Audino Melgar M.

• Doctor of Philosophy-Ruminant Nutrition
• Researcher at Instituto de Innovación Agropecuaria de Panamá (IDIAP)

This study investigated the effects of 67 species of macroalgae on methanogenesis and rumen fermentation in vitro. Specimens were analyzed for their effect on ruminal fermentation and microbial community profiles. Incubations were carried out in an automated gas production system for 24-h and macroalgae were tested at 2% (feed dry matter basis) inc...

This chapter explores the use of supplements to mitigate enteric methane emission in dairy cattle. It begins by highlighting two dietary approaches that can decrease enteric CH4 emission, the first being the improvement of forage quality and the second being the inclusion of concentrate feeds in the diet. The use of of dietary lipids and lipid supp...

Yeast culture and phytonutrients are dietary supplements with distinct modes of action, and they may have additive effects on the performance of dairy cattle. The objective of this study was to investigate the effects of a preparation of phytonutrients and a yeast culture from Saccharomyces cerevisiae on lactational performance, total-tract digesti...

Background Enteric methane emissions from dairy cows are an environmental problem as well as a gross feed energy loss to the animal. Methane is generated in the rumen by methanogenic archaea from hydrogen (H 2 ) + carbon dioxide and from H 2 + methanol or methylamines. The methanogenic substrates are provided by non-methanogens during feed fermenta...

The objective of this study was to investigate the effects of an exogenous enzyme preparation from As-pergillus oryzae and Aspergillus niger on lactational performance of dairy cows. Forty-eight Holstein cows (32 primiparous and 16 multiparous) averaging (± SD) 36.3 ± 8.7 kg/d milk yield and 141 ± 52 d in milk were enrolled in a 10-wk randomized co...

Intensive research in the past decade has resulted in a better understanding of factors driving enteric methane (CH4) emissions in ruminants. Meta-analyses of large databases, developed through the GLOBAL NETWORK project, have identified successful strategies for mitigation of CH4 emissions. Methane inhibitors, alternative electron sinks, vegetable...

RESUMEN. Un total de 36 cerdos (♀Landrace x Yorkshire X ♂Pietrain; 23±2 días edad; 7.41±0.15 kg) fueron utilizados para evaluar el efecto de la suplementación de niveles elevados de zinc (NEZ), en dietas con niveles reducidos de proteína, sobre el desempeño productivo, perfil hematológico y control de diarrea durante 42 días post-destete. Los cerdo...

Background Enteric methane emissions from dairy cows are an environmental problem as well as a gross feed energy loss to the animal. Methane is generated in the rumen by methanogenic archaea from hydrogen (H2) + carbon dioxide and from H2 + methanol or methylamines. The methanogenic substrates are provided by non-methanogens during feed fermentatio...

The objective of this study was to investigate the effects of supplementation of an exogenous enzyme preparation (EEP) on performance, total-tract digestibility of nutrients, plasma AA profile, and milk fatty acids composition in lactating dairy cows fed a reduced-starch diet compared with a normal-starch diet (i.e., positive control). Forty-eight...

The objective of this experiment was to investigate the effect of dietary levels of digestible histidine (dHis) and MP on lactational performance and plasma and muscle concentrations of free AA in dairy cows. A randomized block design experiment was conducted with 48 Holstein cows, including 20 primiparous, averaging (±SD) 103 ± 22 d in milk and 45...

Rumen microbes play an important role in the conversion of indigestible plant material to energy and protein in dairy cows. Sampling for ruminal contents via cannula is considered the gold standard technique for microbial analysis, but the technique requires ruminally cannulated animals and specialized animal facilities. The purpose of this study w...

In ruminants, it has been observed that capsicum oleoresin can alter insulin responses and that high-intensity artificial sweetener can increase glucose absorption from the small intestine. Because glucose metabolism and insulin responses are critical during early lactation, these supplements might have an effect on the metabolic status of dairy co...

This study investigated the effects of an amylase-enabled corn silage on lactational performance, enteric CH4 emission, and rumen fermentation of lactating dairy cows. Following a 2-wk covariate period, 48 Holstein cows were blocked based on parity, days in milk, milk yield (MY), and CH4 emission. Cows were randomly assigned to 1 of 2 treatments in...

The objective of this experiment was to determine the effect of increasing digestible His (dHis) levels with a rumen-protected (RP) His product on milk production, milk composition, and plasma AA concentrations in lactating dairy cows fed a metabolizable protein (MP)-deficient diet, according to the National Research Council dairy model from 2001....

