NR 20. Supplementation of grass silage to lactating Holstein cows grazing a tropical grass
Our objectives were to investigate the effect of silage supplementation under confinement, shade and increasing concentrate feedings on milk production and milk composition. Eight groups of six lactating Holstein cows blocked according to stage of lactation (early and mid) at the beginning of the experiment, were assigned to treatments according to a 4 x 4 Latin Square Design. Experimental treatments were as follows: 1) no silage; concentrate fed 2x/day 2) no silage; concentrate fed 3 x 3) silage fed under cover; concentrate fed 3x/day 4) silage fed in the open; concentrate fed 3x/day. Each of the four experimental periods consisted of 21 days of adaptation and 7 days of data collection. All cows remained on concrete during the day and grazed at the rate of 4.5 cows/ha during the hours 16:30 and 03:30. Feeding concentrate 3x/day resulted in a moderate increase (P>.02) in milk production over feeding 2x a day. The supplementation with silage resulted in a 3 % reduction (P>.01) in yield compared with no silage supplementation. These yield differences were higher for early lactation higher producing cows (interaction square x treatment (P = .03). In spite of the increase in milk yield, increasing the number of concentrate meals to 3x/d resulted in a reduction (P>.03) in milk fat percent. The reverse was true for milk protein; feeding 3x/d resulted in an increase (P>.03) in milk protein percent. Silage supplementation resulted in lower milk protein percent when compared with no silage supplementation. Based on the results of this trial it can be said that supplementation of forage under partial confinement should only be considered when feeding forage of higher quality than pasture or when the farmer has insufficient pasture such as in a drought or when stocking rates are excessively high. Reducing meal size and increasing feeding frequency appears a good strategy to increase milk production.
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociacion Latinoamericana de Produccion Animal
2005
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| Online Access: | https://ojs.alpa.uy/index.php/ojs_files/article/view/102 |
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