Performance Of Beef Cattle Research Articles

142 Mineral requirements of fed cattle

Abstract The purpose of this presentation is to summarize state of the art data related to our understanding of feedlot cattle mineral requirements. To date, mineral requirements of cattle have been estimated based on historical research, some conducted as early as the 1930s and 40s. In comparison to earlier editions of the beef cattle nutritional requirements, relatively few alterations in mineral feeding recommendations were noted in NASEM (2016). However, consultants working in the industry commonly report feeding minerals far in excess of the NASEM (2016) recommendations. In addition, an abundance of mineral supplementation strategies has contributed to misunderstandings associated with cattle mineral requirements. Trace minerals, in particular, are available in a variety of chemical forms that affect site of solubility, potential bioavailability and may allow supplementation via various routes (dietary, injection, bolus, oral drench). Published and unpublished data comparing national vs. industry recommendations of trace minerals on beef cattle performance and data pertaining to source comparisons in fed cattle will be presented.

Effect of extracts from baccharis, tamarind, cashew nut shell liquid and clove on animal performance, feed efficiency, digestibility, rumen fermentation and feeding behavior of bulls finished in feedlot

There is a growing public concern on the use of antibiotics and ionophores in livestock and emerging antimicrobial resistance. Plant extracts and essential oils are natural alternatives having antimicrobial and antioxidant properties. This study evaluated the effects of a mixture of baccharis (Baccharis dracunculifolia) leaves and stems, tamarind (Tamarindus indica L.) seed, cashew (Anacardium occidentale) nut shell liquid, and clove (Syzygium aromaticum) essential oil on animal performance, feed intake, feed efficiency, apparent digestibility, molar concentration of volatile fatty acids and feeding behavior of bulls finished in the feedlot and fed high-grain diets. A total of 32 bulls (½ Angus vs. ½ Nellore) with a mean age of 24 ± 2.0 months and a mean body weight of 418 ± 4.51 kg were distributed in a completely randomized design with four diets and eight replications per diet. The four experimental diets were as follows: CONT – basal diet; MIX2 – basal diet and 2 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX4 – basal diet and 4 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX6 – basal diet and 6 g/animal/d of extracts from baccharis, tamarind, cashew nut liquid shell liquid and clove. Animal performance, dry matter, and other nutrients intake were similar among diets. Dry matter, neutral detergent fiber, and organic matter digestibilities were greater for the MIX2 when compared to other diets. There was an increase in propionate and a decrease in the acetate/propionate ratio when MIX6 was used. A similar effect was observed when orthogonal contrasts comparing the CONT diets with the addition of MIX was used. Feeding behavior was similar among the four diets. Our findings indicated that supplementation of baccharis, tamarind, cashew nut shell liquid, and clove oil (2, 4, and 6 g/animal/d) may be fed to beef cattle once it showed no adverse effects on feed intake and nutrient digestibility. Moreover, it was observed a higher concentration of propionate, a reduction in acetate/propionate ratio, and a greater digestibility of dry matter, neutral detergent fiber, and organic matter. However, more studies should be carried out to determine the effect of higher levels of MIX aiming to use it as a feed additive to improve animal performance and ruminal fermentation in beef cattle finished in feedlot.

PSV-11 Grazing diverse combination of tanniferous and non-tanniferous legumes: Implications for foraging behavior, performance and hair cortisol in beef cattle

