The objective of this study was to determine whetheradding water to a dry diet would reduce sorting andimprove cow performance. Eighteen multiparous lac-tating Holstein cows were used in a cross-over designwith 21-d periods. Treatments had the same dietarycomposition and differed only by adding water (WET)or not (DRY). Diets consisted of 10% alfalfa silage, 30%hay (approximately 80% grass and 20% alfalfa), and60% concentrate [dry matter (DM) basis]. Dietary DMwas 80.8% for DRY and 64.4% for WET. Both dietscontained 16.9% crude protein and 24.3% neutral deter-gent fiber. Particle size was determined using the Wis-consin Particle Size Separator on the as-fed diets. Theseparator has five square-hole screens (Y 1 to Y 5 ) withdiagonal openings of 26.9 mm for Y 1 , 18 mm for Y 2 ,8.98 mm for Y 3 , 5.61 mm for Y 4 , and 1.65 mm for Y 5 ,and one pan. Sorting was calculated on a 60 ° C DM basis(60DM). Predicted intake of Y i was calculated as theproduct of 60DM intake (60DMI) and the 60DM fractionof Y i in the total mixed ration for that screen. For DRYand WET, actual 60DMI by screen expressed as a per-centage of predicted intake was 61.4% vs. 75.2% for Y 1 ,83.8% vs. 98.6% for Y 2 , 85.6% vs. 90.8% for Y 3 , 95.2%vs. 96.0% for Y 4 , 100.1% vs. 101.9% for Y 5 , and 105.9%vs. 102.9% for pan, respectively. Adding water did notaffect total DM intake (28.3 kg/d) or milk production(41.3 kg/d). Neutral detergent fiber intake was 6.42 kg/d for WET and 6.15 kg/d for DRY. Milk fat percentagetended to be higher (3.41% vs. 3.31%) when cows con-sumed WET vs. DRY. No differences in ruminal pH,NH 3 , and volatile fatty acids were observed. Cowssorted against long particles in favor of shorter particleson both diets. Adding water to dry diets reduced sortingand tended to increase neutral detergent fiber intakeand milk fat percentage.
Effect of water addition on selective consumption (sorting) of dry diets by dairy cattle
Giannico, F.;
2005-01-01
Abstract
The objective of this study was to determine whetheradding water to a dry diet would reduce sorting andimprove cow performance. Eighteen multiparous lac-tating Holstein cows were used in a cross-over designwith 21-d periods. Treatments had the same dietarycomposition and differed only by adding water (WET)or not (DRY). Diets consisted of 10% alfalfa silage, 30%hay (approximately 80% grass and 20% alfalfa), and60% concentrate [dry matter (DM) basis]. Dietary DMwas 80.8% for DRY and 64.4% for WET. Both dietscontained 16.9% crude protein and 24.3% neutral deter-gent fiber. Particle size was determined using the Wis-consin Particle Size Separator on the as-fed diets. Theseparator has five square-hole screens (Y 1 to Y 5 ) withdiagonal openings of 26.9 mm for Y 1 , 18 mm for Y 2 ,8.98 mm for Y 3 , 5.61 mm for Y 4 , and 1.65 mm for Y 5 ,and one pan. Sorting was calculated on a 60 ° C DM basis(60DM). Predicted intake of Y i was calculated as theproduct of 60DM intake (60DMI) and the 60DM fractionof Y i in the total mixed ration for that screen. For DRYand WET, actual 60DMI by screen expressed as a per-centage of predicted intake was 61.4% vs. 75.2% for Y 1 ,83.8% vs. 98.6% for Y 2 , 85.6% vs. 90.8% for Y 3 , 95.2%vs. 96.0% for Y 4 , 100.1% vs. 101.9% for Y 5 , and 105.9%vs. 102.9% for pan, respectively. Adding water did notaffect total DM intake (28.3 kg/d) or milk production(41.3 kg/d). Neutral detergent fiber intake was 6.42 kg/d for WET and 6.15 kg/d for DRY. Milk fat percentagetended to be higher (3.41% vs. 3.31%) when cows con-sumed WET vs. DRY. No differences in ruminal pH,NH 3 , and volatile fatty acids were observed. Cowssorted against long particles in favor of shorter particleson both diets. Adding water to dry diets reduced sortingand tended to increase neutral detergent fiber intakeand milk fat percentage.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
