Double-muscled Bulls Research Articles

Different periods of feed restriction before compensatory growth in Belgian Blue bulls: I. animal performance, nitrogen balance, meat characteristics, and fat composition.

Thirty double-muscled Belgian Blue bulls were maintained at a rate of gain of .5 kg/d during four periods of time, 115 (G2), 239 (G3), or 411 (G4) d (low growth period, LGP), before fattening (rapid growth period, RGP). Ten control animals (CG) were fed a diet rich in energy and protein. The G2, G3, and G4 were fed a diet low in energy and protein and the same diet as CG during RGP. Live weight was recorded biweekly, feed intake (FI) daily, and nitrogen balance at three times for each group. At the slaughterhouse, the 7, 8, and 9th ribs were removed to determine carcass composition, meat quality, and meat and fat composition. Compensatory growth reached a maximum 2 mo after refeeding and then decreased rapidly, leading to a sharp increase in the feed conversion ratio. Nitrogen balance was higher in compensating groups ( P < .05). Compensating animals had higher carcass connective and adipose tissue contents (P < .05) but lower meat fat content (P < .05). Cattle exhibiting compensatory growth had higher redness, yellowness, cooking losses, and drip losses, but had lower Warner-Bratzler peak shear force values. The saturated fatty acid content of the fat decreased with the duration of the LGP. During the first 2 mo after refeeding, compensatory growth in double-muscled bulls was ascribed to one or more of the following mechanisms: higher FI, lower maintenance requirements, or better efficiency of lean meat production. Compensatory growth at the expense of higher FI increased peripheral fat but decreased intramuscular fat deposition.

Glucose, alpha-amino nitrogen, and amino acid exchange across the hindlimb in young double-muscled type bulls maintained at two growth rates

The effect of growth rate and protein supplementation on muscle metabolism of eight bulls from the Belgian Blue breed, double-muscled type, was investigated by the arterio-venous difference technique. A low growth (LG) group was maintained at a low growth rate over 36 d, and a rapid growth (RG) group for 28 d before receiving a fattening diet allowing for a rapid growth. At the end of the RG period the RG bulls received a supplement of protected soybean meal. Animals were fitted with an aortic ultrasonic blood flow probe and with catheters in the aorta and the vena cava. The blood flow in the hindlimbs of bulls varied greatly by time of the day but was higher in the RG group. The RG group had a higher arterio-venous difference (AVD) and uptake of alpha-amino nitrogen while AVD in essential amino acids was four times higher and uptake eight times higher. Significant higher AVD or uptake was observed in individual amino acids such as leucine, isoleucine and lysine. The supplementation with protected soybean meal had significant negative effect on the uptake of several amino acids. It was concluded that caution should be exercised when measuring punctually blood flow in muscle tissue, for example by dilution techniques. At high growth rate, the requirements for amino acids are larger than for glucose. Excess protein provides no additional benefit. Key words: Bull, hindlimb catheterism, growth rate, protected soy bean, metabolite

Effect of cimaterol on growth, carcass characteristics and meat quality in double-muscled Belgian White-blue bulls

Thirty-two double-muscled Belgian White-blue bulls, within a liveweight range of 542 (± 37) to 722 (± 31) kg, daily received 0 or 60 μg cimaterol kg−1 liveweight in a corn silage diet for 136 (± 29) d. Cimaterol slightly improved average daily gain from 1.28 to 1.38 kg (P &gt; 0.05). Cold carcass weight and dressing were increased by cimaterol from 497.0 to 514.6 kg (P &lt; 0.05) and from 71.0 to 72.9% (P &lt; 0.001), respectively. Even in extremely meaty animals, cimaterol exerted a significant repartitioning effect towards more meat and less fat, both in the carcass and in the longissimus thoracis muscle. Cimaterol increased the shear force value from 37.1 to 52.7 N (P &lt; 0.001) but had no effect on other organoleptical traits. Key words: Cimaterol, double-muscled bulls, growth, carcass, meat quality

Effects of double-muscling on carcass quality, beef tenderness and myofibrillar protein degradation in Belgian Blue White bulls

