A. Barreras

Effects of feeding different levels of chromium-enriched live yeast in hairy lambs fed a corn-based diet: effects on growth performance, dietary energetics, carcass traits and visceral organ mass

Forty Pelibuey ·Kathdin lambs (35.5 � 0.4 kg) were used in a 56-day feeding experiment to assess the effects of feeding different levels of chromium-enriched live yeast (Cr-YC) on growth performance, dietary energetics, carcass traits and visceral organ mass. The Cr-YC source contained 5.5 · 10 9 colony forming units (CFU) and 0.40 mg of Cr per gram.Treatmentsconsistedofadryrolledcorn-based finishingdietsupplementedwith0,1,2or3gCr-YC/lamb.day.Total daily dosages were: 5.5 · 10 9 CFU and 0.4 mg; 1.1 · 10 10 CFU and 0.8 mg Cr, and 1.65 · 10 10 CFU and 1.2 mg Cr for supplementationlevelsof1,2or3gCr-YC/lamb.day,respectively.Therewerenotreatmentseffectsondrymatterintake.As thelevelofCr-YCsupplementationincreased,averagedailygain,gaintofeedanddietarynetenergywerelinearlyincreased, and observed/expected dry matter intake was linearly decreased. Chromium-enriched live yeast supplementation increased emptybodyweight(EBW),gastrointestinal fillandfullvisceraweight,butdidnotinfluenceorganweightsasaproportionof EBW (g/kg EBW). Cr-YC level did not affect carcass length, backfat thickness, kidney, pelvic and heart fat or body wall thickness,butincreasedhotcarcassweightandlongissimusmusclearea.Ingeneral,treatmenteffectsonpercentageyieldof wholesale cuts (tissue weight as a percentage of cold carcass weight) were small. However, Cr-YC decreased percentage flank. Chromium-enriched yeast supplementation enhances growth rate, longissimus muscle area, and dietary energetic efficiency in finishing feedlot lambs.

Evaluation of isoquinoline alkaloid supplementation levels on ruminal fermentation, characteristics of digestion, and microbial protein synthesis in steers fed a high-energy diet

Four Holstein steers with ruminal and duodenal cannulas were used in a 4 × 4 Latin square design to examine the effect of daily intake of 0, 2, 4 or 6 g/steer of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on the characteristics of ruminal fermentation and characteristics of digestion. The basal diet consisted of a steam-flaked corn-based finishing diet that contained 62% corn and 12% sudangrass hay and the rest of diet was composed of mainly dried distillers grains, molasses, fat, and minerals. The source of QBA+PA used was Sangrovit-RS (Phytobiotics Futterzusatzstoffe GmbH, Eltville, Germany) and supplementation levels of 2, 4, and 6 g Sangrovit-RS∙steer∙d, which represented a net daily ingestion of approximately 6, 12, and 18 mg of QBA+PA compounds, respectively. Inclusion of QBA+PA linearly increased ( = 0.04) flow to the duodenum of nonammonia N and linearly decreased ( < 0.01) duodenal flows of ammonia N. Ruminal microbial efficiency (duodenal microbial N; g/kg OM fermented in the rumen) and protein efficiency (duodenal nonammonia N; g/g N intake) were increased ( < 0.05) as the level of QBA+PA increased. There were no effects of QBA+PA supplementation on ruminal, postruminal, and total tract digestion of OM, starch, and NDF, but postruminal and total tract digestion of N increased ( < 0.01) as the level of QBA+PA increased. Digestible energy of the diet tended to increase (linear affect, = 0.09) with QBA+PA supplementation. Ruminal pH and total VFA molar concentrations were not different between treatments. Ruminal NH-N concentration linearly decreased ( = 0.02) with QBA+PA supplementation. Ruminal molar proportion of acetate increased ( = 0.04) as the supplementation level of QBA+PA increased. It is concluded that QBA+PA supplementation enhances efficiency of N utilization in feedlot steers fed a steam-flaked corn-based finishing diet. This effect was due, in part, to enhanced ruminal microbial efficiency, decreased ruminal degradation of dietary nonammonia N, and enhanced postruminal N digestion.

