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PubMed1990

Evaluation of attributes that affect longissimus muscle tenderness in Bos taurus and Bos indicus cattle.

Biological tenderness differences between longissimus muscles (LM) from Bos indicus and Bos taurus breeds were evaluated. Steers and heifers of Hereford x Angus (H x A, n = 10), 3/8 Sahiwal x H, A or H x A (3/8 SAH, n = 6) and 5/8 Sahiwal x H, A or H x A (5/8 SAH, n = 11) crosses were utilized. Muscle temperature and pH were monitored every 3 h for the first 12 h and at 24 h. Samples were obtained within 1 h and at 24 h postmortem from the LM for determination of calcium-dependent protease (CDP) -I and -II and CDP inhibitor (INH) activities. At 1 and 14 d postmortem, LM samples were removed for determining cathepsin B and B + L activity, soluble and total collagen, sarcomere length, muscle-fiber histochemistry, shear force and sensory-panel traits. Data were analyzed using least squares procedures with fixed effects of breed cross, sex and their interaction. No significant breed cross effects were observed for carcass traits or rates of pH and temperature decline. Steaks from H x A had lower (P less than .05) shear-force values and higher (P less than .05) sensory scores for tenderness at 1 and 14 d postmortem than steaks from 3/8 and 5/8 SAH. Correspondingly, 5/8 SAH had lower (P less than .05) myofibril fragmentation indices than H x A at 1, 3, 7 and 14 d postmortem. Breed cross effects were not significant for sarcomere length, fiber types, soluble and total collagen, cathepsin B and B + L specific activity, CDP-I and -II activity and INH activity within 1 h postmortem. However, INH total activity/100 g of muscle was greater (P less than .01) at 24 h postmortem for 5/8 SAH (208.8 +/- 14.8) and 3/8 SAH (195.6 +/- 19.3) than for H x A (136.3 +/- 14.9). For H x A, SDS-PAGE revealed that by d 1 desmin had been subjected to proteolysis, and by d 14 desmin could not be detected, but a 30,000-dalton component was clearly evident. However, in 5/8 SAH, desmin remained visible at d 14 without a 30,000-dalton component appearing. This reduced protein hydrolysis may account for less tender meat in SAH; INH apparently influences this process.

Animals↗
PubMed1995

Influence of calf genotype on colostral immunoglobulins in Bos taurus and Bos indicus cows and serum immunoglobulins in their calves.

Purebred Bos indicus calves are documented to have lower survival rates than Bos taurus calves. Thus, this study was designed to investigate the possibility that this decreased survival rate may be attributed to dam colostral immunoglobulin (Ig) concentrations and subsequent calf serum Ig concentrations. The specific objective was to determine the effect of breed type of calf on colostrum production, immunoglobulin concentrations in colostrum and calf serum, and availability and absorption efficiency of Ig. Brahman (B) and Angus (A) cattle were reciprocally mated to produce calves of the following types: A x A (n = 8), A x B (n = 9), B x B (n = 11), and B x A (n = 11). At birth, calves were separated from their dams and a blood sample was collected before feeding pooled colostrum (30 mL/kg birth weight) at 1 and 6 h of age. From 6 to 12 h of age, each calf was placed in a box that allowed interaction with the dam but prevented suckling. At 12 h of age, each calf was fed its dam's colostrum and placed with the dam. Additional blood samples were collected at 12, 24, and 48 h after birth. Serum and colostrum samples were analyzed for IgG, IgG1, IgG2, IgM, and IgA using single radial immunodiffusion (RID) assay techniques. The cows were hand-milked after induction of milk letdown with oxytocin at 1 and 12 h after calving. Colostrum volume was recorded, and samples were collected. Brahman cows produced more (P < .001) colostrum at 1 and 12 h than A cows. Total Ig concentrations were obtained by summing IgG, IgG1, IgG2, IgM, and IgA concentrations. Total Ig (P < .02), IgG (P < .005), and IgA (P < .01) concentrations in colostrum were greater in cows producing crossbred calves. Total Ig (P < .006), IgG (P < .02), IgG1 (P < .004), and IgG2 (P < .02) available in colostrum were affected by B x B and A x B breed types of calf. Brahman cows had more Ig available at 1 and 12 h than A cows due to increased production of colostrum. Breed type influenced colostral Ig in cattle. Serum concentrations of total Ig, IgG, IgG1, IgG2, IgM, and IgA in the calf and efficiency of absorption at 6 and 12 h were not affected by breed type, sex of calf, or any interaction.

