Carbon footprint and land requirement for dairy herd rations: impacts of feed production practices and regional climate variations.

Feed production is a significant source of greenhouse gas (GHG) emissions from dairy production and demands large arable and pasture acreage. This study analysed how regional conditions influence GHG emissions of dairy feed rations in a life cycle perspective, that is the carbon footprint (CF) and the land area required. Factors assessed included regional climate variations, grass/clover silage nutrient quality, feedstuff availability, crop yield and feed losses. Using the Nordic feed evaluation model NorFor, rations were optimised for different phases of lactation, dry and growing periods for older cows, first calvers and heifers by regional feed advisors and combined to annual herd rations. Feed production data at farm level were based on national statistics and studies. CF estimates followed standards for life cycle assessment and used emissions factors provided by IPCC. The functional unit was 'feed consumption to produce 1 kg energy corrected milk (ECM) from a cow with annual milk yield of 9 900 kg ECM including replacement animals and feed losses'. Feed ration CF varied from 417 to 531 g CO2 e/kg ECM. Grass/clover silage contributed more than 50% of total GHG emissions. Use of higher quality silage increased ration CF by up to 5% as a result of an additional cut and increased rates of synthetic N-fertiliser. Domestically produced horse bean (Vicia faba), by-products from the sugar industry and maize silage were included in the rations with the lowest CF, but horse bean significantly increased ration land requirement. Rations required between 1.4 to 2 m2 cropland and 0.1 to 0.2 m2/kg semi-natural grassland per kg ECM and year. Higher yield levels reduced ration total CF. Inclusion of GHG emissions from land use change associated with Brazilian soya feed significantly increased ration CF. Ration CF and land use depended on ration composition, which was highly influenced by the regional availability and production of feedstuffs. The impact of individual feedstuffs on ration CF varies due to, for example, cultivation practices and climate conditions and feedstuffs should therefore be assessed in a ration and regional perspective before being used to decrease milk CF. Land use efficiency should be considered together with ration CF, as these can generate goal conflicts.

Physical working conditions in young cattle production in Sweden.

This study investigated physical work environment conditions and sought to identify risk factors in terms of main potential hazards, exposure to physical strain, and the 12-month prevalence of musculoskeletal disorders (MSD) through two postal surveys of Swedish farmers rearing red veal calves (8 to 11 months slaughter age) during April-June 2008 and young bulls (12 to 24 months slaughter age) during March-May 2009. Among 155 red veal producers, the response rate was 45% (n = 59), while among 241 young bull producers finishing 100 or more bulls per year the response rate was 42% (n = 101). A questionnaire was used to obtain general facts about the farm, work time, and frequency of predefined daily and non-daily work tasks. Perceived physical exertion in relation to each work task was assessed by the farmers using the Borg CR-10 scale and further analyzed according to duration and repetitiveness in a physical work strain (PWS) index. The average physical work strain during the predefined work tasks in red veal and young bull finishing was estimated at 3 (moderate strain) on the CR-10 scale. Up to 42% of the surveyed farmers experienced stress and worry about beef production and high levels of potential hazards. High daily work pace and an uncomfortable work climate were other problematic factors. Highly repetitive tasks and physically demanding animal handling were risk factors that increased PWS significantly The 12-month prevalence of MSD was 51% among red veal producers and 65% among young bull producers. Work-related injuries were reported by 20% and 39% of respondents on red veal and young bull farms, respectively, of which 96% and 89% of the cases were related to working with animals.

Variation in carbon footprint of milk due to management differences between Swedish dairy farms.

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 CH4 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 = 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 CO2 equivalents (CO2e)/kg ECM, with an average value of 1.13 kg CO2e/kg ECM. We consider that this variation of ±17%, 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.

Relationship between content of crude protein in rations for dairy cows and milk yield, concentration of urea in milk and ammonia emissions.

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.

Anatomical reconstruction and Evans tenodesis of the lateral ligaments of the ankle. Clinical and radiological findings after follow-up for 15 to 30 years.

In this retrospective study, we assessed the outcome in 99 patients who underwent reconstruction of the lateral ligaments of the ankle for chronic anterolateral instability with a minimum follow-up of 15 years. Two techniques were compared: 54 patients had an anatomical reconstruction (AR group) and 45 had an Evans tenodesis (ET group). They were followed up for 19.9+/-3.6 years and 21.8+/-4.6 years, respectively. During follow-up, seven patients in the AR group and 17 in the ET group required a further operation (p = 0.004). At follow-up, significantly more patients (n = 15) in the ET group had limited dorsiflexion than in the AR group (n = 6, p = 0.007) and 18 in the ET group had a positive anterior drawer test compared with seven in the AR group (p = 0002). In the ET group 27 had tenderness on palpation of the ankle compared with 15 in the AR group (p = 0.001). Stress radiographs showed ligamentous laxity significantly more often in the ET group (n = 30) than in the AR group (n = 13, p < 0.001). The mean values for talar tilt and anterior talar translation were significantly higher in the ET group than in the AR group (p < 0.001, p = 0.007, respectively). There were degenerative changes on standard radiographs in 32 patients in the AR group and 35 in the ET group (p = 0.05). Four patients in the ET group had developed severe osteoarthritis compared with none in the AR group (p = 0.025). Assessment of functional stability revealed a mean Karlsson score of 83.7+/-10.4 points in the AR group and 67.0+/-15.8 points in the ET group (p < 0.001). According to the Good rating system, 43 patients in the AR group had good or excellent results compared with 15 in the ET group (p < 0.001). Compared with anatomical reconstruction, the Evans tenodesis does not prevent laxity in a large number of patients. Long-standing ligamentous laxity leads to degenerative change in the ankle, resulting in chronic pain, limited dorsiflexion and further operations. The functional result deteriorates more rapidly after the Evans tenodesis than after anatomical reconstruction.