Effects of Dietary Forage Proportion on Feed Intake, Growth Performance, Nutrient Digestibility, and Enteric Methane Emissions of Holstein Heifers at Various Growth Stages

Abstract

Simple SummaryEnteric methane (CH4) emission from ruminants is a large source of anthropogenic greenhouse gas production, which is an inevitable by-product when feedstuff is digested and fermented in the rumen, representing approximately 7% of dietary energy loss. Although the Chinese government has committed to reduce CH4 emissions under the requirement of the Copenhagen Accord (2009), there is lack of accurate CH4 emission data from young cows as the guideline of IPCC gives little consideration to the variations of geographic conditions, animal physiology stages, and dietary components of dairy production system. Our study investigated the effects of different dietary forage-to-concentrate on feed intake, growth performance, nutrient digestibility, and enteric CH4 emissions of Holstein heifers under various growth stage, and developed the prediction equations using production and emission data. Our results demonstrated that enteric CH4 emission was significantly affected by dietary composition and physiological condition; results obtained from the current study will be of great importance for development of regional or national emission inventories and mitigation approaches for heifers at specific growth stage.AbstractEnteric methane (CH4) emissions from young ruminants contribute to a substantial proportion of atmospheric CH4 accumulation. Development of emission inventory and mitigation approaches needs accurate estimation of individual emission from animals under various physiological conditions and production systems. This research investigated the effect of different dietary concentrate contents on feed intake, growth performance, nutrient digestibility and CH4 emissions of heifers at various stages, and also developed linear or non-linear prediction equations using data measured by sulphur hexafluoride tracer technique. Increasing dietary concentrate contents increased feed intake and growth rate, enhanced nutrient digestibility, and reduced enteric CH4 emissions. Heifers at the age of 9, 12, and 15 months with an average weight of 267.7, 342.1, and 418.6 kg produced 105.2, 137.4, and 209.4 g/day of CH4, and have an average value of CH4 energy per gross energy intake (Ym) 0.054, 0.064, 0.0667, respectively. Equations relating CH4 emission values with animal and feed characteristics were developed with high determination coefficients for heifers at different growth stages. Dietary concentrate contents had significant influence on overall performance of heifers. These data can be used to develop regional or national emission inventories and mitigation approaches for heifers under various production regimes in China.

Feeding Forage Mixtures of Ryegrass (Lolium spp.) with Clover (Trifolium spp.) Supplemented with Local Feed Diets to Reduce Enteric Methane Emission Efficiency in Small-Scale Dairy Systems: A Simulated Study

“…Jiao et al [ 51 ] also observed that increasing the level of supplementation (2.0, 4.0, 6.0, and 8.0 kg/cow/day) in dairy cows grazing perennial ryegrass led to increased milk production per cow per day, thereby reducing CH 4 emissions per unit of produced milk due to the increase in soluble carbohydrates. As has been shown, an increased proportion of cereal concentrates in the diet decreases enteric CH 4 emissions, whereas the intake of non-structural carbohydrates such as starch increases hydrogen and CH 4 production in the rumen [ 52 ]. Accordingly, Zhu et al [ 48 ] suggested that one option to mitigate CH 4 emissions in dairy cows is to increase milk production through optimization of the ingredients in the diet.…”

Effect of Feeding Improved Grass Hays and Eragrostis tef Straw Silage on Milk Yield, Nitrogen Utilization, and Methane Emission of Lactating Fogera Dairy Cows in Ethiopia

“…Estimated enteric CH 4 emission is the by-product of ruminal fermentation via methanogenesis and is thus substantially affected by a range of factors, including dietary components [ 65 ]. Thus, the methane production variation in our study among the dietary treatments might be related to the difference in the proportion of nutrients, such as the high NDF content of the NPH-based TMR [ 11 ].…”

“…Thus, the methane production variation in our study among the dietary treatments might be related to the difference in the proportion of nutrients, such as the high NDF content of the NPH-based TMR [ 11 ]. Specifically, the fermentation of fibrous materials favors the formation of acetate and butyrate which contribute to the production of CH 4 [ 65 ]. In our study, methane emission per kg of OM intake was lower for the TTS, NGH, and BhH diets than for NPH, thereby indicating that highly digestible roughages are promising means for reducing CH 4 emission.…”

Effects of the Diet Inclusion of Common Vetch Hay Versus Alfalfa Hay on the Body Weight Gain, Nitrogen Utilization Efficiency, Energy Balance, and Enteric Methane Emissions of Crossbred Simmental Cattle

“…This could be attributed to the polyphenolic compounds in legumes, such as condensed tannins, which have been previously shown to be negatively correlated with CH 4 emissions [33]. For rumen fermentation, there is a negative relationship between CH 4 emissions and propionate formation in the rumen, which could depress the activity of methanogens [4,5]. In this study, the lower ratios of acetate to propionate (Table 5) correspond to lower CH 4 emissions after forage supply (Figure 2d) in diet groups with a higher proportion of legumes and this is consistent with the above finding.…”

“…A low NUE could contribute more ammonia emissions to the air and more manure N outputs to the soil [2], which could damage air quality [3] and lead to soil nitrification and acidification [2]. The enteric CH 4 emissions from ruminants not only represent a loss of diet energy [4] but could also contribute to global warming [5]. The development of a diet that can improve the NUE and reduce enteric CH 4 emissions is in demand and would be beneficial to both animal husbandry and in facing global environmental challenges [6,7].…”