Effects of different doses of 3-nitrooxypropanol combined with varying forage composition on feed intake, methane emission, and milk production in dairy cows.

The objective of this study was to investigate the effect of combining different doses of 3-nitrooxypropanol (3-NOP) with varying forage composition on gas emission and production performance of dairy cows. Seventy-two lactating Danish Holstein cows (36 primiparous and 36 multiparous) were enrolled in a continuous randomized block design with an initial 2-week covariate period followed by application of treatments for 12 consecutive weeks. Initial DMI and ECM yield were 23.

Gas Chromatography-Tandem Mass Spectrometry Method for Analyses of Iodoform and Diiodomethane in Multiple Biological Matrices from Dairy Cattle.

A quantitative method was developed and validated to analyze iodoform and its potential metabolite, diiodomethane, in biological fluids from dairy cows, including rumen fluid, duodenal fluid, blood serum, milk, and urine, using liquid-liquid extraction (LLE) and GC-MS/MS. The method showed no matrix effects across different samples, recoveries of spiked samples between 70 and 120%, and relative standard deviations (RSD%) ranging from 0.7 to 14%.

Effect of nitrate supplementation on diurnal emission of enteric methane and nitrous oxide.

The objective of this study was to investigate the effect of nitrate supplementation on diurnal enteric methane (CH) and nitrous oxide (NO) emissions in dairy cows. Four Danish Holstein dairy cows fitted with ruminal cannulas were used in a 2 × 2 crossover design with 2 periods of 14 d duration. Cows were fed ad libitum with 2 experimental diets based on either urea or nitrate (8.

Effect of dietary fat source and concentration on feed intake, enteric methane and milk production in dairy cows.

Dietary fat can be used in dairy cow nutrition to reduce enteric methane (CH), but studies with multiple dietary fat concentrations are scarce. Among fat sources, rapeseed is easily accessible in Europe and North America, and palm kernel fat has been shown to be a potent inhibitor of ruminal methanogenesis. Forty-eight cows (half primiparous and half multiparous) were used in a 6 × 6 Latin square design, with 6 periods of 21 d each.

Phenotypic traits related to methane emissions from Holstein dairy cows challenged by low or high forage proportion.

Limited literature is available identifying phenotypical traits related to enteric methane (CH) production from dairy cows, despite its relevance in relation to breeding for animals with a low CH yield (g/kg DMI) and the derived consequences hereof. This study aimed to investigate the relationships between CH yield and different animal phenotypes when 16 second-parity dairy cows, fitted with a ruminal cannula, were fed 2 diets differing in forage/concentrate ratio in a crossover design. The diets had either a low forage proportion (35% on DM basis; F35) or a high forage proportion (63% on DM basis; F63).

The effect of the fat to starch ratio in young horses' diet on plasma metabolites, muscle endurance and fear responses.

High-starch diets may affect equine hindgut microbiota and increase blood glucose levels, which may cause unwanted physiological changes, but may also elicit behavioural changes such as increased fear reactions. The purpose of the current study was to feed a high starch (300) and low fat (43; HS_LF) or a low starch (60) and high fat (85; LS_HF, g/kg of DM) concentrate within the available commercial range and investigate how muscle endurance and fear reactions of horses respond to different diets. Twenty Danish Warmblood stallions (4 years) were randomly allocated to two treatments: LS_HF (n = 10) and HS_LF (n = 10) for 9 weeks.

Potential of 2 northern European brown seaweeds (Fucus serratus and Fucus vesiculosus) as enteric methane inhibitors in dairy cows.

The 2 brown seaweeds, Fucus serratus and Fucus vesiculosus, have demonstrated antimethanogenic properties in vitro with reductions in CH production ranging from 53 to 63%. This study aimed to investigate the effects of the 2 Fucus seaweeds on enteric CH emissions, DMI, ECM, and nutrient digestibility when fed to dairy cows. The experiment was conducted using 4 multicannulated lactating Danish Holstein dairy cows, which over 3 experimental periods received either: (1) basal diet (CON; diet without any seaweed), (2) basal diet diluted with 4% (DM basis) Fucus serratus (SER), or (3) basal diet diluted with 4% (DM basis) Fucus vesiculosus (VES); resulting in one complete 3 × 3 Latin square and one incomplete 3 × 3 Latin square.

Effect of carbohydrate type in silages and concentrates on feed intake, enteric methane, and milk yield from dairy cows.

Dietary carbohydrate manipulation can be used to reduce enteric CH emission, but few studies have focused on the interaction of the different types of carbohydrates that can affect feed intake and ruminal fermentation. Understanding this interaction is necessary to make the most out of CH mitigation feeding strategies using different dietary carbohydrates. The aim of this study was to test the effect on enteric CH emission, feed intake, and milk production response when cows were fed either grass-clover silage (GCS) or corn silage (CS) as the sole forage source (55% of dry matter, DM), in combination with either barley (BAR) or dried beet pulp (DBP) as a concentrate (21.

