Cattle In Feedlot Research Articles

PSXII-18 Nitrogen balance and ruminal bacterial diversity indexes of Nellore cattle fed with amylolytic and fibrolytic enzymes in feedlot

Abstract This study was carried out to evaluate the use of dietary exogenous enzyme (ENZ) products with amylolytic and fibrolytic activity on nitrogen balance and ruminal alpha and beta diversity of Nellore cattle in feedlot. Rumen cannulated Nellore steers [n = 10; body weigh (BW) = 543 kg ± 28.6 kg] were distributed in a replicate 5 × 5 Latin-square design using individual pens. The treatments consisted of a negative control (CON; without ENZ); Amylase [AML, Amaize, Alltech; 0.5 g/kg of diet dry matter (DM); Xylanase (FBL, Fibrozyme, Alltech; 0.9 g/kg of diet DM]; Half dose (HD; AML 0.25 g/kg of diet DM and FBL 0.45 g/kg of diet DM); and Full dose (FD; AML 0.5 g/kg of diet DM and FBL 0.90 g/kg of diet DM; Table 1). The experimental period lasted 19 d (14 d of adaptation and 5 d of collection). Between d 15 and 18, total urine collection was performed to calculate the nitrogen balance. On d 19 a mixed ruminal sample (6 mL of solid and liquid content) was taken 4 h after feeding and stored at -80 ºC until DNA extraction. Total genomic DNA was extracted using the ZymoBIOMICS DNA Miniprep Kit. The library was prepared using primers for the region V3V4 of the16S rRNA gene; 341F (5’-CCTAYGGGRBGCASCAG-3’) x 806R (5’- GGACTACNNGGGTATCTAAT-3’). The amplicons (~ 470 bp) were sequenced with the Illumina NovaSeq 6000 PE 250 platform. The sequences were analyzed using qiime2 with the SILVA database for the taxonomic assignment. Alpha and beta diversities were calculated in Rstudio using phyloseq. All data were analyzed as orthogonal contrasts assuming treatment as a fixed effect: 1) CON vs. ENZ, 2) AML vs. FBL, 3) HD vs. FD, and 4) AML + FBL vs. HD + FD. Animals that received ENZ had reduced fecal nitrogen excretion (FNE, P = 0.014) and greater efficiency of nitrogen utilization (ENU, P = 0.031) than animals in the CON group. The FBL treatment resulted in greater CP/DOM ratio (P = 0.049), nitrogen balance (P = 0.089), and ENU (P = 0.015) compared with AML treatment. No differences were observed between HD and FD for any nitrogen balance variable (P > 0.10). Animals supplemented with both enzymes (HD + FD) had greater values of N intake (P = 0.018), greater CP/DOM ratio (P = 0.006), and greater FNE (P = 0.002) than animals fed either enzyme alone (AML + FBL). The ENZ supplementation did not impact alpha diversity index or beta diversity (P > 0.10). In conclusion, the addition of exogenous enzymes affected nitrogen balance but not ruminal alpha and beta diversity of Nellore cattle in feedlot.

PSXIII-22 Intake, digestibility, and ruminal parameters of Nellore cattle fed with amylolytic and fibrolytic enzymes in feedlot

