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COMPENSATORY GROWTH IN DOUBLE MUSCLED BULLS
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Different Periods of Feed Restriction Before Compensatory Growth in Belgian Blue Bulls:
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I. Animal Performance, Nitrogen Balance, Meat Characteristics and Fat Composition
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J. L. Hornick
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, C. Van Eenaeme, A. Clinquart, M. Diez, and L. Istasse
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Department of Nutrition, Veterinary Faculty, Sart Tilman
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B43 4000 Liège, Belgium
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Phone: 32-(0)4-3664139
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Fax: 32-(0)4-3664122
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E-mail: HORNICK@.STAT.ULG.FMV.AC.BE.
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The IRSIA (Institut pour l'Encouragement de la Recherche dans l'Industrie et l'Agriculture,
Brussels, Belgium) is gratefully acknowledged for financial help.
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To whom correspondence should be addressed.
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ABSTRACT: Thirty double-muscled Belgian Blue bulls were maintained at a rate of gain of .5 kg/d
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during four length of time, 4 (G2), 8 (G3) or 14 (G4) mo (low growth period, LGP), before fattening
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(rapid growth period, RGP). Ten control animals (CG) were fed a high-energy, high-protein diet. The
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G2, G3, and G4 were fed a low-energy, low-protein diet during LGP and the same diet as CG during
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RGP. Live weight was recorded biweekly, feed consumption (FC) daily, and nitrogen balance at 3
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occasions in each group. At the slaughterhouse, the 7, 8, and 9th ribs were removed to determine
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carcass composition, meat quality, and meat and fat composition. Compensatory growth reached a
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maximum 2 mo after refeeding. The G2 and G4 exhibited compensatory growth ( P < .05) and had
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higher daily FC ( P < .001). Feed conversion ratio (FCR) increased sharply after refeeding. Nitrogen
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balance was higher in compensating groups ( P < .05). Compensating animals had higher carcass
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connective and adipose tissue contents ( P < .05) but lower meat fat content (P < .05). Cattle exhibiting
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compensatory growth had higher redness, yellowness, hue, cooking losses and drip losses, but tended
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to have lower Warner-Bratzler peak shear force (WBPSF) values. The saturated fatty acid (SFA)
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content of the fat decreased with the length of the LGP. Compensatory growth in double-muscled bulls
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at the expense of higher feed intake increased peripheral fat but decreased intramuscular fat deposition.
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Key Words: Belgian Blue Bulls, Compensatory Growth, Animal Performance, Carcass, Meat, Fatty
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Acids
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Introduction
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Compensatory growth is the ability of an animal to exhibit, after disease (Thomas et al., 1978) or
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feed restriction (Wilson and Osborn, 1960), larger growth rates than in unaffected animals of the same
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chronological age. In cattle, compensatory growth is well expressed when feed restriction occurs at a
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relatively late stage of life (Berge, 1991; Berge et al., 1991). Factors contributing to compensation are
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increases in feed intake (Baker et al., 1992), increases in gut-fill weight, or higher efficiency of feed
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utilization (Carstens et al., 1991). The response varies according to the pattern of undernutrition and
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realimentation, and stage of development of the animal (Wilson and Osborne, 1960). The Belgian Blue
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breed, double-muscled type, is a large beef breed with early maturity, characterized by high average
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daily gain, low feed conversion ratio, and high quality of carcass (Clinquart et al., 1991). Currently,
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there is no published work on compensatory growth in Belgian Blue bulls. Therefore, an experiment
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was conducted with Belgian Blue bulls in order to study the effects of a restricted growth, lasting for
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three different durations, on fattening performances. Results are presented in 2 papers. This paper
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summarizes animal performance, nitrogen balance, and carcass, meat, and fat characteristics.
