Association between Ruminal pH and Rumen Fatty Acids Concentrations of Holstein Cows during the First Half of Lactation

Abstract

Ruminal pH in dairy cows follows a diurnal fluctuation; low values are indicative of subacute ruminal acidosis and are associated with alterations of rumen fatty acids concentrations. The objective of the present study was to prospectively study the associations between ruminal pH and the rumen fluid concentrations of short, medium, and long chain fatty acids, under field conditions during the first half of lactation in 53 Holstein cows of a dairy farm. Ruminal fluid was obtained by rumenocentesis, which was performed at 30, 90, and 150 days in milk (DIM). Ruminal pH was measured immediately after collection with a portable pH meter, whereas gas chromatography was used for the determination of ruminal fatty acid concentrations. Mixed linear regression models were used for data analysis. The prevalence of cows with low ruminal pH (≤5.5) was 45.3%, 54.7%, and 66.0% at 30, 90, and 150 DIM, respectively. The concentrations of acetic, propionic, butyric, valeric, isovaleric, caproic and linoleic acids were negatively associated with ruminal pH values, whereas the acetic to propionic ratio was positively associated with rumen pH. Under field conditions and naturally occurring low ruminal pH cases, ruminal concentrations of most fatty acids are negatively related with ruminal pH values

The balance of rumen degradable protein and readily available carbohydrate in sheep rations on in vitro fermentability

“…However, the pH is within the normal range. This is in accordance with the statement by Kitkas et al [14] that rumen pH values range from 5.30 to 6.60, which is within the normal range. In addition, Asin et al [15] added that the rumen pH value ranges from 5.50 to 7.50, which is within the normal range as well.…”

Effect of Calcareous Marine Algae Buffer on High-Producing Dairy Cows during Peak Lactation

“…On average, rumen fluid showed pH values of 6.29 ± 0.44, acetic acid 63.5 ± 1.35 mol%, propionic acid 19.6 ± 1.12 mol%, butyric acid 16.3 ± 0.62 mol%, and ammonia nitrogen 13.7 ± 1.01 mg N/100 g. The measured values are in agreement with those reported by Kitkas et al [30]. They found that a one-point increase in ruminal pH was associated with a significant decrease in concentration of acetic (by 27.6 mmol/L, p < 0.001), propionic (by ca.…”

“…24.0 mmol/L, p < 0.001), and butyric (by 16.0 mmol/L, p < 0.001) acids. According to Kitkas et al [ 30 ], pH decreases with increasing acidity; the higher the ratio of acetic to propionic acid, the higher the rumen pH or the lower the risk of acidosis. The ratio of acetic acid to propionic acid was higher in P2 than in P1, suggesting that in more advanced lactations there is a lower risk of acidosis in cows fed the same TMR.…”

“…An important part of SARA prevention is the measurement of performance indicators [ 23 , 24 ]; feeding behavior [ 25 , 26 , 27 ]; milk quality [ 28 , 29 ]; ruminal fermentation [ 30 ]; and, where appropriate, residual nutrient levels in feces.…”

Evaluation of nutritive values of various non-conventional protein sources as potential feed ingredients for ruminants

“…In our study, the agro-industrial by-product with the highest rumen pH was grasshopper meal at 6.82, while the lowest rumen pH was observed with snail meal at 6.63 (Figure 2). The ideal pH standard according to (Kitkas et al 2022) is 6-7. The high pH of grasshopper meal is due to its low digestibility (Figure 2).…”