Abstract This study was carried out to evaluate the use of dietary exogenous enzyme (ENZ) products with amylolytic and fibrolytic activity on nutrient intake, digestibility, and ruminal volatile fatty acids production (VFA) of Nellore cattle in feedlot. Rumen-cannulated Nellore steers [n = 10; body weight (BW) = 543 kg ± 28.6 BW] were distributed in a replicated Latin-square design (5 × 5) in individual pens. The treatments consisted of a negative control (CON; without ENZ); Amylase (AML; Amaize, Alltech, 0.5 g/kg of DM); Xylanase (FBL, Fibrozyme, Alltech, 0.9 g/kg of DM); Half dose (HD; AML 0.25 g/kg of diet DM and FBL 0.45 g/kg of diet DM); and Full dose (FD; AML 0.5 g/kg of diet DM and FBL 0.90 g/kg of diet DM; Table 1). The experimental period lasted 19 d (14 d of adaptation and 5 d of collection). Between d 15 and 18, total fecal collection was performed and on d 19 rumen fluid was collected at 0, 4, 8, 12, and 16 h post-feeding for ammonia, VFA, and pH determination. The data were analyzed as orthogonal contrasts using SAS: (C1) CON vs. ENZ, (C2) AML vs. FBL, (C3) HD vs. FD, and (C4) AML + FBL vs. HD + FD. There were no C1 differences for nutrient digestibility, total VFA, or ruminal pH (P > 0.10). However, a tendency effect in neutral detergent fiber (NDF) intake (P = 0.065) was observed, where animals fed ENZ had reduced values compared with animals kept in CON group. In the same way, ENZ reduced ther extract (EE) intake (P = 0.023), ruminal ammonia (P < 0.001), and isovalerate proportion (P = 0.080) as well as increased proportion of acetate (P < 0.001), valerate (P < 0.001) and acetate:propionate ratio (P = 0.030). No differences were observed in nutrient intake between AML and FBL (P > 0.10), but AML had greater organic matter (OM) digestibility (P = 0.097) and ruminal valerate (P = 0.039) and decreased butyrate proportion (P = 0.068). Animals that received FD had greater values of dry matter (DM; P = 0.009) and OM (P < 0.001) digestibility than HD. The enzyme combination resulted in greater DM (P = 0.026), OM (P = 0.062), crude protein (P = 0.018), EE (P = 0.063) and NDF (P = 0.040) intake and reduced OM digestibility (P = 0.008) compared with AML and FBL alone. The addition of exogenous enzymes in feedlot diets affected nutrient utilization and ruminal fermentation of Nellore cattle fed a feedlot finishing diet.

Effects of natural additives as an alternative to ionophores on performance and carcass traits of Nellore cattle in feedlot submitted to transport stress

The present study aimed to evaluate the use of natural additives, based on essential oils and yeast cell wall products, as alternatives for monensin as a growth promoter for beef cattle. A total of 160 Nellore bulls with an average initial body weight of 352 kg were randomly distributed (40 animals/treatment) in four collective pens equipped with 24 automatic feeders (6 devices per pen). The feedlot period lasted 116 days, with a 14-day period of animal adaptation to the facilities. After the adaptation period, a transport stress (8 hours/400 km) was induced in all animals to simulate a commercial feedlot situation. The treatments were: 1) CON - Negative control (no additive); 2) MON - Monensin (27 mg/kg of dry matter (DM)); 3) EO - Essential oil-based additive (Valkalor Plus: 1.3 g/ kg DM); 4) EOYW - Essential oil and yeast cell wall-based additive (Viandi Plus: 1.8 g/ kg DM). The EO additive Valkalor Plus (IDENA®, Sautron, France) consists of a blend of essential oils (eugenol and geranyl acetate), while the EOYW additive Viandi Plus (IDENA®, Sautron, France) contains a combination of essential oils (linalol and geranyl acetate) with yeast cell wall. All statistical analyses were performed in SAS version 9.4 (SAS Institute Inc.), using GLIMMIX procedure and comparing the least square means by Tukey’s test at P < 0.05 and tendency between 0.05 <P < 0.10. A tendency (P = 0.091) and a significant effect (P = 0.032) were observed for final body weight (FBW) and average daily gain (ADG), respectively. Treatment MON presented greater FBW and ADG compared to CON (546 kg; 1.656 kg/d vs. 529 kg; 1.486 kg/d) but did not differ from treatment EO and EOYW. Dietary treatment EOYW presented greater dry matter intake (DMI), compared to MON (7 %; P = 0.006), but did not differ from CON and EO (P > 0.10). On the other hand, dietary treatment MON presented greater gain: feed ratio than all other treatments (P = 0.003). The treatments CON and EO presented greater presence of liver abscesses compared to MON and EOYW (P = 0.030). On average, the presence of liver abscess was 4.62 % for MON and EOYW vs. 23 % for CON and EO. Animals fed EO and EOYW diets, particularly during the initial adaptation period (0–12 days), had greater fluctuations in DMI compared to bulls fed CON and MON diets (P < 0.0001). Bulls treated with MON spent more time eating and had a greater DMI rate (min/kg; P < 0.0001) per kg compared to EOYW bulls during both the adaptation phase and the entire study period. In terms of daily feeding behavior, MON and EO-treated bulls exhibited more visits than EOYW bulls throughout the adaptation, final, and overall study periods (P < 0.0001). The serum haptoglobin concentration was greater for animals fed EO and EOYW compared to other treatments on average and at d 116 after enrollment (P < 0.0001). Altogether, these outcomes indicate that EOYW may be a viable alternative to MON in feedlot diets for finishing animals.

