Metanproduktion hos mjölkkor utfodrade med hög andel grovfoder

Metan (CH4) är en växthusgas som bildas vid bland annat idisslarnas foderomvandling. Metan bidrar till den globala uppvärmningen samtidigt som det utgör en energiförlust för idisslaren. Syftet med den här studien var att undersöka hur mycket metan det bildas med olika andelar grovfoder i foderstaten. Grovfodret utgjordes av gräsensilage, baserat på timotej och ängssvingel (omsättbar energi 11,5 MJ/ kg torrsubstans (ts)) som är ett typiskt fodermedel i svensk mjölkproduktion. I denna studie användes svavelhexafluorid (SF6) som spårgas för att mäta metanproduktionen. Värdena jämfördes sedan med empiriska beräkningar samt med värden från analyser av fettsyrasammansättningen i våmmen. I försöket ingick sex våmfistulerade kor av rasen Svensk rödbrokig boskap (SRB). Korna stod avskiljt i en egen avdelning för att mätningarna inte skulle påverkas av andra kor. Korna utfodrades för samma energibehov under hela försöket. De delades in i tre olika behandlingar; låg grovfoderandel (L) 50% grovfoder och 50% kraftfoder, medel grovfoderandel (M) 70% grovfoder och 30% kraftfoder och hög grovfoderandel (H) 90% grovfoder och 10% kraftfoder. Detta var ett change-over försök vilket innebar att alla kor fick alla behandlingar under försökets gång. Försöket delades in i tre perioder och varje mätperiod var 10 dagar där gasprover samlades varje dag. Prover av våmvätska samlades in de fem sista dagarna i varje mätperiod. Mjölkvikter registrerades varje dag under mätperioden och provmjölkning utfördes i varje period, metanproduktionen beräknades per kg mjölk. Det var inga skillnader i metanproduktion mellan behandlingarna (L = 275,3, M = 300,5 och H = 317,0 g CH4/dag, P = 0,1312). Det var heller inga skillnader i g CH4/ kg ts-intag (L = 18,4 , M = 20,1 och H = 20,3 g CH4/kg ts-intag). Det var ingen skillnad i totalmängd flyktiga fettsyror (VFA) eller andel ättiksyra, skillnad fanns i andel propionsyra och smörsyra mellan behandlingarna. Resultaten visar att när korna utfodras med ett grovfoder av hög kvalitet blir det inga större skillnader i metanproduktion mellan foderstater med 50 och upp till 70% grovfoder. Det var skillnad i mjölkavkastningen mellan behandlingarna både i kg mjölk och kg energikorrigerad mjölk (ECM). Det var skillnad mellan behandlingar i g CH4/kg mjölk och g CH4/kg ECM. De empiriska modellerna visade olika värden på metanproduktion beroende på vilka parametrar som innefattades

Methane production in dairy cows

Greenhouse gas emissions from the agricultural sector represent about 14.5% of total emissions related to human activity. Approximately 40% of agricultural sector emissions derive from enteric methane (CH₄) production by ruminants, due to their microbial digestion of feed. Level of CH₄ production varies according to feed type, feed intake and even among individual animals raised under similar conditions, but the underlying mechanism is not well known. This thesis investigated the effects of feed, feed additives, and rumen microbiota on CH₄ production within dairy cows and in a gas in vitro system. Effect of individual cow was stronger than effect of diet for both CH₄ production and methanogenic population when two different levels of forage proportions were fed. Dividing Methanobrevibacter species into two groups better explained the variation in CH₄ production. The effect of individual was evaluated in cows fed the same diet during mid-lactation. High, low and medium emitters were identified and selected for further studies on rumen microbiota. These revealed that CH₄ production was associated with archaeal and bacterial community structure. Differences were observed in volatile fatty acid proportions between communities, but not in fibre digestion or milk production. Tests on feed additives, cashew nut shell extract (CNSE) and glycerol in a gas in vitro system for their ability to reduce CH₄ production showed that CNSE reduced CH₄ production by 18% and had a strong impact on microbiota, while glycerol increased CH₄ production by 12% and had less effect on microbiota compared with the control. Comparison of microbial composition in inoculum from the in vitro control and in inoculum from the donor cow before incubation revealed that the bacterial community was relatively similar, while relative abundance of some species changed for archaeal population. This effect of transfer into another system should be considered when evaluating in vitro data. Evaluation of the in vitro system by comparing predicted and observed CH₄ production on 49 test diets showed an overall good relationship, with small root mean square error for prediction (12.3% and 9.5% of observed mean for fixed and mixed models, respectively). However, the in vitro system had limitations in prediction of concentrate proportion

