Brahman Steers Research Articles

Effect of short-term grain feeding on bovine body-fat colour: a cautionary note

Seventeen Brahman steers were removed from pasture and fed a high grain diet for 8 weeks prior to slaughter. Carotenoid concentrations were determined in samples of serum and subcutaneous fat obtained either from live animals or at slaughter. At slaughter carcass fat colour was assessed according to AUS-MEAT specification. The concentrations of G-carotene in the serum of these animals fell rapidly (over 60%, P lt; 0.001) in the first 2 weeks on the grain diet and then plateaued. There was no change in either the concentrations of carotenoids in subcutaneous fat or in fat colour of these cattle during the whole period of grain feeding. The overall average liveweight gain was 0.59 kg/day. Failure to observe changes in concentrations of carotenoids was unexpected, and may be partly due to the fact that these cattle did not settle to the trial conditions in the feedlot, as indicated by the significantly higher cortisol concentration in their serum compared with the initial slaughter group. The implications of the outcome of this study are discussed.

Triacyglycerol biosynthesis in bovine liver and subcutaneous adipose tissue

1. 1. Adipose tissue from Angus and Brahman steers incubated with [1- 14C]palmitate in the absence and presence of glucose exhibited a greater rate of lipid production than liver ( P < 0.05 ). 2. 2. Homogenates of adipose tissue used in the glycerol-3-phospate acyltransferase assay exhibited a greater glycerolipid specific activity (nmol lipid/mg protein/30 min) when compare to liver ( P < 0.05 ). 3. 3. The inverse was true for liver homogenates when calculated for tissue activity (nmol lipid/g tissue/30 min). 4. 4. Lysophosphatidate was produced in greater ( P < 0.05 ) amounts than all other glycerolipids in the glycerol-3-phosphate acyltransferase assay. 5. 5. The activity of phosphatidate phosphohydrolase in liver homogenates displayed greater rates than their respective adipose tissue homogenates. 6. 6. Diacylglycerol acyltransferase activity was greater in adipose tissue homogenates compared to liver homogenates.

Feedlot performance of Brahman × Angus versus Angus steers during cold weather

Ten Angus and 10 Brahman x Angus F1 steers were used in a 184-d trial to compare feedlot performance during cold weather (-9 to 26 degrees C). Both groups of steers were exposed to the same environment for the same amount of time. All steers were fed for the same number of days regardless of frame score to avoid frame score x environment interactions. Brahman x Angus steers were 30.7 kg heavier (P less than .05) than Angus steers at the start of the trial. Differences in age (Brahman x Angus 40 d younger) for the two breed groups did not affect final live weight or carcass weight. Brahman x Angus steers consumed .2% less feed (P less than .05) as a percentage of BW than Angus steers; however, there was no difference in overall feed efficiency. Angus steers had a higher yield grade, more fat at the 12th rib (P less than .05), and graded 90% Choice; only 10% of the Brahman x Angus were graded Choice. Brahman x Angus steers were taller at the hip (P less than .05) and longer from first rib to aitch bone (P less than .05) and from thoracic vertebrae (T12/T13) to point of hock (P less than .05). Hide thickness determined at the neck, belly, and rump was found to be similar (7.7 mm) between the two groups. Sample hair weight and diameter did not differ between groups. Fiber, fat, protein, and DM digestibility coefficients were similar between groups but Brahman x Angus feces had a higher DM content.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms associated with the variation in tenderness of meat from Brahman and Hereford cattle

To study possible mechanisms for differences in meat tenderness, 10 purebred Hereford and 10 American Grey Brahman steers were fed a typical feedlot diet and slaughtered when ultrasound measurements indicated that they had approximately 1 cm of fat thickness at the 12th rib. Longissimus muscle from Brahman cattle was less (P less than .05) tender after 7, 14, 21, 28 and 35 d postmortem than muscle from Hereford cattle, but muscle from Hereford cattle showed greater improvement in tenderness from 7 to 14 d postmortem than muscle from Brahman cattle (interaction P less than .05). Cathepsin B or cathepsin B+L activities and the myofibrillar response to elevated ionic strength were not different between breeds, but both could be related to the postmortem increase in tenderness of both breeds. Calcium-dependent protease activity, as modulated by calcium-dependent protease inhibitor, seems to play a major role in the inherent tenderness differences between breeds.

