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This study investigated the effect of diets negative in dietary cation–anion difference (DCAD) or restricted in Ca fed prepartum to dairy cows for three weeks on colostrum yield and composition, and the health and growth performance of their calves. Thirty-six pregnant non-lactating Holstein-Friesian cows were randomly assigned to three isoenergetic diets: (1) low Ca: 0.24% Ca, DCAD: +86 mEq/kg; (2) high Ca: 1.23% Ca, DCAD: +95 mEq/kg; and (3) low DCAD: 1.28% Ca, DCAD: −115 mEq/kg (all dry matter (DM) basis). While colostrum quality was not affected, low Ca supply prepartum tended to increase the colostrum yield compared to high Ca (low Ca = 8.81 vs. high Ca = 5.39 kg). However, calves from cows fed low DCAD showed higher serum concentrations of K, lower body weight (BW), starter feed intake and average daily weight gain before weaning compared to low Ca and high Ca calves (53.12 vs. 57.68 and 57.32 kg) but BW was similar postweaning (d 70). In addition, calves from dams fed low DCAD were more likely to develop diarrhea and had increased number of days with abnormal fecal scores. Consequently, calves from low DCAD dams had to be treated more frequently.

This study investigated the impact of carbohydrate source and fluid passage rate (dilution rate) on ruminal fermentation characteristics and microbial crude protein ( MCP ) formation. Three commonly used feeds (barley grain [ BG ], beet pulp [ BP ], and soybean hulls [ SBH ]), which differ considerably in their carbohydrate composition, were incubated together with a mixture of grass hay and rapeseed meal in two identical Rusitec apparatuses (each 6 vessels). Differences in fluid passage rate were simulated by infusing artificial saliva at two different rates (1.5% [ low ] and 3.0% [ high ] of fermenter volume per h). This resulted in six treatments (tested in 3 runs): BGhigh, BGlow, BPhigh, BPlow, SBHhigh and SBHlow . The system was adapted for 7 d, followed by 4 d of sampling. Production of MCP (mg/g degraded organic matter [ dOM ]; estimated by 15 N analysis) was greater with high dilution rate ( DL ; p < 0.001) and was higher for SBH compared to both BG and BP ( p < 0.001). High DL reduced OM degradability ( OMD ) compared to low DL ( p < 0.001), whereas incubation of BG resulted in higher OMD compared to SBH ( p < 0.002). Acetate:propionate ratio decreased in response to high DL ( p < 0.001). Total gas and methane production (both /d and /g dOM) were lower with high DL ( p < 0.001). In our study increasing liquid passage rate showed the potential to increase MCP and decrease methane production simultaneously. Results encourage further studies investigating these effects on the rumen microbial population.

Maintaining product safety and reducing the carbon footprint of production are two sustainability goals of the livestock industry. The objective of this study was to study the impact of Tasco, a product derived from the brown macroalga Ascophyllum nodosum , on the rumen microbiome and its function. The inclusion of Tasco altered both rumen and fecal microbiota levels without affecting rumen fermentation. Tasco reduced fecal Escherichia coli populations and specifically reduced the prevalence of Shiga toxin-producing E. coli O45, O103, O111, and O121 in feces. The findings of this study highlight the application of Tasco as a potential feed additive to reduce pathogen shedding in rams without interfering with ruminal metabolism. The use of Tasco (air-dried Ascophyllum nodosum ) as a feed supplement for ruminants has been reported to affect rumen fermentation and reduce Escherichia coli O157:H7 shedding in feces, but the mode of action behind this phenomenon is unclear. In this study, the effects of four Tasco levels (0, 1, 3, and 5%) on rumen microbiota and rumen/fecal E. coli O serogroups in rams were investigated. Rumen total bacteria and archaea were linearly reduced ( P < 0.001) and protozoa were linearly increased ( P < 0.001) by increasing levels of Tasco. The relative abundances of seven bacterial species and one protozoal species differed among Tasco levels. With Tasco, 14 predicted metabolic pathways were enriched while only 3 were suppressed. A lower ruminal butyrate concentration is possibly associated with enrichment of the “butanoate metabolism” pathway in Tasco-fed rams. The ruminal total E. coli population was linearly reduced ( P < 0.001) by Tasco. Supplementation with Tasco only completely eliminated O121 in the rumen and feces, and higher levels of Tasco (3 and 5%) reduced fecal shedding of serogroups O45, O103, and O111 even though these serogroups were present in the rumen. Our results suggest that Tasco effectively reduced pathogenic E. coli but had only minimal impacts on rumen fermentation in rams. IMPORTANCE Maintaining product safety and reducing the carbon footprint of production are two sustainability goals of the livestock industry. The objective of this study was to study the impact of Tasco, a product derived from the brown macroalga Ascophyllum nodosum , on the rumen microbiome and its function. The inclusion of Tasco altered both rumen and fecal microbiota levels without affecting rumen fermentation. Tasco reduced fecal Escherichia coli populations and specifically reduced the prevalence of Shiga toxin-producing E. coli O45, O103, O111, and O121 in feces. The findings of this study highlight the application of Tasco as a potential feed additive to reduce pathogen shedding in rams without interfering with ruminal metabolism.

