W.P. Weiss, M.E. Koch, and T.E. Steiner
Department of Animal Sciences
Fall-seeded triticale (Trical®) was harvested in the boot stage and ensiled. A commercial mixture of forage sorghum, forage soybeans, and forage peas (Pro-Ton) was planted after the triticale was removed and harvested as silage 65 days later. The sorghum mixture contained 71% sorghum, 18% soybeans, and 11% peas (dry matter basis). Yields of dry matter (DM) were 1.8 and 5.3 tons/acre for the triticale and sorghum mixture, respectively. Three diets were formulated that contained the same amount of neutral detergent fiber (NDF; 32%), crude protein (CP; 16%), and nonfiber carbohydrate (NFC; 41%). One diet contained 39% triticale silage and 61% concentrate, another diet contained 29% sorghum mixture silage and 71% concentrate, and the third diet contained 28% corn silage, 21% alfalfa silage, and 51% concentrate (DM basis). The concentrate mixes were predominantly corn grain and soybean meal. Diets were fed to 12 lactating Holstein cows in a replicated Latin square experiment. Dry matter intake was higher by cows fed the alfalfa and corn silage diet (50.6 pounds/day) than by cows fed triticale (46.2 pounds/day) or the sorghum mixture diets (48.2 pounds/day). Milk production (64.5 pounds/day) and milk composition (3.3% fat and 3.2% protein) were not affected by treatment. Triticale silage and the sorghum mixture silage were acceptable forages for dairy cows but required an additional 2.4 and 8.4 pounds of concentrate DM, respectively, as compared with a conventional alfalfa and corn silage system.
Corn silage and alfalfa are the major forages fed to dairy cows in Ohio. Other forages may fit specific weather, soil conditions, and crop rotation plans better than alfalfa and corn. The nutritional value of these alternative forages must be evaluated to determine whether they are economically viable replacements for conventional forages.
Triticale can be seeded in the fall and be harvested in late spring. In many areas of Ohio, triticale (or other small grains) can be harvested for forage, and the land then can be used for producing corn silage or another summer annual forage crop, such as sorghum. Forage sorghum and sorghum mixtures are usually ready to be harvested sooner than corn silage and are useful when forage will be in limited supply during the late summer. Sorghum, however, is low in protein and high in fiber. Mixing forage sorghum with legumes such as soybeans or forage peas will increase the protein content and decrease the fiber content. The resulting forage should be higher in nutritional value than sorghum. The objective of this experiment was to determine whether diets based on triticale silage or sorghum, soybean and pea silage were nutritionally equivalent to a diet based on alfalfa and corn silages when fed to lactating dairy cows.
Forage triticale (Trical®, Resource Seeds Inc., Gilroy, CA) was planted on October 5, 1993, at OARDC in Wooster (120 pounds/acre). The triticale (boot stage) was mowed on May 17, 1994, and ensiled on May 20. A commercial mixture of forage sorghum, forage soybeans, and forage peas (Pro-Ton, Ag Nation Products, E. Canton, OH) was planted (110 pounds/acre) in the same field on June 3, 1994, mowed on August 15, and ensiled on August 17. Both silages were stored in concrete stave silos (10 X 50 ft). Dry matter yield from the field was determined by weighing all the forage ensiled.
Twelve midlactation Holstein cows (150 days in milk) were used in a replicated (4 squares) 3 X 3 Latin square experiment. Periods were 4 weeks long. Three diets were formulated based on triticale silage, sorghum mixture silage, and alfalfa and corn silages (Table 1). Diets were equal in NDF, CP, and NFC (Table 2). The initial sample of sorghum mix silage used to formulate diets had higher concentrations of NDF than samples collected during the experiment. This resulted in the sorghum mix diet having lower forage NDF than the other two diets. Daily milk production and DM intake were measured. Milk was sampled weekly and analyzed for fat and protein. Dry matter digestibility was measured using chromic oxide as a marker. Analysis of variance was used to test the data statistically. Square, cow, period, and treatment were main effects. Appropriate interactions were included. Single degree of freedom contrasts were used to compare the triticale diet with the control diet and to compare the sorghum mixture diet with the control diet.