Whole-body and tissue protein synthesis in steers losing weight on a low-protein roughage diet: the effect of trenbolone acetate

SUMMARYSix Brahman (Bos indicus) steers implanted with 300 mg trenbolone acetate and six similar nonimplanted steers were fed a low-quality, low-protein roughage diet at 10 g dry matter/kg live weight. They were housed in individual pens for 27 days in 1987 before being placed in metabolism crates for measurement of digestibility, nitrogen retention, and the rate of protein synthesis in the whole body and fractional rate in three muscles and hide.The rate of weight loss of steers treated with trenbolone acetate was significantly (P &lt; 0·05) less than that of controls (–0·34 v. –0·56 kg/day). Treated steers excreted significantly (P &lt; 0·05) less 3-methylhistidine (128 v. 202 μmol) and urea N (0·5 v. 1·6 g/day) in urine. There was a more favourable nitrogen retention in animals implanted with trenbolone acetate (–10 v. –12g/day) but this difference was not significant.Whole-body protein synthesis, calculated from plasma leucine flux, was 511 and 508 g/day in treated and control steers, respectively. Treatment also had no significant effect on the fractional rate of protein synthesis, in skeletal muscle or in hide. The fractional rate of synthesis in muscle was &lt; 1%/day and in hide &lt; 2%/day. These results are discussed in relation to the protein and energy metabolism of undernourished cattle.

Metabolic effects of safflower oil given as a supplement for steers fed roughage diets at restricted intake

Supplements of safflower oil (300 mL/day) were given to groups of steers fed 4 different diets. Hereford steers were fed 6 kg/day lucerne hay (LH) or LH + 33 mg/kg monensin (LHM). Brahman steers were fed 4 kg/day low quality hay (DA) or DA + 1 kg sucrose + 60 g urea + 2.7 g sulfur (DAS). Metabolic measurements were made when the animals were fed an equal portion of the daily ration at hourly intervals. On all diets, safflower oil had no affect on rumen temperature, pH or the concentrations of volatile fatty acids in ruminal fluid. Safflower oil increased concentrations (mg/L) of microbial lipid in ruminal fluid (LH, 160.4 v. 317.1; LHM, 266 v. 541.7; DA, 194.6 v. 321.8; DAS, 172.8 v. 440.5) and increased plasma concentrations (�g/mL) of non-esterified fatty acids (LH, 117.2 v. 180.1; LHM, 101.1 v. 189.5; DA, 218.2 v 325.4; DAS, 197.4 v 311.4), especially 18:1 trans- 11 and polyunsaturated acids. In steers fed DA and DAS, safflower oil reduced protozoal numbers and increased the bacterial mass in ruminal fluid, and increased water intake and the daily amounts of urinary allantoin excreted. The addition of safflower oil to all diets depressed plasma urea concentrations (mg/L) (LH, 233 v. 203; LHM, 236 v. 191; DA, 74.6 v. 47.6; DAS, 96.6 v. 54). The excretion of daily amounts (mg/kg liveweight) of urinary urea increased in animals fed DA (3.5 v. 10.0) and DAS (6.2 v. 13.6) but decreased in those fed LH (208.8 v. 187.9) and LHM (188.8 v. 158.1). Safflower oil supplementation conserved body protein, accelerated liveweight gains in animals fed LH and LHM diets and retarded liveweight loss in those fed DA and DAS diets.

The influence of breed and type of feed on the cholesterol content of the M. longissimus dorsi of steers

The cholesterol content of muscle from pasture-fed Hereford (n = 21) and Brahman (n = 12) steers, and from grain-fed Hereford (n = 20) steers was determined. No significant differences (P&gt;0.05) were detected in the cholesterol content of muscle between breeds or between types of feed. Small, non-significant correlation coefficients were detected between cholesterol content of muscle and carcass fat thickness, while the association between cholesterol content of muscle and intramuscular fat content was stronger but only significant (P&lt;0.05) for the Brahman group. Thus, breed, feed type and possibly carcass fatness were not variables that could be used to reduce the cholesterol content of muscle.

Influence of Phospholipid Content and Fatty Acid Composition of Individual Phospholipids in Muscle from Bison, Hereford and Brahman Steers on Flavor

ABSTRACTNeutral lipid (NL) and phospholipid (PL) fractions and their corresponding fatty acid profiles from the L. dorsi of Bison, Hereford, and Brahman steers of similar age finished on identical diets were determined. Compositional differences were related to sensory characteristics of the samples. Phosphatidylcholine + lysophosphatidylethanolamine (PC + LPE) existed in the highest concentration in all samples evaluated followed by lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE), sphingomyelin (SPH), fraction one and phosphatidylserine (PS). Bison contained more total PL, particularly PC + LPE and LPC, than the other two bovine species. Polyunsaturated fatty acid (PUFA) composition of these PL was greater for Bison. Off‐flavor and aftertaste increased with increasing levels of PC + LPE and LPC due to their greater composition of PUFA.

