Forage-fed Cattle Research Articles

Fatty acid and sensory characteristics of beef from three biological types of cattle grazing cool-season forages supplemented with soyhulls

Over two consecutive years, the effects of allocating divergent biological types of cattle ( n = 107) to fescue pasture without supplementation, or fescue or orchardgrass pasture with soyhull supplementation on chemical, fatty acid and sensory characteristics were investigated. Cattle from the two supplemented treatments produced beef that had increased ( P < 0.05) percentage lipid and decreased ( P < 0.05) polyunsaturated and n-3 fatty acids compared to the control. However, the n-6 to n-3 ratio was still less than four in beef from the supplemented cattle. Additionally, supplementation did not decrease ( P > 0.05) the CLA present in the longissimus, which can commonly occur when forage-fed cattle are supplemented concentrates. Although supplementation did not impact ( P > 0.05) Warner-Bratzler shear force or tenderness, supplementation of soyhulls reduced ( P < 0.05) the grassy flavor intensity of rib steaks when compared to the control. Biological type did not have a significant influence on most traits analyzed in this study. These results suggest that supplementation of soyhulls to cattle grazing forage can reduce grassy flavor intensity without decreasing CLA proportions, but can reduce the n-3 fatty acid proportions present in the longissimus.

Properties of restructured beef steaks from forage- and grain-fed cattle as affected by antioxidant and flavoring agents

Beef trimmings from cattle finished on forage or grain were restructured into steaks to enhance palatability. Steaks were treated with propyl gallate with or without a beefy flavoring agent, stored at −29 °C, and analyzed after 0, 1, 3, and 6 months. The strong grassy flavor of forage-finished beef steaks, detected by a sensory panel, was masked by the beefy flavoring agent, rendering the beef more acceptable by consumers. Propyl gallate retarded lipid oxidation and rancidity development in steaks during extended frozen storage. Microbial populations decreased while color scores, cooking yield, and binding strength of steaks exhibited only minor changes during storage. Thus, the combination of antioxidant and flavoring agents with the muscle restructuring technology provides an effective means to enhance the palatability and storage stability of beef from forage-fed cattle.

Diet influences the ecology of lactic acid bacteria and Escherichia coli along the digestive tract of cattle: neural networks and 16S rDNA.

In this manuscript, the authors have sought to gain a better understanding of the interactions between Escherichia coli and lactic acid bacteria (LAB) isolated from Rogossa MRS agar along the digestive tract of grain- and forage-fed cattle. E. coli from cattle receiving a high-grain diet were more numerous (P<0.05) than from the high-forage diet and the highest numbers were in the faeces. Isolates on Rogossa MRS agar were always greater in the high-grain diet (P<0.05) and contained a significant number of LAB. A random set of Rogossa MRS agar colonies was selected and artificial neural networks were used to develop a relationship between colony description and species which was validated using sequence analysis (16S rDNA). The neural networks correctly predicted species in more than 80 % of cases and was composed, primarily, of Lactobacillus vitulinus, Lactobacillus ruminis, Selenomonas ruminantium, Streptococcus bovis, Acidaminococcus fermentans and Megasphaera elsdenii. In conjunction with statistical diversity indices, it was demonstrated that diversity in the high-fibre diet was always lower and was a consequence of the dominance of Str. bovis. In contrast, the diversity in the high-grain diet was greater (P<0.05) and was a consequence of the decline in Str. bovis. These data demonstrate that there is a positive relationship between coliform and LAB isolates throughout the digestive tract of cattle, and diet is the major factor regulating bacterial composition.

Soybean hulls, wheat middlings, and corn gluten feed as supplements for cattle on forage-based diets.

Soybean hulls, wheat midds, and corn gluten feed are viable alternative supplements for forage-fed cattle. All three result from the processing of major Unites States agricultural crops, so large supplies are available. Their value is better for ruminant animals than for monogastrics because they contain digestible fiber components. These byproducts are widely available throughout the Unites States and will generally be more economical than traditional feed grains or commercial feeds when used appropriately as supplements to forage-based diets. Knowledge about the composition of base forage must be used in planning supplementation strategies because base forages vary in protein and mineral content [9]. Soybean hulls alone may be a good selection in situations in which forages are adequate or high in protein. In situations where forage is marginal or deficient in protein, wheat midds, corn gluten feed, or a mix of soybean hulls and corn gluten feed might be most desirable. All three feeds can be variable in nutrient composition, so they should be analyzed to ensure a balanced nutrient level in diets. Soybean hulls are especially variable in crude protein content and should always be analyzed when forages are marginal or deficient in protein. Despite the fact that published energy levels are substantially lower, research has shown that soybean hulls and wheat midds have a value comparable to corn and soybean meal in forage-based diets. Corn gluten feed has also been comparable to corn and soybean meal in most reports but is closer in value to its published energy levels. In general, results with soybean hulls have been surprisingly good and consistent, whereas responses to wheat midds and corn gluten feed supplementation have been more variable and sometimes disappointing. Feeding rates for soybean hulls can range from low to extremely high depending on forage availability and desired performance. Wheat midds should be limited in most situations to 50% of the expected dry matter intake because of their rapidly digested starch content. Corn gluten feed should be limited to approximately 50% of expected dry matter intake because of its high sulfur content. Several research groups are currently evaluating self-feeding programs for these byproducts, and while the potential for health and production problems exist, results have been encouraging in most cases. Self-feeding would reduce the labor costs of hand feeding and could provide backgrounders with a program to expand cattle numbers on a limited land base.