Animals↗
PubMed1996

Sequence comparison of mitochondrial tRNA genes and origin of light strand replication in Bos taurus and Nellore (Bos indicus) breeds.

Although the complete bovine mitochondrial DNA molecule has been previously sequenced and sequence comparisons of the mitochondrial displacement loop have been performed, detailed sequence information is limited on coding regions of mitochondrial DNA within and among breeds of Bos taurus and Bos indicus. This study analysed polymorphism of the mitochondrial DNA transfer RNA genes for tryptophan, alanine, asparagine, cysteine, tyrosine and the origin of light strand replication among Ayrshire, Canadian, Belgium Blue, Brown Swiss, Hereford, Jersey, Limousine, Piedmontaise, Red Angus, Simmental (Bos taurus) and a Nellore (Bos indicus). Nucleotide sequence analysis of a 420-bp fragment of mitochondrial DNA comprising the five transfer RNA genes showed 100% homology among single individuals of the Bos taurus breeds. The Nellore breed showed guanine to adenine substitutions in the DHU arm of asparagine tRNA and in the origin of light-strand replication. This equates to a 0.5% sequence difference between the Nellore and Bos taurus breeds and may reflect an independent evolutionary origin of the species.

Animals↗
PubMed1997

Genetic effects on beef tenderness in Bos indicus composite and Bos taurus cattle.

Bos indicus composite and Bos taurus cattle, originating from diverse production environments, were used to quantify genetic variation in marbling, 24-h calpastatin activity, and beef tenderness and to identify strategies for prevention of beef tenderness problems in Bos indicus composite cattle. Comparisons among 3/8 Bos indicus breeds (Braford, Red Brangus, Simbrah) revealed significant differences in marbling and 24-h calpastatin activity, but not in tenderness. Compared with Bos taurus cattle, 3/ 8 Bos indicus cattle had similar marbling scores but higher 24-h calpastatin activities. Also, beef from 3/8 Bos indicus composites aged more slowly from 1 to 7 d and was less tender at 4, 7, 14, 21, and 35 d postmortem than beef from Bos taurus cattle. However, beef from 3/8 Bos indicus cattle was relatively tender if it was aged for a sufficient period of time (21 d). The delayed response to aging and greater toughness of beef from 3/8 Bos indicus cattle was associated with Brahman breed effects and was not related to the Bos taurus germplasm source. Marbling was moderately heritable (.52 +/- .21) but exhibited positive genetic correlations with shear force at d 1 through 14 of aging, suggesting that, in these cattle, selection for increased marbling would have an unfavorable effect on beef tenderness. A low heritability estimate for 24-h calpastatin activity (.15 +/- .15), coupled with low genetic correlations between calpastatin activity and shear force at 7, 14, and 35 d, suggested that selection for low calpastatin activity would have little effect on aged beef tenderness. Panel tenderness and shear force at 7, 14, and 21 d were moderately heritable (.27 to .47), indicating that aged beef tenderness could be improved by direct selection (via progeny testing). Comparisons among Simbrah, Senegus x Simbrah, and Red Angus x Simmental steers showed that inclusion of a tropically adapted Bos taurus breed (Senepol) could be an effective strategy for preventing beef tenderness problems in heat-tolerant cattle.

Animals↗
PubMed1983

Fertility on synchronized estrus in crossbred (Bos taurus x Bos indicus) heifers.

