Vitamin B12 and homocysteine levels in blood of dairy cows during subacute ruminal acidosis

Abstract

The aim of this study was to investigate the variations of vitamin B12 and homocysteine in blood of dairy cows during subacute ruminal acidosis (SARA). On 228 subjects ruminal liquid was collected through rumenocentesis technique and rumen pH was immediately measured by a portable pH-meter. On the basis of pH values all cows were classified (bovine class) in Group A (animals with rumen pH>5.7), Group B (animals with rumen pH between 5.6 and 5.7) and Group C (animals with rumen pH<5.6). In relation to the acidosis risk depending on the rumen pH (herd class), the herds were classified in Group 1 (normal herds: less than 33 % cows with rumen pH<5.8), Group 2 (critical herds: more than 33 % cows with rumen pH between 5.5 and 5.8) and Group 3 (acidosis herds: more than 33 % cows with rumen pH<5.5). On blood samples, collected by jugular venipuncture, vitamin B12 and homocysteine were measured by chemiluminescent immunological tests. One-way analysis of variance (ANOVA), followed by Bonferroni test, showed significant differences (P<0.05) for vitamin B12 in bovine class and significant differences (P<0.05) for homocysteine in herd class. The influence of rumen pH values resulted in adequate vitamin B12 and homocysteine levels to meet microbial and cow requirements and fatty acids modifications in dairy cows affected by SARA. Moreover, the increase of vitamin B12 could be due to the presence of analogues which interfere with the transport of the vitamin. These findings provide more information on blood modifications during SARA.

Supplementing lactating dairy cows with a vitamin B12 precursor, 5,6-dimethylbenzimidazole, increases the apparent ruminal synthesis of vitamin B12

“…Use of probiotics able to maintain a higher rumen pH during experimental induction of subacute ruminal acidosis also prevented the decrease in CBL concentration in rumen content observed at that time (Chiquette et al, 2012). Seemingly in contradiction with the effects of rumen pH on CBL concentration in rumen, Cannizzo et al (2012) observed that plasma concentrations of total vitamin B 12 increased in cows with a rumen pH smaller than 5.6. However, this observation is in accordance with Walker and Elliot (1972) and Sutton and Elliot (1972) who reported that decreasing the proportion of forages in the diet increased serum concentrations of total vitamin B 12 (Sutton and Elliot, 1972;Walker and Elliot, 1972) but decreased the proportion of CBL (Sutton and Elliot, 1972).…”

Relationship between Vitamin B12 and Cobalt Metabolism in Domestic Ruminant: An Update

“…The apparent ruminal synthesis of CBL is negatively correlated with the ruminal pH [ 81 ], the disappearance of starch or the intake of starch and is positively correlated with the ADF (acid-detergent fiber) or NDF (neutral-detergent fiber) intakes [ 17 ]. Apparently, in contradiction with the effects of rumen pH on the CBL concentration in the rumen, Cannizzo et al [ 82 ] observed that the plasma concentrations of total vitamin B12 increased in cows with a ruminal pH lower than 5.6 [ 17 ]. This can be important in episodes of subacute ruminal acidosis, which can only show a low productive performance of the dairy animal or fattening steers, and which is characterized by a low ruminal pH (5.5 to 5.0) as a consequence of the low-fiber ration [ 83 ].…”

Feed additives in the diet of high-producing dairy cows

“…The occurrence of acidosis, ketosis, or hypocalcaemia at the start of lactation often leads to early culling of the cow from the herd. Studies have shown that the rational use of feed additives in the diet of cows improves their longevity and reduces the use of energy and protein for milk production, which improves economic outcomes while also helping to protect the natural environment by reducing the excretion of undigested nutrients and the emission of harmful gases [Chung et al 2007, Sirohi et al 2010, Cannizzo et al 2012, Pan et al 2016, Veena et al 2018, Mobeen et al 2019. The proper use of feed additives in the diet of high-producing cows is a challenge, due to their wide assortment and spectrum of activity.…”