Abstract We tested the effect of increasingly diverse combinations of tanniferous legumes (birdsfoot trefoil-BFT, sainfoin-SF) and alfalfa (ALF) on cattle foraging behavior, performance and hair cortisol concentration. Pairs of heifers (401 ± 49.6 kg) grazed three spatial replications of seven treatments (n = 3/treatment): monocultures (BFT, SF, ALF) and all possible 2- and 3-way choices among strips of these legumes in a completely randomized block design in two 25-d periods during 2 consecutive years. The fewest grazing events occurred in BFT (42.0% of the total scans recorded; P < 0.10), with other treatments ranging between 47.8 (SF-BFT) and 52.6% (ALF-SF) of the total scans recorded. Heifers selected a varied diet, preferring SF over BFT or ALF in 46:27:27 and 70:30 ratios (3- and 2-way choice, respectively) and preferred BFT over ALF (62:38 ratio). All treatments followed similar daily grazing patterns (P >0.10), with two major grazing events (1 hour after sunrise and 3 hours before sunset). No differences among treatments were observed for the number of steps taken, motion index, or percentage of time spent standing (1,600, 5,356, and 45.3%, respectively; P >0.10), suggesting that heifers in choice treatments did not invest extra time in walking, searching or patch-switching activities relative to monoculture treatments. Heifers in the 3-way choice gained more BW (1.27 Kg/d) than in monocultures (1.00 kg/d; P = 0.014), or 2-way choices (0.97 kg/d; P = 0.007), suggesting nutritional synergism among legumes in the treatment of greatest diversity. No differences in hair cortisol concentration were observed among treatments, with values ranging between 1.40 (BFT) and 2.12 ng/g (3-way choice) (P >0.10). Thus, forage diversity enhanced animal performance, likely driven by interactions among condensed tannins and dietary protein, without affecting hair cortisol levels or grazing efficiency, explained by the spatial arrangement (strips) of the forage species presented.

PSXI-14 Effects of pen cleaning on feedlot performance and carcass characteristics of beef steers fed during the winter in the northern Great Plains

Abstract The objective of this study was to evaluate the impacts of winter pen cleaning on livestock performance of beef cattle fed to finish in the Northern Great Plains. One hundred fifty-six mixed-breed beef steers (284 ± 14 kg) were assigned to one of 12 pens. Treatments were assigned randomly to pen and consisted of: 1) Control - no cleaning, 2) Apron - bunk aprons (approximately 3 m behind the bunk) cleaned twice throughout the study, and 3) Full - entirety of the pen cleaned twice throughout the study. Full pens or bunk aprons were cleaned on two occasions at 56-day intervals. Pens were stocked at a similar density, approximately 26.9 m2 of pen space per steer. Steers were adapted to and finished a common finishing diet. Cattle were provided fresh bedding weekly, with an estimated 2.5 kg cereal straw·steer−1·d−1 used as bedding during the study. Pen cleaning did not influence (P ≥ 0.48) final body weight (628 ± 12 kg), or average daily gain (1.8 ± 0.03 kg/d). Dry matter intake (10.6 ± 0.24 kg) and feed efficiency (0.167 kg gain:kg dry matter intake) were similar (P ≥ 0.55) across treatment. Hot carcass weight, ribeye area, back fat and yield grade of carcasses were not affected (P ≥ 0.44) by pen cleaning treatment. Increasing extent of pen cleaning increased marbling score (P = 0.03; 444, 463, and 484 ± 11.1 for control, apron, and full, respectively). Quality grade was greater (P < 0.05) in carcasses resulting from steers managed with either pen cleaning strategy compared to control. Further, increasing extent of pen cleaning increased (P = 0.03) quality grade of carcasses. Pen cleaning did not improve animal performance in this study, which was unexpected. Further research on the accumulation of marbling over time with different pen cleaning systems is warranted.

164 Effect of trenbolone acetate, melengestrol acetate, and ractopamine hydrochloride on growth performance of growing beef cattle

Abstract 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.

94 President Oral Presentation Pick: Grazing diverse combinations of tanniferous and non-tanniferous legumes: Implications for beef cattle performance and environmental impact

