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Journal of Dairy Science Jan 2024To investigate the effects of supplemental monensin administration on the metabolic responses of dairy cows, a systematic review and dose-response meta-analysis were... (Meta-Analysis)
Meta-Analysis
Effects of monensin supplementation on rumen fermentation, methane emissions, nitrogen balance, and metabolic responses of dairy cows: A systematic review and dose-response meta-analysis.
To investigate the effects of supplemental monensin administration on the metabolic responses of dairy cows, a systematic review and dose-response meta-analysis were conducted. Initially, 604 studies were identified through comprehensive database searches, including Google Scholar, Scopus, Science Direct, and PubMed, using key words related to dairy cows, monensin, and metabolic outcomes. After a 2-stage screening process, 51 articles with a total of 60 experiments were selected for meta-analysis based on criteria such as study implementation date between 2001 and 2022, presence of a control group that did not receive monensin supplementation, reporting of at least 1 outcome variable, and presentation of means and corresponding errors. The meta-analysis used the 1-stage random-effects method, and sensitivity analyses were performed to assess the robustness of the results. The results showed that the administration of monensin at a dosage of 19 to 26 mg/kg was inversely related to methane emissions and that the administration of monensin at a dosage of 18 to 50 mg/kg resulted in a significant decrease in dry matter intake. Administration of monensin at doses of 13 to 28 and 15 to 24 mg/kg also resulted in a significant decrease in ruminal acetate proportion and an increase in propionate proportion, respectively, with no effects on ruminal butyrate, NH, or pH levels. We found no effects on blood parameters or nitrogen retention, but a significant negative correlation was observed between monensin supplementation and fecal nitrogen excretion. Based on the analysis of all variables evaluated, the optimal dose range of monensin was estimated to be 19 to 24 mg/kg.
Topics: Female; Cattle; Animals; Monensin; Milk; Fermentation; Methane; Rumen; Nitrogen; Dietary Supplements; Diet; Lactation
PubMed: 37709041
DOI: 10.3168/jds.2023-23441 -
Anais Da Academia Brasileira de Ciencias 2024In the last few years, there has been a growing interest in the use of natural feed additives in animal feed. These can be used as replacements for antibiotics, to alter... (Meta-Analysis)
Meta-Analysis
In the last few years, there has been a growing interest in the use of natural feed additives in animal feed. These can be used as replacements for antibiotics, to alter rumen fermentation and increase feed efficiency in ruminants. Therefore, the objective of this study is to evaluate the effects of adding different feed additives in the diet of beef and dairy cattle on their performance, dry matter intake (DMI) and feed efficiency, through a systematic review followed by meta-analysis. The systematic review suggested 43 peer-reviewed publications, according to the pre-established criteria. In beef cattle, the ionophore antibiotics reduced the DMI, improved the feed efficiency without interfering in the average daily gain (ADG). Non-ionophore antibiotics and propolis extract increased the ADG. In dairy cattle, the ionophores, yeast-based additives, and enzyme additives increased the feed efficiency, DMI, and daily milk production (MY), respectively. Essential oil supplementation in beef and dairy cattle had no effect on the feed intake and animal performance. The systematic review and meta-analysis allowed us to conclude that different feed additives have different effects on cattle performance, however, our results suggest that there are a few gaps regarding their effects on animal performance.
Topics: Cattle; Animals; Animal Feed; Dietary Supplements; Eating; Food Additives; Animal Nutritional Physiological Phenomena
PubMed: 38896738
DOI: 10.1590/0001-3765202420230172 -
Journal of Dairy Science Jan 2024A systematic literature review of in vitro studies was performed to identify methane (CH) mitigation interventions with a potential to reduce CH emission in vivo. Data... (Meta-Analysis)
Meta-Analysis
A systematic literature review of in vitro studies was performed to identify methane (CH) mitigation interventions with a potential to reduce CH emission in vivo. Data from 277 peer-reviewed studies published between 1979 and 2018 were reviewed. Individual CH mitigation interventions were classified into 14 categories of feed additives based on their type, chemical composition, and mode of action. Response variables evaluated were absolute CH emission (number of treatment means comparisons = 1,325); total volatile fatty acids (n = 1,007), acetate (n = 783), propionate (n = 792), and butyrate (n = 776) concentrations; acetate to propionate ratio (n = 675); digestibility of dry matter (n = 489), organic matter (n = 277), and neutral detergent fiber (n = 177). Total gas production was used as an explanatory variable in the model for CH production. Relative mean difference between treatment and control means reported in the studies was calculated and used for statistical analysis. The robust variance estimation method was used to analyze the effects of CH mitigation interventions. In vitro CH production was decreased by antibodies (-38.9%), chemical inhibitors (-29.2%), electron sinks (-18.9%), essential oils (-18.2%), plant extracts (-14.5%), plant inclusion (-11.7%), saponins (-14.8%), and tannins (-14.5%). Overall effects of direct-fed microbials, enzymes, macroalgae, and organic acids supplementation did not affect CH production in the current meta-analysis. When considering the effects of individual mitigation interventions containing a minimum number of 4 degrees of freedom within feed additives categories, Enterococcus spp. (i.e., direct-fed microbial), nitrophenol (i.e., electron sink), and Leucaena spp. (i.e., tannins) decreased CH production by 20.3%, 27.1%, and 23.5%, respectively, without extensively, or only slightly, affecting ruminal fermentation and digestibility of nutrients. It should be noted, however, that although the total number of publications (n = 277) and treatment means comparisons (n = 1,325 for CH production) in the current analysis were high, data for most mitigation interventions were obtained from less than 5 observations (e.g., maximum number of observations was 4, 7, and 22 for nitrophenol, Enterococcus spp., and Leucaena spp., respectively), because of limited data available in the literature. These should be further evaluated in vitro and in vivo to determine their true potential to decrease enteric CH production, yield, and intensity. Some mitigation interventions (e.g., magnesium, Heracleum spp., nitroglycerin, β-cyclodextrin, Leptospermum pattersoni, Fructulus Ligustri, Salix caprea, and Sesbania grandiflora) decreased in vitro CH production by over 50% but did not have enough observations in the database. These should be more extensively investigated in vitro, and the dose effect must be considered before adoption of mitigation interventions in vivo.
Topics: Female; Animals; Diet; Milk; Lactation; Propionates; Methane; Tannins; Rumen; Acetates; Nitrophenols; Fermentation; Digestion; Animal Feed
PubMed: 38353472
DOI: 10.1016/S0022-0302(23)00819-6