Three environmental dimensions of beef cattle in tropical feedlot: Water, nutrients and land

This study aims to evaluate water, land, and nutrient efficiencies in a tropical beef feedlot system by providing artificial shading and considering local conditions and feed cultivation. The study was conducted at the Experimental Feedlot of Embrapa Southeast Livestock in Brazil. Forty-eight Nellore bulls were divided into two groups, with one group having shade (GS) and the other without shade (GWS). The animals' body weights, water intake, and dry matter intake were recorded. The water footprint was calculated using a product-focused assessment, considering water consumed in feed production and animal drinking. The nutrient balance and land footprint were also assessed. To both treatments, the crop scenario with soybean and corn first crop produced in Maringa resulted in the lowest water and land footprint values. Corn was the main contributor to green water consumption. The efficiency in water use for corn decreased between the first and second crops. The water footprint of soybean meal varied between production locations. GWS had slightly higher average blue water consumption than GS. In terms of nutrient balance, the GS treatment exhibited lower nitrogen and phosphorus balance values, indicating higher efficiency in the use of these elements. The provision of artificial shading was found to reduce the water footprint and improve nutrient use efficiency. The location of grain production and the timing of corn planting were identified as key factors influencing water and land footprint values.

Hematological and Performance Parameters Trend in Steers and Heifers in Feed Lot and Supplemented with Palm Oil (Elaeis guineensis Jack)

This study compares the daily weight gain (ADG) and the hematological profile of cattle in feed lot and supplemented with palm oil (POil). Overall, 20 male and 24 female Holstein-Cebu (5/8-3/8) cattle with an average weight of 249±43 kg were used. Three groups of eight animals each were formed with females, which were housed and received 0, 2, and 4% POil in the diet (FSWO, FS2O, FS4O). With males, only two groups were formed, one group that kept grazing and received 2% POil (MG2O, n=8) and one group stabled and received 4% POil (MS4O, n=12). Peripheral blood was obtained to determine the hematocrit (HCT), plasma protein concentration (TPP, g/dL), and eosinophil count (EOS), and a complete blood sample was processed in an automatic analyzer to determine the erythron and platelet formula. Analysis of repeated measures over time was performed. Stabled steers showed the highest ADG (1.5kg/d), whereas females received 2 or 4% oil had similar ADG levels (1.3 to 1.4kg/d) than grazing steers. At the first sampling, EOS counts were 1.5 x 103 cells/µL of blood, but they were reduced to 0.23 x 103 cells/µL of blood at the end of the study. The lowest HCT was obtained in grazing steers (32.8%). It is concluded that in stabled steers, the red formula is improved, and the EOS count reduced. Palm oil supplementation generated the highest daily weight gain in stabled steers.

Tiempo necesario para que las bacterias ruminales se adapten a los cambios en la dieta del ganado confinado: Revisión

The system of production in animals’ feedlot is an excellent strategy for periods of food scarcity and lack of space. In feedlot, concentrated diets with high levels of fast-digesting carbohydrates are used. This review was carried out with the objective of addressing the effect of feedlot diets on the ruminal bacterial population in cattle finished in feedlot. Ruminal bacteria respond rapidly to dietary changes, since they reproduce at intervals of less than 60 minutes. The time of colonization of ruminal bacteria indicates the speed that adhere and penetrate into the food. Rumen microorganisms can be associated with food particles at different times. The particle size of food is one of the important factors for degradation, since it determines the attack surface for microorganisms and directly influences the time of colonization of the food. There is a linear relationship between the body size of the animals and the rumination rate, evidencing that it relates the size of the rumen or digestive tract with the body weight of the animals. Restriction and ladder adaptation protocols are the most used by nutritionists in beef cattle in feedlot The inclusion of additives and probiotics is a valid strategy to improve utilization, as long as it is used at appropriate levels. To minimize the negative effects of changes in diets, it is necessary to gradually adapt the ruminal microbiota, either by the adaptation protocols by ladder or by restriction. Both protocols typically improve health and maximize the performance of animals with 14 days of adaptation.