Feed intake in housed dairy cows: validation of a three-dimensional camera-based feed intake measurement system.

Measuring feed intake accurately is crucial to determine feed efficiency and for genetic selection. A system using three-dimensional (3D) cameras and deep learning algorithms can measure the volume of feed intake in dairy cows, but for now, the system has not been validated for feed intake expressed as weight of feed. The aim of this study was to validate the weight of feed intake predicted from the 3D cameras with the actual measured weight.

Predicting CO production of lactating dairy cows from animal, dietary, and production traits using an international dataset.

Automated measurements of the ratio of concentrations of methane and carbon dioxide, [CH]:[CO], in breath from individual animals (the so-called "sniffer technique") and estimated CO production can be used to estimate CH production, provided that CO production can be reliably calculated. This would allow CH production from individual cows to be estimated in large cohorts of cows, whereby ranking of cows according to their CH production might become possible and their values could be used for breeding of low CH-emitting animals. Estimates of CO production are typically based on predictions of heat production, which can be calculated from body weight (BW), energy-corrected milk yield, and days of pregnancy.

Redox balance and immunity of piglets pre- and post-E. coli challenge after treatment with hemp or fish oil, and vitamin E.

This study investigated the influence of polyunsaturated fatty acid composition and vitamin E supplementation on oxidative status and immune responses in weanling piglets pre- and post-E. coli challenge. Suckling piglets (n = 24) were randomly selected from two litters for an oral supplementation (1 mL/day) with fish oil or hemp oil and vitamin E supplementation (60 mg natural vitamin E/mL oil) from day 10 to 28 of age.

The acute effects of rumen pulse-dosing of hydrogen acceptors during methane inhibition with nitrate or 3-nitrooxypropanol in dairy cows.

Dietary methane (CH) mitigation is in some cases associated with an increased hydrogen (H) emission. The objective of the present study was to investigate the acute and short-term effects of acceptors for H (fumaric acid, acrylic acid, or phloroglucinol) supplemented via pulse-dosing to dairy cows fed CH mitigating diets (using nitrate or 3-nitrooxypropanol), on gas exchange, rumen gas, and VFA composition. For this purpose, 2 individual 4 × 4 Latin square experiments were conducted with 4 periods of 3 d (nitrate supplementation) and 7 d (3-nitrooxypropanol supplementation), respectively.

Effects of feeding whole-cracked rapeseeds, nitrate, and 3-nitrooxypropanol on protein composition, minerals, and vitamin B in milk from Danish Holstein cows.

The present study was conducted to assess the individual or combined effects of feeding dietary fat (whole-cracked rapeseed), nitrate, and 3-nitrooxypropanol (3-NOP) on protein profile, mineral composition, B vitamins, and nitrate residues in milk from dairy cows. A total of 48 Danish Holstein cows used in an 8 × 8 incomplete Latin square design were fed 8 factorially arranged diets: (30 or 63 g crude fat/kg DM) × (0 or 10 g nitrate/kg DM) × (0 or 80 mg 3-NOP/kg DM) over 6 periods of 21 d each. In each period, milk samples were collected from individual cows during the third week by pooling milk obtained from 4 consecutive milkings and analyzed for protein profile, including protein modifications, mineral composition, riboflavin, cobalamin, and presence of nitrate residues.

Effects of feeding whole-cracked rapeseeds, nitrate, and 3-nitrooxypropanol on composition and functional properties of the milk fat fraction from Danish Holstein cows.

The aim of this study was to determine the individual and combined effects of supplementing fat with whole-cracked rapeseed (FAT), nitrate (NITRATE), and 3-nitrooxypropanol (3-NOP) on compositional and functional properties of milk fat. An 8 × 8 incomplete Latin square design was conducted with 48 lactating Danish Holstein cows over 6 periods of 21 d each. Eight diets were 2 × 2 × 2 factorially arranged: FAT (30 or 63 g crude fat/kg DM), NITRATE (0 or 10 g nitrate/kg DM), and 3-NOP (0 or 80 mg 3-NOP/kg DM), and cows were fed ad libitum.

How much can performance measures explain of the between-cow variation in enteric methane?

Enteric CH produced from dairy cows contributes to the emission of greenhouse gases from anthropogenic sources. Recent studies have shown that the selection of lower CH-emitting cows is possible, but doing so would be simpler if performance measures already recorded on farm could be used, instead of measuring gas emissions from individual cows. These performance measures could be used for selection of low emitting cows.

Relationship between residual feed intake and digestive traits of fattening bulls fed grass silage- or maize silage-based diets.

