breed, calf sex, sire breed x calf sex, and cow parity and the random effect of sire within sire breed. Birth weight, weaning weight, 205-d adjusted weaning weight, ADG from birth to weaning, and hip height at weaning were greater (P < .001) for B x A calves than for S x A or T x A calves. Greater differences were detected between sexes for B x A than for S x A and T x A (for all traits sire breed x calf sex, P < .05). Sire breed affected (P < .01) the percentage of unassisted calvings (B x A, 87%; S x A, 98%; and T x A, 100%) and tended (P < .10) to affect the percentage of calves that survived until weaning (B x A, 90%; S x A, 94%; and T x A, 98%). Sire breed of calf did not affect (P > .10) length of gestation, and sire breed did not affect the interval from calving to first observed estrus or pregnancy in Angus dams. These results demonstrate that preweaning growth performance of B x A calves was greater than that of either S x A or T x A calves. However, use of Brahman sires on Angus dams led to calving problems and tended to reduce the percentage of calves that survived until weaning. Thus, heavier weaning weights of B x A calves would be an advantage for cow-calf producers marketing calves, but heavier birth weights and calving difficulty attributed to Brahman sires would be a disadvantage.     

Adjustment factors for growth characters of the Damascus goatFacteurs de correction pour les caractères de croissance de la chèvre damascaineKorrekturfaktoren für wachstumsmerkmale bei der damaskusziege

Data on 1542 purebred Damascus kids obtained from the Goat Breeding Unit at Akhelia were used to determine the effects of year, month and type of birth (singles, twins, other multiples), sex of kid and dam lactation number on growth characters of goats. Least squares analyses showed that all factors studied had a significant effect on weaning weight, pre-weaning growth rate and 140-day weight (P<0.01). Type of birth and lactation number effects were small and insignificant for post-weaning growth rate.Adjustment factors were computed across year of birth for the effects of month of birth, type of birth, sex of kid and dam lactation number. These adjustment factors, although developed from a single herd, can be used, with some caution, in a breeding program for the improvement of Damascus goats.     

Evaluation of birth and weaning traits of Romosinuano calves as purebreds and crosses with Brahman and Angus

The objectives of this work were to evaluate birth and weaning traits, to estimate genetic effects, including heterosis and direct and maternal breed effects, and to evaluate calving difficulty, calf vigor at birth, and calf mortality of Romosinuano as purebreds and as crosses with Brahman and Angus. Calves (n = 1,348) were spring-born from 2002 through 2005 and weaned in the fall of each year at about 7 mo of age. Traits evaluated included birth and weaning weight, ADG, BCS, and weaning hip height. Models used to analyze these traits included the fixed effects of year, sire and dam breeds, management unit, calf sex, cow age, and source of Angus sire (within or outside of the research herd). Calf age in days was investigated as a covariate for weaning traits. Sire within sire breed and dam within dam breed were random effects. Estimates of Romosinuano-Brahman and Romosinuano-Angus heterosis (P < 0.05) were 2.6 +/- 0.3 (8.6%) and 1.4 +/- 0.3 kg (4.7%) for birth weight, 20.5 +/- 1.5 (9.5%) and 14.6 +/- 1.4 kg (7.4%) for weaning weight, 79.2 +/- 6.1 (9.8%) and 55.1 +/- 6.0 g (7.5%) for ADG, 0.16 +/- 0.03 (2.7%) and 0.07 +/- 0.03 (1.2%) for BCS, and 2.77 +/- 0.32 cm (2.4%) and 1.87 +/- 0.32 cm (1.7%) for hip height. Heterosis for Brahman-Angus was greater (P < 0.05) than all Romosinuano estimates except those for Romosinuano-Brahman and Romosinuano-Angus BCS. Romosinuano direct effects were negative and lowest of the breeds, except for the Angus estimate for hip height. Romosinuano maternal effects were the largest of the 3 breeds for birth weight and hip height but intermediate to the other breeds for weaning weight and ADG. A large proportion of Brahman-sired calves from Angus dams (0.09 +/- 0.03; n = 11) was born in difficult births and died before 4 d of age. Brahman and Angus purebreds and Romosinuano-sired calves from Brahman dams also had large proportions of calves that died before weaning (0.09 or greater). Results indicated that Romosinuano may be used as a source of adaptation to subtropical environments and still incorporate substantial crossbred advantage for weaning traits, although not to the extent of crosses of Brahman and Angus.     