Economic Viability Analysis of an Oral Anthelmintic Treatment for Cattle in Feedlot

The economic viability of a commercial oral anthelmintic suspension containing 10% fenbendazole was evaluated in Angus x Nelore cattle in a feedlot. Two groups of 37 animals (treated and non-treated) were formed. A random-block design was used based on initial weight, egg count per gram of feces (EPG) and carcass grade. EPG counts and the determination of weight were performed on Days 0, 42 and 122. Carcass grade and yield were determined on the day of slaughter. Economic viability was evaluated using cost-effectiveness, sensitivity and financial analyses, considering three economic scenarios: most likely (M), optimistic (O) and pessimistic (P). The anthelmintic achieved 99.89% efficacy regarding EPG reduction. The animals exhibited an increase of 20.7 kg in live weight, 20.2 kg in live weight gain and 0.166 kg in daily weight gain (p &lt; 0.05). No effects were found on yield or carcass grade (p &gt; 0.05). The genus Haemonchus predominated at the onset of the study, whereas only the genus Cooperia was found after treatment. A net return of 14.60 USD per animal was found in the treated group, which remained viable under O, M and P scenarios, with respective differences of 18.92%, 12.86% and 91.15% in gross profit. The treatment was financially superior under all scenarios (real, M, O and P), with reductions of 1.89, 1.04, 0.48 and 16.39 years for the recovery of the initial investment. These results demonstrate the importance of economic analysis methods in the evaluation and selection of anthelmintics.

Crambe meal and crude glycerin from biodiesel production in diets for finishing of crossbred cattle in feedlot.

Our hypothesis is that crambe meal can totally substitute soybean meal and crude glycerin can partially replace the corn in the diet without leading to losses of nutrient intake and productive performance. Two assays were performed using heifers and steers. In the first assay, 24 Beefalo-Nellore heifers with 18months old with 311.5 ± 5.5kg, and in the second assay, 24 Beefalo-Nellore steers with 18months old with 317.0 ± 6.4kg were evaluated. The experiment was carried out in a randomized complete design, in a 2 × 2 factorial scheme, consisting of two energy sources (corn and crude glycerin) and two protein sources (soybean meal and crambe meal). Both assays had 104 experimental days of feedlot. There was no interaction between the variation sources. There was an effect of protein source on nutrient intake for heifers except to neutral detergent fiber intake, which presented effect of energy source. Heifers fed soybean meal showed higher results for total weight gain and daily weight gain. There was observed effect of energy source on rib eye area and subcutaneous fat thickness. Steers fed soybean meal showed higher neutral detergent fiber intake and non-fibrous carbohydrates. Steers fed corn + crude glycerin showed higher results for total weight gain and daily weight gain. The steers fed soybean meal showed higher averages for subcutaneous fat thickness. Crambe meal and crude glycerin can be used as alternative sources of energy and protein to replace 100% of soybean and 50% of corn, respectively, for finishing Beefalo-Nellore cattle in a feedlot.

Prevalence and patterns of fecal shedding of Shiga toxin–producing Escherichia coli by cattle at a commercial feedlot in South Africa

AbstractHealthy colonized cattle are the major reservoir of Shiga toxin–producing Escherichia coli (STEC) and play a key role in the entry point of the pathogen into the beef chain. Excretion rates and the concentration of the pathogen in feces influence the epidemiology and transmission of the pathogen within herds and to humans. This study evaluated the prevalence and dynamics of fecal shedding of STEC by cattle in a commercial feedlot in Gauteng, South Africa. An initial cross‐sectional survey was conducted; fecal samples were obtained from 106 randomly selected weaned beef calves on arrival at the feedlot using polymerase chain reaction (PCR) to screen by detecting stx1 and stx2 genes. Subsequently, a longitudinal study was conducted, and 15 STEC‐positive and 11 STEC‐negative cattle were sampled monthly and followed to slaughter. STEC O157 and non‐O157 were enumerated in samples using commercial chromogenic agar. Initial prevalence of STEC shedding was 27% (29/106; 95% CI [19, 37%]). All 26 cattle shed STEC intermittently or continuously during the study period, all except one were super‐shedders (≥4 log10 CFU/g) at one or more samplings, and 19 (73%) were persistent or intermittent super‐shedders. Of the 38 STEC isolates recovered, 15 (39%) were serotypeable, representing 11 non‐O157 serogroups, including O101, O168, O178, and O68. The most frequent virulence combination profile was stx1 + eaeA + ehxA (n = 12; 32%). This study confirms the occurrence and variability of STEC super‐shedding in feedlot cattle and highlights that super‐shedding is not limited to STEC O157. It also shows their public health significance.