Abstract This study investigated the fermentation of liquid feed for pigs and the effect of lactic acid bacteria (LAB) supplementation on fermentation rate, dry matter losses (DML), formation of biogenic amines, and degradation of phytate-P. The basal substrate in all three in vitro batch experiments consisted of 50% canola meal, 25% wheat, and 25% barley. The mixed substrates were adjusted to a dry matter (DM) content of 28.4% and fermented in 1-liter vessels at 37 °C for 24 h. Experiment 1 focused on changes in pH profiles over time. Treatments were as follows: 1) liquid feed without additive (control) and 2) liquid feed supplemented with a mixture of Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus lactis (adLAB) at 2.0 × 105 CFU/g liquid feed (wet wt.; n = 8). Substrate pH was measured every 2 h. Experiment 2 focused on DML and the impact of fermentation on phytate-P. Treatments were identical to experiment 1 (control and adLAB; n = 8). Measured parameters included concentration of lactic acid, acetic acid, ethanol, and phytate-P, and DML after 24 h of fermentation. Counts of molds, Enterobobacteriaceae, yeasts, and LAB were determined in one combined sample of all replicates. Dry matter losses were lower in LAB-supplemented fermentations (5.89%) compared to the control (11.8%; P < 0.001). Supplementation with LAB reduced the phytate-P content (2.66 g/kg DM) compared to the control (3.07 g/kg DM; P = 0.002). Experiment 3 evaluated DML and the impact of fermentation on formation of biogenic amines. Treatments were as follows: 1) control, 2) adLAB (2.0 × 105 CFU LAB/g liquid feed), 3) adLys (0.60% DM supplemented lysine), and 4) adLAB+Lys (combination of adLAB and adLys; n = 8). The fermentation of adLys resulted in a nearly complete breakdown of supplemented lysine, whereas only 10% of supplemented lysine was lost in adLAB+Lys. Furthermore, all adLys samples tested positive for cadaverine (mean concentration 0.89% DM), whereas no adLAB samples contained cadaverine above the detection limit (P < 0.001). Results indicate that DML is reduced in fermentations supplemented with homofermentative LAB. Fermentation of liquid feed with homofermentative LAB can effectively reduce the degradation of supplemental lysine and has the potential to further improve P availability.

