Two trials were conducted to determine the effect of protein degradability (low (LD) vs high (HD)) and evaporative cooling (shade cooling vs shade) on performance of 60 lactating Holstein cows in mid-lactation. Cooling and the LD diet increased milk production, 3.5% FCM and feed efficiency in trial 1 (24 cows) while in trial 2 (36 cows) LD diet increased milk production and feed efficiency and cooling did not exert a significant effect. Differences between trials were probably due to higher environmental temperature humidity indexes (77.0 vs 72.0), and a higher quality of the rumen bypass protein in the LD diet in trial 2 than trial 1. Cooling reduced respiration rates in trial 1 and respiration rates, rectal and inner ear temperatures in trial 2. Eating patterns were unaffected by protein degradability or cooling.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/277021 |
| Date | January 1989 |
| Creators | Taylor, Ronald Brian, 1962- |
| Contributors | Huber, J. Tal |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Thesis-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
Page generated in 0.0017 seconds