Search

Summary A beef production trial was conducted with 4 groups of 12 young bulls fed intensively on complete dry rations containing respectively 0, 25, 50 and 75% dried sugar beet pulp pellets and 75, 50, 25 and 0% rolled barley. The digestibility of the four rations was determined with wethers. No significant difference was observed in the digestibility of dry matter, organic matter and nitrogen free extract among the treatments, but crude fiber digestibility of the rations increased with increasing amounts of beet pulp in the diets. The mean daily gain amounted to an average of 1280 g and was not significantly different among the treatments. Intake of dry matter per kg gain increased slightly with increasing amounts of beet pulp in the rations. From the analysis of the feed conversion efficiency can be concluded, that the feeding value of dried sugar beet pulp, used in large amounts for beef cattle, was still approximately 10% lower than this of rolled barley with a crude fiber content of 4% in the dry matter. Results of digestibility trials with 8 different lots of dried sugar beet pulp confirm last statement. Calculated net energy content of beet pulp amounted to an average of 90% of this of rolled barley (± 4% crude fiber in the dry matter). Zusammenfassung Der Einsatz von Trockenschnitzeln und gequetschter Gerste in der Bullenmast Zwolf Jungbullen wurden in 4 Gruppen eingeteilt und erhielten 0 (I), 25 (II), 50 (III) und 75 (IV)% Trockenschnitzel und 75 (I), 50 (II), 25 (III) und 0 (IV)% gequetschte Gerste. Die Verdaulichkeit der 4 Rationen wurde an Hammeln ermittelt. Dabei konnte kein signifikanter Unterschied der Verdaulichkeit der Trockensubstanz, der organischen Substanz und der NfE festgestellt werden. Die Verdaulichkeit der Rohfaser stieg mit hoherem Anteil von Trockenschnitzeln in der Ration an. Die durchschnittliche, tagliche Gewichtszunahme der Tiere stieg bis auf 1280 g an. Dabei zeigte sich kein Unterschied zwischen den Rationen. Die Trockensubstanzaufnahme pro kg Gewichtszunahme erhohte sich mit steigendem Trockenschnitzelanteil in der Ration. Aus der Futterverwertung las sich schliesen, das der Futterwert von Trockenschnitzeln in der Fleischerzeugung ungefahr 10% niedriger liegt als der von gequetschter Gerste mit 4% Rohfaser in der Trockensubstanz. Der berechnete Nettoenergiegehalt von Trockenschnitzeln betragt ca. 90% von dem der gequetschten Gerste.

Zusammenfassung Trockenschnitzel erganzt mit Trockenharnstoff oder flussiger Melasse-Harnstoff-Mischung in der Jungbullenmast An 160 jungen weisblauen Mastbullen wurde ein Mastversuch mit Trockenschnitzeln und NPN-Erganzungen durchgetuhrt. Als Versuchstiere dienten Bullen in zwei Gewichtsklassen, schwere Tiere (374 bis 643 kg Korpergewicht) und mittelschwere Tiere (243 bis 591 kg Korpergewicht). Die negative Vergleichsgruppe (Gruppe I, schwere Bullen) erhielt Trockenschnitzel mit Mineralstoffen und Vitaminen. Gruppe II erhielt Trockenschnitzel erganzt mit 0,85% Harnstoff. Dadurch stieg der Gehalt an Rohprotein in der Ration von 10,8% auf 14,0% in der Trockensubstanz. Die Gruppen III und IV bekamen Trockenschnitzel plus flussige Melasse-Harnstoff-Mischungen. Bei der Gruppe III handelte es sich um eine Erganzung mit einer einfachen Mischung aus Zuckerrohrmelasse mit Harnstoff, bei der Gruppe IV um eine kommerzielle Melasse-Harnstoff-Mischung mit kontrollierter Freisetzung (“controlled release”). Nach Zugabe von Trockenharnstoff betrug die durchschnittliche Tageszunahme bei den schweren Bullen 1325 g und lag bedeutend hoher als in allen anderen Gruppen. Trotz der hoheren Nahrstoffaufnahme pro kg0,75 war die tagliche Gewichtszunahme in den Gruppen III und IV nicht wesentlich hoher als in der negativen Vergleichsgruppe. Die positive Vergleichsgruppe (Gruppe II) zeigte die hochste Ausschlachtungsrate und die beste Futterver-wertung. Die negative Vergleichsgruppe (Gruppe I) der mittelschweren Bullen wurde mit denselben Rationen wie die entsprechenden Gruppen der schweren Bullen gefuttert. Die Gruppen II und III erhielten eine Harnstofferganzung von 0,6 bzw. 1,0% Harnstoff und die Gruppe IV die kommerzielle Melasse-Harnstoff-Mischung. Es zeigte sich, das der niedrigste Harnstoffgehalt (0,6%) genugend Stickstoff enthielt (12,2% Roheiweisgehalt in der Trockensubstanz), um einen Tageszuwachs von 1269 g zu erreichen, was in Vergleich zu den anderen Gruppen signifikant verschieden war. Die niedrigsten, mit der flussigen Melasse-Harnstoff Mischung erzielten Ergebnisse sind vornehmlich der zu kleinen Aufnahme bei einigen Tieren zuzuschreiben. Vorteile nach Zugabe von flussiger Melasse-Harnstoff Mischung statt Trockenharnstoff oder nach Zugabe flussiger Melasse-Harnstoff Mischung vom kontrollierten Freisetzungstyp sind nicht beobachtet worden.

Zusammenfassung Der Einflus von Monensin und Avoparcin auf die Verdaulichkeit und Pansenfermentation Der Einflus von 24 und 29 ppm Monensin und 2 Konzentrationen Avoparcin (24 bis 31 und 61 bis 64 ppm) auf die Verdaulichkeit und die molare Konzentration fluchtiger Fettsauren wurde untersucht mit Hammeln. Die Rationen waren zusammengesetzt aus 85% Maissilage und 15% Kraftfutter. Monensin bewirkte eine signifikant geringere Verdaulichkeit der Trockensubstanz und Rohfaser. Der Einflus auf die Verdaulichkeit des Fettes und der NFE war unterschledlich, wahrend die Verdaulichkeit der organischen Substanz und des Rohproteins nicht signifikant beeinflust wurde. Etwa 30 ppm Avoparcin hatte keinen Einflus auf die Verdaulichkeit der organischen Substanz, von Rohprotein und NFE. Die Verdaulichkeit von Trockensubstanz, Fett und Rohfaser war unterschiedlich. Hohere Konzentrationen Avoparcin verminderten die Verdaulichkeit der Trockensubstanz, der Rohfaser und der NFE im Vergleich mit der Kontrolle, Monensin, und etwa 30 ppm Avoparcin. Der Einflus auf die organische Substanz und das Rohprotein waren verschieden zwischen den Versuchen. Monensin und Avoparcin bewirkten eine Verminderung der Azetatkonzentration und einen Anstieg der Propionatkonzentration, obwohl dieser Effekt nur in einem der zwei Versuche mit 30 ppm Avoparcin gefunden wurde. Avoparcin erzeugte das engste Azetat: Propionat Verhaltnis im Vergleich mit der Kontrolle und Monensin.

Zusammenfassung Es wurde der Einflus von Leinsaatolhydrolysat und Sodium Sulfit incorporiert in komplette Trockenrationen fur Fleischproduktion untersucht. Leinsaatolhydrolysat (4 %) war sowohl zugesetzt zu einer hochenergetischen Ration auf der Basis von 60% Zuckerruben-Trockenschnitzel-Pellets als auch zu einer geringeren energetischen Ration auf der Basis von 60% Luzerne-Pellets. Mit Luzerne wurde eine zweite experimentelle Ration mit 0,8% Na2SO3 studiert. Um isokalorische Rationen zu bekommen, war 4% Rinderfett zu Kontroll-Mischungen zugesetzt worden. Beide Additiven beeinflusten nicht significant die Verdauungskoeffizienten. Weder Leinsaatolhydrolysat noch Na-Sulfit beeinflusten die Fleischbildung gunstig.