This study was performed in Western Maharastra (India). The 272 crossbred heifers were randomly allocated within herds to one of the four following groups: 1) silastic coils, 10 days treatment (n = 65); 2) Norgestomet implants, 10 days treatment (n = 71); 3) prostaglandin F(2alpha) two injections 11 days apart (n = 70); and 4) control (n = 66). Almost all heifers in the treated groups were detected in heat during the four days following treatment (88-100%) vs 26% in the control group in the first 21 days. Mean conception rates at first AIs were respectively 62,48 and 60% in groups 1,2 and 4 (p > 0.05) and only 29% in group 3. By 90 days after treatment, 66, 59, 46 and 33 per cent of the females were pregnant for groups 1 to 4, respectively (p < 0.001). In conclusion, progestogen treatments seemed to be highly satisfactory both in terms of conception rates and intervals from treatment to pregnancy.

Journal Article↗
PubMed1992

Effect of various cooling rates (from 30 degrees C to 5 degrees C) and thawing temperatures on the deep-freezing of Bos Taurus and Bos Bubalis semen.

A total of 36 semen ejaculates, six from each of three Holstein-Friesian bulls and three Murrah buffalo bulls, were frozen in tris citric acid-fructose-egg-yolk-glycerol diluent after 1 hour of equilibration to study the effect of various cooling rates (15, 30, 60 and 120 minutes from 10 degrees to 5 degrees C vs a control sample cooled for 120 minutes from 28 degrees to 5 degrees C) and thawing temperatures (40 degrees C 60 seconds , 60 degrees C 15 seconds and 80 degrees C 5 seconds ) on prefreeze and post-thaw sperm motility. Sperm motility differed significantly (P < 0.01) between various cooling rates in both the Holstein-Friesian bull semen and the Murrah buffalo semen at prefreezing, immediately post-thawing, and after 1 hour of post-thaw incubation at 38 degrees C. Post-thaw sperm motility and survival at 38 degrees C were significantly (P<0.01) higher in Holstein-Friesian bulls at 60 degrees C and 80 degrees C than at 40 degrees C (39.79+/-2.46% and 38.15+/-2.18% Vs 35.16+/-2.19%, and 20.22+/-2.14% and 19.05+/-2.05% vs 14.83+/-1.64%, respectively). In Murrah buffalo bulls the recovery percentage and survival rate increased significantly (P<0.01) with the increase in temperature from 40 degrees C to 80 degrees C (41.72+/-2.45%, 47.45+/-2.09% and 51.61+/-2.06%; and 9.22+/-1.47%, 11.79+/-1.63% and 12.27+/-1.53%, respectively). Prefreeze motility did not differ between cattle and buffalo bulls (64.97+/-1.08% Vs 67.11+/-0.89%, respectively) but post-thaw motility was significantly (P<0.01) higher in the buffalo (46.93+/- 1.39% Vs 37.70+/-1.32%). While incubation survival was higher in the cattle (18.04+/-1.16% Vs 10.96+/-0.89%). A fast cooling rate was found to be detrimental for cattle spermatozoa, whereas the post-thaw buffalo sperm motility deteriorated very quickly at 38 degrees C. The influence of species-by-cooling rate interaction was significant (P<0.01) for post-thaw motility and survival rate, but the species-by-thawing or cooling-by-thawing interactions were not significant. These results suggest that a cooling rate of 2 hour either at 10 degrees C or 28 degrees C is essential for cattle semen. However, buffalo semen can be frozen successfully after 30 minutes of cooling at 10 degrees C. A thawing temperature of 60 degrees C yielded a higher sperm motility rate than 40 degrees C. Thus, our findings can be applied under tropical conditions for the successful freezing-thawing of bovine semen provided conception rates are not affected adversely.

Journal Article↗
PubMed1995

Comparative effects of nematode infection on Bos taurus and Bos indicus crossbred calves grazing on Argentina's Western Pampas.