Carcass properties and meat quality characteristics of 32 Belgian Blue White double-muscled bulls (DM) were compared with those of 59 bulls of the same breed with normal conformation (N). DM showed superior carcass quality as revealed in increased dressing percentage, meat production yield, conformation grade, muscle/fat and muscle/bone ratios (all P < 0·001). Longissimus dorsi (LD) shear force values, drip and cooking losses at 8 days post mortem (pm) were significantly higher ( P < 0·001) for DM, whereas sarcomere lengths were not different. Calpain 1 and calpastatin levels at 1 h and 24 h pm were tremendously decreased in DM as were also cathepsin B and L levels at 1 and 8 days pm ( P < 0·001). As evident from semi-quantitative SDS-PAGE, these differences were accompanied by higher titin and lower 30 kDa levels ( P < 0·001) in DM. Troponin-t levels were not different, but very low. Intramuscular collagen content was significantly lower in DM ( P < 0·001). This suggests that lower background toughness in DM was compensated for by reduced post-mortem proteolytic tenderization. Discrepancy with literature reports regarding tenderness of DM might be related to the extreme muscularity of the Belgian Blue White breed, compared to other DM breeds. The results also suggest that reduced protein turnover might be involved in the muscle hypertrophy phenomenon within this breed, because of likely reduced levels of calpains and cathepsins in living DM animals.

Assessment of respiratory diseases and therapeutic intervention by the forced oscillation technique in feedlot cattle

The forced oscillation technique was used to study pulmonary function in bulls during naturally acquired pulmonary-gastrointestinal disease complex known as shipping fever and as it was treated with two different antibiotics. Fifteen double-muscled bulls of the Belgian White and Blue breed were investigated. Clinical, serological and pulmonary function values were recorded during and after naturally occurring respiratory disease. Total respiratory resistance (R rs) and reactance (X rs) were measured by the forced oscillation technique. The antibiotic ceftiofur (group A, n =10) and oxytetracycline (group B, n = 5) were given over three days. A large increase of R rs at low frequencies with a marked negative frequency dependence, an increase of the resonant frequency, and a decrease of X rs were recorded in the initial stage of the disease. The parameters returned to normal values seven days later. Clinical evidence of recovery was more marked in group A than in group B. These results show that moderate shipping fever induces acute small and large airway obstruction which responds to appropriate antibiotic therapy.

Effect of energy density by dietary incorporation of fats on the performance of double-muscled bulls

The effect of dietary energy concentration by the addition of 2.5 or 5% hydrolysed fat residue or 5% lard was studied in double-muscled bulls of the Belgian white-blue breed. Average daily gain was 1.31 kg and was not significantly affected by the addition of fat, while dressing percentage was significantly increased from 68.4 for the control group to 69.3 for fat-supplemented groups, without modification of the carcass composition. It was not clear if the positive effect on carcass quality was specific to the fat supplementation. The dietary incorporation of hydrolysed fat residue had no negative effects on animal performance in comparison with lard.

Effect of a β-agonist on meat quality and myofibrillar protein fragmentation in bulls

Three experiments were conducted to study the effect of cimaterol on meat quality and myofibrillar protein fragmentation of the Longissimus dorsi muscle. In two experiments (Experiments 1 and 2), conducted with 16 double-muscled Belgian white-blue bulls and 15 Charolais bulls, respectively, half of the animals received 60 μg cimaterol daily per kg liveweight in the diet, during 135 and 93 days, respectively. In a third experiment, 46 normal Belgian white-blue bulls received no or 4 ppm cimaterol in the diet for 246, 127 or 71 days on average. A withdrawal period of 6 days was always applied for cimaterol-treated animals. Ultimate pH, colour and waterholding capacity were not significantly affected. The effect of cimaterol on moisture content was variable, while protein content was increased and fat was reduced. Warner-Bratzler shear force values were increased by cimaterol P < 0·05 in Experiments 2 and 3 and P = 0·07 in Experiment 1). The lower tenderness cannot be explained by differences in sarcomere length or hydroxyproline content. Myofibrillar protein fragmentation was lower when cimaterol was fed, suggesting that cimaterol may reduce myofibrillar protein degradation via a lower activity of the proteolytic enzymes. Length of cimaterol administration only exerted minor effects on meat quality.

A note on the effect of feeding cimaterol on some endocrinological parameters and growth in different types of finishing beef bulls

Investigations were made of the effects of the fi-agonist cimaterol on the growth and hormone status of normal and double-muscled Belgian White-blue bulls. Results indicated that repartitioning effects of this agonist may in part be mediated indirectly through an alteration in the levels of metabolic hormones and that the growth promoting effect is transient.

