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.

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).

Feed characteristics and potential effects on ruminal bacteria of ensiled sugar kelp and winged kelp for Holstein dairy cows.

Seaweed silage has potential as an alternative feed ingredient for dairy cows. This study aims to investigate seaweed's and seaweed silageś nutrient digestibility as well as their impact on the ruminal bacterial composition. The cultivated S.

Review: Improving residual feed intake modelling in the context of nutritional- and genetic studies for dairy cattle.

The residual feed intake (RFI) model has recently gained popularity for ranking dairy cows for feed efficiency. The RFI model ranks the cows based on their expected feed intake compared to the observed feed intake, where a negative phenotype (eating less than expected) is favourable. Yet interpreting the biological implications of the regression coefficients derived from RFI models has proven challenging.

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.

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.

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.

Formation of -α-tocopherol in rumen and intestinal digestibility of tocopherols in dairy cows.

Tocopherol sources in diets are often a combination of -α-tocopheryl acetate (synthetic α-tocopherol) from vitamin supplements and natural tocopherols and 2R-(4'R, 8'R)-5,7,8-trimethyltocotrienol (α-tocotrienols) from the feed sources. Synthetic α-tocopherol consists of 8 different stereoisomers including 2R-(4'R, 8'R)-5,7,8-trimethyltocol (-α-tocopherol), 2R-(4'S, 8'R)-5,7,8-trimethyltocol (-α-tocopherol), 2R-(4'R, 8'S)-5,7,8-trimethyltocol (-α-tocopherol), 2R-(4'S, 8'S)-5,7,8-trimethyltocol (-α-tocopherol), 2S-(4'S, 8'S)-5,7,8-trimethyltocol (-α-tocopherol), 2S-(4'R, 8'S)-5,7,8-trimethyltocol (-α-tocopherol), 2S-(4'S, 8'R)-5,7,8-trimethyltocol (-α-tocopherol), and 2S-(4'R, 8'R)-5,7,8-trimethyltocol (-α-tocopherol). The pre-absorption metabolism of tocopherols and tocotrienols in ruminants differs from monogastric animals due to the extensive microbial fermentation in the anaerobic rumen.

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.

The relationship between feed efficiency and behaviour differs between lactating Holstein and Jersey cows.

In dairy production, high feed efficiency (FE) is important to reduce feed costs and negative impacts of milk production on the climate and environment, yet little is known about the relationship between FE, eating behaviour and activity. This research communication describes how cows differing in FE, expressed as daily energy corrected milk production per unit of feed intake, differed in eating behaviour and activity. We used data from a study of 253 lactations obtained from 97 Holstein and 91 Jersey cows milked in an automatic milking system.

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.

Effect of nitrate supplementation, dietary protein supply, and genetic yield index on performance, methane emission, and nitrogen efficiency in dairy cows.

The objective was to investigate the effect of nonprotein nitrogen source, dietary protein supply, and genetic yield index on methane emission, N metabolism, and ruminal fermentation in dairy cows. Forty-eight Danish Holstein dairy cows (24 primiparous cows and 24 multiparous cows) were used in a 6 × 4 incomplete Latin square design with 4 periods of 21-d duration. Cows were fed ad libitum with the following 6 experimental diets: diets with low, medium, or high rumen degradable protein (RDP):rumen undegradable protein (RUP) ratio (manipulated by changing the proportion of corn meal, corn gluten meal, and corn gluten feed) combined with either urea or nitrate (10 g NO/kg of dry matter) as nonprotein nitrogen source.

Methane emission, nutrient digestibility, and rumen microbiota in Holstein heifers fed 14 different grass or clover silages as the sole feed.

This experiment investigated the variation in enteric methane production and associated gas exchange parameters, nutrient digestibility, rumen fermentation, and rumen microbiome when a range of silages based on different forage types (grass or clover), and different species within the 2 types, were fed as the sole feed to heifers. Three grass species (perennial ryegrass, festulolium, and tall fescue) and 2 clover species (red clover and white clover) were included. Perennial ryegrass was harvested at 2 maturity stages in the primary growth, white clover was harvested once in the primary growth, and 4 cuts of festulolium and tall fescue and 3 cuts of red clover were harvested during the growing season, giving 14 different silage batches in total.

Fiber digestibility and protein value of pulp silage for lactating dairy cows: Effects of wet fractionation by screw pressing of perennial ryegrass.

The aim of the study was to investigate the effects of substituting silage of chopped grass with pulp silage of grass fractionated once or twice in a biorefinery using a screw press on fiber kinetics, protein value, and production of CH in dairy cows. Six lactating multiparous Holstein cows in mid-lactation (176 ± 93 d in milk), cannulated in the rumen, duodenum, and ileum, were used in an incomplete 6 × 4 Latin square design with a 2 × 3 factorial arrangement of treatments. Perennial ryegrass was harvested in third regrowth from the same field at early and late developmental stage (35 and 44 d of regrowth, respectively) and subjected to 1 of 3 types of processing within each developmental stage.

Feeding up to 91% concentrate to Holstein and Jersey dairy cows: Effects on enteric methane emission, rumen fermentation and bacterial community, digestibility, production, and feeding behavior.

Due to climate change, periods of drought might be longer and occur more frequently, which challenges roughage production and requires changed feeding of dairy cattle by increasing the grain content of the diet. This study investigated the effect of diets with concentrate proportions up to 91% of dry matter on dry matter intake (DMI), milk production, enteric methane emission, rumen fermentation, rumen bacterial community structure, nutrient digestibility, and feeding behavior of Holstein and Jersey dairy cows. Twelve Danish Holstein and 12 Danish Jersey cows were fed ad libitum with one of 3 total mixed rations differing in concentrate proportion in a continuous design with staggered approach over 19 to 29 d.

Effects on feed intake, milk production, and methane emission in dairy cows fed silage or fresh grass with concentrate or fresh grass harvested at early or late maturity stage without concentrate.

The objective of the study was to quantify the effects on dry matter intake (DMI), nutrient digestibility, gas exchange, milk production, and milk quality in dairy cows fed fresh grass harvested at different maturity stages. Sixteen Danish Holstein cows in mid-lactation were divided into 4 blocks and used in 4 incomplete 4 × 2 Latin squares with 2 periods of 21 d. The cows received 1 of 4 treatments in each period, resulting in 8 cows per treatment, as follows: grass-clover silage supplemented with 6 kg/d concentrate pellets (SILc), fresh grass harvested at late maturity stage supplemented with 6 kg/d concentrate pellets (LATc), fresh grass harvested at late maturity stage (LAT), and fresh grass harvested at early maturity stage (ERL).

Effects of particle size and toasting of fava beans and forage source on nutrient digestibility, ruminal fermentation, and metabolizable protein supply in dairy cows.

The objective of this study was to investigate the effects of heat treatment (toasting) and particle size alterations (grinding; rolling) on nutrient utilization, ruminal fermentation, and supply of metabolizable protein (MP), and to study the interaction between processing conditions of fava beans and forage type. Six Danish Holstein dairy cows fitted with ruminal, duodenal, and ileal cannulas were used in a 6 × 4 incomplete Latin square design with 4 periods of 21-d duration. Cows were fed ad libitum with 6 experimental diets: diets high in either grass-clover silage or corn silage were combined with ground untoasted, ground toasted, or rolled untoasted fava beans.