Methane emissions from non-lactating pregnant dairy cows while grazing

Potential of grazing management to improve beef cattle production and mitigate methane emissions in native grasslands of the Pampa biome

We tested the hypothesis that improving sward structure through adjustments in forage allowance results in greater forage intake and live weight (LW) gains by beef cattle and lower CH₄ emissions per unit LW gain and unit area in a native grassland ecosystem of the Pampa biome. The experiment was carried out during 2012 and 2013 in southern Brazil. The experimental design was a randomized complete block with two replicates. Treatments consisted of five contrasting forage allowances of a native grassland managed under continuous stocking: 4, 8, 8-12, 12, and 16 kg of dry matter (DM) 100 kg LW^-1 day^-1 (or % LW). The 8-12% LW treatment had a variable forage allowance of 8% LW in spring and 12% LW in summer, autumn, and winter. Forage allowance was controlled by changes in stocking rate (kg LW ha^-1). Average daily gain (kg LW day^-1) was high for forage allowances of 12 and 16% LW but decreased at 8%, reaching the lowest value at 4% LW treatment (p < 0.001). Live weight gain ha^-1 year^-1 was the greatest at forage allowance of 8-12% LW (p < 0.001). Forage DM intake peaked at a forage allowance of 12% LW (p = 0.005). Individual CH₄ emissions remained constant around 150 g day^-1 for the two highest forage allowances and decreased to 118 and 107 g day^-1 under forage allowances of 8 and 4% LW, respectively (p = 0.002). Emissions per unit LW gain and unit area were driven by animal productivity changes and decreased with increasing forage allowance (p = 0.001 and p = 0.040, respectively). We propose that the combination of 8% LW forage allowance during spring and 12% LW during the rest of the year should be targeted to best balance animal production and environmental impact in the Pampa biome.

Review: New feeds and new feeding systems in intensive and semi-intensive forage-fed ruminant livestock systems

The contributions that ruminant livestock make to greenhouse gas and other pollutant emissions are well documented and of considerable policy and public concern. At the same time, livestock production continues to play an important role in providing nutrient-rich foodstuffs for many people, particularly in less developed countries. They also offer a means by which plants that cannot be digested by humans, e.g. grass, can be converted into human-edible protein. In this review, we consider opportunities to improve nutrient capture by ruminant livestock through new feeds and feeding systems concentrating on intensive and semi-intensive systems, which we define as those in which animals are given diets that are designed and managed to be used as efficiently as possible. We consider alternative metrics for quantifying efficiency, taking into account resource use at a range of scales. Mechanisms for improving the performance and efficiencies of both individual animals and production systems are highlighted. We then go on to map these to potential changes in feeds and feeding systems. Particular attention is given to improving nitrogen use efficiency and reducing enteric methane production. There is significant potential for the use of home-grown crops or novel feedstuffs such as insects and macroalgae to act as alternative sources of key amino acids and reduce reliance on unsustainably grown soybeans. We conclude by highlighting the extent to which climate change could impact forage-based livestock production and the need to begin work on developing appropriate adaptation strategies.

Can We Observe Expected Behaviors at Large and Individual Scales for Feed Efficiency-Related Traits Predicted Partly from Milk Mid-Infrared Spectra?

Phenotypes related to feed efficiency were predicted from records easily acquired by breeding organizations. A total of 461,036 and 354,148 records were collected from the first and second parity Holstein cows. Equations were applied to the milk mid-infrared spectra to predict the main milk components and coupled with animal characteristics to predict the body weight (pBW). Dry matter intake (pDMI) was predicted from pBW using the National Research Council (NRC) equation. The consumption index (pIC) was estimated from pDMI and fat, and protein corrected milk. All traits were modeled using single trait test-day models. Descriptive statistics were within the expected range. Milk yield, pDMI, and pBW were phenotypically positively related (r ranged from 0.08 to 0.64). As expected, pIC was phenotypically negatively correlated with milk yield (-0.77 and -0.80 for the first and second lactation) and slightly positively correlated with pBW (0.16 and 0.07 for the first and second lactation). Later, parity cows seemed to have a better feed efficiency as they had a lower pIC. Although the prediction accuracy was moderate, the observed behaviors of studied traits by year, stage of lactation, and parity were in agreement with the literature. Moreover, as a genetic component was highlighted (heritability around 0.18), it would be interesting to realize a genetic evaluation of these traits and compare the obtained breeding values with the ones estimated for sires having daughters with reference feed efficiency records.