Energy and protein requirements were determined for Belgian Blue double-muscled (BB dm) bulls based on the results of two feeding trials and a trial with serial slaughtering. The results of the serial slaughter experiment allowed calculation of chemical composition and energy content of the empty body, as well as protein and energy deposition at various live weights between 350 and 650 kg. Protein requirements were calculated based on the protein requirements for maintenance, the protein mass accreted and the efficiency of protein accretion. Efficiency of protein deposition (g protein accretion/g protein intake for accretion) was derived from the feeding experiments based on marginal protein levels; it decreased from 0.53 to 0.44 with increasing live weight. Energy requirements were also derived from the same database. Net energy for maintenance was estimated, with these animals that received an optimum energy/protein ratio, by subtracting the net energy retained from the net energy intake. Requirements were then determined by summation of the energy requirements for maintenance and the energy requirements for accretion. Conclusively, energy and protein requirements were determined for BB dm bulls for live weights from 350 to 650 kg and for different growth rates. As such, surpluses of energy and protein that BB dm animals require compared to other beef breeds, were quantified.

Information concerning 493 single calvings of the double-muscled beef cow herd of the institute was collected to investigate the relationship between the characteristics of dams and calves with regard to dystocia. Factors affecting dystocia are similar in double-muscled cattle to those in non-double-muscled cattle but the occurrence of dystocia is greatly increased in double-muscled cows. Incidence of caesarean section was significantly correlated with parity (–0·243), age of dam (–0·232), post-partum dam weight (–0·185), and calf birth weight (0·164). Caesarean deliveries were required for 89·5% of the parturitions. Calvings without caesarean section were characterized by higher means for post-partum dam live weight (634·7 kg), age (1675·5 days), parity (3·1) and the ratio of post-partum dam weight to calf birth weight (14·4), compared with 580·2 kg, 1251·1 days, 2·1, and 11·8, respectively for births with caesarean setion, while calf birth weight was lower in non-caesarean calvings (45·8 v. 49·9 kg). Caesarean births involved more male calves than females (55 v. 45%). Even when calf birth weight was 30 kg or lower, and also in multiparous cows, 40 and 86% of the deliveries, respectively, still occurred with a caesarean section.Incidence of caesarean section could not be accurately predicted from pre-partum characteristics such as pre-partum dam weight, age and parity.

Summary Urea infusions were performed on 18 Belgian blue double-muscled bulls, ranging from 308 to 710kg live weight after a fasting period of 16 h. Urea space (US) was determined from the difference in plasma urea concentration between samples taken before and 12, 18 and 24min after mean infusion time. The day after infusion, the bulls were slaughtered and subsequently the body composition was determined. Kg empty body water and empty body protein were quite accurately predicted by US. The precision of the prediction of kg empty body fat was less accurate. However, due to the large live weight interval and the small compositional variation, the fasted live weight (fLW) was a better parameter to estimate the weight of the body components. Prediction of relative body composition (as a percentage) instead of absolute (in kg) improved the standard error of the predictions. In estimating relative body composition, US has proven to be somewhat better than fLW, but the extra precision from using urea infusion was not large enough to justify the extra work of the infusion. The time for equilibration of the urea in the water compartment was obviously longer in this study than in others, presumably due to the lower capillary density of the Belgian blue double-muscled animals.

Changes at consumer level, as well as an image decline of the meat sector, resulted in considerable decreases of fresh meat consumption. Consumer orientation is considered as a prerequisite to slow down or reverse the adverse fresh pork consumption evolution. Consumer perception of pork is taken as the starting point of this article. Focus is first on assessing differences between facts related to nutritional value and healthiness aspects of pork and their perception by Belgian meat consumers. Second, possibilities of improving pork characteristics are identified. Pork is perceived worst as compared to beef and poultry on the attributes leanness, healthiness, taste and tenderness. Consumer-oriented response strategies should focus at improving these intrinsic quality characteristics, before other elements like traceability, labelling or marketing can be implemented successfully. The possibilities to improve nutritional value, healthiness and sensory characteristics pertain to selection, pig diet composition, transport, slaughter and post-slaughter circumstances. A successful adoption of consumer orientation urges for co-operation throughout the entire pork production chain. The identified topics are key attention points for adequate production and marketing by the pork sector, as well as for consequent communication by government and public services.

To optimize performance and carcass quality of Belgian Blue double-muscled bulls four phased feeding regimens were evaluated. All diets were offered ad libitum and consisted of 650 g concentrates and 350 g maize silage per kg dry matter (DM). Total period was divided into three phases (ca. 360 to 460, 460 to 570 and 570 to 680 kg). All four groups received the same maize silage but the different energy and protein densities were applied using different concentrates. During the three phases, the negative control (NC) group constantly received a diet with a low protein and a moderate energy density; the second group (DP) received with each phase diets with decreasing protein density while the energy density remained moderate; the third group (IE) received diets with increasing energy density at a constantly high protein density and the last group (DPIE) received diets which decreased in protein and increased in energy density. The NC group grew significantly slower during the first interval (1·37 v. 1·62 kg/day for the other groups), resulting in a significantly longer total finishing period. During the third period IE had the slowest growth. The NC group needed 21 and 20 days more than the DP and DPIE groups, respectively, to reach the same slaughter weight. The NC group had the lowest DM intake during the first interval, the IE group during the third interval. No significant differences (P > 0·05) were found for food conversion, when expressed as DM or NEF (net energy for fattening). IE had the worst protein conversion while NC had the best, with the two other groups being intermediate. The only important significant difference concerning carcass quality was the improved dressing proportion of the IE and DP groups. Although significant, differences in the fat content of the m. longissimus thoracis are of minor importance. These results proved that for Belgian Blue double-muscled bulls, protein density of the diet can be decreased with increasing live weight, while energy should be increased to give optimal performance.

The extent to which water holding capacity (WHC) techniques: filter paper press method, drip loss and filter paper method, are related to the sensory juiciness appreciation of pork was studied. Additionally four on-line methods: pH1, FOP1 (light scattering), PQM1 (conductivity) and DDLT (Double Density Light Transmission), were evaluated for their ability to predict WHC and juiciness scores. One-hundred and twenty samples of m. longissimus thoracis et lumborum, from animals of different genotypes, were involved in this study. Only WHC results, determined by the filter paper press method, were significantly correlated with juiciness scores (r=-0.24). The results of the filter paper method, either by weighing or visual judging, could not be predicted by the on-line methods. The results of the filter paper press method (F.p.p.-RZ) and drip loss were slightly better correlated with DDLT (respectively, r=0.56 and 0.45) than with PQM1 (r=0.51 and 0.36), FOP1 (r=0.48 and 0.34) and pH1 (r=0.41 and 0.34), although the standard error of estimate of the linear regressions was similar for the four on-line methods. Unfortunately, the on-line techniques incorrectly predicted several WHCs. Juiciness was slightly or not related to the on-line methods. The DDLT technique, which is analogous to the CGM (Capteur Gras/Maigre), an officially accepted carcass grading apparatus in France and Belgium, is as good or better than the classical on-line instruments: pH, FOP and PQM, in predicting WHC.

Properties of the non-carcass parts in combination with empty body and half carcass weight (EBW and CCW; kg) were used to generate equations for predicting empty body chemical composition. Therefore, chemical composition of the non-carcass parts and weight of the depot fatty tissues were determined on 18 Belgian Blue double-muscled fattening bulls. Very high coefficients of determination (R2) were found between the empty body composition and on the one hand the non-carcass parts composition and on the other hand the weight of the fatty tissues. Fat in the empty body was most difficult to predict. The very high coefficients of determination are partly caused by the large variation in slaughter weight (309 to 723 kg). Therefore equations to estimate proportional composition of the empty body are discussed. Although R2 values are strongly reduced, residual standard deviations remain very low and the precision of prediction is good. The proportion of protein is most difficult to predict, as it shows a very small variation. Estimations based on composition of the non-carcass parts are mostly a little more precise than the estimates based on weight of the fatty tissues but as the latter are much easier to determine, these equations will be more appropriate for practical use. Similarly the little improvement of the estimation based on EBW instead of CCW, cannot account for the extra costs and time to determine EBW. The results of the homogenizations have proven that there is very little variation in composition, despite the large range in slaughter weight. As the Belgian Blue double-muscled animals are very deviant from other breeds, the equations found in this study can only be applied for this breed type.