Mating double-muscled and normal cattle for lean beef production

Data from 349 reciprocal matings of double-muscled (DM) and normal (N) cattle resulting in 287 calvings were used to study reproduction in cows, and growth rate and carcass characteristics of their progeny. The DM population was a composite of Angus, Charolais, Galloway and Hereford, while the N cattle was a crossbred group with at least 50% Hereford breeding. The incidence of dystocia and perinatal calf mortality was maximum in DM × DM, intermediate in N × DM and minimum in matings involving N cows ( P < 0.05). DM cows had a higher male to female ratio (2.1:1) than expected ( P < 0.05). The preweaning growth rates of male progeny from DM × DM was lower than those of the progeny resulting from the other mating types. The male progeny from N × DM and N × N had the maximum rate of growth in feedlot and maximum backfat thickness, while the progeny of DM × DM had the minimum values for the two traits ( P < 0.05); the DM × N progeny were intermediate. Rib eye areas in DM × N and N × DM progeny were larger than those from N × N matings ( P < 0.05). Based on rib joint dissection, bulls from the DM × N and N × DM had similar muscle to bone ratio and percent muscle but larger ( P < 0.05) values than bulls from N × N matings. The pattern for percent bone was opposite to that of percent muscle. Male progeny from DM × N were leaner than N × DM and N × N matings ( P < 0.05). Mating of DM bulls to N cows, therefore, appears to be an economically feasible strategy for improving lean meat production.

Resting behaviour of Belgian White-Blue and Friesian fattening bulls in a tie-stall barn

Standing and lying bouts of 11 fattening bulls were recorded continuously during two 1-week trials. There were 6 Friesian bulls and 5 double-muscled bulls from the Belgian White-Blue breed. At the start of Trial 1, the Friesian and Belgian White-Blue bulls averaged respectively. Trial 2 started 84 days later when the liveweight was about 100 kg more. The bulls were tied up in a stanchion barn. Standing up and lying down were recorded by an electrical device. The mean lying times per 24 h of the Friesian bulls were 16.52 h in Trial 1 and 16.13 h in Trial 2; the corresponding values for the Belgian White-Blue bulls were 15.77 and 16.82 h. Differences between breeds and between trials were not significant. The variability between the Belgian White-Blue bulls was larger than between the Friesians. The mean number of lying bouts per 24 h ranged from 12.31 to 16.97, the highest value being observed with the double-muscled animals in Trial 2. Resting behaviour was different between the day and the night. From 18.00 to 06.00 h, the lying time ranged from 9.75 to 10.89 h according to group; from 06.00 to 18.00 h, the corresponding values were 5.56 and 6.71 h. The repartition of lying bouts according to their length was not different between trials for the Friesian bulls. The proportions of lying bouts shorter than 15 min and longer than 1 h were on average 7.6 and 59.2%. For the Belgian White-Blue bulls, the repartition was different between trials: the proportions of lying bouts shorter than 15 min were 4.6 and 7.9% in Trials 1 and 2, respectively; those longer than 1 h were 60.6 and 43.6%. The proportions of lying times of long duration (>2 h) and standing times of short duration (<15 min) were higher for the Friesian than for the Belgian White-Blue bulls.

SEX DIFFERENCES IN CARCASS COMPOSITION AND TISSUE DISTRIBUTION IN MATURE DOUBLE MUSCLED CATTLE

Nineteen mature Double Muscled (DM) cattle consisting of 11 cows and eight bulls were slaughtered between 470 and 710 kg to determine the influence of sex on carcass composition and muscle, bone and fat in DM cattle. Expressed as a percentage of the total side weight, DM bull carcasses had 15% more muscle and 55% less total fat. When sides were compared DM bulls showed a 17% increase in the muscle:bone ratio compared with DM cows. In bull carcasses, there were shifts in muscle weight distribution towards the forequarter. The ratio of hindquarter muscle:forequarter muscle was greater in cows than in bulls. Expressed as a percentage of the total side muscle, significant differences between sexes were found in 48 of the 95 muscles. The most striking sexual dimorphism was found in the neck region, particularly among the muscles responsible for secondary sexual features and those which act to elevate and extend the head. Sexual dimorphism was less pronounced in the distal parts of the both limbs. The cervical vertebrae and scapula made up a greater proportion of total side bone in DM bulls than in DM cows. There was a consistent but nonsignificant trend for the cows to have more of their bone caudally and less anteriorly compared with the bulls. Key words: Carcass composition, muscle distribution, bone distribution, mature Double Muscled cattle, double muscling