Influence of crude protein content and flint maize processing methods on the performance of early-weaning Nellore calves

AbstractThis study aims to determine the effects of dietary crude protein (CP) content of early-weaned calves; and the influence of flint maize processing methods on intake, total tract nutrient digestibilities and performance of Nellore heifer calves. Fifteen early-weaned Nellore female calves (4 ± 0.5 months; 108 ± 13.1 kg) were used. In phase 1, animals were fed one of the following diets for 112 days: 130, 145 or 160 g CP/kg dry matter (DM). In phase 2, animals received one of the two diets for 84 days: 0.60 dry ground maize grain, 0.30 whole-plant maize silage plus 0.10 mineral-protein supplement or 0.90 snaplage plus 0.10 mineral-protein supplement. In phase 1, intake and digestibility of dietary components were not affected (P &gt; 0.05) by increasing dietary CP content. Daily total urinary nitrogen (N) and urinary urea N increased (P &lt; 0.05) in response to increasing dietary CP content. Animal performance was not affected (P &gt; 0.05) by dietary CP content. In phase 2, maize processing methods did not affect (P &gt; 0.05) intake and digestibility of dietary components as well as animal performance, carcase characteristics and carcase composition. Therefore, based on the current experimental condition, we conclude that dietary CP concentrations of 130 g/kg DM can be indicated for early-weaned Nellore calves. However, more studies are recommended to validate this result and to evaluate concentrations below 130 g CP/kg DM for early-weaned Nellore calves. Moreover, snaplage could be used as an exclusive fibre and energy source for finishing cattle in feedlot.

PSXIII-24 Is it possible to finish beef cattle in feedlot and be environmentally friendly?

Abstract To improve production without affecting the environment, the objective of this research was to evaluate a natural additive to replace the conventional growth promoters in finishing beef cattle diets. 160 Nellore bulls were assigned into two treatments, where the only difference was the additive used: natural additive (Fator P - 600 mg/kg DM) and conventional growth promoters (25 mg/kg DM of monensin + 20 mg/kg DM of virginiamycin). The Fator P® is an organic additive certificated by IBD, which is a blend of the compounds; amino acids (lysine, methionine, and tyrosine), choline, minerals, probiotics and essential fatty acids (omega 3 and omega 6). The diet contained 14% CP and 76% TDN. Nellore young bulls (n = 160), weighing 433 ± 7 kg, with an average age of 24 months, were used. The feedlot facilities contained 16 collective pens, in which 10 animals were allocated. The animal performance was evaluated for 84 days, with 21 days of adaptation. Means were compared with 5% of significance. The conventional growth promoters reduced the dry matter intake. Natural 11.33 kg/day and 10.9 kg/day for the conventional. The conventional growth promoters reduced in 0.43 kg of dry matter intake (P = 0.042) or 0.1% of body weight (P = 0.001; 2.26% to 2.16%). No difference in average daily gain (P = 0.58). 1.655 kg/day for natural and 1.625 for the conventional. The feed efficiency ratio wasn’t different (P = 0.71), natural 146 g / kgMSˉ¹ and 148 g / kgMSˉ¹ for conventional. There were no difference in carcass yield (P = 0.89), mean 56.3%. The natural additives can improve the dry matter intake and can be used as an alternative to antibiotics in high concentrate diets for beef cattle in feedlot system. Thus, finishing beef cattle in the feedlot can be environmentally friendly.