Abstract We tested the effect of increasingly diverse combinations of tanniferous legumes (birdsfoot trefoil-BFT, sainfoin-SF) and alfalfa (ALF) on cattle performance, methane (CH4) emissions and nitrogen (N) balance. Pairs of heifers (401 ± 49.6 kg) grazed three spatial replications of 7 treatments (n = 3/treatment): monocultures (BFT, SF, ALF) and all possible 2- and 3-way choices among strips of these legumes in a completely randomized block design of two 15-d periods during 2 consecutive years. Average daily gains (ADG) of heifers grazing the tanniferous legumes (1.05 kg/d) were 40% greater (P < 0.10) than of heifers grazing ALF (0.74 kg/d) during the first year. Heifers grazing the 3-way choice had greater intakes (10.4 vs 7.8 kg/d; P = 0.064) and ADG (1.21 vs. 0.95 kg/d, P = 0.054) than those grazing monocultures, suggesting a nutritional synergism among legumes. The average CH4 emissions for legume monocultures vs. 2- and 3-way choices was 222 vs. 202 and 162 g/kg BW gain (P > 0.10), respectively. For heifers grazing SF and BFT compared with ALF, blood urea N was less (14.3 and 16.8 vs 20.8 mg/dL; P < 0.05) as were urinary N concentrations (3.7 and 3.5 vs 6.0 g/L; P < 0.05), but fecal N concentrations were greater (34.5 and 35.5 vs 30.5 g/kg, respectively; P < 0.05). Combining both tanniferous legumes (SF-BFT) led to the greatest declines in urinary N (2.24 g/L) and urea-N (1.71 g/L) concentration, suggesting that different types of tannins in different legume species result in associative effects that enhance N economy. In addition, heifers grazing 3-way choices partitioned less N into urine (40.7 vs 50.6%; P = 0.037) and retained more N (36.1 vs 25.2%, P = 0.046) than heifers grazing monocultures. In summary, combinations of tanniferous legumes with alfalfa improved animal performance and reduced environmental impacts relative to monocultures, resulting in a more sustainable approach to beef production in pasture-based finishing systems.

227 Impact of feeding Aspergillus subspecies (ssp.) blend and different corn processing methods on finishing beef cattle performance and carcass characteristics

Abstract The objective of this study was to evaluate the effect of feeding Aspergillus ssp. blend in combination with dry-rolled (DRC) or high-moisture corn (HMC) based finishing diets on performance and carcass characteristics. Crossbred beef steers (n = 320; initial BW = 267 ± 9 kg) were utilized in a generalized randomized block design. Cattle were assigned randomly to pens by initial body weight (BW) and pens were assigned randomly to one of four treatments with 8 pens per treatment for simple effect means. Treatments were set up as a 2 × 2 factorial arrangement with factors consisting of corn processing and 0 g / steer daily or 10 g / steer daily Aspergillus ssp. blend. There were no significant interactions (P ≥ 0.23) observed between corn processing and Aspergillus ssp. blend in the diet; therefore, only main effects are discussed. For the main effect of Aspergillus ssp. blend; no significant differences were observed for dry-matter intake (DMI), average daily gain (ADG), feed efficiency (G:F), hot carcass weight (HCW), or carcass traits (P ≥ 0.78). Cattle fed Aspergillus ssp. blend had a greater 12th rib fat (P = 0.05). For the main effect of corn processing, cattle fed DRC had heavier HCW and final BW (P = 0.04), greater ADG (P = 0.05), and greater DMI (P < 0.01). However, steers fed HMC had greater G:F (P < 0.01) compared to DRC. These data suggest that feeding Aspergillus ssp. blend in either with dry-rolled or high moisture corn diets did not significantly improve performance or carcass characteristics in finishing beef steers. While feeding HMC improved feed efficiency compared to DRC, feeding DRC increased ADG (and also DMI) compared to HMC.

280 Relationship of gene markers to residual feed intake, ADG, and marbling of four years of MSU Steer-A-Year steers

Abstract Feeding cattle is one of the largest expenses in beef production systems. Genetic testing has been proposed as a tool to help select livestock that are the most efficient, with greater performance and/or carcass yield or quality. Improved beef cattle performance, increased feed efficiency, and increased carcass value are ongoing goals for beef cattle production. For this study, 118 mix breed feedlot calves were genetically tested with The Merial Ltd (Deluth, GA) Igenity GGP Bovine 50K. We compared genotypic and phenotypic average daily gain (ADG), residual feed intake (RFI) and marbling. Igenity scores were not related to ADG in years 1, 2, and 3 (P > 0.14), but were correlated in year 4 (P < 0.01; r = -0.58). Steer RFI displayed no relationship to the Igenity RFI score (P ≥ 0.29). No linear relationships were observed between actual and predicted marbling but did display tendencies to rank animals similar to actual marbling in years 3 and 4 (P ≤ 0.08; P = 0.34, 0.31, respectively). In summary, we did not see a strong relationship between genetic marker predictions and actual performance characteristics. However, relationships appear to be stronger in later years, suggesting more work is needed to validate genetic markers correlation to feedlot performance.

