Huhtanen, P., Hetta, M. and Swensson, C. 2011. Evaluation of canola meal as a protein supplement for dairy cows: A review and a meta-analysis. Can. J. Anim. Sci. 91: 529Á543. A review and a meta-analysis were conducted to compare the feeding value of soybean meal (SBM) and canola meal (CM) in dairy cows and to evaluate the effects of heat-treatment of CM (TCM) on the performance of dairy cows. The dataset included in total 292 treatment means from 122 studies, in which dietary crude protein (CP) concentration was increased by replacing energy supplements with protein supplements. A mixed model regression analysis with random study effect was used to estimate the marginal production responses to different protein sources. The differences between the slopes were compared by t-test. All protein sources increased dry matter intake, but the responses were greater (PB0.01) for CM and TCM compared with SBM. Feeding CM or TCM produced greater (PB0.01) daily milk yield responses than SBM (3.490.19 and 3.790.25 vs. 2.190.25) kg kg (1 increase in CP intake. Marginal milk protein yield responses (g kg (1 increase in CP intake) were greater (PB0.01) for CM (1369 5.4) and TCM (13398.5) compared with SBM (9898.0). Smaller response to incremental CP intake can partly be related to the higher average dietary CP concentration in SBM studies. Literature data on rumen ammonia N concentration and omasal protein flow did not support the higher ruminal tabulated ruminal CP degradability of CM compared with SBM. It is concluded that CM can successfully be substituted for SBM on isonitrogenous basis and that most feed evaluation systems overestimate metabolizable protein concentration of SBM relative to CM.Huhtanen, P., Hetta, M. et Swensson, C. 2011. É valuation du tourteau de canola comme supple´ment prote´ique pour la vache laitie`re : revue et me´ta-analyse. Can. J. Anim. Sci. 91: 529Á543. Les auteurs ont proce´de´a`une revue et a`une me´ta-analyse afin de comparer la valeur nutritive du tourteau de soja (TS) a`celle du tourteau de canola (TC) pour la vache laitie`re, et e´valuer l'incidence d'un traitement thermique du TC (TCT) sur le rendement des animaux. La base de donne´es consistait en la moyenne de 292 traitements venant de 122 e´tudes dans lesquelles on avait augmente´la concentration de prote´ines brutes (PB) en remplac¸ant les supple´ments e´nerge´tiques par des supple´ments prote´iques. Les auteurs ont recouru a`un mode`le mixte d'analyse par re´gression a`effet ale´atoire pour estimer la re´action marginale de la production aux diffe´rentes sources de prote´ines. L'e´cart entre les pentes a e´te´compare´au moyen du test t. Toutes les sources de prote´ines augmentent l'ingestion de matie`re se`che, mais le TC et le TCT le font plus (P B 0,01) que le TS. Donner du TC ou du TCT accroıˆt plus (PB0,01) le rendement laitier quotidien que donner du TS (3,490,19 et 3,7 9 0,25 c. 2,190,25 kg par kg de kilo de prote´ines brutes supple´mentaires inge´re´). La re´action marginale du rendement en prote´ines du lait (g par kg de PB sup...

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During recent decades, efforts have been made in several countries to diminish the negative environmental influence of dairy production. The main focus has been on nitrogen and phosphorus. Modern dairy production in Western Europe is often based on imported feed-stuffs, mostly protein-rich feeds. In Sweden at least, it is wished that the use of imported feedstuffs in animal production will decrease due to the risk of contamination with Salmonella and the ban of using GMO crops in Swedish dairy production. An experiment was carried out to investigate whether a lower content of crude protein in the diet would decrease the ammonia release from cow manure and whether a well-balanced diet using only feedstuffs of Swedish origin would maintain milk production. Five treatments were arranged in a Latin square design. Two different protein supplements made of ingredients of Swedish origin were each fed at two protein levels, and a fifth imported commercial protein mix was fed at the higher level. The treatments with low protein levels (13.1 to 13.5%) had a significantly lower milk yield, kilograms of ECM, but, on the other hand the net profit, milk income minus feed cost was nearly the same in all treatments except diet C, which had lower feed cost but also lower net profit due to lower milk yield. The content of urea in milk was higher with diets high in crude protein (17%) content. A decreased protein level in the diets did not influence the content of casein or whey protein, but the commercial concentrate showed a tendency to give lower values than the Swedish mixtures. The low protein diets gave significantly lower ammonia release from manure compared with the high protein diets. There were no production differences between the diets of Swedish feeds compared with the imported control. The readily fermentable beet pulp should have helped cows use the higher N diet more efficiently and increased the response. This gives the rumen microbes a possibility to match the inflow of protein with carbohydrates. Income over feed costs shows that it is possible to compile diets using products of Swedish origin and still be competitive. On the other hand, this structure may change quickly due to altered world market prices.

To identify mitigation options to reduce greenhouse gas (GHG) emissions from milk production (i.e. the carbon footprint (CF) of milk), this study examined the variation in GHG emissions among dairy farms using data from previous CF studies on Swedish milk. Variations between farms in these production data, which were found to have a strong influence on milk CF, were obtained from existing databases of 1051 dairy farms in Sweden in 2005. Monte Carlo (MC) analysis was used to analyse the impact of variations in seven important parameters on milk CF concerning milk yield (energy-corrected milk (ECM) produced and delivered), feed dry matter intake (DMI), enteric CH 4 emissions, N content in feed DMI, N-fertiliser rate and diesel used on farm. The largest between-farm variations among the analysed production data were N-fertiliser rate (kg/ha) and diesel used (l/ha) on farm (CV 5 31% to 38%). For the parameters concerning milk yield and feed DMI, the CV was approximately 11% and 8%, respectively. The smallest variation in production data was found for N content in feed DMI. According to the MC analysis, these variations in production data led to a variation in milk CF of between 0.94 and 1.33 kg CO 2 equivalents (CO 2 e)/kg ECM, with an average value of 1.13 kg CO 2 e/kg ECM. We consider that this variation of 617%, which was found to be based on the used farm data, would be even greater if all Swedish dairy farms were included, as the sample of farms in this study was not totally unbiased. The variation identified in milk CF indicates that a potential exists to reduce GHG emissions from milk production on both the national and farm levels through changes in management. As milk yield and feed DMI are two of the most influential parameters for milk CF, feed conversion efficiency (i.e. units ECM produced/unit DMI) can be used as a rough key performance indicator for predicting CF reductions. However, it must be borne in mind that feeds have different CF due to where and how they are produced.

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