Less intensified grazing management with growing fattening bulls

Abstract

-Animal performance, composition and quality of meat from Belgian Blue bulls either fattened indoors (FI) or finished indoors after a previous grazing period were studied during six years. During the grazing period, three intensification managements were tested on a permanent pasture conducted as set stocking. The intensification levels were either high (HN: 140 kg N·ha −1 with 6 bulls·ha −1 ) or moderate with a 33% reduction of nitrogen fertilisation but with the same stocking rate (MN: 93 kg N·ha −1 , 6 bulls·ha −1 ) or low with no nitrogen fertiliser but with a reduced stocking rate (ON, 4 bulls·ha −1 ). The levels of intensification did not affect sward characteristics and chemical composition of the grass. The apparent nitrogen efficiency per ha was larger in the ON plot than in the HN and MN plots (26 vs. 14%). The average daily gain of bulls during the grazing season was similar in the three groups at 1.0 kg·d −1 . The bulls from the FI group were characterised by average daily gains significantly higher than the bulls which were previously grazed and then finished indoors (1.5 vs. 1.2 kg·d −1 ; P < 0.01). The slaughter weight, the carcass composition, the dressing percentage and most of the meat quality parameters were similar between the treatment groups. The inclusion of a grazing period in the fattening system produced a meat which was darker (lower L*, P < 0.01), more red (higher a*, P < 0.05) and had a higher content of linolenic acid (C18:3 n-3) than that of the animals fattened indoors.fattening / bulls / grazing / nitrogen fertiliser / stocking rate Résumé -Désintensification de la conduite de prairies pâturées par de jeunes taurillons. Les performances zootechniques, la composition et la qualité de la viande de taurillons Blanc Bleu belge engraissés uniquement en stabulation (FI) ou finis en stabulation après une période de pâturage ont été étudiées pendant six années. Pendant la période de pâturage, trois niveaux d'intensification ont été testés dans une prairie permanente. Le système de pâturage continu a été employé. Les niveaux d'intensification ont été soit élevé (HN : 140 kg N·ha −1 ; 6 taureaux·ha −1 ), soit modéré avec une réduction de 33 % de la fertilisation azotée mais avec le même chargement (MN : 93 kg N·ha gain quotidien moyen des taureaux pendant la période de pâturage a été identique dans les trois lots (1 kg·j −1 ). Les taurillons du groupe FI ont présenté des gains quotidiens moyens significativement plus élevés que ceux des taurillons ayant séjourné en prairie et finis en stabulation (1,5 vs. 1,2 kg·j −1 ; P < 0,01). Le poids d'abattage, la composition de carcasse ainsi que le rendement à l'abattage et les paramètres de qualité de viande ont été semblables entre les traitements. L'inclusion d'une période de pâturage a produit une viande plus foncée et rouge par rapport au lot FI. Les teneurs en C18:3 ont été plus élevées (P < 0,05) pour les taurillons du lot HN par rapport à celles du lot FI. engraissement / taurillons / pâturage / fumure azotée / chargement

Performance of spring-calving beef suckler cows and their progeny on four contrasting grassland management systems

“…The N-use efficiency (N output input − 1 ha − 1 ) for Systems HH2, HL2, LL2 and LL1 were 0.11, 0.16, 0.16 and 0.17, respectively. Dieguez Cameroni et al (2006) reported an apparent N efficiency of 0.13, 0.15 and 0.26 during the grazing period for growing fattening bulls on high N-high SR, moderate N-high SR and zero N-low SR systems, respectively. From a review of the literature Peyraud and Astigarraga (1998) concluded that lowering levels of N fertilisation (with an appropriate reduction in SR) appeared to be an effective means of reducing N losses of ruminants in grazing systems with little or no change in the animals nutrition or in their individual output.…”

Performance and Carcass Quality of Forage-Fed Steers as an Alternative to Concentrate-Based Beef Production

“…The differences in performance during the housing period between Control bulls and both groups of steers could be attributed to the different energy and protein content of diets. Including forage in the beef diets reduces average daily [page 867] gain and feed efficiency (Dieguez Cameroni et al, 2006;Patterson et al, 2000), depending on the proportion forage:concentrate (Nuernberg et al, 2005) mainly due to the lower energy concentration of forages. Furthermore, the different gender could enlarge the differences in weight gains because it affects both intake and feed efficiency for growth (Andersen and Ingvartsen, 1984).…”