. 2000. Effect of intensity of maceration on digestibility and intake of alfalfa hay and silage fed to sheep. Can. J. Anim. Sci. 80: 113-121. A study was conducted to determine the influence of intensity of mechanical conditioning on the nutritive value of alfalfa conserved as hay or silage. Fresh alfalfa was mowed and conditioned at three levels of maceration prior to field wilting during 45 h for silage (29-39% DM) or 94 h for hay (87% DM, after barn-curing), under light rain conditions during the first 2 d. The conditioning treatments were: control (conventional mowing-conditioning), light maceration (one passage through three knurled steel rolls), medium maceration (two passages), and intense maceration (three passages). Concentrations of NDF, ADF, hemicellulose, CP-NDF, and CP-ADF increased linearly (P < 0.001) with the level of maceration. Silage pH, acetic acid, propionic acid, and butyric acid increased, while lactic acid decreased (P < 0.001), with the level of maceration. The effective rumen degradabilities of DM, CP, and NDF, measured with fistulated cows, were not affected (P > 0.10) by the level of mechanical conditioning. Forty-eight male sheep (46.8 ± 6.7 kg BW) were fed a 100% forage diet according to a completely randomized design with a 2 × 4 factorial arrangement of treatments (two storage methods and four levels of conditioning). Under restricted feeding, DM, NDF, ADF, and hemicellulose digestibilities decreased linearly (P < 0.001) with the level of maceration. However, the digestibility of CP-NDF increased with the level of maceration; the effect was more important in hay than in silage (P < 0.001 for the interaction). When silages were fed ad libitum to 24 sheep, daily DMI was 2.31, 2.88, 2.76, and 2.41% of BW and DM digestibility was 60.8, 60.1, 56.2, and 46.7%, for control, light, medium, and intense maceration, respectively (P < 0.01). The results suggest that light maceration increases DM intake while maintaining digestibility of forages fed to sheep. Because of humid conditions and potential soil contamination due to multiple windrow pickup, intense maceration caused severe nutrient loss, which might be avoided under dry field wilting and good storage conditions. Key words: Alfalfa, hay, silage, digestion, degradability, intake Agbossamey, Y. R., Savoie, P., Seoane, J. R. et Petit H. V. 2000. Effet de l'intensité du conditionnement mécanique sur la digestibilité et la prise alimentaire du foin et de l'ensilage de luzerne chez le mouton. Can. J. Anim. Sci. 80: 113-121. Une étude a été menée afin de déterminer l'influence de l'intensité du conditionnement mécanique sur la valeur alimentaire de la luzerne conservée sous forme de foin ou d'ensilage. La luzerne fraîchement coupée a été traitée à trois niveaux de surconditionnement et fanée au champ durant 45 h pour l'ensilage (29 à 39% MS) ou 94 h pour le foin (87% MS après ventilation en grange), sous des conditions de pluie légère durant les deux premiers jours. Les niveaux de conditionnement étaient: un témoin (conditionnement conventio...

Effect of maceration on nitrogen fractions in hay and silage. Can. J. Anim. Sci. 78: 399-405. An intensive mechanical conditioning treatment, referred to as maceration, was applied at mowing to alfalfa or timothy in order to enhance drying rate, reduce wilting time and possibly reduce respiration losses and proteolysis. In 1995, a laboratory trial was conducted using two levels of force (1750 and 3500 Newton) and five levels of conditioning: a control (no conditioning), one passage, three passages, five passages and seven passages through two steel knurled rolls. All forages were dried in a controlled environment at 30°C and conserved as hay. The level of force did not affect the chemical composition of the forages obtained. However the nitrogen (N) fractions were affected by the level of maceration. As the level of conditioning increased, the soluble N fractions (A and B1) of both forages decreased (P < 0.001). Meanwhile, the slowly degradable N fraction (B3) increased linearly (P < 0.001) in timothy and quadratically (P < 0.003) in alfalfa. The fraction of unavailable N (fraction C) also increased linearly (P < 0.01) with intensity of maceration. In 1996, alfalfa was conditioned in the field at four intensity levels: a control (rubber roll-conditioning), one passage, two passages, and three passages through a full-size mower-macerator with three knurled rolls. The alfalfa dried under poor climatic conditions with alternating rain and sunshine and was conserved as silage at 30% dry matter (DM) after a 40-h wilt or as hay after a 90-h wilt. Neutral detergent fibre (NDF), acid detergent fibre (ADF), and ash contents increased linearly (P < 0.001) with the level of maceration; the increase was greater in hay than in silage. The non protein nitrogen (fraction A) decreased (P < 0.001) while fraction B3 and unavailable N (fraction C) increased (P < 0.001) with level of maceration. The results suggest that maceration decreases the extent of proteolysis during conservation and preserves a higher proportion of the slowly degradable N (escape nitrogen). Key words: Forage, maceration, chemical composition, nitrogen fractionsAgbossamey, Y. R., Savoie, P. et Seoane, J. R. 1998. Effet du surconditionnement sur les fractions azotées du foin et de l'ensilage. Can. J. Anim. Sci. 78: 399-405. Un surconditionnement mécanique intense a été appliqué lors de la fauche de la luzerne et de la fléole des prés dans le but d'accélérer la vitesse de séchage, de réduire le temps de fanage et de réduire possiblement les pertes dues à la respiration et à la protéolyse. En 1995, une expérience a été menée au laboratoire en utilisant deux niveaux de force (1750 et 3500 Newton) et cinq niveaux de conditionnement: un témoin (aucun conditionnement), un passage, trois passages, cinq passages et sept passages du fourrage à travers deux rouleaux broyeurs. Les fourrages ont été séchés à 30°C dans un environnement contrôlé et ont été conservés sous forme de foin. La force appliquée au surconditionnement n'a pas affecté la composition chimique des four...

