Measuring the Phytochemical Richness of Meat: Effects of Grass/Grain Finishing Systems and Grapeseed Extract Supplementation on the Fatty Acid and Phytochemical Content of Beef.

Grass-finished beef (GFB) can provide beneficial bioactive compounds to healthy diets, including omega-3 polyunsaturated fatty acids (n-3 PUFAs), conjugated linoleic acid (CLA), and secondary bioactive compounds, such as phytochemicals. The objective of this study was to compare fatty acids (FAs), micronutrients, and phytochemicals of beef fed a biodiverse pasture (GRASS), a total mixed ration (GRAIN), or a total mixed ration with 5% grapeseed extract (GRAPE). This was a two-year study involving fifty-four Red Angus steers (n = 54). GFB contained higher levels of n-3 PUFAs, vitamin E, iron, zinc, stachydrine, hippuric acid, citric acid, and succinic acid than beef from GRAIN and GRAPE (p < 0.001 for all). No differences were observed in quantified phytochemicals between beef from GRAIN and GRAPE (p > 0.05). Random forest analysis indicated that phytochemical and FA composition of meat can predict cattle diets with a degree of certainty, especially for GFB (5.6% class error). In conclusion, these results indicate that GFB contains higher levels of potentially beneficial bioactive compounds, such as n-3 PUFAs, micronutrients, and phytochemicals, compared to grain-finished beef. Additionally, the n-6:n-3 ratio was the most crucial factor capable of separating beef based on finishing diets.

Effects of Hay, Baleage, and Soybean Hulls Waste Used as Supplemental Feeds on the Nutritional Profile of Grass-Finished Beef.

Grass-finished beef (GFB) has demonstrated wide nutritional variations with some GFB having a considerably higher n-6:n-3 ratio compared to grain-finished beef. To better understand these variations, the current study investigated the effects of commonly used supplemental feeds on the nutritional profile of GFB. This two-year study involved 117 steers randomly allocated to one of four diets: (1) grass+hay (G-HAY), (2) grass+baleage (G-BLG), (3) grass+soybean hulls (G-SH), and (4) baleage+soybean hulls in feedlot (BLG-SH). Feed samples were analyzed for their nutritional value, and beef samples underwent analysis for fatty acids (FAs), vitamin E, minerals, lipid oxidation, and shear force. FAs were measured by GC-MS, vitamin E was analyzed chromatographically, minerals were analyzed by ICP-MS, and lipid oxidation was measured via a thiobarbituric acid reactive substances (TBARS) assay. G-SH beef had the highest n-6:n-3 ratio (p < 0.001), while BLG-SH beef contained less vitamin E (p < 0.001) and higher TBARS values (p < 0.001) compared to the other groups. G-HAY beef contained more long-chain n-3 polyunsaturated FAs compared to the other groups (p < 0.001). In conclusion, G-HAY beef had the most beneficial nutritional profile, while soybean hulls increased the n-6:n-3 ratio of beef.

Fatty Acid and Antioxidant Profile of Eggs from Pasture-Raised Hens Fed a Corn- and Soy-Free Diet and Supplemented with Grass-Fed Beef Suet and Liver.

There is increasing interest in using grass-fed beef (GFB) by-products to augment the nutrient profile of eggs among local pasture-raising systems in the US. The objective of this study was to characterize egg yolk fatty acid and antioxidant profiles using eggs from pasture-raised hens fed a corn- and soy-free diet and supplemented with GFB suet and liver compared to eggs from pasture-raised hens fed a corn and soy layer hen feed and commercially obtained cage-free eggs. The egg yolk vitamin and mineral profile was also assessed by a commercial laboratory. Both pasture-raised groups had twice as much carotenoid content, three times as much omega-3 fatty acid content, and a 5−10 times lower omega-6:omega-3 fatty acid ratio compared to the cage-free eggs (p < 0.001). Eggs from hens fed a corn- and soy-free feed and GFB by-products had half as much omega-6 fatty acid content and five times more conjugated linoleic acid, three times more odd-chain fatty acid, and 6−70 times more branched-chain fatty acid content (p < 0.001). Feeding pasture-raised hens GFB suet and liver reduces agricultural waste while producing improved egg products for consumers, but further research is needed to quantify optimal supplementation levels and the efficacy of corn- and soy-free diets.