This study evaluated the effect of trenbolone acetate + estradiol implants (TBA), melengestrol acetate (MGA), and ractopamine hydrochloride (RAC) on the performance of beef cattle fed barley grain/corn silage diets. Beef cattle (279 ± 10.1 kg) were used in a complete randomized 4-yr study (yr 1, 2, n = 120 heifers and 80 steers; yr 3, 4, n = 120 heifers and 120 steers). Cattle were blocked by weight and randomly assigned to 4 pens/treatment/yr. Treatments were 1) control heifers [no growth promoters (GP)], 2) TBA implanted heifers, 3) MGA heifers, 4) control steers (no GP), and 5) TBA implanted steers (yrs 1 to 4), and included a sixth treatment 6) TBA implanted + RAC steers for yrs 3 and 4. Cattle were fed for a similar duration (262 d ± 8) in all treatments. TBA increased the DMI of steers and heifers (P < 0.001) compared to controls (9.52 vs. 8.73 kg DM/d). MGA did not affect DMI (P = 0.41); however, TBA+RAC steers had grater DMI (P = 0.02; 9.91 vs. 9.58 kg DM/d) compared to TBA steers. Compared to controls, TBA heifers had greater ADG (P < 0.001; 1.45 vs. 1.29 kg), G:F (P < 0.001; 0.157 vs. 0.149), and carcass weight (P < 0.001; 390 vs. 360 kg). TBA also increased steers ADG (P < 0.001; 1.70 vs. 1.41 kg), G:F (P < 0.001; 0.174 vs. 0.161), and carcass weight (P < 0.001; 425 vs. 389 kg). Compared to control heifers, MGA increased (P < 0.01) ADG, G:F, and carcass weight by 8.1%, 7.0%, and 4.7%, respectively. The ADG and carcass weight of TBA+RAC steers increased (P < 0.01) by 5.6% and 3.2%, respectively with no effect (P = 0.87) on G:F compared to TBA steers. This 4-yr study demonstrates the consistent positive impact of conventional growth-enhancing technologies.

This study evaluated the effect of trenbolone acetate + estradiol implants (TBA), melengestrol acetate (MGA), and ractopamine hydrochloride (RAC) on the performance of beef cattle fed barley grain/corn silage diets. Beef cattle (279 ± 10.1 kg) were used in a complete randomized 4-yr study (yr 1, 2, n = 120 heifers and 80 steers; yr 3, 4, n = 120 heifers and 120 steers). Cattle were blocked by weight and randomly assigned to 4 pens/treatment/yr. Treatments were 1) control heifers [no growth promoters (GP)], 2) TBA implanted heifers, 3) MGA heifers, 4) control steers (no GP), and 5) TBA implanted steers (yrs 1 to 4), and included a sixth treatment 6) TBA implanted + RAC steers for yrs 3 and 4. Cattle were fed for a similar duration (262 d ± 8) in all treatments. TBA increased the DMI of steers and heifers (P < 0.001) compared to controls (9.52 vs. 8.73 kg DM/d). MGA did not affect DMI (P = 0.41); however, TBA+RAC steers had grater DMI (P = 0.02; 9.91 vs. 9.58 kg DM/d) compared to TBA steers. Compared to controls, TBA heifers had greater ADG (P < 0.001; 1.45 vs. 1.29 kg), G:F (P < 0.001; 0.157 vs. 0.149), and carcass weight (P < 0.001; 390 vs. 360 kg). TBA also increased steers ADG (P < 0.001; 1.70 vs. 1.41 kg), G:F (P < 0.001; 0.174 vs. 0.161), and carcass weight (P < 0.001; 425 vs. 389 kg). Compared to control heifers, MGA increased (P < 0.01) ADG, G:F, and carcass weight by 8.1%, 7.0%, and 4.7%, respectively. The ADG and carcass weight of TBA+RAC steers increased (P < 0.01) by 5.6% and 3.2%, respectively with no effect (P = 0.87) on G:F compared to TBA steers. This 4-yr study demonstrates the consistent positive impact of conventional growth-enhancing technologies.