Effects of Leptin Gene Polymorphism on Beef Cattle Performance

Livestock specialized cattle breeds combining high energy for both growth and fattening performance are successfully used for high-quality beef production. The use of DNA markers as the additional criteria for sampling and mating the animals allows us to increase the efficiency of selection processes along with improving the meat characteristics of cattle. The objective of the survey was to estimate the effects of leptin gene polymorphism on the growth rates of youngstock and the product quality of beef cattle. The practical science experiment was carried out in 2014–2017. The fattening Hereford and Limousin bull calves (114 and 111 animals, respectively) were genotyped with the technique of polymerase chain reaction (PCR) and subsequent PCR-restriction fragment-length polymorphism analysis (SNP LEP-A422B). A similar genotype distribution among the animals was revealed. Homozygous genotype LEPAA (47.34% and 52.25%, respectively) and allele LEP4 (frequencies of occurrence are 0.68 and 0.71, respectively) are more frequent. The liveweight in both cattle breeds with genotype LEPAA tended to increase at the ages of 8, 12, 16, and 20 months. In addition, an insignificant predominance in body measurements used to assess the proportions of their body parts was ascertained. The analysis of the body conformation indices could indicate harmonious animal development and prove the well-expressed beef forms in the youngstock of all the genotypes for the leptin gene. The postslaughter assessment allowed us to reveal the tendency to increasing the values for the preslaughter liveweight, the hot carcass weight, and the slaughter weight. In addition, the increased carcass yield was recorded in the Hereford bull calves with genotype LEPAA. The surveys ascertained a significant relationship between the analyzed polymorphism and the increases in the internal crude fat weight and the fat yield in the carcasses of bull calves with genotypes LEPAB and LEPBB. The analysis of the morphological composition of Hereford bull calf carcasses revealed a significant relationship between genotype LEPBB and fat contents. Therefore, SNP LEP-A422B genotyping may be used in Hereford and Limousin cattle breeding to improve the meat quality parameters.

Glycerine as a feed supplement for beef and dairy cattle: A meta-analysis on performance, rumen fermentation, blood metabolites and product characteristics.

This study aimed to comprehensively evaluate the effects of glycerine supplementation at various concentrations on performance, rumen fermentation, blood metabolites and product characteristics of beef and dairy cattle in vivo by using a quantitative meta-analysis approach. Meta-analysis was performed by integrating a total of 52 studies from 39 articles and 182 treatments into a database. Data were constructed into an intact database and did not distinguish between beef and dairy cattle, except for the parameters of production performance and product characteristics. Data summarized were analysed by using a statistical meta-analysis that employed a fixed effect of glycerine supplementation level and a random effect of various studies for both beef and dairy cattle. Significance of an effect was stated at the probability level of p<.05, and p<.1 was considered as a tendency of significant. Results revealed that there was a linear decrease on dry matter intake (p<.01) and daily gain (p<.05) of beef cattle with the increasing levels of glycerine supplementation. Glycerine supplementation did not decrease milk production of lactating dairy cows. Molar proportion of acetate in the rumen was decreased (p<.001), whereas propionate and butyrate proportions were increased (both at p<.001) by glycerine supplementation. Generally, glycerine did not change nutrient digestibility except that it reduced fibre digestibility (p<.001). Glycerine supplementation linearly lowered triglyceride and NEFA concentrations (both at p<.05) in the blood serum, but not other blood metabolites. Glycerine tended to linearly increase (p<.1) carcass percentage in beef cattle. Increasing dietary glycerine levels decreased milk fat (p<.01) but elevated milk protein (p<.001). Glycerine tended to increase milk lactose (p<.1) by following a quadratic pattern. The proportion of MUFA was increased quadratically by glycerine supplementation (p<.05), whereas glycerine tended to decrease SFA by following a quadratic pattern (p<.1).