Carcass traits and retail display-life of chops from different goat breed types

Four groups of goats, Boer x Spanish, straightbred Spanish, Spanish x Angora, and straightbred Angora were slaughtered at a constant age according to accepted industry procedures. At 24 h postmortem, various carcass yield and quality measurements were taken. At 48 h postmortem, one side from each carcass was fabricated into major wholesale cuts for dissection into percentage lean, bone, and fat. Rib chops from the opposite side were fabricated, packaged, and displayed in a retail case. Trained panelists evaluated the rib chops over 4 d of retail display for lean color, surface discoloration, and overall appearance; packages were opened and analyzed for off-odor on d 4. When slaughtered at constant ages, Angora goats had lighter (P < .05) live and hot carcass weights than all other breed types, and Boer x Spanish goats had heavier (P < .05) live and carcass weights than Spanish goats. Live and carcass weights for Boer x Spanish and Spanish x Angora goats did not differ (P > .05). Carcasses from Angora goats had considerably smaller (P < .05) longissimus muscle areas than all other breed types. Carcasses from Spanish goats had lower (P < .05) carcass conformation scores than carcasses from Boer x Spanish goats but did not differ (P > .05) from carcasses of the other two breed types. Carcasses from Angora goats had smaller (P < .05) leg circumferences than the carcasses from Boer x Spanish and Spanish x Angora breed types. In general, carcasses from Boer x Spanish and Spanish goats possessed higher (P < .05) percentages of lean and lower (P < .05) percentages of fat for the side than did carcasses from Spanish x Angora and Angora goats. When the Spanish x Angora carcasses were compared to the Angora carcasses, it seemed that the addition of the Spanish breeding tended to increase lean and decrease fatness for most side or primal comparisons. There were no (P > .05) breed type or breed type x day effects for lean color, surface discoloration, overall appearance or off-odor; however, day of display did influence (P < .05) these traits. Crossing Spanish with Angora goats may be an option to improve carcass characteristics over that of straightbred Angora.     

Direct and maternal genetic effects on preweaning characters of Brahman, Hereford and Brahman-Hereford crossbred cattle

Birth weight, preweaning gain and weaning weight (adjusted 180-d weight) data, collected at McGregor, Texas, were analyzed for genetic differences. Breedtypes represented in the data were Brahman, Hereford and various Brahman-Hereford crosses. Preweaning gain was calculated as adjusted 180-d weight less birth weight. All statistical models included effects of dam age, year, season and sex. Analyses were performed using a breedtype model and a regression model that redefined breedtype as direct additive, direct heterotic, maternal additive and maternal heterotic effects. Brahman dams produced calves with lightest birth weights. Brahman-sired calves were heaviest at birth compared with those by other sire breedtypes. The estimated Brahman direct additive effect on birth weight was 4.6 kg greater than Hereford. The Brahman maternal additive effect was 7.5 kg less than Hereford. Direct and maternal heterotic effects on birth weight were 2.2 and .6 kg, respectively. Calves from F1 dams had larger preweaning gains than those of the other breedtypes. The Brahman direct additive effect on preweaning gain was 17.7 kg less than Hereford and the Brahman maternal additive effect was 20 kg greater than Hereford. Direct and maternal heterotic effects on preweaning gain were 19.6 and 19.5 kg, respectively. Results of weaning weight analyses were similar to preweaning gain analyses. The largest effects on weaning weight were direct and maternal heterosis, which were 21.6 and 19.8 kg, respectively.     

Growth and slaughter traits of Boer x Spanish, Boer x Angora, and Spanish goats consuming a concentrate-based diet.