Characteristics from the 8th rib cut: chemical composition, tissue composition after dissection, specific gravity (SG) and m. longissimus thoracis (LT) composition, collected on 17 Belgian Blue double-muscled fattening bulls were used to generate equations for predicting chemical carcass composition. Carcass composition was best predicted from chemical analysis of the 8th rib cut and the empty body weight (EBW) of the bull. Carcass chemical fat content (CCF, kg) was predicted from the 8th rib cut fat content (ether extract, 8RF, kg) by the following regression: CCF=1.94+27.37 8RF (R2=0.957, RSD =9.89%). A higher coefficient was found for carcass water (CCW, kg) predicted from 8RF and EBW: CCW=−2.26+0.28 EBW-34.28 8RF (R2=0.997, RSD=1.48%). No parameter was found to improve the prediction of CCP from EBW solely: CCP=−0.86+0.08 EBW (R2 =0.992, RSD=2.61%). Prediction equations based solely on LT composition had low R2 values of between 0.38 and 0.67, whereas no significant equations were found using SG. However, equations based on EBW had R2 values between 0.78 and 0.99. Chemical components of the 8th rib cut in combination with EBW are most useful in predicting the chemical composition of the carcass of Belgian-Blue double-muscled bulls.

The objective was to determine the effect of feeding diets differing in fibre content and source on backfat skatole content and boar taint score of entire male pigs. Sixty entire male pigs (Pietrain×Seghers hybrid cross) were assigned to four dietary treatments and fed ad libitum, in two phases (grower and fattening), one of the following diets: control, one with 15% sugar beet pulp, one with 30% wheat bran and one with 15% soybean hulls. The diets were isocaloric and isonitrogeneous, but differed in crude fibre content and fibre source. Mean crude fibre contents were 5.2, 7.7, 6.2 and 9.9%, respectively. Animal performance, carcass quality, backfat skatole and indole contents and boar taint scores were not influenced by diet. However, the wheat bran diet group gave a numerically (P=0.219) higher backfat skatole content than the sugar beet pulp diet group (126±182 vs 37±54 ng/g fat; mean±S.D.). Under the experimental conditions, there was no higher risk for skatole formation or boar taint occurrence by feeding fibre-rich diets to entire male pigs, compared with a conventional diet.

In the frame of a feeding experiment with three periods, balance trials were carried out with 18 double-muscled Belgian White–blue bulls, allocated to one of four feeding regimes. The ration consisted of maize silage and concentrate in the ratio of 35:65 on DM basis. Six concentrates were formulated to supply three levels of protein and energy. The three periods corresponded to distinct live weight intervals of 360–460, 460–570 and 570–680 kg. In the first feeding regime, low protein and intermediate energy level were given during the whole trial; in the second regime, protein level decreased at a constant intermediate energy level; in the third regime, the energy level increased at a constant high protein level; in the fourth regime, protein level decreased simultaneously with an increase in the energy level. Total daily intake varied from 6.2 to 9.7 kg for dry matter (DM), from 65 to 106 MJ for metabolisable energy (ME) and from 719 to 1326 g for crude protein (CP) (50 animal observations). At the end of each period, the excretion of the purine derivatives (PD), allantoin and uric acid, was measured after total urine collection during 4 days to estimate microbial nitrogen supply to the duodenum (MNPD). The effect of the intake of DM, organic matter (OM), digestible OM (DOM), digestible carbohydrates (DCHO), total digestible nutrients (TDN), rumen fermentable OM (FOM), metabolisable energy (ME), fermentable ME (FME), CP, digestible CP (DCP) and rumen degradable protein (RDP) on PD and MNPD was examined. Further, the relationship of MNPD to MN, calculated according to different systems, was examined. The amount (mean±SD) of allantoin excreted in urine was 147±23 mmol day−1 and of uric acid 11±3 mmol day−1. The MNPD amounted to 97±21 g day−1, varying from 57 to 154 g day−1, and significantly increased with all measures of nutrient intake. The correlation coefficients, ranging from 0.45 for DCP to 0.57 for DOM and FME, were, however, not significantly different. MNPD showed a larger variation and was on average lower than the potential MN values calculated from the intake of FOM (108±13 g day−1), DCHO (141±16 g day−1) and FME (109±13 g day−1), similar to that calculated from the intake of RDP (99±14 g day−1) and higher than the MN value calculated from the intake of TDN (84±11 g day−1). The correlations of MNPD to the calculated MN values ranged from 0.47 for MNFOM to 0.59 for MNFME, but were not significantly different.

The suitability of backfat high in polyunsaturated fatty acids (PUFA) for salami manufacture was assessed. Eighty pigs (barrows and gilts) were fed four diets, containing 21, 25, 28 and 28 g PUFA/kg feed, originating mainly from soybeans and/or soybean oil in the first three diets and from linseed in the fourth. Salami was prepared with backfat from these pigs, according to gender and dietary treatment. Samples were taken throughout the ripening. The taste panel rejected the two high PUFA (diet 3 and 4) levels; moreover fishy off-flavours were detected for dietary treatment four. Twenty-five grams PUFA/kg feed, corresponding with 23% PUFA in backfat or 15% PUFA in salami, results in acceptable taste, if linoleic acid is the predominant PUFA. However, all PUFA levels resulted in salamis too soft to be commercialized, as evidenced by a fatty film on the salami slicing machine.

The effect of three protein (77, 97 and 117 g DVE (true protein digested in the small intestine) per kg dry matter (DM)) and two energy levels (7·38 and 8·03 MJ NEF (net energy for fattening) per kg DM) on the performance of Belgian White-blue double-muscled finishing bulls and on the quality of their carcasses and meat was investigated. The diet, offered ad libitum, consisted of 650 g/kg concentrates and 350 g/kg maize silage on DM basis.No significant influence was found of the energy level on the growth rate. The low protein level reduced live-weight gain, from 370 to 501 kg (1·43 kg on average v. 2·60 and 1·66 kg daily; P < 0·02). The growth rate during the entire period (370 to 692 kg) and the live weight at slaughter were significantly influenced by the protein content.The bulls given the high energy level lost less weight during the 20-h fasting period before slaughter. Their carcasses were classified with a higher fatness score and a better conformation. These carcasses had a higher fat content, while the proportion of bone in the carcass was lower than in the low energy groups. The cold carcass weight of the low protein groups (456 kg on average) was significantly smaller than that of the four other groups (470 kg on average). Although no differences between the six groups were found concerning the dressing proportion, this measurement was significantly influenced by the protein level (685 g/kg for low protein v. 692 for high protein). The SEUROP conformation was positively influenced by the protein and the energy level, while the fatness score was influenced only by the energy level (5·5 v. 6·0 for the low and the high energy level, respectively). Although the differences in conformation, fatness score and dressing proportion are significant, because of the small variation, the practical meaning is less important.

The effect of the protein content of the concentrate on the performance during a 20-week rearing period was investigated, using thirty-two male and thirty-seven female newborn double-muscled calves, belonging to the Belgian White–Blue breed. A restricted milk diet was fed. Weaning occurred when daily concentrate consumption reached 0.5 kg. The crude protein content of the concentrate amounted to 15% (LP) or 18% (HP) on an as-fed basis. Concentrate and grasshay were fed from a 2-week age onward. Daily concentrate intake was limited to a maximum of 3 kg, while hay was freely available. Weaning occurred at a similar live weight (LP: 80.1 vs. HP: 80.7 kg) and after a similar number of experimental days (LP: 60.5 vs. HP: 57.4 days). Total dry matter (DM) intake during the entire period (LP: 260.2 vs. HP: 267.2 kg) was not affected by dietary crude protein. Liveweight gain after weaning (LP: 0.98 vs. HP: 1.05 kg/d) and during the entire rearing period (LP: 0.78 vs. HP: 0.84 kg/d) was increased when the HP concentrate was fed. DM and net energy were more efficiently used in calves fed the HP concentrate, while protein was less efficiently converted at the higher dietary protein level. Higher dietary protein also increased serum urea concentration. Based on an increased liveweight gain and a better conversion of DM and net energy, on the one hand, and a reduced protein efficiency and a higher serum urea concentration on the other hand, it is concluded that a dietary level of 200 g crude protein (CP) or 114 g true protein digested in the small intestine (DVE) per kg DM is near the optimum in early-weaned double-muscled calves. It improved daily liveweight gain and feed conversion, compared to 167 g CP or 100 g DVE per kg DM. These results give evidence that the optimal dietary protein level in early-weaned double-muscled calves seems to be higher than in non-double-muscled calves.