Continuous grazing of mixed native warm‐season grass in the fescue belt

AbstractContinuous, season‐long (May–August) grazing is the most commonly used grazing strategy among tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] belt beef (Bos taurus) producers. However, little information is available regarding the feasibility of managing native warm‐season grass (NWSG) pastures in this region with continuous, season‐long grazing. We compared stand sustainability, beef cattle performance, and pasture production between continuous (CONT), season‐long grazing and heavy‐early (HEAVY), a modified continuous grazing strategy, on mixed‐NWSG pastures. Heavy‐early was designed to match the growth curve of NWSG, with an initial stocking target of 1.25 times the CONT density until 25 June, at which time stocking was reduced to 0.75 times the CONT density. Pastures were mixed big bluestem (Andropogon gerardii Vitman), indiangrass [Sorghastrum nutans (L.) Nash], and little bluestem [Schizachyrium scoparium (Michx.)]. The plant population (plants m−2) was similar between treatments, but years differed (P &lt; .001), with a 35% reduction from 2017, the third and final year of grazing, to 2018. Despite the decline in plant density, overall tiller density (tillers m−2) increased 14%, indicating that the grazing strategies were likely sustainable. The grazing strategies had similar (P &gt; .05) average daily gain (ADG; kg d−1), animal‐days ha−1, and total gain (kg ha−1). Weaned steer ADG was 0.98 kg d−1 for CONT and 0.89 kg d−1 for HEAVY. Total gain was 379 kg ha−1 for CONT and 334 kg ha−1 for HEAVY. Continuous grazing appears to be an appropriate strategy for managing NWSG pastures in the Fescue Belt.

Economic Performance of Madura Beef Cattle Industry in Sapudi Islan

Madura beef cattle is a productive species and has high economic contribution. The farming system has uniqueness compared to other beef cattle farming systems. This study was conducted in Sapudi Island as main producer of madura beef cattle. The aims of the study were: 1) to analyze the status of the madura beef cattle industry; 2) to identify the critical aspects in madura beef cattle farming system in small island; and 3) to analyze the economic performance of madura beef cattle. The primary data were collected from the farmers and other actors through interviews using questionnaires. Descriptive analyses were used to analyze the data and phenomenon as well as operational efficiency ratio. The result indicates that the population of beef cattle in Sapudi was 39,977 heads and the number of families in this island was only 18.003 families. They raise the madura beef cattle with traditional technology. The critical aspects are: 1) lack of feed availability mainly forage. The farmers buy forage from Situbondo-East Java, 2) they always move their cage periodically to have more fertile land for their farmland. The economic performance of madura beef cattle is high. It is indicated by the positive operational efficiency ratio.

Effects of inoculation of corn silage with Lactobacillus hilgardii and Lactobacillus buchneri on silage quality, aerobic stability, nutrient digestibility, and growth performance of growing beef cattle.

This study evaluated the effects of inoculation of whole crop corn silage with a mixture of heterofermentative lactic acid bacteria (LAB) composed of Lactobacillus hilgardii and Lactobacillus buchneri on ensiling, aerobic stability, ruminal fermentation, total tract nutrient digestibility, and growth performance of beef cattle. Uninoculated control corn silage (CON) and silage inoculated with 3.0 × 105 cfu g-1 of LAB containing 1.5 × 105 cfu g-1 of L. hilgardii CNCM I-4785 and 1.5 × 105 cfu g-1 of L. buchneri NCIMB 40788 (INOC) were ensiled in silo bags. The pH did not differ (P > 0.05) between the two silages during ensiling but was greater (P < 0.001) for CON than INOC after 14 d of aerobic exposure (AE). Neutral detergent insoluble crude protein (NDICP) content (% of DM and % of CP basis) of terminal INOC silage was greater (P ≤ 0.05) than that of CON. In terminal silage, concentrations of total VFA and acetate were greater (P < 0.001), while water-soluble carbohydrates were lower (P < 0.001) for INOC than CON. Yeast and mold counts were lower for INOC than CON (P ≤ 0.001) in both terminal and aerobically exposed silages. The stability of INOC was greater (P < 0.001) than that of CON after 14 d of AE. Ruminal fermentation parameters and DMI did not differ (P > 0.05) between heifers fed the two silages, while there was a tendency (P ≤ 0.07) for lower CP and starch digestibility for heifers fed INOC than CON. Total nitrogen (N) intake and N retention were lower (P ≤ 0.04) for heifers fed INOC than CON. Dry matter intake as a percentage of BW was lower (P < 0.04) and there was a tendency for improved feed efficieny (G:F; P = 0.07) in steers fed INOC vs. CON silage. The NEm and NEg contents were greater for INOC than CON diets. Results indicate that inoculation with a mixture of L. hilgardii and L. buchneri improved the aerobic stability of corn silage. Improvements in G:F of growing steers fed INOC silage even though the total tract digestibility of CP and starch tended to be lower for heifers fed INOC are likely because the difference in BW and growth requirements of these animals impacted the growth performance and nutrient utilization and a greater proportion of NDICP in INOC than CON.

