Abstract
dc:description.abstractThe objective was to summarize management practices, identify factors associated with bacterial counts, and describe the variation in total solids concentrations of milk or milk replacer in automated feeders. Six dairy calf operations in Virginia and 4 in Minnesota employing 1 to 2 sophisticated automated calf feeders were visited biweekly for 26 to 28 wk. An initial management survey was conducted for each farm. Observations on facilities, calf weights and heights, blood samples to estimate serum total proteins, treatment records, digital feeding behavior records, and milk or milk replacer (MMR) samples were collected at each visit. Additional milk replacer (MR) samples were collected for 4 wk pre- and post-circuit cleaning. Samples of MMR were plated on Aerobic Plate Count (APC) and Coliform Count (CCP) Petrifilms. Total solids concentration was estimated for MR samples by refractometry. Feeding plans varied widely between farms. Estimates of calf growth were near industry standards, but the proportion of calves receiving treatment was elevated. Least squares mean APC and CCP were 5.26 and 3.01 log10 cfu/ml for Virginia and 3.80 and 0.61 log10 cfu/ml for Minnesota. Circuit cleaning (CC) caused 13 and 16% log reduction in APC and CCP. However, more frequent CC/wk increased bacteria. Mixer/heat exchanger cleanings decreased bacteria during biweekly farm visits. Chlorine bleach reduced bacteria. Use of silicone feeder hoses increased bacteria. A quadratic effect of MMR liters delivered/d was observed; liters delivered > 147 L decreased APC. Automated feeders delivered 12.26% of MR samples > 2% over and 25.71% > 2% under target solids concentration.
Degree
thesis:*- Name thesis:degree_name
- Master of Science
- Level thesis:degree_level
- masters
- Discipline thesis:degree_discipline
- Dairy Science
- Department dc:contributor.department
- Dairy Science
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2015
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Dietrich, Alyssa
- Chair dc:contributor.committeechair
-
- James, Robert E.
- Committee members dc:contributor.committeemember
-
- French, Patrick D.
- Petersson-Wolfe, Christina S.
Subjects
dc:subject × 3Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- vt_gsexam:6029
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/54595