Cattle handling at abattoirs. 3. The effects of feeding, and of different feeds, during the resting period before slaughter on liveweight carcasses and muscle properties

The effects of feeding lucerne hay or rice straw during the resting period before slaughter on live, carcass and liver weights, bruising, the percentages of condemned head and tongues and of rumens with ingesta spillage, and muscle properties of cattle were examined. The 217 British breed and 70 Brahman steers (mean liveweights of 582 and 603 kg) had been grazing native pastures in northern Queensland. They were transported 440 km by road to an abattoir.The seven groups (each 41 steers) had access to water from unloading at the abattoir (late day 2) until slaughter. Three groups (N2, N4 and N6) were not fed, while two groups were fed ad libitum rice straw (RS4 and RS6) and another two groups were fed ad libitum lucerne hay (LH4 and LH6) from day 3 until 24 h before slaughter. The period from mustering to slaughter was 2 days for group N2,4 days for groups N4, RS4 and LH4, and 6 days for N6, RS6 and LH6.Unfed steers lost 4.7% of their pre-transport liveweight after 3 days and 9.1% after 5 days, while the fed steers lost 34% and 6.7%, respectively.Group N2 had a heavier (P&lt;O.05) mean carcass weight than groups N4, RS4, RS6 and LH6 (351 kg compared with 343-344 kg). Both N2 and LH4 (348 kg) were heavier (P&lt; 0.05) than group N6 (340 kg). Trends in mean dressing percentage were the same as for carcass weight. Group N2 had a heavier (P&lt; 0.05) mean liver weight than all other groups, with no effect of feeding treatment. Group N2 and the fed groups (except RS6) had a greater (P&lt; 0.05) mean water content for the M. longus colli than groups N4 and N6.Treatment had no significant effect on mean bruise score, fat thickness, mean pH value of M. longissirnus dorsi 24 h post mortem, the percentage of carcasses with high (&gt;6.00) pH values, and the percentages of heads and tongue condemned due to ingesta contamination and rumens contaminated with ingesta spillage.

A note on the effect of dry season feeding treatment on the subsequent growth at pasture during the wet season of Brahman steers

An experiment was carried out over successive years (1982 and 1983) to measure the extent to which live-weight advantage as a result of feeding in the dry season was maintained during the subsequent wet season at pasture. Two ages of Brahman steer (weaners and yearlings) were kept on three dry season treatments (molasses, sugar cane or grazing only) from January to May and then turned out to pasture as a single group until November. Although the molasses and sugar cane treatments produced significantly higher live-weight gains during the dry season the resultant weight advantage at turn-out was largely reduced during the wet season due to compensatory growth exhibited by previously restricted animals. Yearlings were less able to compensate than weaners.

Postweaning growth of brahman and santa gertrudis steers under feedlots in the subtropics

Postweaning growth of brahman and santa gertrudis steers under feedlots in the subtropics

Supplementation of steers grazing Stylosanthes hamata pastures at Katherine, Northern Territory

Native perennial grass pastures were oversown with Stylosanthes hamata cv. Verano at 3 fertility levels, i.e, without fertiliser or with suboptimal levels of superphosphate or rock phosphate. Brahman steers, of varying ages, grazed the pastures and their responses to fertility level and direct supplementation with phosphorus and sulfur were determined over 4 years. Phosphorus supplementation doubled liveweight gains during the early and late wet season periods to about 0.9 and 0-7 kg/day, respectively. Pasture fertility level did not affect gains in the early wet season in most years but superphosphate increased the late wet season gains by about 0.1 kg/day. Small weight losses usually occurred in all treatments during the early dry season, with losses increasing with animal age. Weight losses were highest during the late dry season, particularly for the older, phosphorus supplemented, steers. This response was attributed to size rather than to age or supplementation per se. Sulfur supplementation had no effect upon liveweight gain or upon the pastures at any time. In unfertilised pastures, Verano increased to about 25% of the dry matter composition whilst pastures fertilised with superphosphate and rock phosphate became legume dominant after 2 and 3 years, respectively. Fertiliser also increased the nitrogen, phosphorus and sulfur concentrations in the forage, particularly the Verano, with superphosphate more effective than rock phosphate. In pastures where steers were supplemented with phosphorus there was a higher proportion of the naturalised legume Alysicarpus vaginalis and a lesser quantity of forage on offer. Blood inorganic phosphate and rib cortical thickness were reliable indicators of responsiveness of steers to phosphorus supplementation when measured during, or immediately after, the period of active growth.

The effect of supplements of rumen-degradable protein and formaldehyde-treated casein on the intake of low-nitrogen roughages by Bos taurus and Bos indicus steers at different stages of maturity

The response in voluntary feed intake, firstly to supplements of rumen-degradable protein and then to additional supplements of formaldehyde-treated casein (FTC) was studied in Aberdeen Angus (Bos taurus) and Brahman (Bos indicus) steers fed long-chopped spear grass (Heteropogon contortus) and pangola grass (Digitaria decumbens). The intake responses were measured at four stages of maturity of the steers ranging from soon after weaning to near maturity. On diets deficient in nitrogen the magnitude of the intake response to rumen-degradable protein was greater in Angus than in Brahmans. With the exception of the Angus steers fed spear grass soon after weaning, there was no significant response to FTC with either diet beyond that achieved with rumen-degradable protein. From published values of the digestible protein supplied by the diets and the protein requirements of cattle for maintenance, it was calculated that pangola grass, prior to supplementation with FTC, supplied sufficient digestible protein for maintenance. On the other hand, that supplied by spear grass, prior to supplementation with FTC, was substantially below that required for maintenance. These experimental and calculated data are discussed in terms of factors limiting feed intake, and conclusions drawn about protein requirements for the expression of maximum feed intake of roughage diets.

The effects of genotype, age, pregnancy, lactation and rumen characteristics on voluntary intake of roughage diets by cattle

The effects of genotype, age and liveweight, pregnancy and lactation on the voluntary feed intake by cattle of roughage diets of different qualities were studied in a number of experiments. The diets ranged from poor quality (low-nitrogen, high-fibre) spear grass (Heteropogon contortus) hay on which intakes were low ( 1 1 g DM/kg liveweight (LW)) to good quality lucerne (Medicago sativa) hay (26 g DM/kg LW). On the poorest-quality diet, differences in intake between Bos taurus and Bos indicus were not significant. However, on the higher quality diets Herefords (Bos taurus) ate significantly (P &lt; 0.05) more than Brahmans (Bos indicus). In addition, as the quality of the diet improved from speargrass through to lucerne, the breed difference in favour of the Herefords became progressively greater and the variability between animals progressively smaller as a proportion of intake. Another study showed that with increasing age and liveweight of steers, intake per unit body weight declined, the rate of decline being significantly (P &lt; 0.05) greater on good-quality lucerne compared to a poor-quality speargrass diet. There was no significant difference between Aberdeen Angus (Bos taurus) and Brahman steers in the rate of decline of intake of each diet with increasing age and liveweight of the steers. Another experiment which measured intake of pregnant and lactating heifers showed that the amount of feed eaten by pregnant heifers increased with increasing liveweight in late pregnancy, with intake per unit liveweight remaining constant. Lactating cows ate 35% more on a liveweight basis than their nonpregnant, non-lactating counterparts. These results are discussed in relation to mechanisms which control intake of roughage diets in ruminants, especially those associated with energy metabolism.

Digestion of mature pangola grass (Digitaria decumbens) by Bos taurus and Bos indicus cattle

The digestion of mature pangola grass (Digitaria decurnbens) by Hereford (Bos taurus) and Brahman (Bos indicus) steers was studied. There was no significant difference between breeds in the digestion of organic matter (OM) and cell wall constituents (CWC). The OM digestibility in the whole tract was 0.59 with 90% of the digestion occurring in the stomachs. There was a significantly (P &lt; 0.05) greater nonammonia nitrogen flow through the abomasum in Herefords (66 g/day) than Brahmans (59 g/day). Likewise the ratio of crude protein digested in the intestines to digestible OM (DCPi:DOMI) was higher (P &lt; 0.05) in Herefords (0.120) than in Brahmans (0.102). In both breeds 66% of the nitrogen associated with the CWC was digested in the whole tract, essentially all digestion occurring in the stomachs. These results for pangola grass, especially the DCPi:DOMI ratios, are compared with the digestion characteristics of other tropical grasses and are discussed in terms of the capacity of tropical grasses to meet the protein requirements of growing cattle.

