Performance of growing and finishing cattle supplemented with a slow-rlease urea product and urea

Abstract

. 2002. Performance of growing and finishing cattle supplemented with a slow-release urea product and urea. Can. J. Anim. Sci. 82: 567-573. Two growth trials were conducted to study the performance of Angus Crossbred steers supplemented with a slow-release urea product (Optigen® 1200, O) and urea (U). The base diets were composed of corn silage alone during the growth period and corn silage plus cracked corn during the finishing period. Trial 1 consisted of 40 animals [272 ± 4 kg body weight (BW)] individually fed the base diets and six treatments, which were based on corn silage alone and cracked corn supplemented with U or O to supply 50 (U 50 , O 50 ) or 100% (U 100 , O 100 ) of the ruminal N deficiency (U 50 , O 50 , U 100 , and O 100 ) as predicted by the Cornell Net Carbohydrate and Protein System (CNCPS), or with U and O each supplying half of the CNCPS predicted N deficiency (U 25 O 25 ). In trial 2, 120 pen-fed animals (241 ± 7 kg BW) received the base diets and four combinations of U and O (U 100 O 0 , U 66 O 34 , U 34 O 66 , and U 0 O 100 ), which were designed to supply 100% of the ruminal N deficiency predicted by the CNCPS. In trial 1, no differences (P > 0.05) in performance were observed between the U 100 and O 100 treatments, but animals in the U 50 treatment had a greater average daily gain (ADG) (P < 0.05) and feed conversion (P < 0.05) than animals on O 50 treatment. In trial 2, combinations of U and O did not affect animal performance (P > 0.05). No differences were observed in carcass characteristics and predicted carcass and empty body fat for both trials (P > 0.05). We concluded there was no improvement in animal performance when urea was substituted by a slow-release urea/NH 3 product at levels normally found in feedlot cattle diets. , préparés de manière à compenser la totalité de la carence en N prévue par BC. Lors du premier essai, les traitements U 100 et O 100 n'ont donné lieu à aucune variation (P > 0,05) du rendement, mais les animaux qui recevaient le traitement U 50 affichaient un meilleur gain quotidien moyen (GQM) (P < 0,05) et une plus grande valorisation des aliments (P < 0,05) que ceux recevant le traitement O 50 . Lors du deuxième essai, le mélange d'urée et de O n'a pas modifié le rendement des animaux (P > 0,05). Les auteurs n'ont relevé aucun écart au niveau des paramètres de la carcasse et de la quantité de gras prévue dans la carcasse avant et après éviscération (P > 0.05) aux deux essais. Ils en concluent que remplacer l'urée par un mélange d'urée et de NH 3 à libération lente ne donne pas lieu à une amélioration du rendement à la concentration habituelle des rations servies aux bovins d'élevage.

Slow-release urea in supplement fed to beef steers

“…There was no effect (P>0.05) of RU substitution by SRU on DM, CP, NDF and NFC intake. In accordance with these results, Tedeschi et al (2002), for crossbred growing and finishing steers, reported that DMI did not differ between the animals fed RU or SRU in total mixed ration. Probably, the high fermentability of the carbohydrate sources in the diet and the continuous supply of nutrients on ad libitum intake resulted continuous fermentation and sufficient N requirements to support the fermentation.…”

“…Urea {CO (NH 2 ) 2 , 46.5% N} was used as regular urea. For slow-release urea production, the granules of regular urea were covered by an inert biodegradable polymer, which allowed slower rate of urea release in the rumen compared with regular urea (Tedeschi et al 2002). Proximate analysis of feedstuffs is shown in Table 1.…”

Effects of a combining feed grade urea and a slow-release product on performance, dietary energetics and carcass characteristics of steers fed finishing diets

“…They explained that the combination of feed grade U with SRU in diets containing a certain ratio of starch:fibre should promote a better synchrony between starch (high rate of digestion) and fibre (low rate of digestion). In contrast, other studies (Tedeschi et al 2002;PinosRodríguez et al 2010) showed that SRU supplementation to finishing steers did not have positive effects on neither gain nor feed efficiency. The estimated S:ADF ratio of the experimental diets of studies conducted by Tedeschi et al (2002) and by Pinos-Rodríguez et al (2010) was over 5.4; thus, the high S:ADF ratios of the diets used in those studies could be a factor in the absence of effects on the performance and feed efficiency of steers fed a combination of U and SRU.…”

“…U combination did not affect (P = 0.96) ADG, but tended to reduce DMI (5.1%, P = 0.06), and reduced DMI expressed as a percentage of live weight (5.8%, P = 0.02). In a few studies, the absence of effects on feed intake of the combination of U plus SRU products has been observed previously in steers fed a finishing diet (Tedeschi et al 2002;Pinos-Rodríguez et al 2010;Castañeda-Serrano et al 2013). However, a tendency for reduction in DMI has been observed in steers fed diets containing 2.25% of a solution of SRU product based on calcium bond U (Duff et al 2000).…”

The partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea and its effect on the performance, metabolism and digestibility in dairy cows

“…In beef animals, the addition of zeolite had little benefit over urea alone as an NPN source on animal performance, although fibre digestibility was improved (Sadeghi and Shawrang, 2006). In addition, there was little benefit to replacing feed urea with a polymer-coated slow-release urea product on the growth or carcass characteristics of beef animals in the study of Tedeschi et al (2002). Comparatively, few studies have been conducted on the effects of slowrelease urea sources in the diet of high-producing dairy cows.…”