Impact of glucogenic additive in transition dairy cow diets of varying ruminal starch degradability on yield and composition of milk and reproductive parameters
2012
Matras, J., University of Life Sciences, Lublin (Poland). Inst. of Animal Nutrition and Bromatology | Klebaniuk, R., University of Life Sciences, Lublin (Poland). Inst. of Animal Nutrition and Bromatology | Kowalczuk-Vasilev, E., University of Life Sciences, Lublin (Poland). Inst. of Animal Nutrition and Bromatology
A two-factorial experiment was carried out on 6 groups (10 animals each) of Polish Black and White Holstein-Friesian cows in the transition period to determine the effect of glucogenic additive (GA) to the diets containing grains of different ruminal degradability of starch on cow performance. The animals from 3 control groups (C-groups) were fed the diets without any additive, whereas 3 other, experimental ones (A-groups), received the diets with additive of glucogenic preparation (450 g per head/day) comprising calcium propionate and loose propylene glycol (1 : 1). Both control and experimental groups were fed three analogical treatments differing in concentrate composition as follows: 1) maize (M) - low ruminal degradability; 2) barley and wheat (BW) - high ruminal degradability; 3) mixture of all the grains used (MBW). Finally, the treatments were as follows: C-M, C-BW, C-MBW, A-M, A-BW, and A-MBW. The rations of all groups based on maize silage, haylage, and meadow hay were mixed at 69 : 19 : 12 ratio (dry matter (DM) basis) and given ad libitum. The experiment started two weeks before the expected parturition and lasted till the 6th lactation week. Neither GA nor the type of grain in the diets showed significant negative influence on DM intake. The glucogenic additive had a positive effect on some basal nutrient digestibility, elevating significantly DM and crude protein (CD) coefficients of the apparent total tract digestibility (CATTD) by about 3 percentage points. The GA x grain interactions (P less than 0.05) in CATTD of CP and nitrogen-free extract were stated, with the peak values reported in the A-BW treatment. GA increased (P less than 0.05) daily milk yield by nearly 5% in comparison with control treatments. GA x grain interaction was noted with the best effect in the treatment GA + MBW. Besides, the glucogenic additive decreased (P less than 0.05) protein expenditure per 1 kg of fat-corrected milk by ca. 6% and raised (by 0.15 percentage point in week 6) protein content, while lowered the urea milk level in weeks 3 and 6 of lactation by approximately 15%. It showed beneficial effect on cow reproductive indicators reducing the time interval from calving to successful insemination and improving insemination index.
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