Feeding wet brewers' grain to heifers
It has been a common practice now for many years to feed wet brewers' grains (WBG) to dairy cows, but no data were available indicating how to feed it to post-weaned heifers. This research addresses that issue.
Wet brewers' grain can spoil fairly easily, especially during the warm summer months. However, adding an inexpensive preservative, such as salt, can reduce the chance of mold formation, decrease spoilage loss, and ultimately improve animal performance.
Adding up to 2.4% salt to WBG can reduce mold counts and spoilage while replacing corn and soybean meal up to 20% of the dry matter, saving $0.19 per pound of gain in growing heifers. This co-product is readily available at inexpensive prices and can be used in heifer diets to replace the more costly corn and soybean meal.
This research was published in the INSPIRED: A Publication of the New Hampshire Agricultural Experiment Station (Winter 2021)
Researchers: E. Hatungimana, T.S. Stahl, and P.S. Erickson
For many years, it has been a common practice to feed wet brewers' grains (WBG) to dairy cows, but no data were available indicating how to feed it to post-weaned heifers. Therefore, researchers conducted three experiments: 1) evaluate use in limit fed heifer diets with various amounts of salt added as a preservative; 2) evaluate storage properties and their effects on nutrient digestibility; and 3) evaluate use as a total replacement for corn meal and soybean meal. Wet brewers' grains have a propensity to spoil. Therefore, this research determined how preservation can be increased and whether there are positive or negative effects on performance as compared to heifers fed a conventional diet.
In experiment 1, scientists evaluated a preservative or salt and evaluated how it impacted mold and yeast counts nutrient changes and nutrient along with digestibility. This brief will focus only on the salt treatment. For the study, researchers evaluated 8 tubs of fresh WBG, with 107 pounds of WBG per tub. In duplicate, they added and mixed either 0, 1.4%, 2.6% or 3.8% salt. Tubs were kept under cover with temperatures ranging from 55⁰F to 58⁰F. Tubs were stored for 28 days with samples taken every other day for mold and yeast counts. Samples also were taken every seven days for analysis of laboratory nutrient digestibility using rumen fluid in an artificial rumen. Using three ruminally cannulated cows, researchers evaluated dry matter, neutral detergent fiber, acid detergent fiber and protein digestibilities from dacron bags suspended in the rumen. Results indicated that adding 3.8% salt to the WBG reduced mold counts. Salts also increased in vitro digestibility (artificial rumen) and great protein digestibility when evaluating rumen and intestinal digestibility.
In experiment 2, WBG was stored with 0, 0.8%, 1.6% or 2.4% salt for four days. The objective of this experiment was to evaluate the effects of salt treatment on total tract nutrient digestibility and rumen microbial protein synthesis. Heifers were fed the diets for 21 days with the last 7 days for the collection of data. The study was designed as a replicated 4 × 4 Latin square using eight, limit-fed, 8-month-old heifers. The diet was balanced for 5.00 Mcal/lb. metabolizable energy and 14% CP on a dry basis. This experimental design dictates that each animal receives each treatment for one 21-day period. Yeast and mold counts along with storage loss were estimated over 11 days. Yeast counts did not vary among treatments, while mold counts tended to be lower for the 0.8 and 1.6% salt treatments. There were trends for reduced nutrient digestibilities as salt increased, but storage loss was reduced—the highest storage loss was with the 0.8% salt treatment (11.02%) while the lowest loss was with the 2.4% treatment (5.12%). There was a trend for increased purine derivative secretion for the 0.8% and 1.6% salt treatments. Purine derivatives were present in the urine and are indicative of rumen bacteria synthesis. Therefore, rumen bacteria populations would have increased with the presence of 0.8 and 1.6% salt. While not the primary purpose of the study, average daily gain and feed efficiency improved as salt inclusion increased. General conclusions are that the addition and mixing of salt up to 2.4% in the WBG improved storage life and performance in limit-fed 8-month-old heifers.
In experiment 3, researchers evaluated replacing corn meal and soybean meal-based energy and protein mixes with either 10 or 20% WBG on a dry matter basis. The objective was to determine if conventionally raised yearling heifers could perform as well as heifers raised on a corn/soybean meal-based diet. We used 30 yearling heifers (10 per treatment) fed one of the aforementioned treatments. Diets were limit-fed at 5.00 Mcal/lb. of metabolizable energy, and 15% CP on a dry matter basis. Diets were fed for 12 weeks with the total tract nutrient digestibility determined during week 12. Body weights and skeletal measures were taken every two weeks. There were no statistical differences among treatment groups on dry matter intake, body weight, or average daily gain. With dry matter intakes ranging from 19 pounds to 19.8 pounds/day, average body weight ranged from 892, 907, and 902.5 pounds, and average daily gain was 2.27, 2.29, and 2.12 pounds per day for 0%, 10%, and 20% WBG respectively. Digestibilities varied somewhat and were similar for the 0 and 20% WBG treatments. Dry matter intake tended to be greater during the digestibility phase for the 10% WBG treatment resulting in a greater rate of passage through the gut thus reducing digestibilities.
From an economic standpoint, the costs of the energy mix (corn meal based) and protein mix (soybean meal based) were $228.57 and $351.02 per ton (dry basis) respectively. The WBG cost was $172.34 (dry basis) per ton. Therefore, adjusting for corn and soybean meal prices, the costs per pound of dry matter were $0.11, $0.10, and $0.09 for the 0, 10% and 20% WBG, respectively. The cost /gain was $1.00, $0.86 and $0.81 for the 0, 10% and 20% WBG, respectively.
The authors appreciate the collaboration and support of BadLab Brewery, Somersworth, NH; Fernald Dairy Farm, Nottingham, NH; Scruton Dairy Farm, Farmington, NH; and Stuart Farm, Stratham, NH.
This material is based upon work supported by the NH Agricultural Experiment Station, through joint funding of the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 1016574, and the state of New Hampshire. Authors include E. Hatungimana, T.S. Stahl, and P.S. Erickson