Effect of diet on non-nutritive oral behavior performance in cattle: A systematic review

Highlights

• Oral stereotypies are often performed by cattle as a behavioral coping mechanism

• Non-nutritive oral behaviors in cattle may be caused my limited access to roughage

• Non-nutritive oral behaviors may be a behavioral signal of a welfare concern in cattle, but may also be a useful behavioral proxy for rumen status

Abstract

Stereotypies are repetitive behaviors the may be performed in effort to relieve frustration or cope with a sub-optimal environment. Cattle are hypothesized to cope with the differences between forage and grain-based diets with oral stereotypies that manifest as in the form of non-nutritive oral behaviors (NNOB). Diets fed in confinement contain less roughage compared to the predominantly forage diets cattle consume while on pasture. These changes in diet composition, presentation, and time required to consume elicit physiological changes in the rumen and require cattle to spend less time engaged in oral behaviors (e.g. mastication of the cud, using the tongue to grasp and pull on grass) – all factors that contribute to NNOB performance. Allogrooming and self-grooming are also classified as NNOBs, however, they have function and are not stereotypic in nature. The purpose of this systematic review was to evaluate the current state of research regarding the relationship between diet and NNOB performance in cattle. Searches of CAB Abstracts, AGRIS, Scopus and SPAC, performed prior to September 2018 resulted in 22 articles (25 studies) that analyzed the impact of dietary treatments on NNOB performance in both beef and dairy cattle housed in confinement. Increasing dietary roughage levels decreased the performance of NNOBs while limiting dietary roughage increased NNOB performance. However, there was little conclusive evidence to suggest that ingredient type, particle size, total feed amount, mode of feeding, or mineral addition influenced NNOB performance. Strengths of the studies included consistent housing across treatments and valid and reliable methods of behavioral recording. Many studies did not consider weaning method in their animal selection and some studies did not randomize animals into each treatment, identifying an opportunity for improvement in this area of research. Risk of bias was performed using JBI Critical Assessment Tools and a very low risk of bias was found for both randomized and (non-random) quasi-experiment trials. This systematic review examined studies varying in sample size, cattle age/sex and experimental design, showcasing a small yet diverse research area.

Introduction

Cattle are creatures that humans domesticated to manage the land with their mouths. By design, cattle are orally-motivated creatures that have evolved to spend a large portion of their day engaged in orally-centered behaviors (e.g., grazing, ruminating). This ancient oral behavioral drive is necessary for survival, yet can be in conflict with the contemporary cattle lifestyle. Modern modes of agriculture require livestock to be housed and fed in environments that have the potential to restrict the performance of, or limit the duration of time engaged in some natural behaviors – thus altering their overall time budget. Restriction in the duration and frequency of a specific behavior can result in unfulfilled behavioral needs, and these unfulfilled needs can catalyze the manifestation of stereotypic behavior (Mason, 1991). While stereotypic behaviors come in many forms, as ruminants, cattle are predisposed to engage in orally motived stereotypies in the form of non-nutritive oral behaviors (NNOB; Redbo, 1998). Multiple hypotheses have been proposed suggesting that dietary-based or housing-based factors stimulate NNOB performance in both dairy and beef cattle housed in confinement.

Dietary-based contributors of NNOB performance center around three main hypotheses. Summarized by Bergeron et al. (2006), high-grain diets fed in confinement stimulate NNOB performance because said diets reduce rumination time, the scenario prohibits the animal from grazing, and these factors can potentially cause gastrointestinal discomfort. Cattle housed in confinement must adjust to eating larger meals less frequently, which shortens the duration of time required to consume their nutrients and can induce rumen microbiome changes (Swartzkophf-Genswein et al., 2003). While grazing cattle have been observed to ruminate for up to 10.2 h/d (Kilgour, 2012), cattle housed in confinement spent 3.8 ± 9.4 hr/d ruminating (Wolfger et al., 2015). Cattle experiencing these multiple and simultaneous dietary stressors may perform NNOBs in an effort to cope.

Rumination durations are shortened when cattle consume diets that consist of small particle sizes, provide low gut fill, and ferment rapidly. Thus, the low roughage diets provided to cattle during various phases of growth are associated with the reduction in time spent ruminating (Abijaoude et al, 2000). Reduction in time spent engaged in rumination is a hypothesized cause of NNOB performance in confinement. Additionally, gastrointestinal discomfort may catalyze the performance of NNOB. The rumen undergoes a rapid physiological shift when cattle begin to consume high grain diets. Cattle may then be managing this discomfort by performing more oral behaviors in an effort to generate saliva and increase buffer availability to the rumen (Abijaoude et al, 2000).

While most feedyard diets will continue to be high-grain and low-roughage, it is worthwhile to determine how diet characteristics affect NNOB performance. Bergeron et al. (2006) offers a comprehensive summary covering oral stereotypies in captive ungulates; however, no systematic review of the NNOB literature has been conducted. The purpose of this systematic review is to determine which specific dietary components may alter NNOB performance. For this systematic review, the effects of dietary treatment tongue rolling, bar licking, ground licking, and object licking, in addition to self-grooming and allogrooming, were evaluated. Understanding the relationship between management and NNOB performance may provide animal mangers with a behavioral proxy to gauge cattle's welfare state.