Ruminal Bacterial Community Composition in Dairy Cows Is Dynamic over the Course of Two Lactations and Correlates with Feed Efficiency

Abstract

bFourteen Holstein cows of similar ages were monitored through their first two lactation cycles, during which ruminal solids and liquids, milk samples, production data, and feed consumption data were collected for each cow during early (76 to 82 days in milk [DIM]), middle (151 to 157 DIM), and late (251 to 257 DIM) lactation periods. The bacterial community of each ruminal sample was determined by sequencing the region from V6 to V8 of the 16S rRNA gene using 454 pyrosequencing. Gross feed efficiency (GFE) for each cow was calculated by dividing her energy-corrected milk by dry matter intake (ECM/DMI) for each period of both lactation cycles. Four pairs of cows were identified that differed in milk production efficiency, as defined by residual feed intake (RFI), at the same level of ECM production. The most abundant phyla detected for all cows were Bacteroidetes (49.42%), Firmicutes (39.32%), Proteobacteria (5.67%), and Tenericutes (2.17%), and the most abundant genera included Prevotella (40.15%), Butyrivibrio (2.38%), Ruminococcus (2.35%), Coprococcus (2.29%), and Succiniclasticum (2.28%). The bacterial microbiota between the first and second lactation cycles were highly similar, but with a significant correlation between total community composition by ruminal phase and specific bacteria whose relative sequence abundances displayed significant positive or negative correlation with GFE or RFI. These data suggest that the ruminal bacterial community is dynamic in terms of membership and diversity and that specific members are associated with high and low milk production efficiency over two lactation cycles.R uminants, such as cattle, rely upon a rich and diverse community of symbiotic ruminal microbes to digest their feed. These symbionts are capable of fermenting host-indigestible feed into nutrient sources usable by the host, such as volatile fatty acids (1, 2). Ruminants are born without a functional rumen and are thought to acquire their digestive microbes from the environment as the rumen develops (3-6). Although the means by which ruminants acquire this ruminal microbial community remains unclear, the membership and stability of the ruminal community can have a direct and measurable impact on host function and health (7). Importantly, the host requires ruminal fermentation products for body maintenance and growth (8) and milk production (9).Of particular interest, both scientifically and agriculturally, is the impact of the ruminal microbial community on host milk production efficiency in dairy cattle. Two major methods are widely used to calculate milk production efficiency: gross feed efficiency (GFE) and residual feed intake (RFI). GFE is a more traditional measure that is based on the yield of milk produced (corrected to a constant-energy basis) per unit of intake of dietary dry matter (DM) (10). RFI was first applied to weight gain in steers but has more recently been adapted for use in dairy production (11); it is defined as the difference in feed consumption relative to that of other animals on the...

Exploring a Possible Link between the Intestinal Microbiota and Feed Efficiency in Pigs

“…When looking at the intestinal microbiota, similar to previous findings in cattle, the overall intestinal bacterial diversity did not cluster by RFI rank, but rather, RFI-associated variations in community membership were detected (12,34). Interestingly, in our study, microbial diversity, as well as composition, was impacted by both age and intestinal site.…”

Buccal Swabbing as a Noninvasive Method To Determine Bacterial, Archaeal, and Eukaryotic Microbial Community Structures in the Rumen

“…In a recent study involving 118 animals, two different possible low-methane communities were identified in sheep (9), meaning that there could be multiple underlying animal genotypes. Similar studies of dairy cows and steers with differential residual feed intake (RFI) suggest a correlation between RFI and certain rumen bacterial (10)(11)(12) and archaeal (13) taxa. However, due to the logistical and financial challenges of maintaining large dairy or beef research herds, the numbers of animals used in these studies were limited.…”

Metatranscriptomic Profiling Reveals Linkages between the Active Rumen Microbiome and Feed Efficiency in Beef Cattle

“…In addition, rumen microbes can also synthesize most B vitamins to meet the nutritional demands of the host (4). To date, multiple studies have reported that the rumen microbial composition is associated with feed efficiency in beef (5-9) and dairy (10) cattle, suggesting that rumen microbial function is one of the factors that impact the cattle's feed efficiency. Feed efficiency is one of the most important traits in cattle farming because the feed cost accounts for most of the production expense, accounting for 60 to 70% of the total cost in beef production (11).…”