Fatty Acid and Micronutrient Profile of Longissimus Lumborum from Red Angus and Red Angus x Akaushi Cattle Finished on Grass or Grain.

Cattle diet and breed modify the nutritional profile of beef. The objective of this study was to compare the fatty acid (FA) and micronutrient profiles of Red Angus (RA) and RA x Akaushi (AK) crossbreed steers fed either a grass or grain diet. This two-year study randomly assigned steers to the diets using a 2 × 2 factorial experiment. FAs and micronutrients were analyzed. Diet effect was the strongest with grass-finished beef being higher in n-3 polyunsaturated FAs (p < 0.001), conjugated linoleic acid (p < 0.05), vaccenic acid (p < 0.05), iron (p < 0.001), and vitamin E (p < 0.001) compared to grain-finished beef. Breed effects were observed for lauric and myristic acids (p < 0.05), selenium (p < 0.05), and zinc (p < 0.01) with AK containing more of these compounds than RA. Diet × breed effects were non-existent. These results indicate that diet has a stronger influence than breed on modifying the nutritional profile of beef. Because of a more favorable FA and antioxidant profile, consumption of grass-finished beef could benefit human health.

Impact of forage diversity on forage productivity, nutritive value, beef cattle performance, and enteric methane emissions.

Greenhouse gas emissions from the beef industry are largely attributed to the grazing sector, specifically from beef cattle enteric methane emissions. Therefore, the study objective was to examine how forage diversity impacts forage productivity, nutritive value, animal performance, and enteric methane emissions. This study occurred over three consecutive grazing seasons (2018 to 2020) and compared two common Midwest grazing mixtures: 1) a simple, 50:50 alfalfa:orchardgrass mixture (SIMP) and 2) a botanically diverse, cool-season species mixture (COMP). Fifty-six steers and heifers were adapted to an Automated Head Chamber System (AHCS) each year (C-Lock Inc., Rapid City, SD) and stratified into treatment groups based on acclimation visitation. Each treatment consisted of four pastures, three 3.2-ha and one 1.6-ha, with eight and four animals each, respectively. Forage production was measured biweekly in pre- and postgrazed paddocks, and forage nutritive value was analyzed using near-infrared reflectance spectroscopy. Shrunk body weights were taken monthly to determine animal performance. Forage availability did not differ between treatments (P = 0.69) but tended lower in 2018 (P = 0.06; 2.40 t dry matter ha-1) than 2019 (2.92 t dry matter ha-1) and 2020 (P = 0.10; 2.81 t dry matter ha-1). Crude protein was significantly lower for COMP in 2018 compared with SIMP. Forage acid detergent fiber content was significantly lower for the COMP mixture (P = 0.02). The COMP treatment resulted higher dry matter digestibility (IVDMD48) in 2018 and 2019 compared with the SIMP treatment (P < 0.01). Animal performance did not differ between treatments (P > 0.50). There was a tendency for the COMP treatment to have lower enteric CH4 production on a g d-1 basis (P = 0.06), but no difference was observed on an emission intensity basis (g CH4 kg-1 gain; P = 0.56). These results would indicate that adoption of the complex forage mixture would not result in improved forage productivity, animal performance, or reduced emission intensity compared with the simple forage mixture.

Cow efficiency: modeling the biological and economic output of a Michigan beef herd.