Liveweight gains and carcass traits of high grade Simmental, Hereford, Africander x Hereford and Brahman x Hereford feedlot yearling steers

Sixty-three high grade Simmental (S), 40 Hereford (H), 96 Africander x Hereford (AH) and 33 Brahman x Hereford (BH) steers were fed high concentrate feedlot rations from about 8 months of age to slaughter at about 12 months to compare their suitability for producing feedlot beef. Selection for slaughter was made when estimated fat cover and liveweight were closest to market requirements (6-10 mm rib fat and 320-360 kg, respectively). The steers were slaughtered in 3 groups and their carcasses electrically stimulated. Mean slaughter liveweights and carcass weights were 398 and 212, 350 and 182, 349 and 189, 335 and 181 kg for S, H, AH and BH, respectively. Daily liveweight gains during the 4 months on feedlot rations were 1.53, 1.37, 1.24 and 1.25 kg/steer, respectively. Fat depths at rib 12-1 3 and sacral crest sites for S, H, AH and BH were 6.2 and 8.1, 7.3 and 10.3, 8.0 and 10.4,7.3 and 10.0 mm, respectively. In the same order, yield of saleable meat was 77.4, 75.7, 76.3 and 77.2%, and the S and BH had less fat trim than H and AH. Warner-Bratzler peak force shear values (kg) and cooking loss (%) were 3.4 and 33, 3.6 and 34, 3.9 and 34, 5.0 and 35 for S, H, AH and BH, respectively. There were no commercially important differences between H, AH and BH in terms of fat cover at preferred carcass weights and tenderness. However, feedlot liveweight gain favoured the H. Although S steers had highest liveweight gains, many steers did not have sufficient fat cover until liveweights were above the preferred range.

The accretion and distribution of carcass tissues in steers during growth between 9 and 15 months of age

Carcass muscle, fat and bone weights, and distribution in 12 Brahman x Hereford steers between 9 and 15 months of age were obtained by carcass side dissection. The tissue proportions of liveweight and carcass weight at mean age 13 months, and the regression estimates of tissue accretion and distribution were compared. The carcass muscle and bone components of liveweight gain decreased by 18 and 24% respectively, and carcass fat increased by 64% when all tissues were compared to composition at 13 months of age. The tissue components relative to carcass weight gain followed the same pattern. The decrease in muscle and bone growth relative to liveweight gain was greater in the hindquarters. Whereas hindquarter muscle, fat and bone were 530, 570 and 450 g/kg respectively of carcass muscle, fat and bone at the mean age of slaughter, they were 500, 570 and 420 g/kg of the respective carcass tissue accretions between 9 and 15 months. The disproportionate decrease in muscle accretion between the carcass quarters was largely a result of differences in growth among the 26 heaviest carcass muscles.

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.

Carcass characteristics and composition of Brahman, angus and Brahman x Angus steers fed for different times-on-feed

Twenty-five steers of each of three breedtypes (Angus, Brahman and F 1 Brahman x Angus) were sorted by frame size and muscle thickness, assigned to groups (five steers of each breedtype) to be fed for 0, 56, 112, 168 or 224 days, slaughtered and compared for various carcass traits. Steers of each breedtype had similar dressing percentages. Carcasses from all three breedtypes merited similar USDA quality and yield grades; breedtypes differences in quality grade were slight. Differences were found in the fat deposition patterns exhibited by the three breedtypes. Brahman steers tended to deposit more of their total fat as subcutaneous fat early in the feeding period. Angus steers had more ( P < 0·05) seam fat as a percentage of carcass weight at all five feeding periods and more ( P < 0·05) kidney, pelvic and heart fat at two of the five feeding periods than Brahman steers. Brahman steers had a higher percentage of their separable lean in the muscles of the round than did steers of the other breedtypes.

Physical, chemical, histological and palatability characteristics of muscles from three breed-types of cattle at different times-on-feed

Forty-five steers (9–12 months of age) of Angus (n =15), Brahman (n = 15) and Brahman × Angus (n = 15) breed-types were fed a high-energy diet and then slaughtered after 0, 112 or 224 days of feeding. At 7 days post mortem, the M. longissimus and M. biceps femoris were removed from the left side of each carcass and steaks were obtained for determination of sensory panel ratings, Warner-Bratzler shear force, sarcomere length, collagen content and collagen solubility. Tenderness ratings of steaks from the M. longissimus and M. biceps femoris from Angus were generally higher than ratings for steaks from Brahman or Brahman × Angus steers. Steaks from Brahman × Angus received higher tenderness ratings than steaks from Brahman steers in only a few comparisons. The three breed-types of cattle responded to time-on-feed differently; Brahman cattle needed to have been fed longer than Angus cattle to produce equally tender beef. With increased time-on-feed, M. longissimus tenderness increased for all breed-types, but M. biceps femoris tenderness was not related to time-on-feed. Few significant differences were observed among breed-types and among time-on-feed periods for collagen content or collagen solubility. Tenderness differences were closely correlated with the contractile state of the muscle which, in turn, was associated with weight, subcutaneous fat thickness and temperature decline of the carcass.