3-Nitrooxypropanol Decreased Enteric Methane Production From Growing Beef Cattle in a Commercial Feedlot: Implications for Sustainable Beef Cattle Production

Effects of the investigational methane (CH4) inhibitor 3-nitrooxypropanol (3-NOP) on animal performance, health and enteric CH4 production of beef cattle were evaluated in a commercial feedlot. Two concurrent studies were conducted: a large pen study (4,048 cattle, eight pen replicates per experimental group) to measure animal performance and health and a small pen study (a subset of 50 cattle from the large pen study, n = 25 per experimental group) to measure enteric CH4 emissions. Within the study, animals (body weight ± SD, 282 ± 8 kg) were assigned in a completely randomized design to one of two groups: control, fed a backgrounding diet (70% corn or barley silage, 30% steam-flaked barley grain concentrate; dry matter (DM) basis) and 3-NOP, fed the backgrounding diet containing 3-NOP. The treatment group in the large pen study was adapted to 3-NOP (12 ± 3 d) before receiving the final target level of 200 mg/kg of DM, which was fed for 108 ± 8 d. Animals in the small pen CH4 emissions study received a basal diet or a basal diet with 3-NOP, with the dose increased every 28 d: low (150 mg/kg DM; 1.27 g/d), medium (175 mg/kg DM; 2.25 g/d), and high (200 mg/kg DM; 2.75 g/d). Intake in the small pens was monitored by electronic feeding bunks and CH4 was measured using the GreenFeed system. In the large pen study, total weight gained, average daily gain, and animal health variables were not affected by 3-NOP, but DM intake (DMI) tended to decrease (P = 0.06) by 2.6% relative to control (8.07 kg/d), while gain:feed ratio tended to be improved (P = 0.06) by 2.5% relative to control (0.161 kg weight gain/kg DMI). In the small pen study, average daily consumption of 3-NOP increased with inclusion rate whereas average DMI was decreased by 5.4% (P = 0.02) compared with control (10.4 kg/d). On average, addition of 3-NOP decreased (P = 0.001) CH4 emissions (g/d) by 25.7% and yield (g CH4/kg DMI) by 21.7%. In conclusion, supplementing a backgrounding diet with 3-NOP decreased CH4 yield and tended to improve feed efficiency of beef cattle fed in a commercial feedlot with no negative impacts on animal health.

Prediction of dry matter intake by feedlot beef cattle under tropical conditions

Context Dry matter intake (DMI) is the variable that most affects beef cattle performance in feedlot conditions. Accurate prediction of DMI is essential because it is the basis for calculating nutritional requirements for maintenance and production. Aims A meta-analysis was conducted to develop DMI prediction models for feedlot beef cattle under tropical conditions, and to compare the models with those proposed by the National Research Council, USA, in 2000 and 2016, as well as those recommended by the Brazilian System of Nutritional Requirements (BR-Corte) and published by Azevêdo and colleagues in 2010 and 2016. Methods The dataset was created from 56 published studies conducted under tropical conditions. The dataset was randomly separated into two subsets for statistical analysis. The first subset was used to develop the models to predict DMI, and the second to evaluate the adequacy of the prediction models. The models were developed by using mixed linear and nonlinear analysis. Key results A nonlinear model and a linear model to predict DMI are proposed. These models were similar in terms of accuracy and were superior to the other evaluated models. The nonlinear and linear models explained, respectively, 59% and 62% of the DMI variation and had greater accuracy and precision than the other models. The 2016 model used by BR-Corte explained 55% of the DMI variation, and underestimated it at 0.20 kg/day. The remaining three models presented a systematic constant bias and were not adequate for predicting DMI. Conclusion The proposed nonlinear and linear prediction models of beef cattle in feedlot developed under tropical conditions are more precise and accurate than those recommended by the National Research Council and the 2010 model used by BR-Corte. They also present better prediction quality of DMI from beef cattle in feedlots under tropical conditions than the 2016 model used by BR-Corte. Implications The proposed models in the present study are the most suitable for use in predicting the DMI of beef cattle under tropical conditions.

