Effect of Mineral Salt Blocks Containing Sodium Bicarbonate or Selenium on Ruminal pH, Rumen Fermentation and Milk Production and Composition in Crossbred Dairy Cows.

Hathaichanok Insoongnern,Tipwadee Prapaiwong,Napongphot Suphrap,Saisamorn Potirahong,Chalong Wachirapakorn,Wuttikorn Srakaew

doi:10.3390/vetsci8120322

Abstract

Ruminal pH is an important physiological parameter that regulates microbe activity; optimizing ruminal pH may improve rumen fermentation and milk production. The purpose of this experiment was to determine the effect of sodium bicarbonate (NaHCO3) or selenium (Se) in mineral salt block (MSB) supplementation on ruminal pH, rumen fermentation, milk yield and composition in Holstein Friesian crossbred dairy cows. Four crossbred dairy cows with an initial weight of 456 ± 6 kg in mid-lactation were assigned at random using a 4 × 4 Latin square design. The experiments were divided into four periods, each lasting 21 days. Each cow was fed a basal diet supplemented with a different type of mineral salt block: a control with no MSB supplementation, and MSB groups with MSB containing NaHCO3 (MSB-Na), MSB containing Se (MSB-Se), and conventional commercial MSB (MSB-Com). MSB-Na contained NaHCO3 (500 g/kg) to prevent acidosis, MSB-Se contained organic Se (15 mg/kg) as an antioxidant, and MSB-Com was a positive control mineral salt block. The results show that there was no significant difference in feed intake between treatments, but there was a significant difference in mineral salt intake between treatments (p < 0.05). Supplementing mineral blocks had no effect on nutrient intake or apparent digestibility (p > 0.05). Ruminal pH was not different between treatments at 0 and 1 h post-feeding, but at 2 and 4 h post-feeding, ruminal pH in cows fed MSB-Na and MSB-Se was significantly higher (p < 0.05) than it was in cows fed MSB-Com and the control. Total volatile fatty acid (VFA), acetic, propionic, butyric, and ammonia nitrogen and blood urea nitrogen were not influenced by mineral blocks supplementation. Milk yield, milk composition and energy-corrected milk (ECM) were not affected by supplementing mineral blocks. However, compared with the control, the somatic cell count (SCC) in the milk was reduced (p < 0.05) by supplementation with the mineral salt block. Based on the results of the experiments, it was concluded that MSB-Na or MSB-Se supplementation improved ruminal pH while having no effect on feed intake, rumen fermentation, milk yield, or composition, though it did reduce SCC in milk. However, additional research should be conducted to investigate the effect of MSB on rumen ecology and milk production in dairy cows fed a high-concentrate diet.

Highlights

Minerals, in addition to energy and protein, are important nutrients that play a role in a variety of metabolic activities and are constituents of the body’s composition
Animals were chosen based on their body weight (BW), milk yield, and day in milk (DIM), and they were handled with care to avoid unintentional errors
Mineral salt blocks were classified as follows: MSB containing NaHCO3 (MSB-Na) containing NaHCO3 (500 g/kg), which was used to avoid rumen acidosis, MSB containing Se (MSB-Se) had organic Se (15 mg/kg), which was used as an antioxidant, and MSB-Com was used as a positive control mineral salt block, which is a commonly accessible commercial salt block

Summary

Introduction

In addition to energy and protein, are important nutrients that play a role in a variety of metabolic activities and are constituents of the body’s composition. Because most minerals are in insufficient concentrations in feeds, animals frequently exhibit signs of insufficiency, resulting in decreased productivity and health. Microelement deficiencies in dairy and beef cattle are frequently observed in temperate areas [1,2]. Garg et al [3] and Bhanderi et al [4] reported that serum samples were below the critical levels of Cu and Zn due to deficiencies of these elements in forages. Microminerals found in forages, such as zinc and copper, are found at levels below the requirements for dairy cows [1]. Micromineral deficiency is very common and frequent in tropical conditions. Supplementation by adding minerals to the feed, mineral licks, and/or single/repeated injection of particular microelements, as well as combinations of the these methods, are all options. Each method has its own set of benefits and drawbacks

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