Nötkreaturens metanproduktion i Sverige – en jämförelse mellan 1937 och 2019

Antalet nötkreatur i Sverige har halverats under det senaste århundradet. Senast Sverige hade en så liten population nötkreatur som nu var på 1700-talet.Antalet mjölkkor i dag är bara 16 procent av antalet 1937, då Sverige hade som störst antal mjölkkor.Den totala mjölkproduktionen i Sverige har nästan halverats sedan 1937 (från 4,9 miljoner ton 1937 till 2,7 miljoner ton 2019).Den totala köttproduktionen har ökat med 28 procent mellan 1937 och 2019, framför allt genom att späd-och gödkalvar som tidigare slaktades vid mycket ung ålder nu föds upp till ungnöt och på grund av bättre utfodring och avel mot större djur.Den totala proteinproduktionen var 29 procent högre år 1937 än 2019 på grund av att Sverige då hade en betydligt större mjölkproduktion.Metanutsläppen från dagens population av nötkreatur i Sverige är i samma storleksordning som metanutsläppen från nötkreaturen i Sverige på 1870-talet.Metanutsläppen från mjölk-och nötköttsproduktionen i Sverige har minskat med ungefär 35 procent sedan 1937.Metanutsläppen från mjölkkorna (metan per kilo totalt protein från mjölk och kött) har halverats sedan 1937.Metanutsläppen per total mängd producerat protein från hela nötkreatursproduktionen är lägre idag än på 1930-talet på grund av en mer effektiv produktion. Men det är stora skillnader i metanproduktion per kilo produkt till följd av utvecklingen mot specialiserad mjölkproduktion och specialiserad nötköttsproduktion.Det har skett en förändring i produktion från en nästan helt och hållet grovfoderbaserad, integrerad mjölk-och nötköttsproduktion – till en specialiserad och insatsberoende mjölkproduktion och en separat dikoproduktion.Den svenska mjölk-och nötköttsproduktionen har förändrats mycket de senaste 100 åren. Antal nötkreatur har minskat markant och följaktligen även den totala metanproduktionen från nötkreaturen. Samtidigt har produktionen av nötkött och mjölk ökat per individ

Using machine learning methods to predict dry matter intake from milk mid-infrared spectroscopy data on Swedish dairy cattle

In this research communication we compare three different approaches for developing dry matter intake (DMI) prediction models based on milk mid-infrared spectra (MIRS), using data collected from a research herd over five years. In dairy production, knowledge of individual DMI could be important and useful, but DMI can be difficult and expensive to measure on most commercial farms as cows are commonly group-fed. Instead, this parameter is often estimated based on the age, body weight, stage of lactation and body condition score of the cow. Recently, milk MIRS have also been used as a tool to estimate DMI. There are different methods available to create prediction models from large datasets. The main data used were total DMI calculated as a 3-d average, coupled with milk MIRS data available fortnightly. Data on milk yield and lactation stage parameters were also available for each animal. We compared the performance of three prediction approaches: partial least-squares regression, support vector machine regression and random forest regression. The full milk MIRS alone gave low to moderate prediction accuracy (R-2 = 0.07-0.40), regardless of prediction modelling approach. Adding more variables to the model improved R-2 and decreased the prediction error. Overall, partial least-squares regression proved to be the best method for predicting DMI from milk MIRS data, while MIRS data together with milk yield and concentrate DMI at 3-30 d in milk provided good prediction accuracy (R-2 = 0.52-0.65) regardless of the prediction tool used

Full-lactation performance of multiparous dairy cows with differing residual feed intake

Residual feed intake (RFI) is an efficiency trait underpinning profitability and environmental sustainability in dairy production. This study compared performance during a complete lactation of 36 multiparous dairy cows divided into three equal-sized groups with high (HRFI), intermediate (IRFI) or low RFI (LRFI). Residual feed intake was determined by two different equations. Residual feed intake according to the NorFor system was calculated as (RFINorFor) = (NEintake)–(NEmaintenance + NEgestation + NEmilk—NEmobilisation + NEdeposition). Residual feed intake according to the USA National Research Council (NRC) (RFINRC) was calculated as: RFI = DMI − predicted DMI where predicteds DMI = [(0.372× ECM)+(0.0968×BW0.75)]×(1−e−0.192×(DIM/7+3.67)). Cows in the HRFINorFor group showed higher daily CH4 production, CH4/ECM and CH4 yield (g/kg DMI) than IRFINorFor and LRFINorFor cows. Cows characterized by high efficiency (LRFINorFor) according to the NorFor system had lower body weight. Dry matter intake and apparent dry matter digestibility were not affected by efficiency group but milk yield was lower in the low efficiency, HRFINorFor, group. Cows characterized by high efficiency according to the NRC system (LRFINRC) had lower dry matter intake while yield of CH4 was higher. Daily CH4 production and CH4 g/kg ECM did not differ between RFINRC groups. Dairy cows characterized by high efficiency (both LRFINorFor and LRFINRC cows) over a complete lactation mobilized more of their body reserves in early lactation as well as during the complete lactation. The results also indicated great phenotypic variation in RFI between different stages the lactation