Timing of eating during transition impacts feedlot cattle diet and liveweight gain

The timing of eating, relative to when feed is offered, is affected by the social rank of feedlot cattle due to limited feed bunk space. As cattle can select feed based on dietary preference, the timing of eating for cattle in feedlot may be associated with the ingested diet composition. Our objectives were to determine the nutritive value and timing of feed ingested by 100 feedlot cattle during transition and the association of timing of eating with feeding behaviours and average daily gain (ADG). Cattle behaviour and timing of eating were determined on 100 feedlot cattle using accelerometer-based ear tag sensors from days 3 to 6 post feedlot induction (observation period), and the ongoing impact of this period on ADG was determined for the full feed period (75 days). To determine eating patterns at the time of feed offer, cattle were grouped according to the number of days they were recorded as eating within 1 h of feed being offered across 4 observation days, G0: not present across 4 days, G1: present for 1 day, G2: 2 days, G3: 3 days and G4: present for each of the 4 days. Total mixed ration (TMR) samples were collected for nutritive value analysis from four locations along the feed bunk from the time feed was offered and at hourly intervals thereafter for 7 h each day during the observation period. The composition of feed in the bunk changed across the 7 h of measurement (P < 0.05). The DM and CP of feed increased from 65 to 70% and 15 to 16%, respectively, and the NDF decreased from 36 to 32%. Thus, the preferred TMR feed component was the fibrous dietary fraction. However, the overall composition of the ingested diet for 7 h post feeding was similar between groups. Cattle in G0 had reduced eating time (0.7 vs 4.8%; P < 0.001), rumination time (4.5 vs 19.5%; P < 0.001) and ADG (1.0 vs 1.3 kg/d; P < 0.05) across the study, as compared with cattle in G4. Offering a more fibrous ration during feedlot transition, and customised cattle segregation and/or customised feeding regimes based on sensor derived feeding behaviour profiles during acclimation to feedlot can optimise ADG, animal welfare and feedlot profit.

169 Investigating relationships between weather variables and dry matter intake of beef cattle in feedlot

Abstract Currently, the amount of feed delivered daily in feedlots is based on the previous day’s consumption and the estimated animal growth. Nevertheless, factors such as weather variables may influence feed consumption. The objective of this study was to evaluate the effect of weather on dry matter intake (DMI) in beef cattle finished in a commercial feedlot facility in South America. A total of 8.388 animals (Nellore and crossbreed Nellore x Angus) divided across 55 pens were evaluated from July 2018 to April 2019. The animals entered the feedlots with average body weight (BW) of 337 ± 28 kg and had a harvest BW of 517 ± 33 kg, with an average of 125 ± 25 days in feedlot. Daily feed consumption in each pen was estimated by subtracting any morning leftover feed from the total feed amount delivered on the previous day. Data on 16 weather variables for the farm location (latitude and longitude) was acquired using the Dark Sky API and processed in R. The weather variables were clustered via hierarchical cluster into groups given by: G1) humidity, cloud cover, and precipitation; G2) dew point, temperature (max, min, apparent max and apparent min), and day length; G3) atmospheric ozone and pressure; G4) UV index and visibility; G5) wind speed and gust; and G6) moon phase. Variables in G3 were positively correlated with DMI, while G2 and G4 presented negative correlations. The most important correlations were for day length (r = -0.74, P &amp;lt; 0.01), apparent max temperature (r = -0.65, P &amp;lt; 0.05), dew point (r = -0.65, P &amp;lt; 0.05), ozone (r = 0.62,P &amp;lt; 0.05), and pressure (r = 0.61, P &amp;lt; 0.05). In conclusion, several weather variables presented potential as candidate for the development of predictive models of DMI of beef cattle in feedlots.

Economic-Financial Metanalysis of Termination of Nellore Cattle in Feedlot in Brazil

This study aimed to evaluate the economic and financial viability of the creation of Nellore cattle in feedlot in Brazil. To do so, we performed a meta-analysis of productive data of Brazilian research published in the last ten years, and before the data, simulated to economic analysis. Three scenarios were simulated, the first according to projections of commodity prices, the second with a reduction of 10% of those prices and the third with an increase of 10%. In first scenario the termination provided positive net income, with total factor productivity (TFP) of R$ 1.04. On the other hand, with the increase of 10% of the costs of production, there is an income and a negative rate of return. On the other hand, with a reduction of 10% of the costs of production, the system will only 1,289 animals and, at the same time, the TFP shall be 1.16, with a return rate of 16.32%. We observed payback with values of less than one year, but with an increase of 10% on the cost with feeding all indicators were negative. Sensitivity analyzes showed that in most scenarios evaluated, only in situations more unfavorable economic performance indicators were not attractive. A meta-analysis of data from the termination of bovine animals shows that, before the current scenario, the price of commodities provides favorable economic indices, but with a negative variation of 10% on the price of the same, the indicators are to be negative, even with the price of the @ remaining stable.