Breed differences in resistance or tolerance to naturally acquired gastrointestinal nematodes were compared between Aberdeen Angus (AA) and Santa Gertrudis (SG) weaned steer calves grazing in a temperate environment. Within breeds, one half of the calves was untreated: AAU (n = 17) and SGU (n = 18) while the other half was treated with moxidectin monthly: AAT (n = 14) and SGT (n = 14). All calves were grazed on the same contaminated pasture from autumn to winter, when each group was separated to uninfected paddocks for the remaining period of the study. Faecal egg counts, plasma pepsinogen levels (PPL), herbage larval counts and liveweight (LW) were recorded monthly. Egg counts and PPL of AAU and SGU increased from autumn to early winter when calves showed heavy parasitism (mainly Trichostrongylus axei) and severely sick calves needed emergency treatment. On the clean paddocks, parasitological parameters progressively decreased. Late winter egg counts were higher (P < 0.05) in SGU than in AAU. PPL of SGU were higher than AAU ones, but no significant differences were detected. Larval differential counts of SGU showed fewer Cooperia (P < 0.08) and higher T. axei (P < 0.002) proportions than those of AAU. Numbers of severely sick and dead SGU calves (61%) were greater (P < 0.01) than those numbers of AAU calves (17.5%). Cumulative LW gains differences within SG breed were higher (P < 0.0001) than those differences within AA breed (P < 0.003). LW gains of AAU during autumn-winter period were greater (P < 0.002) than those of SGU.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Cryopreservation of Bos taurus vs Bos indicus embryos: are they really different?

Cryopreservation with storage at very low temperatures is essential to make full use of this technology for both biological and commercial reasons. However, most mammalian cells will die if exposed to these temperatures unless they are exposed to cryoprotectant solutions and cooled and warmed at specific rates. Lowering temperature below 0 degree C introduces the risk of intracellular ice formation, which likely increases rapidly as the temperature falls. Evidence indicates that ice formation during cooling can cause significantly more damage than ice formation during warming. Comparisons of the toxicity of various cryoprotectants indicated that ethylene glycol (EG) is a nontoxic compound for murine and bovine embryos. The 3.6 M EG solution resulted in similar high survival rates when compared with nonfrozen embryos; deleterious effects of high concentrations of EG became apparent at 7.2 M. The use of EG provides a nontoxic method for the rapid and simplified controlled freezing of in vivo bovine compact morulae-early blastocyst, avoiding the risk of injury caused by high concentrations of cryoprotectants usually required for vitrification. However, in vivo embryos used for freezing and thawing require further studies to understand the ultrastructural changes during the freezing procedure with EG as the single cryoprotectant, especially between Holstein and Nelore cows. This paper describes the ultrastructure of bovine compact morulae-early blastocysts derived by in vivo methods from Holstein and Nelore cows to investigate the fresh morphology as well as that after exposure to cryoprotectant and cryopreservation by conventional slow freezing, quick freezing (nitrogen vapor), and vitrification.

Animals↗
PubMed2003

Use of primers derived from a new sequence of the bovine Y chromosome for sexing Bos taurus and Bos indicus embryos.

A bovine male-specific marker was identified in our laboratory through random amplified polymorphic DNA (RAPD) analysis. This fragment of 3216 bp was cloned, sequenced and mapped by fluorescent in situ hybridization (FISH) on the taurine Yq. Primers derived from this sequence were initially screened by polymerase chain reaction (PCR) for their ability to detect Y-specific segments in zebu and taurine genomic DNA. Two of these primers amplified a 655 bp Y-specific sequence present in taurine and zebu male genomic DNA. These primers were then used for detecting the 655 bp male sequence in DNA from 173 zebu and 30 taurine embryos, which had been previously sexed using primers for the sequence BC 1.2. The results revealed an accuracy of 100%.

Animals↗
PubMed1985

Utilization of low-quality roughage by Bos taurus and Bos indicus cattle. 1. Rumen digestion.

