In a feeding trial set up as a 2 x 2 factorial design, the effect of 30 g and 40 g of potassium per kg of DM in a diet containing 100 % or 200 % of Swiss sodium recommendations on mineral metabolism and on selected parameters of 12 dairy cows was investigated. The desired K and Na contents were adjusted by feeding hay differing in its natural K content and by varying NaCl supplementations. The experimental rations contained comparable energy, protein and mineral concentrations, except for K, Na and chloride. Hay was offered close to ad libitum, though within a same block cows were fed the same amount. Concentrate allowances were constant. After an adaptation period of 47 days followed a balance period of 2 x 4 days with quantitative faeces and urine collection.Increasing K supply from 30 g to 40 g per kg of diet DM resulted in a significant higher water consumption (103 l/cow, day; 119 l/cow, day) and urine production (30 kg/cow, day; 52 kg /cow, day). Mg digestibility tended to be reduced (10 %; 5 %). Ca, P, Mg, Na, and Cl retention did not differ significantly between the two K levels. Likewise, milk mineral content – except for Iodine – remained unaffected. The diet containing 40 g of K compared to 30 g of K significantly decreased iodine milk content from 1.04 mg/kg DM to 0.74 mg/kg DM. With respect to K, Na and Cl serum concentrations, the two dietary K levels had no biologically relevant effect. The high K supply, however, caused an intensified alkalization of the metabolism.
While botanical composition, growth cycle and phenological stage are integral factors, they are not the sole determinants of the quality of grass silages from intensively managed permanent meadows.
Food that is unsuitable for human consumption does not affect the growth performance or carcass composition of pigs to which it is fed. This makes it a promising solution for reducing food waste.
Horses are ridden or driven on a variety of surfaces, which differently absorb the impact forces exerted on hooves, limbs and the horse's entire body. Objective measurement of the functional properties of equestrian arena surfaces is therefore of great importance.