Influence of feed intake fluctuation and frequency of feeding on nutrient digestion, digesta kinetics, and ruminal fermentation profiles in limit-fed steers.

Abstract

Nine crossbred beef steers (344 +/- 26 kg) fitted with ruminal cannulas were used in a randomized complete block design to evaluate the effects of feeding frequency and feed intake fluctuation on total tract digestion, digesta kinetics, and ruminal fermentation profiles in limit-fed steers. In Period 1, steers were allotted randomly to one of four dietary treatments: 1) feed offered once daily at 0800; 2) feed offered once daily at 0800 with a 10% fluctuation in day-to-day feed intake; 3) feed offered twice daily at 0800 and 1700; and 4) feed offered twice daily at 0800 and 1700 with a 10% fluctuation in a day-to-day feed intake. In Period 2, steers were reallocated across treatments. The 90% concentrate diet was fed at 90% of the ad-libitum consumption by each steer. Chromium-EDTA and Yb-labeled steam-flaked corn were intraruminally infused at 0800 on d 1 and 3 and Co-EDTA and Er-labeled steam-flaked corn were infused on d 2 and 4 of the 4-d collection period. Ruminal samples were collected at 0, 3, 6, 9, 12, 15, 18, and 24 h after the 0800 feeding, and total feces were collected for 4 d. Total tract digestibilities of OM, N, and starch were lowest (fluctuation x frequency, P < .05) when feed was offered twice daily with a 10% fluctuation in intake. Ruminal fluid volume and passage rate were not affected (P > .10) by feeding frequency or intake fluctuation. A frequency x fluctuation x sampling time interaction occurred (P < .01) for ruminal pH. Steers fed a constant amount of feed once daily had higher (P < .05) ruminal pH at 0, 3, 18, and 24 h than steers fed once daily with a 10% fluctuation in feed intake. Total VFA concentration was greater (P < .01) at 9 h after the 0800 feeding when feed was offered once vs twice daily. Feeding twice daily increased (P < .05) the molar proportion of acetate and decreased (P < .05) the molar proportion of propionate. Increasing feeding frequency resulted in a more stable ruminal environment; however, the increased acetate:propionate ratio with twice-daily feeding might result in lower efficiency of energy utilization by limit-fed steers.

Effect of ractopamine hydrochloride and zilpaterol hydrochloride on growth, diet digestibility, intake and carcass characteristics of feedlot lambs

“…There are no other reports of daily DMI variation in lambs treated with β-AA; although, in studies carried out separately in feedlot steers, Abney et al (2007) and Montgomery et al (2009a) observed a significant increase in daily DMI variation in animals treated with RH and ZH, respectively; whereas in both studies, and in concurrence with present study, greater day-to-day DMI variation from β-AA treatment did not decreases animal performance. It seems that a greater DMI variation is needed to alter performance, since literature reports indicate that 10% (Schwartzkopf-Genswein et al, 2004;Soto-Navarro et al, 2000) or 20% (Zinn, 1994) daily intake variation did not affect significantly growth performance.…”

Impact of Feed Efficiency and Diet on Adaptive Variations in the Bacterial Community in the Rumen Fluid of Cattle

“…However, previous studies suggest that prefeeding VFA concentrations are similar between diets (41,48) and individuals (53) and are their lowest before feeding (11), representing a suitable baseline indicator (28). Moreover, longer periods of adaptation lead to more stable rumen environments and fermentation characteristics (29,50,53).…”

Ruminal Fermentation and Fill Change with Season in an Arctic Grazer: Responses to Hyperphagia and Hypophagia in Muskoxen (Ovibos moschatus)

“…The most active microbes may be suppressed in muskoxen during winter if ruminal conditions of pH, SCFA, and osmolality become more variable because of changes in feeding frequency, absorption, and thermoregulation. Less frequent feeding in muskoxen during winter (Forchhammer 1995) may increase variation in ruminal pH and SCFA, as reported for domestic ruminants (Kaufmann et al 1980;Soto-Navarro et al 2000). Muskoxen may also reduce the effort of regulating ruminal conditions during winter because the endogenous heat increment after consumption of a standard meal declines between summer and winter; that is, muskoxen spend less energy on processing a meal in winter than in summer (Lawler and White 2003).…”