The purpose of this study was to evaluate the effect of a phytogenic feed additive (Digestarom® (DA), Biomin, Getzersdorf, Austria) on growth performance, feed intake, carcass traits, and liver abscesses of finishing beef steers. One hundred and twenty Angus × Charolais crossbred steers (initial BW 488 ± 26.5 kg) were used in a 110-d feeding experiment. Steers were blocked by weight and randomly assigned to 12 pens with 10 steers per pen. Each pen was allocated to 1 of 3 diets. Each diet contained 86.5% barley, 10.0% barley silage and 3.5% vitamin and mineral supplement on a dry matter basis. Digestarom® replaced barley grain in the vitamin and mineral supplement at 1.41 and 2.82 g/kg, to achieve average daily intakes of DA of 0 (Control), 0.5 (LowDA) and 1.0 g (HighDA) per steer. Diets were prepared once daily and offered ad libitum intake. Two pens per treatment were equipped to record individual feed intake ehavior. Steers were weighed every 28 d and carcass traits and liver scores were recorded at slaughter. Dry matter intake (average 9.34 kg/d) and final BW (average 669 kg) did not differ among treatments. Average daily gain (ADG) tended (P < 0.09) to increase in response to DA supplementation (control, 1.82; LowDA, 1.87; and HighDA, 1.95 kg/d), but gain:feed ratio was not affected. Supplementation of DA affected rib-eye area quadratically (P < 0.05) with the largest area observed for LowDA. Total abscessed livers were not affected, whereas proportion of severe liver abscesses was numerically lower (P < 0.15) with DA (31 and 43% for LowDA and HighDA, respectively) compared to the control (50%). The positive effect of DA on ADG and percentage of severely abscessed livers should be validated in larger scale feedlot studies.

This study investigated the effect of treatment of wheat straw using ammonia fiber expansion (AFEX) and exogenous fibrolytic enzymes (Viscozyme) on fiber digestibility, rumen fermentation, microbial protein synthesis, and microbial populations in an artificial rumen system [Rumen Simulation Technique (RUSITEC)]. Four treatments were assigned to 16 vessels (4 per treatment) in 2 RUSITEC apparatuses in a randomized block design. Treatments were arranged as a 2 × 2 factorial using untreated or AFEX-treated wheat straw with or without exogenous fibrolytic enzymes [0 or 500 µg of protein/g straw dry matter (DM)]. Fibrolytic enzymes were applied to straw, prior to sealing in nylon bags. The concentrate mixture was provided in a separate bag within each fermentation vessel. The RUSITECs were adapted for 8 d and disappearance of DM, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) was measured after 48 h of incubation. Ammonia fiber expansion increased (P < 0.01) the disappearance of wheat straw DM (69.6 vs. 38.3%), NDF (65.6 vs. 36.8%), ADF (61.4 vs. 36.0%), and CP (68.3 vs. 24.0%). Total dietary DM, organic matter (OM), and NDF disappearance was also increased (P ≤ 0.05) by enzymes. Total microbial protein production was greater (P < 0.01) for AFEX-treated (72.9 mg/d) than untreated straw (63.1 mg/d). Total gas and methane (CH4) production (P < 0.01) were also greater for AFEX-treated wheat straw than untreated straw, with a tendency for total gas to increase (P = 0.06) with enzymes. Ammonia fiber expansion increased (P < 0.01) total volatile fatty acid (VFA) production and the molar proportion of propionate, while it decreased (P < 0.01) acetate and the acetate-to-propionate ratio. The AFEX-treated straw had lower relative quantities of fungi, methanogens, and Fibrobacter succinogenes (P < 0.01) and fewer protozoa (P < 0.01) compared to untreated straw. The pH of fermenters fed AFEX-treated straw was lower (P < 0.01) than those fed untreated straw. Both AFEX (P < 0.01) and enzymes (P = 0.02) decreased xylanase activity. There was an enzyme × straw interaction (P = 0.02) for endoglucanase activity. Enzymes increased endoglucanase activity of AFEX-treated wheat straw, but had no effect on untreated straw. The addition of enzymes lowered the relative abundance of Ruminococcus flavefaciens, but increased F. succinogenes. These results indicate that AFEX increased the ruminal disappearance of wheat straw and improved fermentation and microbial protein synthesis in the RUSITEC.