GROWTH PATTERNS OF MUSCLE, FAT AND BONE, AND CARCASS COMPOSITION OF DOUBLE MUSCLED AND NORMAL CATTLE

Eighteen Double Muscled (DM), 18 Beef Synthetic (SY) and 18 Hereford (HE) bulls were serially slaughtered from approximately 250 to 800 kg liveweight to determine the influence of maturity type and "double muscling" on tissue growth patterns and compositional differences which were examined by using the allometric equation Y = aXb after transformation to common logarithms (log10). As liveweight (LW) increased, the proportions of total side fat (TSF) and subcutaneous fat (SCF) increased, the proportions of total side muscle (TSM) and intermuscular fat (IMF) remained relatively constant and the proportion of total side bone (TSB) decreased. Relative to LW, DM had a similar growth rate for TSM and lower growth rates for TSF, SCF and IMF than HE and SY. All breed types had similar growth rates for TSB on LW. Relative to dissected side weight (DSW) and TSB, the DM bulls had a higher growth rate for TSM than did the HE and S Y bulls. Differences existed between DM and the more normal genotypes in carcass composition. DM was characterized by a high muscle:liveweight ratio, a high proportion of muscle in the carcass, high muscle:bone and muscle:fat ratios and a low proportion of fat compared to the more normal genotypes. Objective criteria to discriminate between HE and DM were SCF, muscle:bone and TSMTMF ratios, and between SY and DM were TSB and muscle:bone ratio. Key words: Beef bulls (young), growth patterns, carcass composition, double muscling, breed type

Plasma testosterone and LH responses to LHRH in double-muscled bulls treated with trenbolone acetate and zeranol.

Twenty-four double-muscled Belgian White Blue bulls were assigned, according to body weight, to two groups with and without treatment with anabolic agents. Implants containing 140 mg trenbolone and 36 mg zeranol (Forplix) were inserted sc on the upper face of the ear flap. Plasma concentrations of testosterone and luteinizing hormone (LH) were determined at d 0, 30 and 60 of the experimental period. Mean testosterone levels at d 0 for treated and controls were, respectively, 2.1 and 1.7 ng/ml during the 10-h sampling period. At d 30 and 60, testosterone levels were strongly depressed in implanted bulls (.2 ng/ml) as compared with 2.5 and 1.7 ng/ml in control bulls (P less than .001 at d 30 and P less than .01 at d 60). Average plasma LH concentrations were identical in the two groups at d 0 and 60 (1.1 and 1.5 ng/ml, respectively), but showed a slight decrease at d 30 in the treated group (P less than .10). The pulsatile character of LH and testosterone profiles was abolished by the Forplix treatment. Luteinizing hormone-releasing hormone (LHRH) injection at d 0 was followed in both groups by an immediate and sharp increase in plasma LH concentrations. The LH response reached a maximal value between 20 to 40 min postinjection and then declined rapidly. On the contrary, Forplix treatment strongly reduced LH and testosterone responses to LHRH stimulation in treated animals. Average daily gain and feed to gain ratios were 1.087 +/- .127 and 7.52 +/- .32 kg, respectively, for the control bulls and 1.335 +/- .092 and 6.24 +/- .24 kg for the Forplix-treated bulls, thus clearly showing a beneficial effect of Forplix treatment.

Testosterone plasma profiles, as a function of age in young bulls from the bovine double-muscled Belgian white blue breed a preliminary report

Plasma testosterone (T) 10 hour-profiles were determined at 10-day intervals in 29 young double-muscled bulls from the BBB-V breed between the ages 130 days and 190 days. Age at onset of T pulsatile profiles allowed to distinguish 3 groups of animals: group A, 18 animals, appearance of pulsatile T profiles between 150 and 180 days group B, 5 animals, appearance of pulsatile T profiles between 150 and 190 days group C, 6 animals, appearance of pulsatile T profiles at (or over) 190 days. We hypothesize that early appearance of pulsatile T profiles might mean precocity in onset of male puberty and sexual maturity. If this assumption is true, determination of T plasma profiles at a well specified age, might allow early selection of sexually precocious and capable BBB-V males.

EFFECT OF FASTING ON PLASMA GLUCOSE KINETICS IN DOUBLE-MUSCLED CATTLE

The effect of a 4-day fast on plasma glucose kinetics was determined with three 14-mo-old carrier bulls and three of their double-muscled (DM) half-siblings. Glucose entry rate and irreversible loss were less (P &lt; 0.05) during fasting for both animal types. Glucose pool size was greater (P &lt; 0.05) in carrier than in DM bulls. Key words: Plasma, glucose kinetics, double-muscled bulls