Gastrointestinal tract location of Escherichia coli O157:H7 in ruminants.

Experimentally inoculated sheep and cattle were used as models of natural ruminant infection to investigate the pattern of Escherichia coli O157:H7 shedding and gastrointestinal tract (GIT) location. Eighteen forage-fed cattle were orally inoculated with E. coli O157:H7, and fecal samples were cultured for the bacteria. Three distinct patterns of shedding were observed: 1 month, 1 week, and 2 months or more. Similar patterns were confirmed among 29 forage-fed sheep and four cannulated steers. To identify the GIT location of E. coli O157:H7, sheep were sacrificed at weekly intervals postinoculation and tissue and digesta cultures were taken from the rumen, abomasum, duodenum, lower ileum, cecum, ascending colon, descending colon, and rectum. E. coli O157:H7 was most prevalent in the lower GIT digesta, specifically the cecum, colon, and feces. The bacteria were only inconsistently cultured from tissue samples and only during the first week postinoculation. These results were supported in studies of four Angus steers with cannulae inserted into both the rumen and duodenum. After the steers were inoculated, ruminal, duodenal, and fecal samples were cultured periodically over the course of the infection. The predominant location of E. coli O157:H7 persistence was the lower GIT. E. coli O157:H7 was rarely cultured from the rumen or duodenum after the first week postinoculation, and this did not predict if animals went on to shed the bacteria for 1 week or 1 month. These findings suggest the colon as the site for E. coli O157:H7 persistence and proliferation in mature ruminant animals.

Efeitos da monensina sobre a fermentação e sensibilidade de bactérias ruminais de bovinos sob dietas ricas em volumoso ou concentrado

Objetivou-se avaliar os efeitos da monensina sobre as mudanças nos padrões de fermentação e resistência à perda do potássio intracelular das bactérias ruminais provenientes de quatro bovinos recebendo dietas ricas em volumoso ou concentrado. As bactérias obtidas por centrifugação diferencial foram resuspensas em um meio pobre em potássio, no qual foi medida a perda do potássio intracelular, em 10 minutos de incubação, pelo uso de nível crescente de monensina. Os produtos de fermentação foram obtidos após 24 horas de incubação da cultura com feno de gramínea (100 mg/10 mL). As bactérias obtidas de animais recebendo dieta com 90% de concentrado produziram metade do metano e apresentaram metade da relação acetato propionato que as bactérias de animais recebendo forragem. Mais monensina foi requerida para diminuir a produção de metano e a relação acetato:propionato em bactérias de animais alimentados com 90% de concentrado que naquelas de animais recebendo forragem. A quantidade de monensina necessária para causar metade da perda máxima de potássio intracelular em bactérias de animais recebendo 90% de concentrado foi 12 vezes maior que aquela necessária em bactérias de animais recebendo forragem. Uma vez que as bactérias de animais recebendo forragem são mais sensíveis à monensina que aquelas de animais recebendo dietas ricas em concentrado, espera-se maior efeito deste ionóforo no desempenho de bovinos em dietas ricas em volumoso.

Modeling intermittent digesta flow to calculate glucose uptake capacity of the bovine small intestine.

To test the hypothesis that the uptake capacity of the bovine small intestine for glucose is upregulated to match or slightly exceed glucose delivery, glucose was continuously infused into the proximal duodenum of four cannulated holstein heifers. Every 3 days, infusion rates were increased by an average of 34 mmol/h. A model of glucose disappearance from multiple boluses of intestinal digesta was used to estimate the transporter maximum velocity and functional maximum uptake capacity for the entire small intestine from average ileal glucose flows during the third day of each period. Because of its intermittency, digesta flow remained independent of simulated transit time. For each unit increase in glucose infusion rate, uptake capacity increased by only 0.55 units. Excess capacity for glucose uptake was approximately twofold in forage-fed cattle and declined to below delivery at infusions of >208 mmol/h added glucose, approximately three times the normal load. Calculations for cattle, sheep, and rats indicate that the glucose transport capacity of the small intestine is typically underutilized because of a fraction of time that transporters are not in contact with digesta.