Reducing methane production from stored feces of dairy cows by Asparagopsis taxiformis

The objective was to evaluate whether methane (CH4) production from stored feces of cows previously supplemented with Asparagopsis taxiformis (AT) in their diet was lower compared with the feces of cows not supplemented with AT. We also investigated the possibility of further reducing CH4 production by adding AT to the stored feces of cows. Fecal samples were provided from a feeding trial (during two different periods) of four cows divided into two different groups. One group was supplemented with AT at a level of 0.5% of the total organic matter intake, and the other group was not supplemented with AT. A 2 × 2 factorial design was set in the laboratory for the incubation of feces. Fecal samples from the two groups of cows were divided into two subsamples receiving either no addition of AT or the addition of AT at a level of 0.5% of OM incubated. This resulted in four treatments with two replicates per period. The same design was repeated during period two. In total, 400 g of fresh fecal samples were incubated in 1 L serum bottles for 9 weeks at 39°C in a water bath. CH4 and total gas production were measured on days 1, 4, and 7 and subsequently every 2nd week until the end of the incubation period. Enteric CH4 production showed a significant reduction (61%) when AT was supplemented in the diet of dairy cows. We found that CH4 production from the feces of dairy cows supplemented with AT in their diet was only numerically lower (P = 0.61). Adding AT to the feces of dairy cows significantly reduced CH4 production from the feces by 44% compared with feces without AT. There were no differences observed in the bacterial and archaeal community profiles of fecal samples between cows fed AT and those not fed AT. This study concludes that the addition of AT to stored feces can effectively reduce CH4 production from the feces of dairy cows

Effects on rumen microbiome and milk quality of dairy cows supplemented the macroalgae Asparagopsis taxiformis in a grass silage-based diet

Peer reviewe

Effects on rumen microbiome and milk quality of dairy cows supplemented the macroalga Asparagopsis taxiformis in a grass silage-based diet

The objective was to determine the effects on rumen microbiome and milk quality of reducing the methane (CH4) produced from enteric fermentation by the addition of Asparagopsis taxiformis (AT) to the diets of dairy cows. Six Nordic Red cows at 122 ± 13.7 (mean ± SD) days in milk, of parity 2.7 ± 0.52 and producing 36 kg ± 2.5 kg milk per day at the start of the trial were divided into three blocks by milk yield and assigned to an extra-period Latin-square change-over design comprising two dietary treatments. An extra period of observation was added to the Latin-square change-over design to control for carry-over effects. The dietary treatments were a diet consisting of grass silage and a commercial concentrate mixture (60:40) either not supplemented or supplemented with 0.5% AT on an organic matter intake basis. On average, daily CH4 production, CH4 yield, and CH4 intensity decreased by 60%, 54%, and 58%, respectively, in cows fed the diet supplemented with AT. Furthermore, hydrogen gas emitted by cows fed diets supplemented with AT increased by more than five times compared with cows fed a non-AT-supplemented diet. Feed intake was decreased and milk production altered, reflecting a decreased yield of milk fat in cows fed an AT-supplemented diet, but feed efficiency increased. Rumen fermentation parameters were changed to promote propionate rather than acetate and butyrate fermentation. The most prominent change in milk quality was an increase in bromine and iodine when the diet was supplemented with AT. The reduction in CH4 was associated with a shift from Methanobrevibacter to Methanomethylophilaceae in the archaeal population and a lower relative abundance of Prevotella in the bacterial population. Changes in milk fat odd-numbered and branched-chain fatty acids in the current study of AT supplementation support observed differences in ruminal archaeal and bacterial populations

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950-2019 : a comprehensive demographic analysis for the Global Burden of Disease Study 2019

Background: Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods: 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10–14 and 50–54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings: The global TFR decreased from 2·72 (95% uncertainty interval [UI] 2·66–2·79) in 2000 to 2·31 (2·17–2·46) in 2019. Global annual livebirths increased from 134·5 million (131·5–137·8) in 2000 to a peak of 139·6 million (133·0–146·9) in 2016. Global livebirths then declined to 135·3 million (127·2–144·1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2·1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27·1% (95% UI 26·4–27·8) of global livebirths. Global life expectancy at birth increased from 67·2 years (95% UI 66·8–67·6) in 2000 to 73·5 years (72·8–74·3) in 2019. The total number of deaths increased from 50·7 million (49·5–51·9) in 2000 to 56·5 million (53·7–59·2) in 2019. Under-5 deaths declined from 9·6 million (9·1–10·3) in 2000 to 5·0 million (4·3–6·0) in 2019. Global population increased by 25·7%, from 6·2 billion (6·0–6·3) in 2000 to 7·7 billion (7·5–8·0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58·6 years (56·1–60·8) in 2000 to 63·5 years (60·8–66·1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019