Performance evaluation and metabolic profile in cattle supplemented with amino acids and minerals solution.

We aimed to evaluate the effects of parenteral supplementation with a formulation based on amino acids (Roboforte) on the performance and metabolic profile of cattle in feedlot. Forty Nellore steers were distributed according to weight in four experimental groups: Control (without supplementation), Rob1 (one Roboforte application at baseline), Rob2 (two applications at baseline and after 28 days) and Rob7 (weekly applications until day 42, totaling seven). The study had a total duration of 65 days, with 16 days for adaptation to the confinement diet and 49 days (7 weeks) in confinement. The animals were evaluated weekly for weight gain and blood collection for hematological and biochemical evaluations. Statistical analysis considered the effects of time, treatment and interaction. Significant differences (P &lt; 0.0001) were observed in the mean body weight with lower mean weight to control group in relation to the supplemented groups, however, no differences in body weight were observed in relation to the frequency of application of Roboforte. It was verified the effect of the time in the great majority of the variables, which is compatible with the alteration of the diet due to the confinement. Based on the results of hepatic and renal function, it can be stated that the product Roboforte is safe for use in cattle, even when applied weekly. The concentration of glucose was higher in Rob2 and Rob7 groups than in the other groups. In the present study, the application with Roboforte resulted in a higher weight performance of Nelore cattle, being recommended its use in confinement systems take into consideration the productive and metabolic aspects. Further studies should evaluate the economic aspect of this supplementation.

Xylazine sedation and gunshot for depopulation of cattle

A depopulation protocol utilizing intramuscular sedation with xylazine followed by euthanasia via gunshot was evaluated for effectiveness and practicality in a group of 43 feedlot calves in a commercial feedlot setting. Sedation and euthanasia were successful in all 43 calves. The time required to complete the procedure was 46 minutes from the first xylazine injection to the last gunshot. Utilization of this depopulation method demonstrates that cattle in a commercial feedlot can be euthanized in a rapid manner that is practical and efficient, while also maintaining an acceptable level of animal welfare. Expansion to larger herds, including the total population of a large feedlot, may still be challenging. The use of this depopulation method should be considered for future livestock emergencies.

Respuesta conductual de bovinos productores de carne en finalización intensiva en clima desértico cálido

The modification of the natural environment in beef production can induce behavioral changes in cattle. In order to assess the behavioral response based on indicators of animal welfare of beef cattle in feedlot in warm desert environmental conditions; a prospective observational study was conducted with a duration of four weeks. Behavioral guidelines, environmental temperature, relative humidity and temperature and humidity index (THI), were recorded at 8:00 h, 12:00 h, and 16:00 h. Environmental temperature, relative humidity and THI average was 28.7 °C, 24.1 %, and 72.8 units, respectively. During observational period, the beef cattle to be subject at comfort condition (THI≤74). By environmental effect at 12:00 h the usual indicators: eating and drinking, are inhibited (P≤0.01), and grooming decreased (8.2 vs. 13.2 x 100; P≤0.01) Agonist indicators: mounts, threats, Flehmen sign and bumps decrease significantly at 12:00 h (P≤0.01), when the ITH value is greater than 75 units. The highest panting rate (25 x 10000) was observed at 12:00. The diurnal behavioral response of cattle in feedlot on warm desert climate is due to biological rhythms to adapt to the environment that ensures their survival.

PSXIV-27 Do mycotoxin contaminated diets and yeast-derived adsorbent affect meat quality of finishing Nellore cattle in feedlot?

PSXIV-27 Do mycotoxin contaminated diets and yeast-derived adsorbent affect meat quality of finishing Nellore cattle in feedlot?