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Materials and Methods
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Animals and Management
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The Animal Care and Use Council of our institute approved the use and treatment of animals in
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this study. A total of 40 Belgian Blue bulls, double-muscled type, initial age and weight range of 9.7
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mo and 310 ± 38 kg, were divided into four groups of similar live weight. In each group, four animals
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were randomly penned in individual stalls allowing for collection of urine and feces, and the remaining
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six were housed in a stanchion barn with straw as bedding. Each group was randomly assigned to one
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of the four treatments. The first group (control, CG) was given from the beginning ad libitum access to
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a fattening diet allowing for rapid growth. The fattening diet was based on sugar beet pulp
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complemented with cereals, protein from vegetable origin, and a mineral mixture (Table 1). During
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three periods with different lengths of time, the other groups received a limited quantity of a low-
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energy, low-protein diet calculated to support an ADG of .5 kg daily gain (LGP, low growth period).
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The low growth diet was based on pelleted straw complemented with dried lucerne, cereals, protein
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from vegetable origin, and mineral mixture. The three groups, namely groups 2, 3, and 4 (G2, G3, G4),
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received the low-growth diet for 115, 239, and 411 d, respectively. Subsequently, G2, G3 and G4 were
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adapted to the concentrate fattening diet over a 15-d period of transition. The amount of concentrate
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feed was then progressively increased and animals were allowed to consume their ration on an ad
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libitum basis for about 1 mo after the beginning of the transition period. The concentrate diet was
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offered during the rapid growth period (RGP) which lasted until the animals were slaughtered. The
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animals were fed twice daily at 0600 and 1400 and were slaughtered per group when mean live weight
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reached at least 600 kg and when the average daily gain (ADG) was lower than 1 kg/d at two
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consecutive measurements.
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Measurements
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Feed intake of the bulls was recorded each day and live weight at 15-d intervals. Feed samples
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were withdrawn at regular intervals for chemical analysis. At the slaughterhouse, abdominal fat was
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removed from the carcass. Carcass weight was recorded and pH of both Longissimus thoracis muscles
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were measured (7, 8, 9 ribs) 1, 2, and 4 h postmortem using a Portamess 751 knick pH-meter (Knick
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GmbH & Co, Berlin, Germany) with an Ingold "penetration" pH-electrode (Ingold AG, Urdorf,
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Switzerland).
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Two days after slaughter, the 7, 8, and 9th ribs were removed from the carcass. They were
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dissected in order to separate lean meat, fat and connective tissue, and bones. Regressions of Martin
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and Torreele (1962) for double muscled cattle were then used to assess the composition of the carcass.
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Meat quality was determined from one 2.5-cm-thick cut of the longissimus thoracis muscle. Five
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measurements of the final pH were performed on this cut at 48 h postmortem using the technique
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described above. At the same time, the HunterLab Labscan II device was used for objectively
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measuring CIE Lab brightness (L*), redness (a*) and yellowness (b*) on 5 spots 2.5 cm diameter. Hue
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was estimated by a*/b* ratio. Seven days later, the cut was weighed in order to estimate drip loss, and
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heated in open plastic bags in a waterbath for 50 min at 75°C. After heating, they were cooled in cold
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tap water to room temperature, bags were drained, and cuts were mopped gently dry with paper tissue.
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The difference between raw and heated weights was recorded as cooking loss and expressed as a
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percentage of the raw weight. Warner-Bratzler shear force was determined with a Lloyd LR5K
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perpendicular to the fiber direction on 10, 1.25-cm-diameter cores obtained from the heated cuts.
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The dry matter, ash, ether extract, and crude protein concentrations of the diets were determined
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according to official procedures (AOAC, 1975). The lipids from peripheral, intermuscular and
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intramuscular fat samples were extracted and saponified as described by Ter Meulen et al. (1975). The
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fatty acid composition of fat samples was determined by gas chromatography.
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Statistical Analysis and Mathematical Modelling
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Bulls were blocked (n = 10) by group (Figure 1). One-way analysis of variance, using group as a
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factor of variation, was used to analyze data. Data relative to muscle, connective and adipose tissue,
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