Effect of rumen-protected choline supplementation on productive performance of lactating dairy cows

الملخص EN

Nine Holstein lactating cows, with an average live body weight of 550 ± 50 kg, at1st to 3rd seasons of lactation, were selected and randomly assigned to three similar groups (three cows each).

Cows were used in a lactation study for a total of 12 weeks (4-week prepartum to 8-weeks postpartum) to investigate the effect of feeding two levels of rumen protected choline (RPC) supplementation, at 40 or 50 grams RPC / cow / day, or with no supplement (control) on compare milk production parameters and performance of dairy cows.

Results showed insignificant differences (P > 0.05) among groups in the digestibility coefficients of DM, OM, CF, EE and NFE, and also in nutritive value as TDN %, while CP digestibility coefficient and nutritive value as DCP % in RPC groups were significantly (P < 0.05) higher than the control group.

The milk yield of treated groups with 40 and 50 gm of RPC were higher than control (11.39 % and 22.62 %) and fat corrected milk (4 %) at 10.88 % and 21.45 % higher than the control group.

Insignificant (P > 0.05) differences were observed between the groups in their average daily DM and TDN intake, while results of DCP intake were significantly (P < 0.05) higher in favor of groups fed both levels of RPC.

The treated group with 50 gm RPC was significantly (P < 0.05) better than control for feed conversion, DM, TDN and DCP.

No significant differences (P > 0.05) were observed in change of body weight through the experimental period among all the three groups.

However RPC groups showed numerically lower weight losses compared to the control.

Insignificant differences were found among the groups in the content of milk protein, fat, SNF, TS and lactose.

No significant differences were noted between the groups in AST, ALT and cholesterol contents, while RPC groups recorded significant (P < 0.05) low values of triglycerides and LDL and significantly (P < 0.05) higher values of HDL compared with the control.

The groups of 50 and 40 gm RPC recoded lower feed cost for production of 1 kg milk being 3.17, 3.47compared to control at 3.77 LE, and increase in the daily net milk revenue being 58.76, 47.76, compared to control at 37.78 LE, and economic feed efficiency being 89.3 %, 73.0 % for the control at 59.2 %.

Relative economic efficiency were156 %, 126.4 % and 100 % compared with the control group, respectively.

The obtained results indicated that RPC supplementation at 40 or 50 g / head/day could improve digestibility, milk yield and composition, feed conversion, and economic efficiency in lactating Holstein cows.

More researches are needed with higher number of dairy animal.