Effects of trace mineral supply from rumen boluses on performance, carcass characteristics, and fecal bacterial profile in beef cattle

The experiment was conducted to evaluate trace mineral supplies of copper (Cu), cobalt (Co), selenium (Se), and iodine (I) using rumen boluses (a slow-release leaching technology) on performance, carcass characteristics, and fecal bacterial profile in beef cattle. Total 36 beef Angus steers were used in a completely randomized block design and received a diet without supplementation of Cu, Co, Se, and I (NCON), a diet supplemented with Cu, Co, Se, and I (PCON), or the NCON diet with rumen boluses providing Cu, Co, Se, and I (Bolus). The experiment consisted of 8 weeks of a backgrounding, 4 weeks of a transitioning, and 12 weeks of a finishing phase. Data collected from the experiment were dry matter intake (DMI), average daily gain (ADG), feed efficiency (gain to DMI, kg/kg), and carcass data from individual animals. In the last week of the backgrounding and finishing phase, fecal samples were collected from individual animals and fecal bacterial diversity was determined. All data were analyzed using the MIXED procedure of SAS. No difference in DMI and growth performance among treatments was observed during the backgrounding phase. Interactions of treatments by week for DMI (P < 0.01) and ADG (P = 0.09) were observed during the finishing phase where DMI and ADG were greater for PCON and Bolus compared with NCON during the first 6 weeks of the finishing phase. Carcass characteristics did not differ among treatments except that Bolus had higher quality grade (P = 0.036) compared with NCON and PCON. During the backgrounding phase, the relative abundance of Bifidobacterium was greater (P = 0.026) for Bolus vs. NCON and PCON and that of Treponema was greater (P = 0.01) for PCON vs. NCON and Bolus. During the finishing phase, the ratio of Firmicutes to Bacteroidetes was lower (P = 0.032) for PCON compared with NCON and Bolus without a difference between NCON and Bolus. However, those changes in bacterial diversity during the backgrounding and finishing phases did not influence performance and carcass characteristics of beef steers. In conclusion, trace minerals of Cu, Co, Se, and I need to be provided to meet or exceed the requirements for optimal performance especially during a finishing phase and the trace mineral supply via rumen boluses may have potential to improve a carcass quality grade. In addition, fecal bacterial diversity was altered by trace mineral supply and the method of the supply.

A meta-analysis of the effects of dietary supplementation in tropical forage-fed cattle

The objective of this study was to, through a meta-analysis of published data, evaluate the effects of dietary supplementation on the performance of beef cattle grazed on Brachiaria pastures during the rearing and finishing phases of growth. Data from 15 Brazilian studies were analyzed, totaling 462 animals given different types and levels of supplementation. Animals were divided into two categories: 319 in the rearing phase, and 143 in the finishing phase. The reviewed studies evaluated the effects of protein, energy, and protein/energy supplementation on animal performance parameters. Daily weight gain and final live weight were analyzed using forest plots. Daily weight gain during the rearing phase was similar across all supplement types used. Animals given supplementation gained an average of 119 g more per day compared to those who received no supplementation. Specifically, protein supplementation resulted in an increase of 28.22 kg. Animals given supplementation of any kind, represented by the subgroups shown in the plots, gained an average of 24.47 kg more compared to the control group.

Effects of pen cleaning on feedlot performance and carcass characteristics of beef steers fed during the winter in the northern Great Plains

