Six Hereford steers averaging 256 kg were used in a 2 x 3 factorial arrangement within a 6 x 6 Latin square design to study the effect of forage conservation (silage vs hay) and N supplementation (0, 200 g of fish meal plus 43 g of urea, or 400 g of fish meal) on ruminal characteristics, digestibility, blood urea, and in situ degradability of DM, N, and ADF. Dry matter intake of forage and total DMI did not differ among treatments (P greater than .05) and averaged 5.3 and 5.5 kg, respectively. Steers fed silage had greater (P less than .05) pH and concentrations of ammonia N, isobutyrate, isovalerate, and valerate in the rumen than in the rumen of those fed hay. Nitrogen supplementation increased (P less than .05) concentrations of total VFA and valerate in the rumen. Digestibility of N and ADF was greater (P less than .05) for silage than for hay, and N supplementation increased digestibility of N. Plasma urea concentrations were greater (P less than .05) for steers fed silage than for those fed hay. These data suggest that feed utilization is better with silage than with hay and is increased by N supplementation.
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http://dx.doi.org/10.2527/1992.703876x | DOI Listing |
Animals (Basel)
January 2025
School of Agriculture and Food Sustainability, The University of Queensland, Gatton, QLD 4343, Australia.
The extent of endocrine changes in response to various levels of heat stress and subsequent recovery is not well understood. Two cohorts of 12 Black Angus steers were housed in climate-controlled rooms (CCR) and subjected to three thermal periods: PreChallenge (5 d), Challenge (7 d) and Recovery (5 d). PreChallenge and Recovery provided thermoneutral conditions.
View Article and Find Full Text PDFJ Sci Food Agric
January 2025
College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China.
Background: Dietary supplementation for beef cattle, using natural plant extracts, such as oregano essential oil (OEO), has proven effective in enhancing growth performance, beef production quantity and quality, and ensuring food safety. However, the precise mechanisms underlying these effects remain unclear. This study investigated the impact of OEO on carcass traits, muscle fiber structure, meat quality, oxidative status, flavor compounds, and gene regulatory mechanisms in the longissimus thoracis (LT) muscles of beef cattle.
View Article and Find Full Text PDFJ Anim Sci
January 2025
University of Reading, School of Agriculture, Policy and Development, Earley gate, RG6 6EU Reading, United Kingdom.
This study investigated the effects of different protein sources on feed intake, nutrient, and energy utilization, growth performance, and enteric methane (CH4) emissions in growing beef cattle, also evaluated against a pasture-based diet. Thirty-two Holstein × Angus growing beef were allocated to four dietary treatments: a total mixed ration (TMR) including solvent-extracted soybean meal as the main protein source (SB; n = 8), TMR with local brewers' spent grains (BSG; n = 8), TMR with local field beans (BNS; n = 8), and a diet consisting solely of fresh-cut Italian ryegrass (GRA; n = 8). Every four weeks, animals were moved to digestibility stalls within respiration chambers to measure nutrient intakes, energy and nitrogen (N) utilization, and enteric CH4 emissions.
View Article and Find Full Text PDFJ Anim Sci
January 2025
Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546, USA.
With the growing bourbon industry in the southeastern U.S. leading to increased production of liquid distillery byproducts, there is a pressing need to explore sustainable uses for whole stillage [containing residual grain (corn, rye, malted barley) and liquid after ethanol separation] in livestock nutrition.
View Article and Find Full Text PDFJ Anim Physiol Anim Nutr (Berl)
January 2025
Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand.
The objective of this study was to examine the impact of black soldier fly larval oil (BSFO) on feed consumption, nutritional digestibility, ruminal characteristics and methane (CH) estimation in Thai-indigenous steers. Four male Thai native steers (Bos indicus) weighing 383 ± 9.0 kg were used in this investigation.
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