The triticale was high in CP and NDF (Table 3). Overall, its nutrient composition was similar to other small grains harvested in the boot stage. At the time of mowing, samples from the sorghum mixture were collected and manually separated into sorghum, soybean, and pea components. Approximately 71% of the DM was sorghum, 18% soybeans, and 11% field peas. The sorghum mixture was low in CP and high in NDF. The CP content of the mixture was higher than what would be expected from pure sorghum (approximately 8%), but NDF values were similar to pure sorghum. Yields of DM were 1.8 tons/acre for triticale and 5.3 tons/acre for the sorghum mixture. Total yield of the double crop system was 7.1 tons of DM/acre.
| Table 1. Ingredient composition of diets (% of dry matter). | |||
| Control | Triticale | Sorghum mix | |
| Corn silage | 28.0 | . . . | . . . |
| Alfalfa silage | 21.0 | . . . | . . . |
| Triticale silage | . . . | 39.0 | . . . |
| Sorghum mix silage1 | . . . | . . . | 29.0 |
| Corn grain | 27.0 | 40.2 | 43.5 |
| Soybean meal | 7.2 | 3.9 | 9.6 |
| Soyhulls | 6.6 | 5.7 | 6.0 |
| Roasted soybeans | 4.0 | 4.0 | 4.0 |
| Distillers grains | 3.3 | 3.6 | 4.0 |
| Molasses | 0.9 | 1.1 | 1.3 |
| Sodium | 0.4 | 0.5 | 0.5 |
| Limestone | 0.8 | 1.2 | 1.2 |
| Mineral/vitamin premix2 | 0.8 | 0.8 | 0.9 |
| 1 Sorghum mix silage contained 71% sorghum, 18%
forage soybeans, and 11% forage peas (DM basis).
2 Premix contained trace mineral salt, dicalcium phosphate, magnesium oxide, selenium, and vitamins A, D, and E. | |||
| Table 2. Nutrient composition of diets (% of dry matter). | |||
| Control | Triticale | Sorghum mix | |
| Forage | 49.0 | 39.0 | 29.0 |
| Digestible DM | 57.6 | 58.1 | 57.2 |
| CP | 16.4 | 15.7 | 16.0 |
| NDF | 32.1 | 32.7 | 31.5 |
| Forage NDF1 | 20.5 | 20.6 | 18.4 |
| Nonfiber carbohydrate | 40.5 | 40.7 | 41.2 |
| 1 Forage NDF comprised 64, 63, and 58% of total NDF. | |||
| Table 3. Nutrient composition of forages (DM basis). | ||||
| Nutrient | Corn silage | Alfalfa | Triticale | Sorghum mix |
| DM, % | 36.7 | 60.6 | 28.4 | 37.0 |
| CP, % | 8.1 | 20.4 | 16.7 | 11.0 |
| NDF, % | 40.9 | 42.9 | 52.9 | 62.3 |
Cows fed the alfalfa and corn silage-based diets consumed more (P < 0.05) DM than cows fed the triticale or the sorghum mixture diet (Table 4). Because diets were equal in NDF, cows fed the control diet also consumed more NDF than did cows fed the triticale or sorghum mixture diets. Dry matter digestibility did not differ among treatments and averaged 57.5%. Cows fed the control diet produced the same (P > 0.50) amount of milk as did cows fed the triticale or the sorghum mixture diet. Milk composition and yields of milk protein and fat were not different among treatments.
| Table 4. Performance of cows fed diets with different forages. | |||
| Control | Triticale | Sorghum mix | |
| DM intake, pounds/day | 50.3 | 45.9 | 47.6 |
| Milk, pounds/day | 65.1 | 64.2 | 64.1 |
| Milk fat, % | 3.25 | 3.32 | 3.25 |
| Milk protein, % | 3.21 | 3.17 | 3.18 |
Relative economic values for the alternative forages were calculated using three different corn prices ($2.75, $3.25, and $3.75/bu), three different soybean meal prices ($200, $225, and $250/ton), and setting the price of alfalfa at $120/ton of DM ($100/ton of hay equivalent) and corn silage at $63/ton of DM ($25/ton of corn silage, as fed). To maintain similar income over feed costs as the control diet, the sorghum mixture was worth between $86 and $90/ton of DM when corn was $2.75/bu. When corn was $3.75/bu, the sorghum mixture was worth between $70 and $75/ton of DM. The value of triticale DM was insensitive to changes in both the corn and soybean meal price. Within the range of corn and soybean meal prices used, triticale was worth about $109/ton of DM. If alfalfa and corn silage can be produced at the costs used in this example, then triticale is an economical alternative when it can be produced for less than $109/ton of dry matter. The sorghum mixture would be an economical alternative when it can be produced for less than about $72/ton (with $3.75/bu corn) or $88/ton (with $2.75/bu corn). These relative values are dependent on the price of alfalfa and corn silage. If those prices increase, the relative value of the alternative also would increase.