Effects of Combining Feed Grade Urea and a Slow-release Urea Product on Characteristics of Digestion, Microbial Protein Synthesis and Digestible Energy in Steers Fed Diets with Different Starch:ADF Ratios

As a result of the cost of grains, the replacement of grains by co-products (i.e. DDGS) in feedlot diets is a common practice. This change produces diets that contain a lower amount of starch and greater amount of fibre. Hypothetically, combining feed grade urea (U) with slow release urea (Optigen) in this type of diet should elicit a better synchrony between starch (high-rate of digestion) and fibre (low-rate of digestion) promoting a better microbial protein synthesis and ruminal digestion with increasing the digestible energy of the diet. Four cannulated Holstein steers (213±4 kg) were used in a 4×4 Latin square design to examine the combination of Optigen and U in a finishing diet containing different starch:acid detergent fibre ratios (S:F) on the characteristics of digestive function. Three S:F ratios (3.0, 4.5, and 6.0) were tested using a combination of U (0.80%) and Optigen (1.0%). Additionally, a treatment of 4.5 S:F ratio with urea (0.80% in ration) as the sole source of non-protein nitrogen was used to compare the effect of urea combination at same S:F ratio. The S:F ratio of the diet was manipulated by replacing the corn grain by dried distillers grain with solubles and roughage. Urea combination did not affect ruminal pH. The S:F ratio did not affect ruminal pH at 0 and 2 h post-feeding but, at 4 and 6 h, the ruminal pH decreased as the S:F ratio increased (linear, p<0.05). Ruminal digestion of OM, starch and feed N were not affected by urea combination or S:F ratio. The urea combination did not affect ADF ruminal digestion. ADF ruminal digestion decreased linearly (p = 0.02) as the S:F ratio increased. Compared to the urea treatment (p<0.05) and within the urea combination treatment (quadratic, p<0.01), the flow of microbial nitrogen (MN) to the small intestine and ruminal microbial efficiency were greater for the urea combination at a S:F ratio of 4.5. Irrespective of the S:F ratio, the urea combination improved (2.8%, p = 0.02) postruminal N digestion. As S:F ratio increased, OM digestion increased, but ADF total tract digestion decreased. The combination of urea at 4.5 S:F improved (2%, p = 0.04) the digestible energy (DE) more than expected. Combining urea and Optigen resulted in positive effects on the MN flow and DE of the diet, but apparently these advantages are observed only when there is a certain proportion of starch:ADF in the diet.

Influence of protein nutrition and virginiamycin supplementation on feedlot growth performance and digestive function of calf-fed Holstein steers

Two experiments were conducted to examine the influence of protein and virginiamycin (VM) supplementation on feedlot growth performance, digestion, and metabolizable AA (MAA) supply of calf-fed Holstein steers. Growth performance and dietary energetics were evaluated in 120 Holstein steers (127 ± 9 kg). During the initial 112-d feeding period, a steam-flaked corn-based diet was balanced to meet either 100% (MAB) or 87% (UREA) of MAA requirements. Diets were supplemented with or without 22.5 mg/kg VM in a 2 × 2 factorial arrangement. Subsequently (d 112 to 308), all steers received the UREA diet with or without VM. During the initial 112-d, MAB increased ADG, G:F, and dietary NE ( < 0.01). Thereafter, when all steers received the UREA diet, ADG, G:F, and dietary NE were not different ( > 0.10) across initial supplementation treatments. Overall (d 1 to 308), MAB did not affect ADG ( > 0.10) but enhanced G:F efficiency ( = 0.03) and dietary NE ( = 0.05). During the initial 112-d period and through the remainder of the experiment, VM increased G:F ( < 0.01) and dietary NE ( < 0.01). Four Holstein steers (146 ± 4 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square design to evaluate initial 112-d treatment effects on digestive function. There were no treatment effects ( > 0.10) on ruminal digestion of OM, NDF, starch, microbial efficiency, or total tract digestion of OM and NDF. The MAB increased indispensable AA flow to the small intestine ( < 0.01) and total tract digestion of N ( < 0.01) and starch ( = 0.04). Observed AA supply to small intestine was in agreement with expected supply ( = 0.96). Virginiamycin decreased ( = 0.04) nonammonia N flow to the small intestine and did not affect ( > 0.10) total tract N digestion. Extrapolating from AA supplies in the metabolism study, MAB satisfied indispensable AA requirements during the initial 112-d period, whereas the UREA diet met 73.5% and 79.2% of methionine and lysine requirements, respectively. During the subsequent periods (d 112 to 308) indispensable AA supplies exceeded theoretical requirements. We conclude that enhancements in energy utilization when diets are balanced to meet MAA requirements of calf-fed Holstein steers during the initial 112-d feedlot period remain appreciable throughout time on feed. Virginiamycin enhanced efficiency of energy utilization throughout the feedlot growing-finishing period.

