Nutrition

News 964 views last update:6 Aug 2012

Research: Supplements for grazing dairy cows

At the Maringá University in Brazil production performance and milk composition of grazing dairy cows fed pelleted or non-pelleted concentrates treated with or without lignosulfonate and containing ground sunflower seeds were studied.

Effects of feeding supplements which contained ground sunflower seeds in a pelleted versus non-pelleted concentrate treated with, or without, 50 g/kg lignosulfonate were evaluated in 8 multiparous Holstein cows under grazing conditions.
 
Trial setup
Cows were assigned to a double 4 × 4 Latin square design experiment with four 21 d experimental periods.
 
Whole diet total tract apparent digestibility, dry matter (DM) intake, milk production, milk composition, ruminal fermentation characteristics and milk fatty acid profile were determined.
 
At the beginning of the experiment, cows were 556 ± 39.8 kg of body weight and 100 ± 62.6 d in milk.
 
Results
There was no interaction between pelleting and lignosulfonate for any parameter studied.
 
Lignosulfonate and pelleting had no effect on DM intake (i.e., concentrate + pasture) and lignosulfonate had no effect on nutrient intakes (i.e., concentrate + pasture).
 
Intake (i.e., concentrate + pasture) of ether extract was lower for cows fed pelleted than for those fed non-pelleted concentrates, but there was no difference among treatments in total intake of other nutrients.
 
Pelleting had no effect on digestibility, but decreased milk fat concentration.
 
Milk production, milk concentrations of crude protein, lactose and total solids, and milk yields of crude protein and fat were similar among treatments.
 
Pelleting had more effects than lignosulfonate treatment on milk fatty acid profiles, with concentrations of trans11-18:1 and conjugated linoleic acid (CLA) being, respectively, 178% and 200% of those found in milk fat of cows fed non-pelleted concentrates.
 
Conclusion
Pelleting may improve the nutritional value of concentrates containing ground sunflower seeds as a source of CLA precursors in milk fat of grazing dairy cows.
 
However, there was no positive additive or synergistic effect between lignosulfonate treatment and pelleting.
 
 
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