Abstact: The purpose of this study was to evaluate the effect of a phytogenic feed additive (Digestarom [DA]; Biomin, Getzersdorf, Austria) on growth performance, feed intake, carcass traits, fatty acid composition, and liver abscesses of finishing steers. One hundred twenty Angus × Charolais crossbred steers (488 ± 26.5 kg) were used in a 110-d feeding experiment. Steers were blocked by weight and randomly assigned to 12 pens with 10 steers per pen. Each pen was allocated to one of three diets. Each diet contained 86.5% barley, 10.0% barley silage, and 3.5% vitamin and mineral supplement on a dry matter (DM) basis. The diets contained 0, 0.05, and 0.1 g DA/kg complete diet (DM basis), to achieve average daily DA intakes of 0 (control), 0.5 (LowDA), and 1.0 g (HighDA) per steer. Diets were prepared once daily and provided ad libitum. Two pens per treatment were equipped to record individual feed intake behavior. Steers were weighed every 28 d and carcass traits and liver scores were recorded at slaughter. Dry matter intake (average: 9.34 kg/d) did not differ (P > 0.05) among diets. Average daily gain tended to increase linearly as DA increased (control: 1.82; LowDA: 1.87; and HighDA: 1.95 kg/d; P < 0.09), but gain:feed ratio was not affected. Supplementation of DA affected longissimus muscle area quadratically (P = 0.05) with the largest area observed for LowDA. However, dressing percentage decreased linearly in response to increasing level of DA (P < 0.01). Total abscessed livers were not affected, whereas proportion of severe liver abscesses was numerically lower with DA (30.8% and 42.5% for LowDA and HighDA) compared to the control (50%).

Abstract This study investigated the effect of treatment of wheat straw using ammonia fiber expansion (AFEX) and exogenous fibrolytic enzymes (Viscozyme) on fiber digestibility, rumen fermentation, microbial protein synthesis, and microbial populations in an artificial rumen system [Rumen Simulation Technique (RUSITEC)]. Four treatments were assigned to 16 vessels (4 per treatment) in 2 RUSITEC apparatuses in a randomized block design. Treatments were arranged as a 2 × 2 factorial using untreated or AFEX-treated wheat straw with or without exogenous fibrolytic enzymes [0 or 500 μg of protein/g straw dry matter (DM)]. Fibrolytic enzymes were applied to straw, prior to sealing in nylon bags. The concentrate mixture was provided in a separate bag within each fermentation vessel. The RUSITECs were adapted for 8 d and disappearance of DM, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) was measured after 48 h of incubation. Ammonia fiber expansion increased (P < 0.01) the disappearance of wheat straw DM (69.6 vs. 38.3%), NDF (65.6 vs. 36.8%), ADF (61.4 vs. 36.0%), and CP (68.3 vs. 24.0%). Total dietary DM, organic matter (OM), and NDF disappearance was also increased (P ≤ 0.05) by enzymes. Total microbial protein production was greater (P < 0.01) for AFEX-treated (72.9 mg/d) than untreated straw (63.1 mg/d). Total gas and methane (CH4) production (P < 0.01) were also greater for AFEX-treated wheat straw than untreated straw, with a tendency for total gas to increase (P = 0.06) with enzymes. Ammonia fiber expansion increased (P < 0.01) total volatile fatty acid (VFA) production and the molar proportion of propionate, while it decreased (P < 0.01) acetate and the acetate-to-propionate ratio. The AFEX-treated straw had lower relative quantities of fungi, methanogens, and Fibrobacter succinogenes (P < 0.01) and fewer protozoa (P < 0.01) compared to untreated straw. The pH of fermenters fed AFEX-treated straw was lower (P < 0.01) than those fed untreated straw. Both AFEX (P < 0.01) and enzymes (P = 0.02) decreased xylanase activity. There was an enzyme × straw interaction (P = 0.02) for endoglucanase activity. Enzymes increased endoglucanase activity of AFEX-treated wheat straw, but had no effect on untreated straw. The addition of enzymes lowered the relative abundance of Ruminococcus flavefaciens, but increased F. succinogenes. These results indicate that AFEX increased the ruminal disappearance of wheat straw and improved fermentation and microbial protein synthesis in the RUSITEC.