Influence of Ionophore Supplementation on Growth Performance, Dietary Energetics and Carcass Characteristics in Finishing Cattle during Period of Heat Stress

Forty-eight crossbred heifers (378.1±18 kg) were used in a 56-d feeding trial (four pens per treatment in a randomised complete block design) to evaluate the influence of ionophore supplementation on growth performance, dietary energetics and carcass characteristics in finishing cattle during a period of heat stress. Heifers were fed a diet based on steam-flaked corn (2.22 Mcal NEm/kg) with and without an ionophore. Treatments were: i) control, no ionophore; ii) 30 mg/kg monensin sodium (RUM30); iii) 20 mg/kg lasalocid sodium (BOV20), and iv) 30 mg/kg lasalocid sodium (BOV30). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. The maximum THI during the study averaged 93, while the minimum was 70 (THI average = 79.2±2.3). Compared to controls, monensin supplementation did not influence average daily gain, the estimated NE value of the diet, or observed-to-expected DMI, but tended (p = 0.07) to increase (4.8%) gain to feed. Compared to controls, the group fed BOV30 increased (p≤0.03) daily gain (11.8%), gain to feed (8.3%), net energy of the diet (5%), and observed-to-expected DMI (5.2%). Daily weight gain was greater (7.6%, p = 0.05) for heifers fed BOV30 than for heifers fed MON30. Otherwise, differences between the two treatments in DMI, gain to feed, and dietary NE were not statistically significant (p>0.11). Plotting weekly intakes versus THI, observed intake of controls was greater (p<0.05) at THI values ≤77 than ionophore groups. When THI values were greater than 79, DMI of control and MON30 were not different (p = 0.42), although less than that of groups fed lasalocid (p = 0.04). Variation in energy intake was lower (p>0.05) in the ionophores group (CV = 1.7%) than in the control group (CV = 4.5%). Inclusion of ionophores in the diet resulted in relatively minor changes in carcass characteristics. It is concluded that ionophore supplementation did not exacerbate the decline of DM intake in heat-stressed cattle fed a high-energy finishing diet; on the contrary, it stabilised feed intake and favoured feed efficiency. Ionophore supplementation reduced estimated maintenance coefficients around 10% in finishing cattle during a period of heat stress. This effect was greatest for heifers supplemented with 30 mg lasalocid/kg of diet.

Influence of Quaternary Benzophenantridine and Protopine Alkaloids on Growth Performance, Dietary Energy, Carcass Traits, Visceral Mass, and Rumen Health in Finishing Ewes under Conditions of Severe Temperature-humidity Index

Twenty Pelibuey×Katahdin ewes (35±2.3 kg) were used to determine the effects of the consumption of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on growth performance, dietary energetics, visceral mass, and ruminal epithelial health in heat-stressed ewes fed with a high-energy corn-based diet. The basal diet (13.9% crude protein and 2.09 Mcal of net energy [NE] of maintenance/kg of dry matter) contained 49.7% starch and 15.3% neutral detergent fiber. Source of QBA+PA was Sangrovit RS (SANG) which contains 3 g of quaternary benzophenathridine and protopine alkaloids per kg of product. Treatments consisted of a daily consumption of 0 or 0.5 g SANG/ewe. Ewes were grouped by weight and assigned to 10 pens (5 pens/treatment), with two ewes per pen. The experimental period lasted 70 days. The mean temperature humidity index during the course of this experiment was 81.7±1.0 (severe heat stress). There were no treatment effects on water intake. Dry matter intake was not affected (p = 0.70) by treatments, but the group fed SANG had a numerically (11.2%) higher gain in comparison to the control group, SANG improved gain efficiency (8.3%, p = 0.04), dietary NE (5.2%, p<0.01) and the observed-to-expected NE (5.9%, p<0.01). Supplemental SANG did not affect (p≥0.12) carcass characteristics, chemical composition of shoulder, and organ weights (g/kg empty body weight) of stomach complex, intestines, and heart/lung. Supplemental SANG decreased liver weight (10.3%, p = 0.02) and increased visceral fat (16.9%, p = 0.02). Rumen epithelium of ewes fed SANG had lower scores for cellular dropsical degeneration (2.08 vs 2.34, p = 0.02), parakeratosis (1.30 vs 1.82, p = 0.03) and neutrophil infiltration (2.08 vs 2.86, p = 0.05) than controls. It is concluded that SANG supplementation helped ameliorate the negative effects of severe heat on growth performance of feedlot ewes fed high-energy corn-based diets. Improvement in energetic efficiency may have been mediated, in part, by anti-inflammatory effects of supplemental SANG and corresponding enhancement of nutrient uptake.