The number of Boer crossbred meat goats has been increasing rapidly, although how their growth and slaughter traits compare with those of Spanish goats and influences of maternal genotype have not been thoroughly evaluated. This information would be useful to achieve optimal meat goat production systems and yield of goat products desired by consumers. Therefore, postweaning growth (9 to 24 wk of age) and slaughter traits (212 +/- 5.0 d of age) of Boer x Spanish, Spanish, and Boer x Angora wethers (n = 16, 18, and 18 for growth measures, respectively, and n = 6 per genotype for slaughter traits) consuming a concentrate-based diet were compared. Over the 16-wk performance period, ADG, DMI, and ADG:DMI were greater (P < 0.05) for Boer crossbreds than for Spanish goats (ADG: 154, 117, and 161 g; DMI: 646, 522, and 683 g/d; ADG:DMI: 263, 235, and 261 g/kg for Boer x Spanish, Spanish, and Boer x Angora, respectively). Dressing percentage (46.3, 47.3, and 47.0% of BW; SE = 1.21) and quality grade score (11.17, 9.67, and 11.17 for Boer x Spanish, Spanish, and Boer x Angora, respectively; SE = 0.66 [12 = Choice+; 11 = Choice; 10 = Choice-; 9 = Good+]) were similar among genotypes. Weights of some noncarcass components were greater for Boer crossbreds than for Spanish goats, but relative to empty BW, noncarcass component weights were similar among genotypes. Concentrations of moisture, ash, fat, and protein in carcass and noncarcass components did not differ among genotypes. Contributions to the carcass of different primal cuts were similar among genotypes, and there were few differences in concentrations of separated lean, bone, and fat in primal cuts. In conclusion, when consuming a concentrate-based diet, early postweaning growth rate was similar between Boer x Spanish and Boer x Angora wethers and greater for Boer crossbreds than for Spanish wethers. Slaughter traits were primarily related to differences in final BW.     

波尔山羊繁殖性状遗传参数的估计

对 2 4 8窝波尔山羊的胎产羔数、羔羊初生重和 2月龄体重的资料进行了遗传分析。结果表明 :公羊和胎次均对母羊产羔数具有显著的影响(P <0 0 5)。不同产羔季节对羔羊初生重和 2月龄体重也具有显著影响。产羔数的遗传力为 0 1 52 ,属低遗传力 ,而羔羊初生重和 2月龄体重 2个性状 (0 433 ,0 347)有中等或较高的遗传力。波尔母羊胎产羔数与羔羊初生重、 2月龄体重之间存在显著或极显著的表型相关 ,但是它们之间却存在显著或极显著的负遗传相关 (P <0 0 5或 P<0 0 1 )。羔羊的初生重和 2月龄体重间 ,无论是表型相关还是遗传相关 ,都呈极显著的正相关(P <0 0 1 )。     

Short-term effects of maternal feed restriction during pregnancy on goat kid morphology, metabolism, and behavior

Morphometric, metabolic, and behavioral modifications were studied in goat kids after maternal feed restriction during the last one-third of pregnancy. At birth, only kids from twin and triplet litters were studied [n=40 kids born to control dams (CONT) and n=38 born to restricted dams (REST)] and only males thereafter (n=13 CONT and 15 REST kids) until slaughter at 6 wk of age. Kids born to restricted goats had a smaller abdominal girth at birth (P<0.01) and tended to have a smaller body mass index (P=0.10) and a smaller density index (P=0.09) than kids born to CONT goats. Male REST kids had a lighter birth weight (P=0.03) than male CONT kids, but no differences (all P>0.10) were found for BW and morphometric measurements thereafter. Decreased NEFA concentrations suggested that male REST kids mobilized their body reserves less than CONT kids at birth (P<0.01). No modifications in drinking tests at 3 and 5 wk of age were observed, or in feeding behavior and emotional reactivity at 5 wk of age (all P>0.10). In conclusion, maternal feed restriction in the last one-third of pregnancy resulted in a decrease in birth size, but male kids rapidly caught up, and there were no changes in behavior, morphology, or metabolism during rearing.     