Summary The tryptophan (Trp) requirement was investigated in post weaning piglets from 5 to 10 weeks of age (7–20kg). Three feeding trials were conducted. All piglets were randomly alloted according to age, sex, weight, pre-weaning growth and ancestry to the different dietary treatments. Ad libitum feed intake (per 6–7 pigs) and daily gain (individual) were recorded at 5 and 10 weeks (end of experiment). In the first trial 72 Belgian Landrace (BL) and 60 Pietrain × Seghers Hybrid (P × SH) piglets were used for two dietary treatments. The basal diet, 16% crude protein (CP), 1.06% lysine (Lys) and 0.14% Trp, was supplemented up to 0.19% Trp. This trial revealed a significant improvement in daily gain from 0.14% (0.10% ileal digestible Trp) to 0.19% Trp (0.15% ileal digestible Trp). The second trial was based on a lower CP content (14%) and a similar Lys level. Trp was increased in steps from 0.16% to 0.18, 0.21 and 0.24%. One hundred and fifty-eight BL and 147 P × SH piglets were divided over the four feeding regimes. No improvement in growth was obtained for the levels above 0.16% Trp (0.11% ileal digestible Trp). It was presumed that Thr was the limiting factor. A third trial was conducted, which consisted in a 3 × 3 factorial experiment, using the same CP level as in trial 2, but a lower Lys level (1.03%) and combined three Trp levels (0.18, 0.21 and 0.23%) with three Thr levels (0.65, 0.72 and 0.79%). Nine groups of 49 animals (all P × SH) were used in this experiment. Only a slightly favourable tendency of Trp towards increasing daily feed intake was found and the growth and feed: gain ratio were not affected at all. The Thr, on the contrary, led to increasing growth figures. The optimum Thr level seemed to have been reached by the 0.72% total Thr or 0.57% ileal digestible Thr level, yielding a ratio of 65% of Thr:Lys. For Trp, the requirement was difficult to predict in the conditions of the experiment, as no optimum appeared for Trp from the animal performance results. Zusammenfassung Der Tryptophanbedarf von Ferkeln in Abhangigkeit vom Threoningehalt in der Ration Alle Ferkel wurden nach Alter, Geschlecht, Gewicht, Zunahme vor dem Absetzen und Abstammung den verschiedenen Diaten zugeordnet. Die ad libitum Futteraufnahme (fur jeweils 6–7 Schweine) sowie die taglichen Zunahmen (einzeln) wurden mit 5 und 10 Wochen (letztmalig) aufgenommen. Im ersten Versuch wurden 72 Ferkel der Belgischen Landrasse (BL) und 60 Pietrain × Seghers Hybriden (p × SH) fur 2 Futterungsversuche eingesetzt. Die Basisdiat bestand aus 16% Rohprotein, 1,06% Lysin (Lys) und 0,14% Tryptophan (Trp) und wurde auf 0,19% Trp erganzt. Dieser Versuch ergab einen signifikanten Anstieg der taglichen Zunahmen von 0,14% (0,10% dunndarmverdauliches Trp) bis 0,19% Trp (0,15% dunndarmverdauliches Trp). Im zweiten Versuch wurde ein niedriger Rohprotein- und ein vergleichbarer Lys-Gehalt eingesetzt. Der Tryptophangehalt wurde von 0,16% uber 0,18% und 0,21% auf 0,24% gesteigert. 158 BL und 147 p × SH Ferkel wurden auf diese 4 Diaten aufgeteilt. Keine Wachstumsverbesserung wurde mit Tryptophangehalten uber 0,16% (0,11% dunndarmverdauliches Trp) erzielt. Anzunehmen ist, das Thr der limitierende Faktor war. Ein dritter Versuch, der aus eimen 3 times 3 faktoriellen Experiment bestand, erfolgte mit der gleichen Rohproteinmenge wie Versuch 2. Dabei wurden aber eine niedrigere Lysinmenge (1,03%) sowie drei verschiedene Thr-Mengen eingesetzt (0,65%, 0,72%, 0,79%). Fur diesen Versuch kamen 9 times 49 Tiere (alle P × SH) zum Einsatz. Dabei wurde bei Trp nur eine geringfugige Tendenz zu steigender Futteraufnahme festgestellt; das Wachstum sowie das Verhaltnis von Futteraufnahme und Gewichtszunahme wurden nicht beeinflust. Im Gegensatz hierzu fuhrte Thr zu einer deutlichen Wachstumszunahme. Der optimale Thr-Gehalt schien bei 0,72% Gesamt-Thr oder 0,57% dunndarmverdaulichem Thr zu liegen, was ein Verhaltnis von 65% Thr zu Lys ergibt. Der Trp-Bedarf konnte im Rahmen der Versuchsbedingungen nicht ermittelt werden, da aus den Ergebnissen der Futterungsversuche kein Optimum hervorging.

Fifty maize silages with known in vivo organic matter digestibility (VOMD) were used to compare the potential of chemical parameters (dry matter (DM), crude protein (CP), crude fibre (CF), crude fat (Cfat), ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), starch (STA), in vitro digestibility (with rumen fluid (RFOMD) or commercial cellulases (COMD)) and NIRS (monochromator: 1100–2500 nm) in predicting VOMD and calculated metabolizable (ME) and net energy lactation (NEL). A second series of 51 maize silages with digestibility and energy value based on RFOMD served as test set. Further, the possibilities of NIRS to predict chemical composition and calculated protein value (DVE and OEB) were investigated. NIRS-equations, developed by partial least squares analysis, were tested by internal and external validation. The correlation with VOMD was highest for COMD (r = 0.82), followed by RFOMD (0.81), ADF (−0.77) and NIRS-predicted VOMD (0.75). ADL could explain some supplemental variance in VOMD besides ADF and RFOMD, but not with COMD. Multiple linear regressions to predict ME and NEL, irrespective of being based on chemical parameters, RFOMD or COMD had similar residual standard deviations of about 0.21 and 0.16 MJ kg−1 DM, respectively. With NIRS the standard error of prediction amounted to 0.28 and 0.20 MJ kg−1 DM, respectively. The relative ability of NIRS to predict chemical composition was very good for residual moisture, STA, ADF, NDF and CP, moderate for CF and ADL and low for ash. The prediction potential for OEB was moderate and nihil for the little varying DVE-content.

Zusammenfassung Der Einflus der Kastration bei Schweinen der Belgischen Landrasse und Seghers-Hybrid-Schweinen auf sensorische Eigenschaften des Fleisch- und Fettgewebes Ziel dieses Versuchs war, die Folgen der Kastration mannlicher Tiere der belgischen Landrasse (n = 31) und des Seghers-Hybrid-Schweines (n = 65) zu quantifizieren. Insgesamt 33 Jungeber, 34 Borge und 29 weibliche Tiere wurden ad libitum gefuttert. Im Vergleich zu den Kastraten lag die Futterverwertung der Jungeber durchschnittlich niedriger. Die Schlachtkorperanalyse zeigte einen 4 (BL) bis 5% (Seghers hybrid) hoheren Fleischanteil fur die Jungeber als die Kastraten. Die Fleischbeschaffenheitsmerkmale dagegen waren nicht beeintrachtigt. Etwa 35, 20 und 15% der Jungeber zeigten ‘off-odours’ bei Ruckenspeck sowie ‘off-odours’ und ‘off-flavours’ bei Muskelfleisch. Es mus bemerkt werden, das auch bei den Jungsauen und etwas weniger bei den Kastraten, Geruchsabweichungen beobachtet wurden. Etwa 25–20% der Jungeberschlachtkorper zeigten hohere Gehalte an Skatol und Adrostenon als die ublich festgestellten sensoriellen Grenzwerte. Alter und Gewicht beim Schlachten beeinflusten die sensoriellen Merkmale im Muskel- und Fettgewebe nicht, obwohl der Androstenon-Gehalt mit wachsendem Alter zunimmt. Etwa 35 und 30% der ‘off-odours’ im Fett konnten durch den Skatol- und Androstenon-Gehalt erklart werden. Die Fleisch-‘off-odours’-Frequenz konnte nur fur 18% durch den Androstenon-Gehalt erklart werden.

