Effects of replacing wild rye, corn silage, or corn grain with CaO-treated corn stover and dried distillers grains with solubles in lactating cow diets on performance, digestibility, and profitability

Abstract

The objective of this study was to measure the effects of partially replacing wild rye (Leymus chinensis; WR), corn silage (CS), or corn grain (CG) in dairy cow diets with CaO-treated corn stover (T-CS) and corn dried distillers grains with soluble (DDGS) on performance, digestibility, blood metabolites, and income over feed cost. Thirty tonnes of air-dried corn stover was collected, ground, and mixed with 5% CaO. Sixty-four Holstein dairy cows were blocked based on days in milk, milk yield, and parity and were randomly assigned to 1 of 4 treatments. The treatments were (1) a diet containing 50% concentrate, 15% WR, 25% CS, and 10% alfalfa hay (CON); (2) 15% WR, 5% CG, and 6% soybean meal were replaced by 15% T-CS and 12% DDGS (RWR); (3) 12.5% CS, 6% CG, and 5% soybean meal were replaced by 12.5% T-CS and 12%DDGS (RCS); (4) 13% CG and 6% soybean meal were replaced by 7% T-CS and 13% DDGS (RCG). Compared with CON treatment, cows fed RCS and RCG diets had similar dry matter intake (CON: 18.2 ± 0.31 kg, RCS: 18.6 ± 0.31 kg, and RCG: 18.4 ± 0.40 kg). The RWR treatment tended to have lower dry matter intake than other treatments. The inclusion of T-CS and DDGS in treatment diets as a substitute for WR, CS, or CG had no effects on lactose percentage (CON: 4.96 ± 0.02%, RWR: 4.97 ± 0.02%, RCS: 4.96 ± 0.02%, and RCG: 4.94 ± 0.02%), 4% fat-corrected milk yield (CON: 22.7 ± 0.60 kg, RWR: 22.1 ± 0.60 kg, RCS: 22.7 ± 0.60 kg, and RCG: 22.7 ± 0.60 kg), milk fat yield (CON: 0.90 ± 0.03 kg, RWR: 0.86 ± 0.03 kg, RCS: 0.87 ± 0.03 kg, and RCG: 0.89 ± 0.03 kg), and milk protein yield (CON: 0.74 ± 0.02 kg, RWR: 0.72 ± 0.02 kg, RCS: 0.73 ± 0.02 kg, and RCG: 0.71 ± 0.02 kg). Cows fed the RWR diet had higher apparent dry matter digestibility (73.7 ± 1.30 vs. 70.2 ± 1.15, 69.9 ± 1.15, and 69.9 ± 1.15% for RWR vs. CON, RCS, and RCG, respectively) and lower serum urea N (3.55 ± 0.11 vs. 4.03 ± 0.11, 3.95 ± 0.11, and 3.99 ± 0.11 mmol/L for RWR vs. CON, RCS, and RCG, respectively) than cows fed other diets. No significant differences were noted in apparent neutral detergent fiber digestibility among the treatments. Compared with CON treatment, the RWR, RCS, and RCG treatments generated an additional $0.77, $0.70, and $0.81 income over feed cost per cow per day, respectively. In conclusion, feeding diets containing a portion of T-CS and DDGS can improve profitability of the treatment groups without negatively affecting the lactation performance of mid- to late-lactation cows.

The value of corn stover for Chinese dairy farms

“…In the default situation, the profit of arable farmers was 3281 RMB/ha/yr. The price of corn stover is always low due to its high lignin content and low degradability (Shi et al, 2015).…”

“…As a result, the profit of dairy farms in China decreases. Utilization of local forages such as corn stover may help dairy farmers to reduce feed costs due to the lower price of corn stover (Shi et al, 2015b) and to increase their profit since in general, feed costs are the greatest expense in dairy farms (Buza et al, 2014). Last but not the least, making the best use of corn stover can improve the efficiency with which land is used.…”

“…In recent years, the profit of dairy farms in China decreased due to the lower price of raw milk and higher price of commonly used feedstuffs, such as ground corn (GC), soybean meal (SBM), and high quality forages Shi et al, 2015). Since feed costs are the greatest component of total operating expenses on most dairy farms (Buza et al, 2014), reducing feed costs would be an effective method to improve the profit of dairy farms.…”

“…Since feed costs are the greatest component of total operating expenses on most dairy farms (Buza et al, 2014), reducing feed costs would be an effective method to improve the profit of dairy farms. Utilization of crop residues may help dairy farmers to reduce feed costs (Shi et al, 2015).…”

“…Whole plant corn silage (WPCS) is widely used in dairy farms globally (Khan et al, 2015). Corn stover silage (CSS), the silage of the stems and leaves obtained after harvesting the ears from the plants, is rarely included in a ration of high producing cows (Wang et al, 2014), due to its greater neutral detergent fiber (NDF) and acid detergent lignin (ADL) content and lower degradability, leading to a lower net energy (NE) content compared with WPCS (Shi et al, 2015). Since low producing and dry cows require less energy than high producing cows, it may be possible to include CSS as a major forage source in the ration of low energy demanding cows without compromising their productive performance.…”