The objective of this experiment was to determine the effect of increasing digestible His (dHis) doses on milk production, milk composition, and plasma AA concentrations in lactating dairy cows fed diets that meet or exceed their energy and metabolizable protein (MP) requirements. In a companion paper (Räisänen et al., 2021) results are presented o...

Microbial syntrophy (obligate metabolic mutualism) is the hallmark of energy-constrained anaerobic microbial ecosystems. For example, methanogenic archaea and fermenting bacteria coexist by interspecies hydrogen transfer in the complex microbial ecosystem in the foregut of ruminants; however, these synergistic interactions between different microbe...

The purpose of this study was to investigate the effect of 3-nitrooxypropanol (3-NOP), a potent methane inhibitor, on total and metabolically active methanogens in the rumen of dairy cows over the course of the day and over a 12-wk period. Rumen contents of 8 ruminally cannulated early-lactation dairy cows were sampled at 2, 6, and 10 h after feedi...

Asparagopsis taxiformis (AT) is a source of multiple halogenated compounds and, in a limited number of studies, has been shown to decrease enteric CH4 emission in vitro and in vivo. Similarly, oregano has been suggested as a potential CH4 mitigating agent. This study consisted of 2 in vitro and 2 in vivo experiments. Experiment (Exp.) 1 was aimed a...

This study investigated the effects of feeding solvent-extracted canola meal (CM), extruded soybean meal (ESBM), or solvent-extracted soybean meal (SSBM) on an equivalent crude protein basis on performance, plasma AA profiles, enteric gas emissions, milk fatty acids, and nutrient digestibility in lactating dairy cows. Fifteen Holstein cows (95 ± 20...

The objective of this experiment was to compare ruminal fluid samples collected through rumen cannula (RC) or using an oral stomach tube (ST) for measurement of ruminal fermentation and microbiota variables. Six ruminally cannulated lactating Holstein cows fed a standard diet were used in the study. Rumen samples were collected at 0, 2, 4, 6, 8, an...

The objective of this study was to investigate the effect of 3-nitrooxypropanol (3-NOP), an enteric methane inhibitor under investigation, on short-term dry matter intake (DMI) in lactating dairy cows. Following a 1-wk adaptation period, 12 multiparous Holstein cows were fed a basal total mixed ration (TMR) containing increasing levels of 3-NOP dur...

This study examined the effect of 3-nitrooxypropa-nol (3-NOP), an investigational substance, on enteric methane emission, milk production, and composition in Holstein dairy cows. Following a 3-wk covariate period, 48 multi-and primiparous cows averaging (± standard deviation) 118 ± 28 d in milk, 43.4 ± 8 kg/d milk yield, and 594 ± 57 kg of body wei...

The relationship between DM intake ( DMI ) and enteric methane emission is well established in ruminant animals but may depend on measurement technique (e.g. spot v . continuous gas sampling) and rumen environment (e.g. use of fermentation modifiers). A previous meta-analysis has shown a poor overall (i.e. 24 h) relationship of DMI with enteric met...

The objective of this experiment was to assess a new method to determine the bioavailability (BA) of rumen-protected (RP)His, RPLys and RPMet products by determining rumen escape (RE) and fecal excretion of undigested AA from RPAA. Eight lactating Holstein cows (79±21 days in milk, 53.0±7.0 kg/d milk yield), four of which rumen-cannulated, were use...

This experiment was designed to test the effect of inclusion rate of 3-nitrooxypropanol (3-NOP), a methane inhibitor, on enteric methane emissions in dairy cows. The study was conducted with 49 multiparous Holstein cows in a randomized complete block design in 2 phases; phase 1 was with 28 cows, and phase 2 with 21 cows. Cows were fed a basal total...

This study investigated Se-dependent parameters in ewes after supplementation with an experimental Se product (P-Se) in comparison to sodium selenite. Six Dorset ewes averaging 93.0 (SE = 2.5) kg initial body weight were used in a replicated 3 × 3 Latin square design experiment balanced for residual effects. The study began with a 2-wk background,...

ABSTRACT This study examined the effect of 3-nitrooxypropanol (3-NOP), a substance under investigation, on enteric methane (CH4) emission, rumen fermentation, lactational performance, sensory properties of milk, and the resumption of ovarian cyclicity in early-lactation dairy cows. Fifty-six multi- and primiparous Holstein cows, including 8 that we...

We examined the relationship of enteric methane emission, measured using the GreenFeed system (GF), and dry matter intake (DMI) in a 15-week experiment with lactating dairy cows receiving a control diet or a diet containing the investigational product 3-nitrooxypropanol (3-NOP at 60 mg/kg feed DM). Daily methane emission and DMI were clustered into...