One hundred and ten fattening pigs of a Piétrain × Hybrid cross-barrows and gilts in equal numbers-were distributed over five feeding formulas, containing increasing amounts of polyunsaturated fatty acids (PUFA), in the form of rapeseed. The aim of the study was to evaluate the maximum admissible amount of PUFA in the pig diet before problems-in terms of backfat consistency and storage stability-occur and to investigate the incorporation of dietary PUFA in intramuscular fat as well. A tendency towards reduced feed (energy) intake was obvious from the 7% rapeseed inclusion level, apparently resulting in a somewhat thinner backfat layer. None of the backfat samples showed a visible yellow discolouration instead thin backfat layers appeared as pink. Backfat consistency was lower for gilts and decreased with increasing dietary PUFA levels. PUFAs in the feed and in backfat were very well correlated (0.8-0.9) as expected; correction for de novo fat synthesis (by means of backfat thickness) did not alter the correlations within one sex group. Thresholds for PUFA in feed-15 g PUFA/kg feed-and for PUFA in back-fat-iodine value of 70 or 15% PUFA-were all surpassed in this experiment: 18 g PUFA/ kg feed resulted in maximally 22% PUFA in the outer backfat layer. The backfat PUFA limit was reached at relatively low feed PUFA levels. This might be explained by thin and hence more unsaturated backfat layers in lean or underweight pigs. Oxidative stability of the backfat after storage for 1 year in the freezer was satisfactory. The total intramuscular fat (IMF) content showed no obvious relationship with diet, in contrast with sex: barrows had more IMF than gilts. IMF consisted in 80% apolar phase and 20% polar fraction. The apolar fraction showed similar feed and sex tendencies as backfat, although correlations between feed and apolar fraction PUFAs were higher for gilts than for barrows. The amount of phospholipid was invariable throughout all treatments. Only linoleic acid-the major fatty acid-showed some feed and sex influence. In view ofthf results obtained the threshold for feed and backfat PUFA can be as high as, respectively, 18 g PUFA/kg feed and 22% PUFA in backfat, without deterioration of fresh and frozen backfat. However, for meat processing, demands could be more severe.

Sixty-four grass silages with known in vivo organic matter digestibility (VOMD) were used to compare the potential of chemical parameters (dry matter (DM), crude protein (CP), crude fibre (CF), crude fat, ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), water-soluble carbohydrates (WSC)), in vitro digestibility (with rumen fluid (RFOMD) or commercial cellulases (COMD)) and near-infrared reflectance spectroscopy (NIRS, 1100–2500 nm) in predicting VOMD and calculated metabolizable energy (ME) and net energy for lactation (NEL). Further, the possibilities of NIRS to predict chemical composition and calculated protein values (digestible protein in the intestine and degraded protein balance) were investigated. NIRS equations, developed by partial least-squares analysis, were tested on a second set of 36 grass silages with digestibility and energy values based on COMD. VOMD showed the highest correlation with NIRS-predicted VOMD ( r = 0.89), followed by COMD (0.83), RFOMD (0.81) and ADL (−0.73). Combining RFOMD with DM and CP could explain 78% of the variance in VOMD, whereas COMD in combination with CP, CF and DM accounted for 84% of the variance. Best multiple linear regressions based on RFOMD or COMD had residual standard deviations of 0.32 MJ kg −1 DM for ME and 0.23 MJ kg −1 DM for NEL. About the same accuracy for the prediction of the energy value could be reached with NIRS-predicted VOMD and determined ash content. The potential of NIRS to predict the chemical composition of grass silages was highest for CP, followed by WSC, moisture, CF, ash, NDF, ADF and ADL. NIRS also seems to have prospects for protein evaluation.

Zusammenfassung Der Einflus von mehrfachungesattigten Fettsauren (extrudierte Rapssaat) auf Leistung, Schlachkorper-, Fleisch- und Fettqualitat beim Schwein In der vorliegenden Untersuchung wurde der Einflus steigender Gehalte an Rapssaat und damit an steigenden Gehalten mehrfachungesattigter Fettsauren (PUFA) in der Ration auf die Leistung, Schlachtkorper-, Fleisch- und Fettqualitat bei Schweinen gepruft. Zugleich wurde das Geschlecht der Schweine beruksichtigt. Auserdem wurde der Einflus dieser Rationen auf die Ruckenspeck-Konsistenz und Fettstabilitat wahrend der Lagerung untersucht. Jeweils 55 Eber und Sauen erhielten Rationen mit 0, 5,25, 7, 8,75 und 10,5% Rapssaat bzw. 5,1, 9,9, 13,3, 14,7 und 18,0 g PUFA/kg Futter. Die Schweine mit den drei hochsten Rapssaatgehalten wiesen eine signifikant niedrigere Futteraufnahme auf. Die taglichen Zunahmen lagen bei den Sauen niedriger als bei den Ebern, dafur war die Futterverwertung bei den Sauen gunstiger als bei den Ebern. Es konnte kein signifikanter Einflus der Futterung auf die Schalchtkorperqualitat und die Fleischqualitat beobachtet werden. Allerdings wiesen die Sauen magerere Schlachtkorper auf, so das ihre Schlachtkorper eine bessere Klassifizierung erreichten. Zwischen den Geschlechtern wurde kein Unerschied hinsichtlich der Fleischqualitat beobachtet. Die Erhohung des PUFA-Gehaltes in der Ration fuhrte zu weicherem und rotlichem Ruckenspeck, was bei den Sauen starker ausgepragt war als bei den Ebern. Die Jodzahl des Ruckenspeckfettes stieg mit dem PUFA-Gehalt im Futter linear an, dabei war das Ruckenspeckfett der Sauen starker ungesattigt als das der Eber und die ausere Fettschicht starker ungesattigt als die innere Fettschicht. Die Fettstabilitat wurde nicht durch oxidative Prozesse negativ beeintrachtigt. Zur Erzeugung von Frischfleisch konnen Rationen mit bis zu 18 g PUFA/kg Futter eingesetzt werden, was bei Sauen zu einer Jodzahl von ca. 83 und bei Ebern von ca. 78 fuhrt. Dabei ist aber zu bedenken, das ein Rapssaatgehalt von uber 7% bzw. 13 g PUFA/kg Futter zu einer herabgesetzten Futteraufnahme fuhren kann.

Forty-eight culled dairy cows were assigned to one of two treatment groups to investigate the effect of a β-adrenergic agonist in mature cattle. They were finished during a 63-day period on a concentrate diet, containing 0 or 4 mg/kg cimaterol. No food was given in the 20 h prior to slaughter.Cimaterol had no effect on food intake, but significantly improved food conversion efficiency and increased live-weight gain, carcass weight and dressing proportion (P < 0·05). Cimaterol induced muscle hypertrophy as evidenced by an improved EUROP carcass classification and a higher longissimus thoracis (LT) cross-sectional area (P < 0·001). EUROP fat score and fat content in the carcass and the LT were lowered (P < 0·05). Cimaterol resulted in brighter meat (higher L-value: 37·0v.35·6; Pv.46·4 Newton; P

By means of a scanning monochromator and partial least-squares analysis, near-IR reflectance spectroscopy (NIRS) calibrations were developed to predict the chemical composition and the energy value of two different sets of compound feeds for cattle. The first set contained 179 compounds of heterogeneous nature, for which the energy value was calculated from in vivo digestibility. The second set consisted of 163 commercial dairy compounds for which the energy value was predicted from enzymatic digestibility. Spectral and reference data were highly correlated for all parameters, except for ash. For the first set, the root mean square error of prediction (RMSEP) amounted to 0.5% (percentage units) for moisture, 1.4% on dry matter basis (DM) for crude protein, 1.4% on DM for crude fibre, 0.7% on DM for crude fat, 2.1% for in vivo digestibility, 0.37 MJ kg−1 DM for metabolizable energy (ME) and 0.27 MJ kg−1 DM for net energy lactation (NEL). Prediction of ME and NEL with regression equations based on enzymatic digestibility was somewhat more accurate, with an RMSEP of 0.30 MJ kg−1 DM and 0.22 MJ kg−1 DM, respectively. For the more homogeneous second set, the RMSEP was lower for all parameters: 0.3% for moisture, 1.1% on DM for crude protein, 0.9% on DM for crude fibre, 0.3% on DM for crude fat, 1.3% for enzymatic digestibility, 0.30 MJ kg−1 DM for ME and 0.18 MJ kg−1 DM for NEL. It was proved that calibrations derived from energy values predicted from enzymatic digestibility were hardly less accurate than those derived from in vivo data. Calibrations based on the currently used NIRS instrument with 19 filters gave similar results to those based on the full spectrum for moisture, crude protein and crude fat, were less accurate for crude fibre, and clearly failed for energy evaluation. It was concluded that NIRS can be used as a screening method for the control of the chemical composition and the energy value of compound feeds for cattle.