Influence of litter size and creep feeding on preweaning gain and influence of preweaning growth on growth to slaughter in barrows

The importance of birth-to-weaning average daily gain as a determinant of weight at a final age and yield of marketable pork was investigated. Treatments were imposed to create variation in birth-to-weaning ADG independent of birth weight. Newborn pigs were cross-fostered to create litters of four through 14 pigs/litter. Creep feed was offered to pigs from 5 d of age or during last 2 d before weaning at 13 to 20 d (average = 17 d). Growth rate and carcass dissection data were obtained from 195 barrows that were slaughtered at an average age of 170 d (SD = 7.5), weight of 109 kg (SD = 10.5). All traits measured were influenced by birth dam and sire (P < 0.01). Quadratic and cubic effects (P < 0.09) of litter size on birth-to-weaning ADG and weaning weight were different between the creep feeding treatments. Data revealed a positive influence (P < 0.04) of creep feeding from 5 d of age on birth-to-weaning ADG and weaning weight in larger size (> 8) litters. Importance of the independent variables birth weight, birth-to-weaning ADG, weaning weight, and birth weight plus birth-to-weaning ADG in determination of measures of postweaning growth and yield of marketable pork were examined by step-down regression analysis. Initial models included the linear and quadratic effects of the independent variables. In general, R2 for models ranked birth weight < birth-to-weaning ADG < d-17 weaning weight < birth weight + birth-to-weaning ADG. The R2 of models for BW at 170 d of age were 0.11 (P < 0.01) using birth weight as the independent variable, 0.16 (P < 0.01) using birth-to-weaning ADG, 0.19 (P < 0.01) using d-17 weaning weight, and 0.21 (P < 0.01) using birth weight + birth-to-weaning ADG. The model for effect of birth-to-weaning ADG on BW at 170 d of age indicated that a 10-g advantage in birth-to-weaning ADG produced a 0.94-kg advantage in BW at 170 d of age. Positive relationships (P < 0.05) between birth-to-weaning ADG and measures of postweaning growth and carcass yield suggest management practices that increase birth-to-weaning ADG may be advantageous in pork production.     

Estimating non-genetic and genetic parameters of pre-weaning growth traits in Raini Cashmere goat

Data and pedigree information used in the present study were 3,022 records of kids obtained from the breeding station of Raini goat. The studied traits were birth weight (BW), weaning weight (WW), average daily gain from birth to weaning (ADG) and Kleiber ratio at weaning (KR). The model included the fixed effects of sex of kid, type of birth, age of dam, year of birth, month of birth, and age of kid (days) as covariate that had significant effects, and random effects direct additive genetic, maternal additive genetic, maternal permanent environmental effects and residual. (Co) variance components were estimated using univariate and multivariate analysis by WOMBAT software applying four animal models including and ignoring maternal effects. Likelihood ratio test used to determine the most appropriate models. Heritability ( \texth_\texta² ) \left( {{\text{h}}_{\text{a}}^2} \right) estimates for BW, WW, ADG, and KR according to suitable model were 0.12 ± 0.05, 0.08 ± 0.06, 0.10 ± 0.06, and 0.06 ± 0.05, respectively. Estimates of the proportion of maternal permanent environmental effect to phenotypic variance (c ²) were 0.17 ± 0.03, 0.07 ± 0.03, and 0.07 ± 0.03 for BW, WW, and ADG, respectively. Genetic correlations among traits were positive and ranged from 0.53 (BW-ADG) to 1.00 (WW-ADG, WW-KR, and ADG-KR). The maternal permanent environmental correlations between BW-WW, BW-ADG, and WW-ADG were 0.54, 0.48, and 0.99, respectively. Results indicated that maternal effects, especially maternal permanent environmental effects are an important source of variation in pre-weaning growth trait and ignoring those in the model redound incorrect genetic evaluation of kids.     