Several studies tried to identify digestive determinants of individual variation in feed efficiency between fattening bulls, because of their importance for breeding and management strategies. Most studies focused on single traits or single diet. Little is known about diet-dependent differences in digestive determinants and on their relative importance in distinguishing divergent residual feed intake (RFI) bulls.

Gas exchange, rumen hydrogen sinks, and nutrient digestibility and metabolism in lactating dairy cows fed 3-nitrooxypropanol and cracked rapeseed.

Fat in the form of cracked rapeseed and 3-nitrooxypropanol (3-NOP, market as Bovaer) were fed alone or in combination to 4 Danish Holstein multicannulated dairy cows, with the objective to investigate effects on gas exchange, dry matter intake (DMI), nutrient digestion, and nutrient metabolism. The study design was a 4 × 4 Latin square with a 2 × 2 factorial treatment arrangement with 2 levels of fat supplementation; 33 g of crude fat per kg of dry matter (DM) or 64 g of crude fat per kg of DM for low and high fat diets, respectively, and 2 levels of 3-NOP; 0 mg/kg DM or 80 mg/kg DM. In total, 4 diets were formulated: low fat (LF), high fat (HF), 3-NOP and low fat (3LF), and 3-NOP and high fat (3HF).

Effect of fumaric acid in combination with or nitrate on in vitro gas production, pH, and redox potential.

Reduction in enteric methane (CH) emissions from cattle can be achieved through use of feed additives, which often results in increased emission of hydrogen (H). The objective of this study was to investigate in vitro effects of a known hydrogen sink, fumaric acid, in combination with either of 2 methane inhibitors, the macroalga or nitrate, on CH and H production, feed degradability, pH, and redox potential. A corn silage (0.

Effects of dietary fat, nitrate, and 3-nitrooxypropanol and their combinations on methane emission, feed intake, and milk production in dairy cows.

The objective of the present study was to investigate the effect of individual and combined use of dietary fat, nitrate, and 3-nitrooxypropanol (3-NOP) on dairy cows' enteric methane (CH) emission and production performance. Twenty-four primiparous and 24 multiparous Danish Holstein cows (111 ± 44.6 d in milk; mean ± standard deviation) were included in an incomplete 8 × 8 Latin square design with six 21-d periods.

Effects of dietary inclusion of 3 Nordic brown macroalgae on enteric methane emission and productivity of dairy cows.

Macroalgae are receiving increased attention as antimethanogenic feed additives for cattle, but most in vivo studies are limited to investigating effects of the red macroalgae Asparagopsis spp. Hence, this study aimed to investigate the CH mitigating potential of 3 brown macroalgae from the Northern Hemisphere when fed to dairy cows, and to study the effects on feed intake, milk production, feed digestibility, and animal health indicators. The experiment was conducted as a 4 × 4 Latin square design using 4 lactating rumen, duodenal, and ileal cannulated Danish Holstein dairy cows.

Enteric methane emission of dairy cows supplemented with iodoform in a dose-response study.

Enteric methane (CH) emission is one of the major greenhouse gasses originating from cattle. Iodoform has in studies been found to be a potent mitigator of rumen CH formation in vitro. This study aimed to quantify potential of iodoform as an anti-methanogenic feed additive for dairy cows and investigate effects on feed intake, milk production, feed digestibility, rumen microbiome, and animal health indicators.

Three years of situated social learning and development of diverse cow-calf contact systems in Danish organic dairy farms.

This study had 2 aims: first, to describe the intent of a learning process among farmers about cow-calf contact (CCC) systems using a so-called Stable School approach, where farmers advise farmers. The second aim was to identify the main themes that arose from the conversations held throughout the 21 meetings that focused on the topic of CCC. The meetings were hosted by 10 host farmers.

The ileal and total tract digestibility fibre and nutrients in pigs fed high-fibre cereal-based diets provided without and with a carbohydrase complex.

The effect of carbohydrase can be variable according to the complexity of cereal grains and co-products. Studies on the effect of carbohydrase on cereal diets varying in complexity are scarce. This study was conducted to investigate the apparent ileal (AID) and total tract digestibility (ATTD) of energy, fibre and nutrients in pigs fed diets based on cereal grains and co-products without and with supplementation with a carbohydrase complex in the form of xylanase, arabinofuranosidase and β-glucanase.

Influence of key factors on ammonia and nitrous oxide emission factors for excreta deposited by livestock and land-applied manure.

Ammonia (NH) and nitrous oxide (NO) emissions from livestock manure management have a significant impact on air quality and climate change. There is an increasing urgency to improve our understanding of drivers influencing these emissions. We analysed the DATAMAN ("DATAbase for MANaging greenhouse gas and ammonia emissions factors") database to identify key factors influencing (i) NH emission factors (EFs) for cattle and swine manure applied to land and (ii) NO EFs for cattle and swine manure applied to land, and (iii) cattle urine, dung and sheep urine deposited during grazing.