Invited review: Current perspectives on eating and rumination activity in dairy cows

Abstract

Many early studies laid the foundation for our understanding of the mechanics of chewing, the physiological role of chewing for the cow, and how chewing behavior is affected by dietary characteristics. However, the dairy cow has changed significantly over the past decades, as have the types of diets fed and the production systems used. The plethora of literature published in recent years provides new insights on eating and ruminating activity of dairy cows. Lactating dairy cows spend about 4.5 h/d eating (range: 2.4-8.5 h/d) and 7 h/d ruminating (range: 2.5-10.5 h/d), with a maximum total chewing time of 16 h/d. Chewing time is affected by many factors, most importantly whether access to feed is restricted, intake of neutral detergent fiber from forages, and mean particle size of the diet. Feed restriction and long particles (≥19 mm) have a greater effect on eating time, whereas intake of forage neutral detergent fiber and medium particles (4-19 mm) affects rumination time. It is well entrenched in the literature that promoting chewing increases salivary secretion of dairy cows, which helps reduce the risk of acidosis. However, the net effect of a change in chewing time on rumen buffing is likely rather small; therefore, acidosis prevention strategies need to be broad. Damage to plant tissues during mastication creates sites that provide access to fungi, adhesion of bacteria, and formation of biofilms that progressively degrade carbohydrates. Rumination and eating are the main ways in which feed is reduced in particle size. Contractions of the rumen increase during eating and ruminating activity and help move small particles to the escapable pool and into the omasum. Use of recently developed low-cost sensors that monitor chewing activity of dairy cows in commercial facilities can provide information that is helpful in management decisions, especially when combined with other criteria. Although accuracy and precision can be somewhat variable depending on sensor and conditions of use, relative changes in cow behavior, such as a marked decrease in rumination time of a cow or sustained low rumination time compared with a contemporary group of cows, can be used to help detect estrus, parturition, and some illnesses. This review provides a comprehensive understanding of the dietary, animal, and management factors that affect eating and ruminating behavior in dairy cows and presents an overview of the physiological importance of chewing with emphasis on recent developments and practical implications for feeding and managing the modern housed dairy cow.

Feed restriction of F1 Holstein × Zebu cows in the final third of lactation modifies intake, nutrient digestibility, feeding behavior, and performance

“…This behavior also justifies the greater digestibility of DM and fibrous fraction and the lower rumination time of these animals due to the reduction in particle size of the feed, which favors a higher performance of microorganisms in the substrate. Beauchemin (2018) reported that the physicochemical composition of the diet associated with particle size is the factor that most interferes with rumination time, justifying the findings of this study, since the diet was the same in all treatments. Welch and Hooper (1988) stated that time spent for rumination is highly correlated (0.96) with NDF intake in cattle.…”

Effects of feeding synthetic zeolite A during the prepartum period on serum mineral concentration, oxidant status, and performance of multiparous Holstein cows

“…Compared with other studies that measured rumination during the dry cow period, both treatments had above-average daily rumination rates (Liboreiro et al, 2015;Kaufman et al, 2016;Paudyal et al, 2016) suggesting that the observed reduction may not be of critical importance. The difference in time spent ruminating during the prepartum period between the 2 treatments may reflect the difference in particle size (Beauchemin, 2018) or DMI. Although particle size was not determined in this study, the diets were identical except for the addition of zeolite A to the EXP diet, creating a dilution effect of the diet.…”

Validating the use of bovine buccal sampling as a proxy for the rumen microbiota using a time course and random forest classification approach

“…1). This result is likely associated with the constant mixing of rumen contents due to the contractions of the reticulorumen, which would result in indistinguishable variation in our observed rumen microbial OTU counts (12). This finding contrasts from previously published work that identified noticeable differences in sample composition from five different locations of the rumen lumen via PCR DGGE surveys (45).…”