Effects of breed and harvest age on feed intake, growth, carcass traits, blood metabolites, and lipogenic gene expression in Boer and Kiko goats

The objectives of this experiment were to determine the effects of 2 different breeds (BR), Boer and Kiko, and 4 post-weaning harvest ages (HA; Days 0, 29, 56, and 85) on growth, carcass traits, blood metabolites, and lipogenic gene expression. Forty-eight goat (Capra hircus) kids (BW = 23.9 ± 1.50 kg; 3 to 4 mo) were used in a 2 × 4 factorial arrangement of treatments. Goats were stratified by BW within BR and randomly assigned to 4 HA. Kids were born between March 15 and April 7 to purebred does, and were represented by at least 3 purebred sires within each BR. They were fed a grain/hay (80:20) diet once per day. At designated HA, randomly pre-assigned goats (n = 6) from each BR were transported to the Meat Science Lab at Mississippi State University, Starkville, MS, and were harvested. There were no interactions (P > 0.10) between BR and HA. Boer tended (P = 0.08) to have greater initial BW, final BW (P = 0.05), and G/F ratio (P = 0.05). Although the 80:20 grain/hay diet was reinforced by adjusting DMI, both BR had similar total DMI, Boer kept that ratio, while Kiko consumed more (P = 0.001) hay (70:30, grain/hay) and had more (P = 0.001) DMI when expressed as g/kg BW. Boer tended to have greater transportation shrink (P = 0.07), HCW (P = 0.08), and cold carcass weights (CCW; P = 0.08), with greater (P = 0.001) carcass fat. No differences (P > 0.10) were observed in carcass shrink, dressing percentage, 12th rib fat thickness, and LM area between the 2 BR. When expressed as percentage empty BW, carcass bone was similar (P = 0.25), whereas muscle percentage (P = 0.02) was greater for Kiko and fat percentage was greater (P = 0.001) for Boer. Fat as a percentage of CCW remained relatively similar (P > 0.10) for both BR for the 2nd and 3rd HA. Differences were more evident (P = 0.01) at the 4th HA. Boer reached targeted harvest weight (29 kg) at the 3rd HA, while fat deposition continued (P = 0.01) during the 4th HA. Breed had no effect (P > 0.10) on meat color (L*, a*, b*) but HA affected (P = 0.001) all color values. Boer had similar 3-hydroxyl-3-methylglutaryl-CoA synthase mRNA abundance, but was greater (P < 0.03) in acetyl CoA carboxylase compared with Kiko. There was no difference (P = 0.52) in total serum fatty acids (FA, mg/mL) between the 2 BR. As animals aged, their total serum FA increased (P < 0.05) and changed to an undesirable profile. Kiko had a greater (P = 0.02) percentage of muscle and less (P = 0.001) fat in the carcass. We concluded that different BR might need different harvest endpoints and feed input according to consumer acceptability.     

Effects of different weaning programs on growth of Saanen kids

The aim of the study reported here was to compare the performances of kids reared according to three different weaning programs. In the first program (T1), the dams were not milked in the evening and the kids accompanied their dams from 17.00 hours until the next morning. In the second program (T2), the dams of the kids were milked at 17.00 hours and then the kids accompanied their dams until the next morning, being separated from their dams at 08.00 hours. In the third program (T3), the kids were subjected to the T1 program for the first 4 weeks of the study, and to the T2 program for the last 4 weeks of the study. The kids in all the groups were weaned at 8 weeks of age. The weaning programs had significant effects on average daily weight gains (ADG) of the kids during weeks 1–4 and weeks 1–8 of the study (P < 0.05). In the weeks 1–8 period, the kids on the T1 program had a higher ADG than those on the T2 program (P < 0.05). However, the kids on T1, T2 and T3 programs had similar ADG post‐weaning. The dry matter intake of the starter feed of the kids of the T3 program was higher than that of the kids of the T1 and T2 programs. The results of the present study indicated that the three weaning programs did not result in any significant effect on the growth of Saanen kids. Hence, the T3 program can be used if the starter feed intake is desirable.     