In recent decades, beef cattle producers have selected cattle for biological traits (i.e., improved growth) to maximize revenue, leading to an increase in average cow body size. However, matching cow size to the production environment would allow producers to maximize productivity and economic returns per unit of land. This may help meet the goals of sustainable intensification, but environmental complexity and varying cow-calf production systems dictates a regional approach. The objective of this experiment was to examine the biological efficiency and economic returns of a Northern Michigan cow-calf system. We hypothesized that biological efficiency and economic returns would decrease with increasing cow body size. Data were collected from a Red Angus cow herd located at the Lake City AgBio Research Center in Lake City, MI from 2011 to 2018 on cow age, weight, and body condition score at weaning, and subsequent 205 d adjusted calf weaning weight (WW), sex, and yearling weight. Biological efficiency was defined as WW as a percentage of cow body weight (DBW). Enterprise budgeting techniques were used to calculate expected net returns from 2011 to 2018 after classifying cows into 11 BW tiers at 22.67 kg intervals beginning at 430.83 kg. Forward-looking net present value (NPV) was calculated using the same tier system, for a 10-yr production cycle with the baseline being a 200 d grazing season. Weaning weight increased with increasing DBW (P < 0.01), but the percentage of cow body weight weaned was reduced by -38.58 × Ln(DBW) (P < 0.01). This led to cows weaning 26.38 kg/ha more with every 100 kg drop in DBW. Expected net returns from 2011 to 2018 did not differ by DBW tier on a per cow basis but did on a per ha basis with a decrease in $10.27/ha with each increase in DBW tier (P < 0.01). Net present value was maximized in the baseline scenario at 453.51 kg DBW and decreased in value as DBW increased. These results suggest that for a Northern Midwestern cow-calf herd, comparatively lighter cows provide a higher economic value on a land basis.

Seasonal differences exist in the polyunsaturated fatty acid, mineral and antioxidant content of U.S. grass-finished beef.

There is increased consumer interest in grass-finished beef (GFB) with retail sales reaching $272 million in 2016. GFB contains higher omega-3 fatty acid levels compared to grain-finished beef, but variations in fatty acid (FA), mineral, and antioxidant content by producers and season is poorly documented. Hence, GFB samples from cattle finished in both fall and spring were obtained from four producers representing several US sub-regions. FAs were extracted using microwave-assisted extraction, derivatized to methyl-esters, and quantified using gas chromatography-mass spectrometry. Mineral content was quantified using coupled plasma mass-spectrometry and antioxidants were quantified via UV-absorption. Overall, total omega-3 FA content was greater in beef from cattle finished in the spring (13.4 mg/100g beef) than the fall (10.3; P<0.001). Additionally, α-tocopherol was present in greater amounts in spring-finished beef (259 vs. 223 ug/100g beef, P<0.001) as was the micromineral selenium (18.2 vs. 17.3ug/100g beef, P = 0.008). Despite using the same feed in fall and spring, cattle from producer 4 had higher total omega-3, omega-6, and total polyunsaturated fatty acids in spring compared to fall (P<0.010). These results suggest there are seasonal differences in omega-3 and omega-6 fatty acids, minerals and antioxidants in grass-finished beef independent of finishing diet.

Could the breed composition improve performance and change the enteric methane emissions from beef cattle in a tropical intensive production system?

Crossbreeding has been used to improve performance in beef cattle, however the effects of breed composition on methane (CH4) production, yield and intensity from cattle raised in tropical intensive and integrated systems remain unknown. To assess the impact of breed composition on performance and methane emissions, Nellore (NEL; yr 1: BW = 171.5 ± 19.4 kg; n = 10; yr 2: BW = 215.8 ± 32.3 kg, n = 25) and Angus x Nellore crossbred (AN; yr 1: BW = 214.2 ± 26.4 kg, n = 10; yr 2: BW = 242.5 ± 32.2 kg, n = 25) were compared. The animals grazed on integrated crop-livestock system in the growing phase (stocking rate 2452 kg BW/ha, herbage mass 4,884 kg dry matter (DM)/ha, forage allowance 5.9 kg DM/100kg BW) and then were finished in a feedlot. Steers (n = 8) from each breed composition were randomly selected in each phase to measure CH4 production using a sulfur hexafluoride (SF6) tracer technique and DM intake (DMI) using titanium dioxide. Compared with NEL, AN had both superior total gain and average daily gain (ADG) in the grazing period. The AN presented greater ADG in the feedlot with a shorter finishing period and resulted in greater carcass yield and carcass ADG. Methane production (kg/period) was lower in NEL (19% less) than AN in grazing (P<0.01), and no difference was observed in feedlot. The NEL had less CH4 intensity (CH4/BW) in grazing but greater CH4 per unit of ADG in the feedlot compared to AN. Breed composition did not influence the CH4 yield (CH4/DMI) in either phase, despite the difference in feedlot DMI (kg/day). In conclusion, crossbreeding may be an option to improve performance and reduce the CH4 per ADG in tropical climate conditions, resulting in lower methane emission per kg of meat produced.