Effect of an Immunomodulatory Feed Additive in Mitigating the Stress Responses in Lactating Dairy Cows to a High Concentrate Diet Challenge

Abstract

Dairy cows are often exposed to multiple stressors in a lactation-cycle, with sub-acute ruminal acidosis (SARA) a frequent example of nutritional stress. SARA affects ruminal and intestinal equilibrium resulting in dysbiosis with localized and systemic inflammation impacting animal health and productivity. OmniGen-AF (OMN, Phibro Animal Health Corporation, Teaneck, NJ, USA) is a feed product recognized for modulating innate immune function, especially during periods of stress. The objective of this study was to determine the effects of OMN in lactating dairy cows fed a high-starch, low-fiber diet. Twenty-four blocked cows were assigned to control or treatment (55 g/d). After the additive adaptation (49 d) cows were fed the challenge diet (28 d). Milk, rumination and pH were continuously recorded; components, rumen fluid, and blood were taken in multiple time-point and analyzed. Results showed that the challenge decreased the rumination, shifted ruminal fluid composition, decreased milk production and the components, and slightly increased the time below pH 5.5, with no differences between groups. The treatment produced greater rumen butyrate and lower lactate, prompter regeneration of red blood cells, increase of neutrophils, lower paraoxonase, gamma-glutamyl-transferase, and β-hydroxybutyrate, with no differences on other tested inflammatory markers. Results show that OMN helps modulating some of the metabolic and immunological responses to SARA.

Evaluation of fecal sampling time points to estimate apparent nutrient digestibility in lactating Holstein dairy cows

“…The TMR fed was adequate in terms of nutrient composition ( 36 ), and particle size (peNDF = 19.52 ± 2.18% of DM) was in line with previous studies based on similar rations ( 37 – 40 ). Fecal composition was normal for a cow in this lactation phase and the apparent total tract digestibility of the different nutrients indicates a good level of digestion ( Table 1 ).…”

Stayability in Simmental cattle as affected by muscularity and body condition score between calvings

“…Straczek et al ( 58 ) reported that Simmental cows have a greater capacity to adjust the NEB state compared to Holsteins, restoring earlier the BCS loss after the lactation peak. Consequently, cows with good conditions at the onset of second lactation are more prone to perform better along the lactation and to be more resilient to the different metabolic disorders and reduced fertility ( 65 ). It is worth considering that farmers rearing Simmentals may decide to cull cows with higher muscularity at a certain point for beef purposes in order to increase the herd profit.…”

Localization and characterization of atrial depolarization waves on the surface electrocardiogram in dogs with rapid supraventricular tachycardia

“…Variables that did not comply with the above assumptions were normalized using the BoxCox transformation. 23 When significance was detected (P < .05), the results were separated using Tukey's multiple comparison test.…”

“…Thus, the residuals were checked for an approximately normal distribution. Variables that did not comply with the above assumptions were normalized using the BoxCox transformation 23 …”