Estimation of additive, maternal and non-additive genetic effects of preweaning growth traits in a multibreed beef cattle project

Data from purebred and crossbred calves, consisting of Afrikaner (AF), Charolais (CH), Simmental (ST) and Hereford and Aberdeen Angus combined (HA), were analyzed to estimate breed additive effects, breed maternal effects, average individual heterosis and average maternal heterosis. The traits studied were birthweight (BW), weaning weight (WW) and preweaning average daily gain (ADG) (kg). A multiple regression procedure was used for the estimation of these genetic effects and for predictions for breed crosses that were not included in the data set. Crosses containing higher proportions of CH or ST were heavier at birth and weaning than the other crosses and purebreds. The direct effects of BW were negative and significant (P < 0.05), except that of the CH, which was the highest. The regression coefficients were ?24.87, ?18.16, ?22.80 and ?27.02 for AF, CH, ST and HA, respectively. The maternal effects were not significant. Both average individual and average maternal heterosis regression coefficients were also not significant for BW. Regression coefficients of both direct and maternal effects for WW were not significant and were characterized by large standard errors. Average individual heterosis and average maternal heterosis regression coefficients were, however, significant (P < 0.01) and the values were 5.34 and 2.19, respectively. A similar pattern was observed for ADG, except for the regression coefficients of the maternal effects, which were significant, with larger estimates for AF and ST reflecting their superior mothering ability. The values were 0.01, 0.13, 0.13, 0.03; ?0.82, ?0.85, ?0.85, ?0.81; 0.03 and 0.01 for direct effects and maternal effects of AF, CH, ST and HA; and average individual heterosis and average maternal heterosis, respectively. Means and standard errors of purebreds and their F₁ crosses not included in the dataset were predicted.     

Genetic and phenotypic parameter estimates for growth traits in Boer goat

An understanding of influencing factors and genetic principles affecting the growth traits is needed to implement optimal breeding and selection programs. In this study, heritabilities (direct additive and maternal) of body weights at birth (BW0), 90 days (BW90) and 300 days (BW300) of age and average daily gains from birth to 90 days (ADG0-90), birth to 300 days (ADG0-300) and 90 days to 300 days (ADG90–300) of age in Boer goats were estimated on the basis of 1520 Boer goats at Boer Goat Breeding Station in Yidu, China, during 2002–2007. The parameters were estimated using a DFREML procedure by excluding or including maternal genetic or permanent maternal environmental effects, four analysis models were fitted in order to optimize the model for each trait. Influencing factors such as parity, litter size, kidding year and season, as well as sex of kids and some significant interactions among these factors were investigated as the fixed effects for the models. The results showed that the birth year and maternal genetic effects such as parity and litter size of dam were important determinants of the genetic parameter estimates for pre-weaning growth traits, and environmental effects such as birth year, season and sex of kids had some significant effect on post-weaning growth traits. The mean values and standard errors (SE) of direct additive heritability estimates calculated with the optimum model were 0.17 ± 0.07, 0.22 ± 0.08, 0.07 ± 0.07, 0.10 ± 0.08, 0.30 ± 0.12 and 0.08 ± 0.10 for BW0, BW90, ADG0-90, BW300, ADG0-300 and ADG90–300, respectively. For pre-weaning weights, correlation estimates between direct additive and maternal genetic (r_a–m) effect were high and negative ranging from − 0.74 to − 0.86.     

Characterization of breeds of Bos indicus and Bos taurus cattle for maternal and individual traits