The dry matter degradation in the rumen and pH decrease of nine primary feedstuffs, three compounds feeds and three combinations of each two primary feedstuffs, were evaluated by means of in sacco and in vitro incubations. The ingredients included barley, wheat, manioc, maize, sorghum, sugar beet pulp, soya-bean meal, soya-bean hulls and maize gluten feed. The compound feeds differed in content and composition of the starch and sugars fraction, as well as in fibre content. The three combinations each consisted of a rapidly and slowly degradable feedstuff. The feedstuffs were incubated for different times to examine optimal incubation conditions for both estimating methods. For the in sacco technique, best predictions were obtained after 3 h of incubation. In this way, ingredients were ranked in order of decreasing dry matter degradation: manioc, wheat, barley, maize gluten feed, beet pulp, soya-bean meal, maize, sorghum, soya-bean hulls. With the in vitro method, better results were observed when rumen fluid was taken after rather than before feeding. After 5 h of incubation, ingredients were ranked in order of declining pH decrease: manioc, wheat, beet pulp, maize gluten feed, barley, maize, soyabean meal, sorghum, soya-bean hulls. Except for beet pulp, in vitro ranking agreed fairly well with in sacco results. The validity of these techniques was examined by limited results of in vivo experiments, where the effect of the nature of the compound feed on rumen fermentation was investigated. In vivo, a clear difference in risk for rumen disturbances could be observed between the three compound feeds. In sacco and in vitro, however, the compound feed with the high content of slowly degradable starch, could hardly be distinguished from the crude fibre rich compound feed. As only a limited amount of in vivo material was available, the estimating value of these methods require confirmation.

Zusammenfassung Zum Einflus des Proteingehaltes auf Gewichtsentwicklung, Schlachtkorper- und Fleischqualitat, Hormongehalt im Blut und Stickstoffbilanz bei Belgischen weisblauen Doppellenderbullen. Der Einflus von drei Proteingehalten auf Gewichtsentwicklung, Schlachtkorper- und Fleischqualitat wurde mit 24bzw. 51 Belgischen weisblauen Doppellenderbullen zwischen 375 und 720 kg in zwei aufeinanderfolgenden Jahren untersucht. Der Proteingehalt der Rationen betrug 77 (L), 85 (M) und 97 (H) g darmverdauliches Protein (DVP), oder 137, 146 und 166 g Rohprotein pro kg Trockensubstanz. Zu Beginn lag die tagliche Lebendmassezunahme der Gruppe L mit 1,41 kg niedriger als die der Gruppen M und H mit 1,48 kg. Danach kompensierten die Tiere von Gruppe L teilweise die Minderzunahmen, so das die tagliche Zunahme fur die ganze Versuchsdauer nicht unterschiedlich war (L: 1,30 kg; M und H: 1,34 kg). Die tagliche Aufnahme an Trockensubstanz und Energie pro kg LM0,75wurden nicht durch einen erhohten Proteingehalt beeinflust, dagegen war der Futteraufwand pro kg Zuwachs leicht reduziert. Die Schlachtkorperqualitat zeigte keine wesentlichen Unterschiede. Ein Proteingehalt uber 77 g DVP oder 137 g Rohprotein in der Ration verbesserte die Produktionsmerkmale nicht. Hohere Proteingehalte reduzierten die Konzentration von Thyroxin und Trijodthyronin im Blutserum. Stickstoffbilanzen mit 6 zusatzlichen Bullen bei 400 und 600 kg Lebendmasse zeigten eine 32% hohere Stickstoffretention fur den hochsten Proteingehalt (54.3 g/Tag) im Vergleich mit dem niedrigsten Proteingehalt (41 g/Tag). Dieser Effekt konnte nicht gesichert werden wegen der grosen Variation. Die Stickstoffausscheidungen waren erhoht.

The relation between the intrinsic carcass and meat quality and the organoleptical characteristics of three genotypes of pigs was studied. In total 411 pigs, consisting of 121 BL-genotype pigs, 115 hybrids (Seghers Hybrid) and 175 Large White-genotype pigs, were screened. Slaughter day and genetic background had a great impact on the intrinsic meat quality parameters. The factor 'slaughter day' implies the stunning method besides the total specific transport and slaughter conditions. Whatever the genetic background is, halothane susceptibility is obviously the crucial factor. Selection against the halothane gene positively influences the intrinsic and sensory meat quality parameters. This study also suggests that an increase in the intramuscular fat content, if desirable in the interest of the sensory meat quality, can be achieved without deterioration of the zoo-technical performance and the carcass quality of the pigs.

Because the current pepsin-cellulase method of De Boever et al. (1986) (Animal Feed Science and Technology, 1986, 14: 203–214) underestimates the digestibility of palm kernel cake, the procedure was adapted by using a cellulase mixture and adding gammanase. In a comparative test on 28 currently used raw materials, the modified method not only increased the digestibility of palm kernel cake (+ 13.7% units), but also that of soya bean hulls (+ 4.7%), whereas the other feeds were little affected. Further, new equations to predict metabolizable energy (ME) and net energy lactation (NEL) were derived for normal (n = 61; ME 9.3–13.9; NEL 5.4–8.5 MJ kg−1 DM) as well as for fibre rich (n = 37; ME 3.8–12.7; NEL 1.9–7.6 MJ kg−1 DM) compound feeds and raw materials. For normal concentrates, best multiple linear regressions based on the new enzymatic method (EN), the original pepsin-cellulase digestibility (CE) and on rumen fluid digestibility (RF) had similar residual standard deviations (RSD) of about 0.25 and 0.20 MJ kg−1 DM for ME and NEL, respectively. For fibre-rich concentrates, the RSDs of RF equations were lower (ME 0.28; NEL 0.20 MJ kg−1 DM) than those of EN equations (ME 0.43; NEL 0.28 MJ kg−1 DM) and CE equations (ME 0.50; NEL 0.32 MJ kg−1 DM). However, when validated, EN equations appeared more accurate than CE and RF equations and the use of tabular values; the ME of 28 mixed feeds was predicted with errors of 2.7%, 2.8%, 3.7% and 3.3%, respectively, whereas for 16 raw materials the errors amounted to 3.3%, 3.6%, 5.0% and 4.3%, respectively. Prediction errors with NEL equations were 0.5–1.1% higher.

The use of beet for beef production after ensiling together with maize was studied in two experiments involving 112 and 114 White-blue bulls. In the first experiment maize silage (I) was compared with mixed silage of maize and fodder beet (II) or sugar beet (III) (ratio: 2/1, DM-basis). In the second experiment maize silage (I) was compared with mixed silage of 0.67 maize and 0.33 sugar beet (II) or maize silage and fresh sugar beet (ratio: 2/1, DM basis) (III) or fresh sugar beet and potatoes afterwards at 4% of the live weight and maize silage (IV). From day 113 onwards, mixed silage was also fed to group III and sugar beet were replaced by raw potatoes in group IV. The basic diet was always supplemented with concentrate at 0.75% of the live weight. In experiment 1 live weight gain was slightly but not significantly higher for the mixed silages, although daily net energy intake per kg metabolic weight was higher. Feed efficiency was not significantly different among groups. Mixed silages yielded more fat in the carcass. In the second experiment initial growth rates were not significantly affected by the use of sugar beet or mixed silages. Afterwards, they were increased in comparison with maize silage. Also in this experiment, daily net energy intake was increased by sugar beet, or by potatoes. Energy efficiency did not differ among groups. This experiment did not show significant differences for the carcass composition. However, EUROP fatness score was higher for diets containing one third sugar beet. Most meat quality parameters were not affected by the diets. Only the lightness was different between III and IV.

Two experiments were conducted to compare the nutritive value of wheat gluten feed (WGF), maize gluten feed (MGF) and sugarbeet pulp (SBP). The protein content of WGF averaged 165 g kg−1 dry matter (DM), and was intermediate between that of MGF (208 g kg−1 DM) and SBP (96 g kg−1 DM). WGF had the lowest crude fibre content. Organic matter digestibilities of WGF and MGF, determined in wethers, were similar in Experiment 1, but differed in Experiment 2. In both experiments, organic matter digestibilities of WGF and MGF were lower than in SBP. The crude fibre digestibility of WGF was lower than in the other two feeds. Energy digestibility was significantly lower in WGF than in SBP with an intermediate value for MGF. Based on both experiments, the average energy and protein values of WGF were intermediate between MGF and SBP, except for the intestinal digestible protein, which was lowest in WGF.