Six Hereford and six Brahman steers were fed ad lib. Pangola grass (Digitaria decumbens) and Spear grass (Heteropogon contortus) hay alone and supplemented with rumen-degradable nitrogen and sulphur and minerals. The rumen digestion of the two feeds was determined by reference to the disappearance of substrate from nylon bags suspended in the rumen and withdrawn after intervals ranging from 8 to 120 h. The digestion of the unsupplemented Pangola grass diet occurred more rapidly in Brahmans than in Herefords and was associated with higher rumen ammonia concentrations in Brahmans (40 v. 16 mg/l). The rumen NH3 concentrations were increased to over 100 mg/l by supplementation. The digestion rate increased in both breeds after supplementation and the breed difference disappeared. Increases in digestion rate were not achieved above NH3 concentrations of 60-80 mg/l. Spear grass, especially the cell-wall-constituent fraction, was more resistant to digestion than Pangola grass. Digestion of the unsupplemented Spear grass diet proceeded more rapidly in Brahmans than in Herefords. The digestion rate in Brahmans were similar irrespective of whether the diet was supplemented or not. Supplementation increased digestion rate in Herefords.

Ammonia↗
PubMed1997

Microsatellite DNA variation and the evolution, domestication and phylogeography of taurine and zebu cattle (Bos taurus and Bos indicus).

Genetic variation at 20 microsatellite loci was surveyed to determine the evolutionary relationships and molecular biogeography of 20 different cattle populations from Africa, Europe and Asia. Phylogenetic reconstruction and multivariate analysis highlighted a marked distinction between humpless (taurine) and humped (zebu) cattle, providing strong support for a separate origin for domesticated zebu cattle. A molecular clock calculation using bison (Bison sp.) as an outgroup gave an estimated divergence time between the two subspecies of 610,000-850,000 years. Substantial differences in the distribution of alleles at 10 of these loci were observed between zebu and taurine cattle. These markers subsequently proved very useful for investigations of gene flow and admixture in African populations. When these data were considered in conjunction with previous mitochondrial and Y chromosomal studies, a distinctive male-mediated pattern of zebu genetic introgression was revealed. The introgression of zebu-specific alleles in African cattle afforded a high resolution perspective on the hybrid nature of African cattle populations and also suggested that certain West African populations of valuable disease-tolerant taurine cattle are under threat of genetic absorption by migrating zebu herds.

Africa, Western↗
PubMed1992

Evaluation of reproductive traits in Bos taurus and Bos indicus crossbred heifers: relationship of age at puberty to length of the postpartum interval to estrus.

Records of age at puberty (AAP) and duration of the postpartum interval to estrus (PPI) for heifers calving first at 2 yr of age were used to determine the relationship between the two reproductive traits. The study from which these records were obtained was designed in a 2 x 2 x 2 factorial arrangement of treatments. Angus x Hereford (AH; n = 148) and Brahman x Hereford (BH; n = 148) heifers were allotted within breed after weaning by weight into light (LW) and heavy (HW) weight blocks. Heifers were assigned by age to different levels of energy (low or high) in diets calculated to reach a target weight of 55% (LE) or 65% (HE) of their projected mature weight by the onset of the breeding period. Data were analyzed within breed and included only records for which both AAP and PPI were available. Pearson correlation coefficients for AAP to PPI were r = -.12 (P = .20) and r = .05 (P = .71) for AH and BH, respectively. Eliminating animals that experienced dystocia from the analyses yielded correlations of r = -.27 (P = .02) and r = .06 (P = .65) for Ah (n = 69) and BH (n = 51), respectively. When energy level, weight block, and energy level x weight block were included in the model for PPI, analyses of variance indicated that PPI among AH heifers was influenced most by the weight at which heifers began the trial after weaning (P = .01) but not by energy level (P = .23) or the interaction of energy level x weight block (P = .48).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