Influence of feeding live yeast on microbial protein synthesis and nutrient digestibility in steers fed a steam-flaked corn-based diet

Abstract Four cannulated Holstein steers (264±5 kg) were used in a 4×4 Latin square design to evaluate the influence of feeding different levels (0, 10, 20, or 30 g/steer/d) of live yeast (LY) on microbial protein synthesis and characteristics of digestion of the finishing diet. The LY contained 5.5×109 CFU/g. Ruminal pH was not affected by LY supplementation. LY level decreased linearly duodenal flow of ruminal digestion of neutral detergent fiber (NDF) but did not affect duodenal flow of feed N, nonammonia N, or microbial N. LY supplementation did not affect ruminal digestion of organic matter (OM), N, microbial efficiency, or N efficiency but linearly increased ruminal digestion of NDF. Total tract digestion of OM, NDF, and digestible energy improved linearly as LY level supplementation increased. Supplemental LY improves NDF and OM digestion enough to improve the DE of the diet, and the level of supplementation affects the magnitude of the responses.

Energy value of unfermented dried grape pomace as substitute of alfalfa hay in diets for growing lambs

ABSTRACT: The energy value of unfermented dried grape pomace (DGP) was evaluated in an 84 d feeding trial on 16 PelibueyxDorper lambs (17.8 ± 2.0 kg). The control diet contained 90% mature alfalfa hay and 10% concentrates. Treatments consisted in the replacement (DM basis) of alfalfa hay by DGP at 0, 10, 20 or 30%. Lambs were blocked by weight and assigned individually to pens. Increasing DGP level in diet tended (P=0.06) to decrease daily gain and linearly increased (P=0.04) dry matter intake (DMI); thus, feed efficiency, dietary energy, and observed-to-expected diet NE were linearly decreased (P<0.01), increasing linearly (P<0.01) observed-to-expected DMI coefficient as DGP level was increased in the diet. There were no effects of treatments on carcass characteristics. Using the replacement technique, the energy value of DGP were 0.80, 0.75 and 0.67 Mcal ENm/kg DM, for 10, 20 and 30% of inclusion, respectively. It is concluded that the estimated NE of DGP at 10% inclusion level in the diet is very similar to the NE value assigned by the NRC (2007) for the fermented DGP. Increasing the inclusion of DGP levels beyond 10% decreases its energy value, maybe due to the negative associative effects of chemical compounds (such as phenols) naturally contained in DGP.

Delay implant strategy in calf-fed Holstein steers: growth performance and carcass characteristics

ABSTRACT The influence of live weight (LW) at first implanting on growth performance and carcass characteristics was evaluated in calf-fed Holstein fed a steam-flaked corn-based diet. Treatments were: (1) control (not implanted); (2) first implanted at 267 kg LW; (3) first implanted at 291 kg LW, and (4) first implanted at 321 kg LW. All implanted cattle were re-implanted on d-112 of trial. Both the initial and final implants contained 120 mg of trenbolone acetate and 24 mg of oestradiol. Compared with non-implanted controls, implanting increased (P < .01) overall dry matter intake (DMI, 5.9%), average daily gain (ADG,16.7%), gain efficiency (ADG:DMI; 9.4%), and estimated dietary net energy for maintenance (NEm, 8.6%) and gain (NEg, 9.7%). Increasing LW at first implanting decreased overall DMI (linear effect; P = .01), but did not affect overall ADG (P = .17) or gain efficiency (P = .32). Within the range of 267–321 kg, weight at first implanting did not affect growth-performance or carcass characteristics. Interval growth performance of implanted and non-implanted calves was a predictable function of LW.

Influence of levels of DL-malic acid supplementation on milk production and composition in lactating Pelibuey ewes and pre-weaning weight gain of their suckling kids

Fifteen hair Pelibuey ewes were allotted individually to examine the effect of DL-malic acid (MA) supplementation level (0, 2 and 4 g of MA/kg of feed) during the first weeks of lactation on feed intake, milk yield and composition and pre-weaning weight gain of their suckling kids. Milk yield (P = 0.04) and milk efficiency (P = 0.03) increased linearly as MA supplementation increased, but dry matter intake (DMI) and milk composition (percentage of total solids, protein and fat) were not affected (P > 0.05). Increases on milk yield with no effect on milk composition led to a greater (linear effect, P = 0.02) milk protein yield. The ingestion of MA by the ewes resulted in a greater (linear, P < 0.01) average daily gain of their kids. Supplementation with 4 g of DL-ML per kilogram of feed increased milk production, milk protein yield and milk efficiency with no effect on DMI and milk composition. This milk production increase led to a greater daily gain of pre-weaned kids fed with milk as the unique feed source.