The objective of this study was to evaluate the impacts of winter pen cleaning on livestock performance of beef cattle fed to finish in the northern Great Plains. To accomplish our research objective, 156 mixed-breed beef steers (284 ± 14 kg) were stratified by weight and randomly assigned to one of 12 open-lot feedyard pens for a 195 day feeding study. Treatments were assigned randomly to pen and consisted of: 1) Control - no cleaning, 2) Apron - bunk aprons cleaned twice throughout the study, and 3) Full - entirety of the pen cleaned twice throughout the study. Full pens or bunk aprons were cleaned on d 49 and 133. Pens were stocked at 30.1 m2 of pen space per steer. Steers were adapted to and finished on a common finishing diet. Fresh wheat straw was placed on bedding areas weekly, with an estimated 2.5 kg cereal straw·steer−1·d−1 used as bedding during the study. Pen cleaning did not influence (P ≥ 0.48) animal performance. Hot carcass weight, ribeye area, back fat and yield grade of carcasses were not affected (P ≥ 0.44) by pen cleaning treatment. We observed that increasing extent of pen cleaning increased (P = 0.03) marbling score (444, 463, and 484 ± 11.1 for control, apron, and full, respectively). Increasing extent of pen cleaning resulted in increased (P = 0.03) quality grade of carcasses. Visual assessment of pen condition, apron score, and tag score were impacted by cleaning regimen by period interaction (P ≤ 0.01). Pen cleaning resulted in improved pen conditions or apron scores compared to control pens, and decreased tag scores compared to control steers (P < 0.05). Pen cleaning did not improve animal performance but did improve marbling score of carcasses in this study.

Effects of bismuth subsalicylate and encapsulated calcium-ammonium nitrate on enteric methane production, nutrient digestibility, and liver mineral concentration of beef cattle.

Two randomized block designs were performed to evaluate the effects of bismuth subsalicylate (BSS) and encapsulated calcium-ammonium nitrate (eCAN) on enteric methane production, nutrient digestibility, liver mineral concentration, and performance of beef cattle consuming bahiagrass hay (Paspalum notatum; ad libitum) and sugar cane molasses [1.07 kg/d; dry matter basis]. Experiment 1, used 25 crossbred steers [335 ± 46 kg of initial body weight (BW)] with a 2 × 2 + 1 factorial arrangement of treatments for two 20 d periods. Factors were nonprotein nitrogen (NPN) source (350 mg/kg BW of nitrate or 182 mg/kg BW of urea), BSS (0 or 58.4 mg/kg BW), and a negative control (NCTRL; bahiagrass hay and molasses only). Steers were re-randomized for a second period (n = 10/treatment total). Intake, apparent total tract digestibility and enteric methane were evaluated. Experiment 2 used 75 crossbred heifers in 25 pens (3 heifers/pen; 279 ± 57 kg of initial BW), consuming the same diet and treatments as experiment 1, to determine liver mineral concentration and growth performance over 56 d. Orthogonal contrasts were used to evaluate the effects of NPN (NCTRL vs. others), source of NPN (NS; urea vs. eCAN), BSS, and NS × BSS. For experiment 1, no interactions were observed for any variables, nor were there any effects of NPN on total tract digestibility of nutrients, except for crude protein. Digestibility of all nutrients was reduced (P ≤ 0.021) for steers consuming eCAN compared with urea. There was no effect (P > 0.155) of BSS on digestibility of nutrients; however, BSS reduced (P = 0.003) apparent S retention. Enteric CH4 emission (g/kg BW0.75) was decreased (P = 0.051) by 11% with the addition of eCAN compared with urea. For experiment 2, no NS × BSS interactions (P ≥ 0.251) were observed to affect liver mineral concentration; however, the addition of BSS decreased liver concentration of Cu (P = 0.002) while increasing Fe concentration (P = 0.016). There was an NS × BSS interaction (P = 0.048) where heifers consuming eCAN and BSS had lesser final BW compared with heifers consuming urea and BSS. While eCAN may be a viable resource for mitigating enteric CH4 production of forage-fed cattle, the negative effects on digestibility should be considered. Furthermore, BSS, at the amount provided, appears to have no negative effects on digestibility of nutrients in forage-fed cattle; however, there may be deleterious impacts on performance depending upon what nitrogen source is supplied.

