The Use of Removed Mesquite Brush as a Fiber Replacement in Silage Production.

Mesquite (Prosopis L.) is considered an invasive browse species in most of the American Southwest. Mechanical intervention removes yields an excess of organic debris. Anecdotal evidence in the past has supported using such browse as feed for livestock. Thus, our objectives were to (1) determine the nutritive value and fermentation characteristics of silage produced with mesquite biomass, and (2) evaluate solvent treatment of mesquite biomass prior to ensiling. In Experiment 1, we evaluated mesquite inclusion rate (0, 250, 500, 750, or 1000 g kg−1 DM), length of fermentation (28, 56, or 84 d), and silage inoculant. In Experiment 2, we evaluated the effects of mesquite pre-treatment with acid (H2SO4) or alkali (NaOH) solutions. Concentrations of NDF, ADF, and ADL, as well as IVTD, decreased (p < 0.05) with increasing mesquite inclusion. However, 250 g mesquite kg−1 DM did not differ from grass silage. There was no effect (p > 0.05) of inoculation, though increasing length of incubation did increase (p < 0.05) VFA production and decrease (p < 0.05) silage pH. Solvent treatment did not improve ensiling properties. Results are interpreted to mean that mesquite biomass may be effectively incorporated into silage at levels up to 250 g kg−1.

Nutritive Value Variation and In Vitro Digestibility of Hempseed Meal.

Hempseed meal (HSM) is left after oil extraction of hemp and may act as a protein source in livestock. The first phase of this research evaluated variation in nutritive value and in vitro dry matter digestibility (IVDMD) of HSM from various sources in North America; the second phase utilized IVDMD to evaluate the efficacy of hempseed meal as an ingredient in ruminant feed. In phase one, the source had no contribution to variance for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), or crude protein (CP) (p ≥ 0.20). However, batch within source contributed to variation for NDF (50%), ADF (37%), ADL (13%), and CP (31%; p ≤ 0.01). Irrespective of differences in nutritive value, there was no contribution to variation (p = 0.23) of any measured response on in vitro true digestibility (53.0%). In phase two, two experiments evaluated HSM IVDMD as (1) a concentrate replacement or (2) a protein replacement in rations at varying rates. In the first experiment, IVDMD decreased (p < 0.05) with increasing levels of HSM. In the second experiment, IVDMD decreased (p < 0.01) as HSM inclusion increased. Although IVDMD decreased as HSM inclusion increased, values still met the digestibility threshold for ruminant rations, indicating that HSM has potential as an alternative protein ingredient.

Nutritive Value Variation of Paunch Manure as an Alternative Feed Ingredient.

Ruminants, which have multi-compartmented stomachs, are adapted to digest cellulosic materials, which constitute the primary expense on ranches and dairies. Industrial byproducts can be repurposed for livestock diets to decrease these costs. Therefore, finding alternative feedstuffs may benefit the economics of livestock production. The goal of this project was to evaluate the variation in nutritive value of ruminal waste as a potential feedstuff. Twelve paunch samples were collected from individual cattle across multiple harvest dates at the Tarleton State University Meat Laboratory, Stephenville, TX. Samples were dried and assayed for dry matter (DM), crude protein (CP), sequential neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL), and physically-effective fiber (peNDF). Samples were subjected to batch-culture in vitro digestibility assays for the determination of digestibility coefficients. Mean NDF, ADF, ADL, CP and peNDF concentrations were 681, 399, 109, 150, and 387 g kg-1 DM, respectively. Contribution to variance from sample for NDF, ADF, ADL, CP, and peNDF were 75.3, 41.9, 33.0, 51.2, and 71.3%, respectively. In vitro true digestibility (IVTD) and in vitro NDF digestibility (IVNDFD) were recorded as 462 and 216 g kg-1 DM, respectively. Contribution to variation of sample for IVTD and IVNDFD were 31.0 and 30.7%, respectively. Results indicate that rumen waste harvested from abattoirs may be useful for sustainable livestock production, while reducing environmental threats posed by disposal, but the viability of the product is highly dependent on the source animal. For full viability of application in a sustainable system, a centralized receiving and compositing system may be useful for developing a consistent product.