Feeding protein supplements in alfalfa hay-based lactation diets improves nutrient utilization, lactational performance, and feed efficiency of dairy cows

Abstract

Due to the increasing cost of soybean meal and concerns of excess N being excreted into the environment, new protein supplements have been developed. Two products that have shown potential in increasing N utilization efficiency are slow-release urea (SRU; Optigen; Alltech Inc., Nicholasville, KY) and ruminal-escape protein derived from yeast (YMP; DEMP; Alltech Inc.). The objective of this study was to assess the effects of feeding these 2 supplements in alfalfa hay-based [45.7% of forage dietary dry matter (DM)] dairy diets on nutrient utilization, feed efficiency, and lactational performance of dairy cows. Twelve multiparous dairy cows were used in a triple 4 × 4 Latin square design with one square consisting of ruminally cannulated cows. Treatments included (1) control, (2) SRU-supplemented total mixed ration (SRUT), (3) YMP-supplemented total mixed ration (YMPT), and (4) SRU- and YMP-supplemented total mixed ration (SYT). The control consisted only of a mixture of soybean meal and canola meal in a 50:50 ratio. The SRU and the YMP were supplemented at 0.49 and 1.15% DM, respectively. The experiment consisted of 4 periods lasting 28 d each (21 d of adaptation and 7 d of sampling). Cows fed YMPT and SYT had decreased intake of DM, and all supplemented treatments had lower crude protein intake compared with those fed the control. Milk yield tended to have the greatest increase in YMPT compared with the control (41.1 vs. 39.7 kg/d) as well as a tendency for increased milk fat and protein yields. Feed efficiencies based on yields of milk, 3.5% fat-corrected milk, and energy-corrected milk increased at 10 to 16% due to protein supplementation. Cows fed protein supplements partitioned less energy toward body weight gain, but tended to partition more energy toward milk production. Efficiency of use of feed N to milk N increased by feeding SRUT and YMPT, and milk N-to-manure N ratio increased with YMPT. Overall results from this experiment indicate that replacing the mixture of soybean meal and canola meal with SRU and YMP in alfalfa hay-based dairy diets can be a good approach to improve nutrient utilization efficiencies in lactating dairy cows.

An investigation of feeding high-moisture corn grain with slow-release urea supplementation on lactational performance, energy partitioning, and ruminal fermentation of dairy cows

“…Optigen®, a blended, controlled release urea product in a polyester polyurethane coating, allows the diffusion of the urea through micropores that slow down the rate of nitrogen release in the rumen (Galo et al 2003). The dietary concentration of the SRU was chosen based on a previous lactation study (Neal et al 2014). Slowrelease urea has a CP concentration of 256%, which has 11% less N than urea due to the vegetable oil coating of SRU.…”

“…Milk energy was calculated as (0.0929 × milk fat concentration) + (0.0563 × milk TP concentration) + (0.0395 × milk lactose concentration) (NRC 2001). Estimated NE l value was calculated by total net energy used for maintenance, BW gain, and milk divided by DMI (Neal et al 2014).…”

“…Thus, it is important to maintain microbial protein synthesis with the lowest dietary CP input to meet the metabolizable protein requirements of the cows to support milk production and optimize N utilization efficiency (Agle et al 2010). In addition to soybean meal and canola meal, very common protein supplements, slow-release urea (SRU) has been used in lactation rations to provide adequate supply of ruminal ammonia (Inostroza et al 2010;Neal et al 2014). Ruminal ammonia-N (NH 3 -N) concentration of 5.0 mg 100 mL −1 , derived from in vitro continuous culture experiments by Satter and Slyter (1974), is often accepted as the concentration required to support maximal growth of ruminal microorganisms.…”

“…Ruminal ammonia-N (NH 3 -N) concentration of 5.0 mg 100 mL −1 , derived from in vitro continuous culture experiments by Satter and Slyter (1974), is often accepted as the concentration required to support maximal growth of ruminal microorganisms. In a recent study (Neal et al 2014), replacing soybean meal and canola meal with SRU increased feed and N utilization efficiencies [1.35 to 1.46 kg milk kg −1 dry matter (DM) and 0.25 to 0.28 kg milk protein kg −1 dietary CP, respectively] when feeding high-forage diets (24.5% alfalfa hay and 30.4% corn silage) to lactating cows. Hence, SRU has a potential to improve nutrient utilization and lactational performance when supplemented in lactation diets consisting of a relatively great concentration of alfalfa hay.…”

A short review on the research progress in alfalfa leaf protein separation technology

“…Due to good protein quality, high protein content, complete and reasonable proportion of amino acid composition, providing the right amount of fat, sugar and soluble starch and a variety of minerals and vitamins, alfalfa leaf protein can be employed for feed additives . Many studies have reported that alfalfa leaf protein could replace part of the feed to reinforce feed quality and animal growth. In adult chicken feed, when 50–100% fishmeal was replaced by alfalfa leaf protein, egg production was not affected and egg quality improved; for chick feed, alfalfa leaf protein could replace 50–75% fishmeal, and survival rate was promoted by 3.4–4.2%; in broiler chickens feed, when 7.4–11.8% animal protein feed was replaced by alfalfa leaf protein, average weight increased by 4–11.8% .…”