This study evaluated effects of 3-nitrooxypropanol (3-NOP), an investigational product, on enteric methane emission and lactational performance of Holstein cows. Forty multi-and primiparous cows (118 ± 28 days in milk) were blocked and fed a control diet or a diet containing 60 mg 3-NOP/kg feed dry matter for 15 consecutive weeks. Enteric gaseous e...

We examined the relationship of enteric methane emission, measured using the GreenFeed system (GF), and dry matter intake (DMI) in a 15-week experiment with lactating dairy cows receiving a control diet or a diet containing the investigational product 3-nitrooxypropanol (3-NOP at 60 mg/kg feed DM). Daily methane emission and DMI were clustered into...

The objective of this experiment was to evaluate productive and reproductive effects of replacing solvent-extracted soybean meal (SSBM) with extruded soybean meal (ESBM) in a total mixed ration for early-lactation dairy cows. Thirty-four Holstein cows (12 primiparous and 22 multiparous) were used in a randomized complete block design experiment wit...

Use of 3-nitrooxypropanol (3-NOP) to decrease emissions of enteric methane in dairy cows

The objective of this experiment was to investigate the effects of a Saccharomyces cerevisiae-based direct-fed microbial product (SDM) and an exogenous enzyme product (ENZ) on enteric methane emission, milk yield and composition, total-tract digestibility of nutrients, ruminal fermentation, and nitrogen excretion and secretion in lactating dairy co...

Three cafeteria feeding design experiments were conducted to test whether young ruminants have flavor preferences. Experiment 1 was with 11 Dorset × Suffolk weaned lambs of both sexes, aged 5 mo and averaging 47.5 (standard deviation = 5.8) kg of body weight. The lambs were offered a choice of 5 flavored concentrate premixes (FCP) and an unflavored...

Use of 3-nitrooxypropanol (3-NOP) on enteric methane mitigation in dairy cows

Brown midrib brachytic dwarf pearl millet (Pennisetum glaucum) forage harvested at the flag leaf visible stage and subsequently ensiled was investigated as a partial replacement of corn silage in the diet of high-producing dairy cows. Seventeen lactating Holstein cows were fed 2 diets in a crossover design experiment with 2 periods of 28 d each. Bo...

The objective of this study was to investigate the effect of 3 soybean sources differing in fatty acid profile and processing method on productivity, milk composition, digestibility, rumen fermentation, and enteric methane emission in lactating dairy cows. The soybean sources were conventional, high-linoleic-acid variety extruded soybean meal (ESBM...

Con el objetivo de evaluar la suplementación proteica con urea de baja solubilidad sobre las características del ambiente ruminal, se utilizó dos novillos provistos de fístula ruminal, alimentados con heno de Digitaria swazilandensis más una mezcla de granos, reemplazando 30% del requerimiento proteico de mantenimiento por urea altamente soluble en...

Nitrogenous fractions from greenhouse grown 15N-labeled alfalfa, preserved as hay or silage, were isolated and incubated to investigate the rate and extent of utilization of 15N-labeled N fractions by mixed ruminal microorganism in vitro. The experimental protocol included the N insoluble in water (INSN), soluble protein N (SPN), non-protein N (NPN...

The objective was to determine the effects of three exogenous polysaccharide-degrading enzyme preparations (EPDE) on ruminal fermentation and forestomach and total tract digestion of dietary nutrients in dairy cows. Four late-lactation, ruminally and duodenally cannulated, Holstein cows were allocated to dietary treatments in a 4×4 Latin square des...

Ruminal inoculum enriched with particle-associated microorganisms was collected from two lactating dairy cows fed an alfalfa hay/cereal silage/concentrate diet 1h before feeding and used to evaluate effects of essential oils (EO) on ruminal fermentation in short-term in vitro incubations. Ruminal ammonia N was labeled with 15N and native and hydrol...

The effect of type of grain (corn vs. barley) and amylopectin content of barley grain (normal vs. waxy) on ruminal fermentation, digestibility, and utilization of ruminal ammonia nitrogen for milk protein synthesis was studied in a replicated 3 x 3 Latin square design trial with 6 lactating dairy cows. The experimental treatments were (proportion o...

This study was conducted to investigate the effect of dextrose, starch, NDF, and a carbohydrate (CHO) mix on utilization of ruminal ammonia in dairy cows. Four ruminally and duodenally cannulated Holstein cows (BW = 788 +/- 31 kg; 217 +/- 35 d in milk) were allocated to four treatments in a 4 x 4 Latin square design trial. Cows were fed an all alfa...