Physical structure of 14 maize silages was investigated; chewing activity was measured with eight cows over 4 d. Silages were harvested from the milk dough dent to the hard dough dent stages of maturity and chopped at lengths of 4 to 16mm. Silages were fed for ad libitum intake and were supplemented with 2kg of soybean meal. Eating, ruminating, and total chewing indexes varied from 16.5 to 25.3, 34.3 to 50.2, and 50.8 to 75.5 min/kg of silage DMI, respectively. Ruminating and total chewing indexes decreased as maturity stage increased. Eating index was not significantly affected by chopping to 4 to 8mm lengths but was higher for the 16-mm maize. Ruminating index was higher with 8-mm than with 4-mm maize, but coarser chopping had no additional effect. Thus, total chewing index increased continuously as chopping length increased from 4 to 16mm. Chemical (DM, crude fiber, NDF, ADF, lignin, and starch) and physical parameters (particle size, milling resistance, and density) and in vitro digestibility were used to derive equations to predict ruminating and total chewing indexes. In vitro digestibility and the fraction of vegetative plant particles retained on a 2.38-mm sieve were the main determinants of both chewing indexes.

Physical structure of 19 grass silages was investigated by measuring chewing activity with a group of eight cows for 4 d. Eating, ruminating, and total chewing indexes varied considerably among cows. Silages were made from perennial ryegrass different in growth stage at harvest, chopping lengths, and preservation methods. Eating index varied from 17.2 to 35.0 min/kg, ruminating index from 39.7 to 61.9 min/kg, and total chewing index from 58.5 to 96.9 min/kg of DMI. Chewing indexes increased from the vegetative to the generative growth stage of grass silages and decreased, not always significantly, when chopped to 24 mm. Compared with wilted silages, direct-cut silages had higher eating and total chewing indexes because of lower palatability and higher water content, but ruminating index was only slightly affected by preservation method. Chemical (DM, crude fiber, NDF, ADF, lignin, sugars) and physical parameters (median particle size, milling resistance, density) and in vitro digestibility were used to derive equations to predict ruminating and total chewing index. Crude fiber explained 82 and 75% of the variation, respectively, in ruminating and total chewing indexes. The supplemental contribution of physical characteristics was only marginal.

The effect of substitution of concentrates by ensiled ground high-moisture maize grain on voluntary feed intake and milk production by dairy cattle was investigated. In the first trial, 5.3 kg of concentrate (control ration) was substituted by 6 kg high-moisture maize grain (3.65 kg dry matter (DM)), 1 kg soybean meal and 400 g of a mineral-vitamin mixture (experimental ration). In the second trial, the concentrate supply was individually adapted to the requirements. This concentrate was partially or totally substituted by high-moisture maize grain, 1 kg soybean meal and 350 g of the mineral-vitamin mixture. The quantity of maize grain was restricted to 6 kg and averaged 5.25 kg (3.24 kg DM). The two trials were carried out according to a cross-over design with 10 and 12 lactating Holstein cows, respectively. The basal ration consisted of 60% (DM basis) whole-crop maize silage and 40% pre-wilted grass silage. The ensiled maize grain had a DM content of 614 g kg −1 , an in vitro organic matter (OM) digestibility of 87.3% and an estimated net energy value of 8.61 MJ kg −1 DM. The maize grain was well preserved. In the two trials, roughage intake was 0.7 and 0.4 kg DM lower for the experimental rations, whereas total DM intake was 0.4 and 0.1 kg lower. For the control and experimental ration, the average milk yield was 26.1 kg and 25.9 kg in Trial 1, and 24.9 kg and 24.5 kg in Trial 2, respectively. Milk fat content was 0.09 and 0.07 percentage units lower for the experimental rations, whereas milk protein content hardly differed. In contrast to the somewhat lower milk fat and milk protein yield, the daily liveweight gain was 90 and 119 g higher for the rations containing maize grain.

Three experiments have been conducted to study the effect of virginiamycin in young grazing-bulls (Experiment 1) and heifers (Experiments 2 and 3). Rotational grazing on permanent grassland was practised and animals were supplemented with 1 kg dried sugarbeet pulp per head daily. Control groups did not receive virginiamycin via the supplement, while it was incorporated at 120, 300 and 200 mg kg−1 for the treatment groups in Experiments 1 to 3 respectively. Average daily liveweight gain was significantly increased from 0·59 to 0·72 kg in Experiment 1 and from 0·73 to 0·81 kg in Experiment 3, but was not affected in Experiment 2 (0·51 vs 0·55 kg). Virginiamycin also increased liveweight gain per ha by 12, 7 and 13%, respectively, for the three experiments. Grazed area per animal was not enlarged to the same extent as the calculated daily energy allowances, which may suggest an improved digestibility and/or rumen fermentation.

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 on nylon-bag digestibility of rolling and steam-flaking as such or followed by grinding through a 1-mm screen was studied in wheat, barley and maize grains. Digestibilities of ground grains were not different, irrespective of rolling or steam-flaking, except flaked and ground barley, which was less digestible than ground barley. Rolled and flaked grains were less digestible than ground grains, except for rolled wheat which was not different from ground wheat. These results suggest that particle size due to grinding is more important than other methods of processing. Dry matter and protein degradabilities of steam-flaked grains were investigated by in sacco technique and compared with unprocessed grains. Dry matter degradability during incubation periods up to 24 h was reduced for steam-flaked wheat and barley, but increased for flaked maize. Protein degradability was lower for flaked grains.

Zusammenfassung Der Einflus von Futterfetten auf die Gewichtsentwicklung Schlachtkorperqualitat und perirenale Fettsaurezusammensetzung bei Mastbullen Hundert weisblaue Belgische Jungbullen erhielten ein Alleinfutter ohne Fettzusatz (Kontrolle), mit 2,5% bzw. 5% Destillationsfett oder 5% Schweineschmalz uber etwa 200 Tage vor der Schlachtung. Die taglichen Zunahmen wurden durch den Einsatz von Futterfetten statistisch nicht beeinflust und betrugen 1,37, 1,38, 1,42 und 1,32 kg. Die tagliche Aufnahme an Trockensubstanz pro kg LM0,75 lag am hochsten mit 83,3 g bei 2,5% Destillationsfett in der Ration. Sie lag niedriger mit 81,7 g bei 5% Destillationsfett und bei 78,9 g bei Schweineschmalz im Vergleich zu 82,2 g in der Kontrollgruppe. Der Futteraufwand betrug in der Kontrollgruppe 6,82 kg und 6,75 bzw. 6,58 kg Trockensubstanz pro kg Zuwachs fur Destillationsfett und 6,73 kg fur Schweineschmalz. Der Energiezuwachs lag bei Fettzulage niedriger ohne vorherige HCl-Hydrolyse. Nach vorangegangenem HCl-Aufschlus waren beide Werte gleich. Die Schlachtausbeute zeigte keine wesentlichen Unterschiede. Der Einsatz von Destillationsfett erhohte den Fettgehalt und reduzierte den Fleischgehalt im Schlachtkorper. Die Fettsaure des Nierenfettgewebes wurde signifikant durch die eingesetzte Fettart beeinflust.

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.

In the Dutch protein evaluation system (Tammingaet al., 1994) microbial protein synthesized in the rumen is estimated from the fermentable organic-matter (FOM) content. The reference method to determine FOM is byin situincubations of food in the rumen of fistulated animals. However, this is a cumbersome, time-consuming and expensive procedure. In practice, FOM is estimated from the digestible organic-matter content (DOMD) corrected for crude fat (Cfat), rumen escape protein (EP) and starch (ES) and the fermentation products (FP), using tabular values. Apart from being indirect, this approach takes little or no account of the variability within foods. Although anin vitromethod based on rumen fluid may give a good prediction ofin situFOM for the majority of the foodstuffs (Coneet al., 1994), an enzymatic method is preferable for practical reasons. From the organic-matter (OM) degradation by a mixture of amylase and other carbohydrate degrading enzymes at 39°C during 0, 2, 6 and 24 h, Coneet al. (1996) obtained a moderate correlation within situFOM for 29 grass and grass silage samples (R2= 0.88; residual s.d. = 37 g/kg dry matter (DM)) and 80 samples of concentrates, maize and clover (R2= 0.77; residual s.d. = 42 g/kg DM). In this study a modified version of the enzymatic method of de Boeveret al. (1994), normally used to predict thein vivoOM digestibility and energy value of concentrates, was tested for its reliability to predictin situFOM of compound foods and forages.

