Acta Vet. Brno 2020, 89: 19-29
The effect of propylene glycol delivery method on blood metabolites in dairy cows
Four dairy cows in a positive energy balance were used to study the effect of propylene glycol supplementation variants on blood indices. The treatments were: without glycol, glycol mixed with the total mixed ration (TMR), glycol delivered as top dressing (TD), and glycol administered as an oral drench (OD). Oral drenching had the positive effect of higher blood insulin concentration 1.5 and 2.5 h after supplementation compared to the TD method (P ≤ 0.05). Glycol supplemented as TD had the negative effect of higher concentration of non-esterified fatty acids (NEFA) 3.5 h after supplementation (P ≤ 0.05) with a trend towards a higher mean concentration of this marker (P ≤ 0.1). A decreasing tendency was recorded for the NEFA concentration 1.5 h after glycol supplementation with TMR or OD (P ≤ 0.1). Glycol supplemented as OD had the positive effect of lowering the β-hydroxybutyric acid concentration 1.5 and 2.5 h after feeding (P ≤ 0.05). A downward trend in the mean β-hydroxybutyric acid level after glycol delivery as OD was also observed (P ≤ 0.1). Glycol supplemented as TD had the negative effect of decreasing dry matter intake of the diet (P ≤ 0.05). Glycol supplemented as OD had a more glucogenic effect than as part of the TMR. Due to reduction of dry matter intake and the lowest glucogenic effect, using glycol as TD is unjustified. The results confirm that the best method of propylene glycol administration is OD, which can be useful in the prevention of ketosis, however, it should be confirmed in a long-term experiment covering the transition and early lactation periods.
Funding
The study was supported by the Polish State Committee for Scientific Research, Grant No. N N311 310736. The authors thank the Polish State Committee for Scientific Research for financial support. The authors would like to thank Janusz Kędziora and the Wilkowice farm staff for the care, management, and feeding of the cows.