Characterization of proteolytic activities of rumen bacterial isolates from forage-fed cattle

Characterization of proteolytic activities of rumen bacterial isolates from forage-fed cattle

Characterization of proteolytic activities of rumen bacterial isolates from forage-fed cattle.

The proteolytic activities of eight strains of ruminal bacteria isolated from New Zealand cattle were characterized with respect to their cellular location, response to proteinase inhibitors and hydrolysis of artificial proteinase substrates. The Streptococcus bovis strains had predominantly cell-bound activity, which included a mixture of serine and cysteine-type proteinases which had high activity against leucine p-nitroanilide (LPNA). The Eubacterium strains had a mainly cell-associated activity with serine and metallo-type proteinases which showed high activity against the chymotrypsin substrate, N-succinyl alanine alanine phenylalanine proline p-nitroanilide (NSAAPPPNA) and some LPNA activity. A Butyrivibrio strain, C211, had a cell-bound mixture of cysteine and metallo-proteinase activities and strongly hydrolysed NSAAPPPNA and LPNA while the high activity Butyrivibrio-like strain, B316, had a cell-bound, mainly serine proteinase activity which strongly hydrolysed NSAAPPPNA. A Prevotella-like strain, C21a, had a mixture of cysteine, serine and metallo-proteinase activities which were cell-bound and hydrolysed LPNA. The activities of these strains did not match those of the bacterial fraction of rumen fluid, which contained activities mainly of the cysteine type with specificity towards the substrate N-succinyl phenylalanine p-nitroanilide. The contribution of these strains to proteolysis in the rumen is discussed.

Estimating Ruminal Nitrogen-to-Energy Balance with in situ Disappearance Data

Microbial growth in the rumen is a pivotal part of any ruminant protein system, and there is an optimal balance between available nitrogen (N) and energy in the rumen. When the nitrogen-to-energy balance in the rumen is optimal, apparent ruminal N digestion (percentage of intake) equals 0. In situ digestion can be used to estimate the ruminally degraded N:ruminally degraded organic matter (OM;g/kg) ratio. The relationship between in vivo apparent ruminal N digestion and dietary N concentration (percentage of OM), dietary N concentration relative to in vitro digestible OM (IVDOM; percentage of IVDOM), and the ruminally degraded N:ruminally degraded OM ratio were evaluated with data from 10 studies in which cattle consumed forage diets. A moderate relationship (r2 = 0.49) was noted between apparent ruminal N digestion (Y) and dietary N (X; % of OM; Y = 42.94X -110.54); this equation predicted that apparent ruminal N digestion would equal 0 at a N concentration of 2.57 +/-0.95% of OM. There was a weak relationship (r2 = 0.14) between apparent ruminal N digestion (Y) and the N:IVDOM ratio (X; Y= 21.64X -97.77); this equation predicted that apparent ruminal N digestion would equal 0 at a N concentration of 4.57% of IVDOM. A strong relationship (r2 = 0.67) was noted between apparent ruminal N digestion (Y) and ruminally degraded N:ruminally degraded OM (X; Y = 4.327X -117.04); this equation predicted that apparent ruminal N digestion would equal 0 at a ruminally degraded N:ruminally degraded OM ratio of 27.03 +/- 0.71 g/kg. The ruminally degraded N:ruminally degraded OM ratio was a better predictor of apparent ruminal N digestion than dietary N concentration expressed relative to either OM or IVDOM. The ruminally degraded N:ruminally degraded OM ratio seems to be a useful tool for predicting apparent ruminal N digestion and managing the nutrition of forage-fed cattle.

COMPARISON OF FORAGE DIGESTION BY CATTLE AND HORSES

Two trials compared digestion of Saskatchewan-grown hays by cattle and horses. In the first study, Altai wildrye (Leysum angustus Trin.), smooth bromegrass (Bromus inermus Leyss.), crested wheatgrass (Agropyron cristatum L.), Kentucky bluegrass (Poa pratensis L.), oat hay (Avena sativa L.) and reed canarygrass (Phalaris arundinaceae L.) hays were fed to six beef steers and six crossbred geldings. The second study compared alfalfa hay (Medicago sativa L.) to dehydrated alfalfa pellets. Voluntary dry matter intake (VDMI) of hay by cattle was related to neutral detergent fiber content (R2 = 0.66). No single nutrient reliably predicted VDMI by horses. Cattle and horses had the highest VDMI for bromegrass hay in trial 1. Cattle had similar intakes of dehydrated alfalfa pellets and alfalfa hay, but horses ate 17% more (P &lt; 0.05) hay than pellets. Cattle digested 28–82% more (P &lt; 0.05) fiber from grass hays than horses which may account for their higher dry matter (DM) digestion of these hays. Cattle and horses utilized legume feeds similarly. Energy intakes of all animals exceeded maintenance except for cattle fed reed canarygrass hay. True crude protein digestibility and metabolic fecal protein of forage-fed cattle and horses were estimated at 83.4 and 80.3%, and 2.67 and 2.17 g 100 g−1 DM intake, respectively. Horses had higher true digestibilities of Ca (75%) than P (33%) but cattle digested more P (76%) than Ca (32%). Endogenous fecal Ca excretion for cattle and horses were assessed at 6.5 and 22.1 mg kg−1 body weight (BW), respectively, while endogenous fecal P excretions were 13.3 and 10.2 mg kg−1 BW, respectively. Key words: Horse, cattle, legume, grass, crude protein, fiber