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 > 0.05). Cold carcass weight and dressing were increased by cimaterol from 497.0 to 514.6 kg (P

To evaluate the taste preference of the consumer for meat from homozygous (NN) halothane negative pigs or heterozygous (Nn) halothane negative pigs, a consumer test was conducted at the "Agriflora" exhibition, concerning Flemish agriculture and horticulture, held from 8 to 10 January 1999 in Ghent, Belgium. The carcass quality of both tested genotypes was similar, while acidity, colour and drip loss were inferior and cooking loss and Warner-Bratzler shear force superior for the Nn pigs compared with the NN pigs. One hundred and seventy-one visitors completed the test correctly. No significant difference was found between NN- and Nn-meat for the tastiness scores. These results do suggest that elimination of the halothane gene from the pig population does not guarantee a better eating quality of the meat.

Four hundred and thirty-three double-muscled and two hundred and two non-double-muscled Belgian Blue bulls, with mean cold carcass weights of 470±27 and 414±33 kg, respectively, were studied to investigate the relationships between the SEUROP fat grade, the anatomical fat content in the carcass (adipose tissue) and the chemical fat content in the Longissimus thoracis. The relationships between the shear force value and the lightness of the meat and fat characteristics were also studied. A moderate correlation was found between the fat characteristics within each data set with correlation coefficients, ranging from 0.4 to 0.6. The correlation coefficients increased to 0.70-0.85 when the data sets were pooled. Fat characteristics of the carcass and meat showed only limited predictive power (R(2)0.15) for meat tenderness and colour. This study also shows that double-muscled animals belong to a sub-population of the Belgian Blue breed rather than deviants from the non-double-muscled animal.

The extent to which modification of Warner-Bratzler shear force (WBSF) determinations, relating to storage and preparation of the meat, aperture of the V-shaped cutting blade and shearing velocity, improve the relationship with sensory tenderness perception of pork was studied. Additionally four on-line methods: pH1, FOP1 (light scattering), PQM1 (conductivity) and DDLT (Double Density Light Transmission), were evaluated for their ability to predict tenderness. Sensory tenderness evaluation was conducted on 120 frozen (at -18°C for several months) samples of m. longissimus thoracis et lumborum. After overnight thawing, the meat was grilled to an internal temperature of 74°C and scored on an eight-point scale, from extremely tough to extremely tender. The standard WBSF procedure (protocol A) consisted of heating fresh meat samples (stored for 48 h at 4°C post slaughter) at 75°C for 50 min, cooling in cold tap water for 40 min, taking cylindrical cores parallel to the fibre direction, and shearing at a velocity of 200 mm/min with a blade aperture of 60°. For the prediction of sensory tenderness, the WBSF standard procedure (protocol A) showed the lowest variance (R(2)=15%) and the highest standard error of the estimate (SEE=0.97 N) compared to the other WBSF protocols. A decrease in shearing velocity, from 200 to 100 mm/min and, a replacement of the cutting blade with an aperture of 60° by one with an aperture of 30° led to improvements of R(2) (respectively, 19% vs. 13% and 47% vs. 23%) and SEE (respectively, 0.93 N vs. 0.97 N and 0.80 N vs. 0.97 N) and thus were better predictors of tenderness. A blade aperture of 30° instead of 60° also led to considerably lower WBSF values (22.1 N vs. 30.0 N). Freezing, frozen storage and thawing of the meat, prior to WBSF measurement, resulted in higher shear force values (32.7 N vs. 28.7 N) and a better prediction of tenderness, R(2) (25% vs. 15%) and SEE (0.94 N vs. 1.00 N). Furthermore, preparing the frozen stored meat for WBSF determination in the same way as for the sensory evaluation, namely grilling instead of boiling, led to higher WBSF values (35.5 N vs. 32.7 N) and a further improvement in the prediction of tenderness (R(2)=31% vs. 25% and SEE=0.90 N vs. 0.94 N). From the on-line instruments: pH, FOP and PQM, pH was best in predicting tenderness. Linear regression with tenderness as dependent variable and the on-line techniques as independent variables revealed the following R(2): 16, 8, 8 and 10% and SEE: 0.96, 1.01, 1.01 and 1.00 N for, respectively, pH1, FOP1, PQM1 and DDLT. Thus, the classical instruments and the DDLT technique, which is analogous to the CGM (Capteur Gras/Maigre), an officially accepted carcass grading apparatus in France and Belgium, are not good predictors of tenderness.

The extent to which instrumental colour determinations by FOPu (light scattering), Gofo (reflectance) and Labscan II (CIE L*, CIE a* and CIE b*, hue and chroma) are related to the Japanese colour grades was studied. Additionally, four on-line methods: pH1, FOP1, PQM1 (conductivity) and DDLT (Double Density Light Transmission, analogous to Capteur Gras/Maigre), were evaluated for their ability to predict subjectively and objectively colour. One hundred and twenty samples of m. longissimus thoracis et lumborum, from animals of different genotypes, were analysed. Of the instrumental colour determinations, CIE L* (r=-0.82), FOPu (r=-0.70) and Gofo (r=0.70) were best correlated with the Japanese colour scores. The Japanese colour grades could be predicted by the on-line instruments, pH1, FOP1, PQM1 and DDLT, with determination coefficients between 15 and 28%. Ultimate meat colour, determined by Japanese colour standards, FOPu, Gofo and CIE L*, was better predicted by DDLT than by the classic on-line instruments: FOP1, pH1 and PQM1, although the standard error of the estimate was similar for all instruments. This means that DDLT, although originally designed for estimating lean meat percentage, can additionally give information about meat quality, in particular colour. However, it must be stressed that the colour estimate by DDLT refers to a population of animals, rather than to individual pigs, because of the number of erroneously assigned samples.

Seventy-eight hybrid pigs (Pietrain × Seghers hybrid cross, 38 barrows and 40 gilts) were fed ad libitum diets, containing either 0.4%, 0.7% or 1.0% α-linolenic acid (C18:3n-3), originating from linseed. The variation in polyunsaturated fatty acid content in the feed (1.19%, 1.52% and 1.88%, respectively) was mainly attributed to variations in α-linolenic acid content. Meat quality evaluated by physical measurements (pH, light scattering, conductivity, colour, light reflection, tenderness, water holding capacity) was not influenced, to any significant extent, by the fatty acid composition of the feed. A subjective judgement of cohesiveness revealed no abnormalities. Dietary fat source, sex and intramuscular fat (IMF) level affected the fatty acid pattern of the IMF. The α-linolenic content in the IMF increased from 1.2% to 2.3% for the barrows and from 1.4% to 2.9% for the gilts with increasing αlinolenic acid content in the feed. A multiple paired comparison test for taste, tenderness and juiciness on 45 meat samples (M. longissimus thoracis) revealed no significant differences among the feed groups.

Two experiments were conducted to study the effect of a different duration of dietary cimaterol on animal performances and carcass characteristics in finishing Belgian White-blue bulls. They received a concentrate diet ad libitum during 228 days on average, containing no cimaterol (control) or 4 ppm cimaterol during 71, 127 or 246 days (experiment 1) or during the last 76, 108 or 136 days before the end of the fattening period (experiment 2). Prior to slaughter a 6-day withdrawal period was applied. There was a significant increase in the growth rate immediately after the onset of the cimaterol feeding. A long-term cimaterol administration of 4.5 to 8 months tended to decrease daily gain towards the end of the experiment. Average daily feed intake was only slightly reduced when cimaterol was fed from the beginning of the experiment. Feed conversion was improved by cimaterol, but the effect was smaller after a long-term administration. Increased Longissimus dorsi area and hindleg width revealed muscle hypertrophy in cimaterol-treated bulls. Dressing percent and carcass meat content were increased. Optimum duration of 4 ppm dietary cimaterol varied between 2.5 and 4 months.