PENAMPILAN REPRODUKSI SAPI POTONG LOKAL DI KECAMATAN BOLAANG KABUPATEN BOLAANG MONGONDOW

REPRODUCTIVE PERFORMANCE OF LOCAL BEEF COWS IN BOLAANG DISTRICT OF BOLAANG MONGONDOW REGENCY. This study aims to determine the reproductive performance of local beef cattle in Bolaang District, BolaangMongondow Regency. This study used local beef cattle owned by breeders who were taken as samples in several villages in Bolaang District, Bolaang Mongondow Regency. This study used a survey method to obtain primary and secondary data collection. Data analysis regarding the studied variables used descriptive analysis referring to the measurement of each variable. The results showed that service per conception was 1.38, conception rate was 70%, pregnancy period was 276.47 days, animal age of first calving was 32.022 months, and calving interval was 375.26 days. Based on these results of study, it can be concluded that the reproductive performance of local beef cattle in Bolaang district, Bolaang Mongondow regency was categorized into normal reproductive performance of local beef cattle. Key word: Reproduction, Local beef cow, Bolaang district,

Effects of increasing nitrogen levels in Mombasa grass on pasture characteristics, chemical composition, and beef cattle performance in the humid tropics of the Amazon.

Improving beef cattle production in pasture-based systems without expanding agricultural land has been the focus of several studies over the last decades. Nitrogen fertilization is one of the available strategies with high potential to optimize cattle performance in tropical systems. This study aimed to evaluate the effects of increasing nitrogen levels (150, 300, and 450kgha-1 of Nyear-1) in Megathyrsus maximus cv. Mombasa in the humid tropics of the Amazon. The following parameters were evaluated: pasture agronomic characteristics, herbage chemical composition, and beef cattle performance. A total of 24 nine-month-old Nellore bulls with initial mean weight of 173 ± 1.95kg were used for the performance test. The experimental design was a randomized block with three treatments. Herbage mass and leaf mass contents were increased by the highest nitrogen level (P < 0.05). Nitrogen levels elevated the forage accumulation rate, final leaf blade length, and pre-grazing canopy height(P < 0.05). The crude protein content increased at the highest N level (P < 0.05). The neutral detergent fiber and acid detergent fiber contents decreased with increasing N levels. The stocking rate and total weight gain per hectare were higher in bulls grazing pastures fertilized with 450 compared with 150kgha-1 of Nyear-1(P < 0.05). The average daily gain was influenced by N levels (P < 0.05). Nitrogen levels at 300 and 450kg increased animal weight gain and productivity per area by increasing forage yield and improving the chemical composition of Mombasa grass.

Grazing diverse combinations of tanniferous and non-tanniferous legumes: Implications for beef cattle performance and environmental impact

We tested the effect of increasingly diverse combinations of tanniferous legumes (birdsfoot trefoil-BFT, sainfoin-SF) and alfalfa (ALF) on cattle performance, methane (CH4) emissions and nitrogen (N) balance. Pairs of heifers (401 ± 49.6 kg) grazed three spatial replications of 7 treatments (n = 3/treatment): monocultures (BFT, SF, ALF) and all possible 2- and 3-way choices among strips of these legumes in a completely randomized block design of two 15-d periods during 2 consecutive years. Average daily gains (ADG) of heifers grazing the tanniferous legumes (1.05 kg/d) were 40% greater (p < 0.10) than of heifers grazing ALF (0.74 kg/d) during the first year. Heifers grazing the 3-way choice had greater intakes (10.4 vs 7.8 kg/d; p = 0.064) and ADG (1.21 vs. 0.95 kg/d, p = 0.054) than those grazing monocultures, suggesting a nutritional synergism among legumes. The average CH4 emissions for legume monocultures vs. 2- and 3- way choices was 222 vs. 202 and 162 g/kg BW gain (p > 0.10), respectively. For heifers grazing SF and BFT compared with ALF, blood urea N was less (14.3 and 16.8 vs 20.8 mg/dL; p < 0.05) as were urinary N concentrations (3.7 and 3.5 vs 6.0 g/L; p < 0.05), but fecal N concentrations were greater (34.5 and 35.5 vs 30.5 g/kg, respectively; p < 0.05). Combining both tanniferous legumes (SF-BFT) led to the greatest declines in urinary N (2.24 g/L) and urea-N (1.71 g/L) concentration, suggesting that different types of tannins in different legumes result in associative effects that enhance N economy. In addition, heifers grazing 3-way choices partitioned less N into urine (40.7 vs 50.6%; p = 0.037) and retained more N (36.1 vs 25.2%, p = 0.046) than heifers grazing monocultures. In summary, combinations of tanniferous legumes with alfalfa improved animal performance and reduced environmental impacts relative to monocultures, resulting in a more sustainable approach to beef production in pasture-based finishing systems.