Manipulation of Lean Deposition in Forage-fed Cattle

Manipulation of Lean Deposition in Forage-fed Cattle

A COMPARISON OF MONENSIN AND CHLORTETRACYCLINE IN HIGH-CONCENTRATE AND HIGH-FORAGE DIETS FOR IMPLANTED AND NONIMPLANTED FINISHING STEERS AND HEIFERS

In a factorial design experiment, 452 steers and heifers were fed ground forage or rolled grain-based diets supplemented with chlortetracycline (CTC) or monensin (MON). The effects of implanting steers with either 200 mg progosterone and 20 mg estradiol benzoate (PEB) or 36 mg resorcylic acid lactone (RAL) and heifers with 200 mg testosterone propionate and 20 mg estradiol benzoate (TEB) were also determined. On average, grain-fed cattle gained faster (P &lt; 0.01) than forage-fed cattle, requiring 13 days less to reach finished condition. They also required 13% less feed per unit gain (P &lt; 0.01) and dressed out 1.29 percentage units higher than forage-fed cattle but "cut out" only 0.4 percentage units higher, returning $18.78 more per head to labor. Heifers, averaging across all other treatments, gained slower (P &lt; 0.05), required 6.7% more feed per unit gain but dressed out and "cut out" as well as steers, to return $7.39 less to labor per head. Cattle fed diets supplemented with MON took 4 days longer to finish, ate less (P &lt; 0.05) feed but did not gain significantly more efficiently than those fed CTC-supplemented rations. Steers fed MON also had lower (P &lt; 0.05) dressing percentages and returned $10.09 less per head to labor. Implanted cattle gained (P &lt; 0.01) faster and more efficiently but required the same number of days to reach finished condition as did unimplanted cattle, thus producing heavier carcasses and returning to labor, on average, about $17.93 and $12.26 more for steers and heifers, respectively. The acetic/propionic acid ratio in the rumen fluid was significantly lower for cattle fed diets containing MON than for those fed diets fed CTC. Cattle fed forage-based diets and those receiving implants yielded significantly leaner carcasses than those fed grain-based diets or those receiving no implant. Key words: Monensin, chlortetracycline, implants, forage, beef steers, beef heifers

Product Yield from on the Rail Boning of Hot and Chilled Sides from Forage-Fed Cattle

ABSTRACT CARCASS sides were obtained from the slaughter of 33 forage-fed mixed-breed steers. The carcasses received an average USDA yield grade of 2.9, a quality grade of high standard, and a skeletal and lean maturity score of A. The average hot carcass weight was 265 kg. The mean yield percentage of boneless meat when removed hot was 0.99 greater (P < 0.01) than that of carcasses chilled boned after 24 h in a cooler at 2 C. A comparison of the mean weights for hot- and chilled-boned products shows that the hot-boned yield was higher for 12 of the 16 meat cuts and lean trim listed. The mean yield weight of boneless meat per equivalent carcass was 199.74 kg for hot-boned sides and 197.32 kg for chilled-boned sides. The mean shrink for hot-boned sides was 1.42% less than that for chilled-boned sides.

Effect of Feeding Regimen and Vacuum-Packaged Storage on Sensory and Physical Properties of Beef Steaks

The longissimus, semitendinosus and semimembranosus muscles from 12 grain-fed and 12 forage-fed cattle were vacuum packaged, stored for either 7 or 21 d and retail packaged and displayed. Primal and retail cut appearance traits and sensory attributes were evaluated. Longissimus steaks had a more yellow fat color after 5 d of display (P<0.05) and semitendinosus had a more intense flavor (P<0.05) when taken from forage-fed cattle. Generally, there were only a few minor differences in sensory properties due to feeding regimen. Primal and retail cut appearance traits (primarily muscle color and percentage surface discoloration) of all three muscles were significantly affected by the length of storage; however, storage period affected sensory properties on only the longissimus and semitendinosus muscles.