Angus, Boran and Red Poll sires were mated to Ankole, Boran and small East African Zebu (Zebu) females to produce the cows characterized in this study, which produced calves by Friesian, Brown Swiss, Simmental, Boran and Red Poll sires. Individual traits included cow parturition weight, cow weight at weaning, cow mean weight and cow weight change from parturition to weaning; maternal traits included calf crop born percentage, preweaning viability percentage, overall viability percentage, birth weight, weaning weight, weight at 12, 18 and 24 mo and calf weight weaned per cow exposed to breeding (productivity index). Cows by Angus and Red Poll sires significantly exceeded cows by Boran sires (all cows in this comparison had Ankole and Zebu dams) in weaning weight of progeny and in cow weight at parturition and at weaning. Cows by Red Poll sires significantly exceeded cows by Boran sires in birth weight of progeny. Progeny of cows by Boran sires significantly exceeded progeny of cows by Angus and Red Poll sires in 24-mo weight. Cows by Angus and Red Poll sires did not differ (P greater than .05) in any of the traits analyzed. Cows with Ankole and Boran dams significantly exceeded cows with Zebu dams (all cows in this comparison had Angus and Red Poll sires) in progeny weight at birth, 18 mo and 24 mo and in cow weight at parturition and at weaning. Cows with Boran dams significantly exceeded cows with Zebu dams in weaning and 12-mo weight of progeny and significantly exceeded cows with Ankole dams in weaning weight of progeny. The significantly heavier weaning weight and significantly lighter 24-mo weight of the 3/4 Bos taurus progeny of cows with Angus and Red Poll sires relative to the 1/2 Bos taurus progeny of cows with Boran sires suggest that cattle that are 1/2 Bos taurus breed composition have greater general adaptation than cattle with 3/4 Bos taurus breed composition in the postweaning nutritive and climatic environment under which this experiment was conducted. Significantly heavier weights of Angus and Red Poll crossbred cows relative to Boran crossbred cows (all breeds crossed on Ankole and Zebu cows) indicate that the two Bos taurus breeds exceed the Boran (Bos indicus) breed in additive direct genetic effects for size when they have general adaptation to the environment.     

Cow-calf and feedlot performances of Brahman-derivative breeds

A study was conducted to compare Brangus, Beefmaster, Gelbray, and Simbrah breed influences for economically important traits. Brangus (9), Beefmaster (12), Gelbray (10), and Simbrah (7) sires were used in purebred and crossbred (Brahman x Hereford F1 cows) matings to generate calves (326) in eight breed groups. Beefmaster cows were of similar size (448 kg), Brangus and Gelbray cows were 11% heavier (501 and 503 kg), and Simbrah cows were 21% heavier (548 kg) compared to Brahman x Hereford F1 cows (452 kg). Calves sired by Brangus and Beefmaster bulls had lower birth weights (35 vs 38 kg; P < 0.05), preweaning growth rates (0.87 vs 0.91 kg x d(-1); P < 0.01), and weaning weights (206 vs 219 kg; P < 0.01) than Gelbray- and Simbrah-sired calves. Birth weights, preweaning ADG, and weaning weight and hip heights were similar between Brangus- and Beefmaster-sired calves. Simbrah-sired calves had greater preweaning growth rates (0.94 vs 0.88 kg x d(-1); P < 0.05), weaning weights (227 vs 211 kg; P < 0.01), and adjusted 205-d hip heights (126 vs 122 cm; P < 0.05) than Gelbray-sired calves. Straightbred Angus steers were introduced in the postweaning portion of the study. Steer calves were placed on feed at an average age of 14.5 mo. Steers were removed from the feedlot upon attaining a targeted 10 mm of backfat. Feedlot ADG did not differ among sire breeds. Brahman-derivative sired steers required an additional 54 d on feed (P < 0.01) and were 86 kg heavier (P < 0.01) at harvest than Angus steers. Continental-Brahman steers spent an additional 25 d on feed (P < 0.05) and were 35 kg heavier (P < 0.01) at harvest than British-Brahman steers. Simbrah-sired steers were 52 kg heavier (P < 0.01) at harvest than Gelbray-sired steers when fed for a similar number of days (211 vs 203 d). However, straightbred Simbrah steers required an additional 12 d on feed (P < 0.01) and weighed 47 kg more (P < 0.01) than Simbrah-sired crossbred steers. The economic value of the heavier calf weaning weights may be offset by the attendant larger cow size of the Continental-Brahman compared to the British-Brahman breeds. Similarly, the heavier weights of Continental-Brahman compared to British-Brahman steers, when harvested at a prescribed level of fatness may be viewed as a benefit, but the increased number of requisite days in the feedlot is a disadvantage.