. 1998. Performance of lambs fed either hay or silage supplemented with canola or fish meals. Can. J. Anim. Sci. 78: 135-141. Forty-eight lambs (29.0 ± 4.7 kg BW) were used to study the effects of protein supplementation of forages on performance and diet digestibility. Lambs were fed grass hay or silage ad libitum plus a daily supplement of either: C, a control supplement supplying 1.2 g kg -1 BW of dry molasses and 0.6 g kg -1 BW of minerals, vitamins and lasalocid; CM, control supplement + 5.48 g kg -1 BW of canola meal; or FM, control supplement + 3 g kg -1 BW of fish meal. Apparent digestibility of all dietary components was higher in lambs fed silage than in those fed hay (P < 0.04). Addition of CM or FM improved apparent digestibility of energy and crude protein (CP) of lambs fed hay (P < 0.02) and CP digestibility of lambs fed silage (P < 0.01). Apparent digestibility of CP was higher in lambs fed FM than in those fed CM with either hay or silage (P < 0.03). Addition of CM or FM tended to decrease ADF digestibility of silage-based diets (P < 0.06). Apparent ADF digestibility of hay-based diets was lower in lambs fed CM than in those fed FM (P < 0.02). Forage DM intake was similar for all treatments. Addition of CM or FM to the diets improved average daily gains by 24% (P < 0.03), an effect that was higher with hay (35.1%, P < 0.02). Feed efficiency was 23.6% better in lambs fed protein-supplemented hay than in those receiving C (P < 0.04). Neither dressing percentage nor carcass lean yield was affected by protein supplementation. Digestible DM and TDN intakes were higher in lambs fed silage (P < 0.03) as a result of higher apparent digestibility for silage than hay. Furthermore, CM increased TDN intake by 7.6 and 8.2% in lambs fed hay and silage, respectively, compared with lambs fed FM. Addition of canola and fish meals improved forage nutritive value for lambs.Key words: Canola meal, fish meal, forages, digestibility, lambs, growth Agbossamey, Y. R., Petit, H. V., Seoane, J. R. et St-Laurent, G. J. 1998. Performance des agneaux nourris avec du foin ou de l'ensilage supplémenté avec du tourteau de canola ou de la farine de poisson. Can. J. Anim. Sci. 78: 135-141. Quarante-huit agneaux mâles (29,0 ± 4,7 kg poids vif) ont été utilisés afin d'étudier les effets de la supplémentation protéique des fourrages de dactyle sur les performances zootechniques et la digestibilité des rations. Les animaux ont été alimentés à volonté avec du foin ou de l'ensilage et ils ont reçu une quantité fixe de l'un des trois suppléments suivants: T, supplément témoin contenant 1,2 g kg -1 PV jour -1 de mélasse sèche et 0,6 g kg -1 PV jour -1 de minéraux, vitamines et Bovatec; TC, supplément témoin + 5,48 g kg -1 PV jour -1 de tourteau de canola; FP, supplément témoin + 3 g kg -1 PV jour -1 de farine de poisson. La digestibilité apparente de toutes les composantes de la ration a été plus élevée chez les agneaux recevant de l'ensilage que pour ceux recevant du foin (P < 0,04). L'addition des suppléments protéiques a amélioré la d...

Fresh alfalfa was mowed and conditioned mechanically at four levels: a control (rubber rolls), macerated once (a single passage through three finely corrugated rolls set at 1-mm clearance), macerated twice (two passages), and macerated thrice (three passages). Alfalfa was then field-wilted either for 45 h and conserved as chopped silage at 30% dry matter (DM) or for 94 h and stored as baled hay at 85% DM. The eight forage treatments (four mechanical conditioning levels x two conservation systems) were fed to 24 sheep (three replications per treatment) during 5 wk. At the beginning of wk 5, a 15-g sample of chromium-mordanted forage (3.5% Cr) was fed to each sheep, and feces samples were collected at 30 different times over 7 d, between 10 h and 168 h after Cr ingestion. Four models were used to estimate the passage rates, the time delay, and the mean retention time (MRT). A two-compartment time-dependent model and a multicompartment model produced the best fit (average r2 of 0.96) to represent the Cr concentration in the feces over time. When compared with alfalfa hay, alfalfa silage had a higher (P < 0.01) time-dependent turnover rate (0.0949 vs 0.0733/h), a lower (P = 0.03) time delay (9.1 vs 11 h), and a lower (P = 0.04) MRT (57.8 vs 64.4 h). Maceration did not affect significantly (P > 0.10) the time delay or the MRT. However, the MRT of macerated alfalfa hay tended to be higher than the MRT of control hay. Experimental data based on marker concentration in the feces can be used satisfactorily to assess differences in MRT between treatments, but they should be used with caution to estimate the partition of retention time within the gastrointestinal tract.