Methods
To evaluate the effects of CaP supplementation on feed intake, milk yield and milk composition, energy balance, blood metabolites and urine ketones in early lactation Holstein dairy cows from 1 to 63 days in milk (DIM), 32 multiparous Holstein dairy cows, blocked by lactation number, previous 305-day milk production, and expected calving date, were arranged into four groups in a randomized block design.
Treatments were control, LCaP, MCaP and HCaP with 0, 100, 200 and 300 g calcium propionate per cow per day respectively.
The supplement of food grade CaP (99.8% of CaP) was hand-mixed into the top one-third of the daily ration. Cows were fed ad libitum a total mixed ration consisting of equal proportion of forage and concentrate.
Results
Feed intake, milk yield and components were not affected by CaP supplementation.
The energy balance, expressed as the difference between energy input and output, tended to be higher (p = 0.08) for CaP-supplemented cows during the 63-DIM period, especially during the first 21-DIM lactation.
Calcium propionate-supplemented cows showed a trend (p = 0.09) towards less loss of body weight (BW) during the 63-DIM period.
Concentrations of glucose in plasma and insulin in serum were higher for cows fed CaP relative to control and linearly (p < 0.01) increased with increasing CaP supplementation.
Concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA) and urine ketones were lower for CaP-supplemented cows at 7, 14 and 21 DIM of lactation and linearly (p < 0.01) decreased with increasing CaP supplementation.
Conclusion
These results indicated that nutrient digestibilities and energy status may have been improved.
Reference
Effects of calcium propionate supplementation on lactation performance, energy balance and blood metabolites in early lactation dairy cows. Liu et al., Journal of Animal Physiology and Animal Nutrition, in Press.
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