Ng. Belibasakis et D. Tsirgogianni, EFFECTS OF NIACIN ON MILK-YIELD, MILK-COMPOSITION, AND BLOOD COMPONENTS OF DAIRY-COWS IN HOT WEATHER, Animal feed science and technology, 64(1), 1996, pp. 53-59
Twenty multiparous Friesian cows, 90 +/- 30 days postpartum, were allo
cated to two groups of ten cows according to calving date, lactation n
umber and daily milk yield, and assigned randomly to one of two diets
in a cross-over experiment. The experimental diet consisted of concent
rate and maize silage in the proportions 1:1 (dry matter basis) contai
ning either 0 or 10 g niacin per cow per day, which was handmixed into
the concentrate. The diets were offered individually as total mixed r
ations in two equal proportions at 09:00 and 20:00 h in amounts suffic
ient to ensure 10% refusals. Dry matter, metabolisable energy and crud
e protein intakes, as well as milk yield, milk protein proportion and
yield, milk lactose, total solids and solids-not-fat proportions were
not affected by niacin supplementation. In contrast, niacin supplement
ation increased milk fat proportion and yield. No differences were obs
erved in blood serum concentrations of glucose, total protein, triglyc
erides, cholesterol, Na, K, Ca, P or Mg. However, the serum concentrat
ion of urea was lower when the cows were supplemented with niacin.