Jill Heemstra

Document Type

Thesis - University Access Only

Award Date

1996

Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Scott Kronberg

Abstract

Leafy spurge costs producers millions of dollars annually, largely because cattle are unwilling to graze it. Ensiling has been shown to reduce the levels of toxins in other plants. With that in mind, leafy spurge/grass haylage (LSGH) was ensiled with a microbial inoculant. Oat/rape haylage (ORH) was used as the control diet. Twenty-five crossbred yearlings (416.1 ± 25.9 kg) were stratified by weight and sex across five treatment groups. Group 1 (OAT) was offered as ORH ad libitum. Group 2 (SPURGE) was offered as LSGH ad libitum. Group 3 was a paired-feeding control group that was offered ORH in an amount equal to the average amount of LSGH that SPURGE consumed at the previous feeding. Group 4 (MIX) was gradually introduced to an increasing percentage of LSGH mixed in with ORH. Group 5 (PAIR) was a paired-feeding control group that was offered only ORH in quantities equal to the amount of haylage that Group 4 consumed at the previous 1 h feeding. All rations were offered for 1 h in the morning and 1 h in the evening. The OAT, SPURGE, and MIX groups consumed similar amounts of OM at the first feeding (P=.52). The SPURGE group consumed essentially no LSGH thereafter and was removed from the trial along with their paired-feeding group. On days 1-3, SPURGE consumed less OM than OAT and MIX groups (P2O3) was used to determine apparent digestibility of OM, CP, ADF, NDF and GE in the rations offered to the MIX and PAIR groups. The intakes of OM, GE, CP, DE, NDF and ADF were similar between MIX and PAIR (P≥.64). The digestion coefficients for DM, CP, NDF, and ADF of the ration offered to MIX were lower than those for PAIR (P≤.01). However, apparently digested DM, CP, NDF, and ADF as well as DE were similar between the two groups (P≥.10). Blood was sampled on Days -7, 7, 21 and 29 and analyzed for metabolic indicators. LSGH intake did not impact aspartate aminotransferase, bilirubin, calcium, chloride, creatinine kinase, glucose, magnesium, sodium, albumin, globulin, albumin/ globulin ratio, hematocrit, hemoglobin, and white blood cell counts. LSGH intake caused differential responses in levels of gamma glutamyltransferase, phosphorus, serum urea nitrogen, total protein potassium, and sodium/ potassium ratio relative to those animals which received only ORH, although none of these differences appear to be indicative of organ damage. MIX and PAIR were euthanized at the end of the four-week trial, carcasses were examined and tissues sampled. No lesions were observed on the carcasses or on any of the tissue samples. No infectious agents or significant amounts of internal parasites were detected in any of the animals. However, diarrhea was observed in the animals that received LSGH. In a second trial, five crossbred yearlings (Group CT) were adapted to a mixture of 21% LSGH and 79% ORH for 14 d. On Day 1, they were simultaneously offered three mixtures containing 21% spurge haylage and 79% ORH. They were allowed access to the feed for 1 h each morning and 1 h each evening for three days. The three spurge haylage types included leafy spurge ensiled with only a microbial inoculant (LSGH), spurge ensiled with the same inoculant and a cellulolytic/hemicellulolytic enzyme mixture (ENZ) and spurge ensiled with the inoculant and molasses (MOL). The animals consumed an average of 4.56 kg DM/d of the mixture containing ENZ, 0.27 kg of the mixture containing MOL and 0.37 kg of the mixture containing LSGH. ENZ was much preferred over the other two (P

Library of Congress Subject Headings

Cattle -- Feeding and feeds
Leafy spurge

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright