Effects of feed additives on rumen and blood profiles during a starch and fructose challenge

Abstract

We evaluated the effect of feed additives on the risk of ruminal acidosis in Holstein heifers (n = 40) fed starch and fructose in a challenge study. Heifers were randomly allocated to feed additive groups (n = 8 heifers/group): (1) control (no additives); (2) virginiamycin (VM); (3) monensin + tylosin (MT); (4) monensin + live yeast (MLY); and (5) sodium bicarbonate + magnesium oxide (BUF). Heifers were fed 2.5% of body weight (BW) dry matter intake (DMI) per day of a total mixed ration (62:38 forage:concentrate) and feed additives for a 20-d adaptation period. Fructose (0.1% of BW/d) was included for the last 10d of the adaptation period. On d 21, heifers were fed to target a DMI of 1.0% of BW of wheat, fructose at 0.2% of BW, and their feed additives. Rumen fluid samples obtained by stomach tube and blood samples were collected weekly as well as during a 3.6-h period on challenge day (d 21). Virginiamycin and BUF groups maintained a consistently high DMI across the 20-d adaptation period. The MLY heifers had low DMI of the challenge ration. Average daily gain and feed conversion ratio were not affected by feed additives. All rumen and plasma measures changed weekly over adaptation and over the challenge sampling period with the exception of rumen total lactate and histamine concentrations, plasma oxidative stress index, and ceruloplasmin. Substantial within- and between-group variation was observed in rumen and plasma profiles at challenge sampling. No significant group changes were observed in rumen total volatile fatty acids, propionate, acetate-to-propionate ratio, isobutyrate, caproate, isovalerate, total lactate, d- and l-lactate, and pH measures on challenge day. Acetate concentration was increased in the BUF and control groups on challenge day. Butyrate concentration was lower in the MLY and MT groups compared with other groups at challenge. Valerate concentrations were lowest in the control, VM, and BUF groups and lactate concentrations were numerically lower in the MLY, VM, and BUF groups. Total lactate concentrations were >10mM for each group throughout the challenge. Ammonia concentrations were lower in the MLY and MT groups. Histamine concentrations were decreased in MLY and increased in the VM and BUF groups. Plasma oxidative stress measures were not influenced by feed additives weekly or on challenge day, except for an increase in biological antioxidant potential in the control, VM, and MT groups on challenge day. Despite the large within-animal variation, all feed additives modified rumen function and may influence the risk of acidosis by different mechanisms; however, none stabilized the rumen in all heifers.

Plasma oxidative stress biomarkers and progesterone profiles in a dairy cow diagnosed with an ovarian follicular cyst

“…Plasma ceruloplasmin concentrations observed in this case study were within the range reported in heifers (Golder et al 2014). Ceruloplasmin is a serum ferroxidase that contains greater than 95% of the copper found in plasma (Hussein et al 2012) and is involved in cellular pro-oxidant and antioxidant processes (Ehrenwald & Fox 1996).…”

Review: Enhancing gastrointestinal health in dairy cows

“…Another mechanism through which replacing starch with sugars may enhance rumen health and nutrient utilisation, is that this stimulates butyrate production, and, thereby, the energy supply to and functionality of the rumen epithelium (Dionissopoulos et al, 2013;Malhi et al, 2013). Golder et al (2014b and2014c) also observed that sugars differ in their effect on reticulo-rumen function, including the production of lactic acid.…”

“…Sensible approaches to controlling the risk include testing for quality, rumen degradability and/or risk of acidosis (a near IR reflectance test has been developed for this purpose); establishing a regular supply from a consistent source; and careful and consistent processing of grain. Use of by-products of human food production including flour and maize manufacturing processes and distilling wastes and fats to maintain the energy density of the diet and to control starch and sugar intakes are strategies employed to reduce the risk of acidosis and potentially increase the profitability of production (Lean et al, 2013;Golder et al, 2014b and2014c).…”

Invited review: An evaluation of the likely effects of individualized feeding of concentrate supplements to pasture-based dairy cows

“…Rumen modifiers such as monensin, virginiamycin, tylosin, and lasalocid have been evaluated for their ability to control the risk of acidosis (RAGFAR, 2007). Although evidence suggests that various rumen modifiers may provide some control of acidosis risk (Golder et al, 2014) when cows are fed high levels of concentrates (14 and 16 kg of DM; Auldist et al, 2013a) or when substantial ruminal concentrations of lactic acid (>20 mmol/L) were present (Golder et al, 2014), the risk of acidosis was not controlled by the rumen modifiers used. The large variability between animals in response to rumen modifiers (Golder et al, 2014) supports the need for a biomarker indicative of poor rumen function to ensure all animals are managed optimally.…”