Brahman Genetics Negatively Impact Protein Degradation and Tenderness of Longissimus Lumborum Steaks, but do Not Influence Collagen Cross-Linking

Beef tenderness is an important factor contributing to consumer eating satisfaction of beef products. Tenderness is dependent on several factors including: breed-type, postmortem age time, myofibrillar muscle protein degradation, and collagen content. During the past 30 years, numerous studies have indicated steaks from cattle with a greater percentage of Brahman genetics are tougher than steaks from Bos taurus cattle. The cause of tougher steaks is commonly attributed to Brahman cattle having a greater calpastatin activity which inhibits calpains, the enzymes responsible for myofibrillar protein degradation during the postmortem aging process. Some researchers have reported calpastatin activity was poorly correlated to tenderness of steaks from Brahman cattle. Others have reported sensory panelists indicated steaks from cattle with increasing percentages of Brahman genetics have an increase in the amount of connective tissue or collagen. Additionally, researchers have reported an increase in expression of genes that play a role in cross-linking of collagen which decreases collagen solubility. Due to these findings, we hypothesized steaks from cattle with greater Brahman genetics have more collagen cross-links and therefore a less soluble collagen fraction. The objective of this study was to evaluate the effect of Brahman genetics on protein degradation, collagen cross-linking, and meat tenderness of strip loin steaks

Effects of sorghum particle size on milling characteristics, growth performance, and carcass characteristics in finishing pigs

A total of 200 finishing pigs (PIC TR4 × 1050; average initial BW of 103.2 lb) were used in a 69-d growth assay to determine the effects of sorghum particle size on growth performance. Pigs were sorted by sex and ancestry and balanced by BW, with 5 pigs per pen and 10 pens per treatment. Treatments were a corn-soybean meal-based control with the corn milled to a target mean particle size of 600 μm, and sorghum diets milled to a target mean particle size of 800, 600, or 400 μm. Actual mean particle sizes were 555 μm for corn, and 724, 573, and 319 μm for sorghum, respectively. Feed and water were offered on an ad libitum basis until the pigs were slaughtered (average final BW of 271 lb) at a commercial abattoir. Reducing sorghum particle size improved (linear, P \u3c 0.01) F/G, and we observed a tendency for decreased (P \u3c 0.06) ADFI. Reducing sorghum particle size from 724 to 319 μm had no effects on HCW, backfat thickness, loin depth, or percentage fat-free lean index (FFLI), but tended to increase (P \u3c 0.06) carcass yield. Pigs fed the sorghum-based diets had no difference in growth performance or carcass characteristics compared with those fed the control diet, except carcass yield, which was numerically greater (P \u3c 0.07) for pigs fed the sorghum-based diets. When using a regression equation, we determined that sorghum must be ground to 513 μm to achieve a F/G equal to that of a corn-based diet, with corn ground to 550 μm. In conclusion, linear improvements in F/G and carcass yield were demonstrated with the reduction of sorghum particle size to 319 μm. In this experiment, sorghum should be ground 42 μm finer than corn to achieve a similar feeding value.; Swine Day, Manhattan, KS, November 17, 201

Effect of Pellet Cooling Method, Sample Preparation, Storage Condition, and Storage Time on Phytase Activity of a Swine Diet

Temperature and moisture content have been identified as two factors that influ­ence enzyme inactivation. Phytase may be further degraded in feed samples if there is moisture left in the sample and it is not properly stored prior to analysis. Therefore, the objective of this experiment was to determine the effect of cooling method, sample preparation, storage condition, and storage time on phytase stability. In Exp. 1, treat­ments were arranged in 2 × 2 factorial with main effects of sample preparation (none or freeze-dried) and storage condition (ambient storage or freezer storage). Diets were mixed 3 separate times to provide 3 replicates per treatment. The result of Exp. 1 demonstrated that there was no interaction between drying process and storage condi­tion for mash samples collected from the mixer. The sample drying process and storage condition did not impact the phytase stability. In Exp. 2, treatments were arranged in a 2 × 3 factorial with main effects of cooling method (counterflow cooler or freezer) and sample preparation (non-dried then freezer storage, freeze-dried then freezer storage, freeze-dried then ambient storage). The diet was steam conditioned for approximately 45 s at 185°F using a 5.1- × 35.8-in single shaft conditioner of a pellet mill (California Pellet Mill model Cl-5, Crawfordsville, IN) at a production rate of 2.2 lb/min by holding the feeder at a constant speed setting. The sample was collected at the end of the conditioner and did not pass the pellet die. The conditioner was run 3 separate times to provide 3 replicates for each treatment. The result of Exp. 2 demonstrated that there was no interaction between the cooling method and sample preparation for phytase stability of conditioned mash samples. The cooling method and sample prepara­tion did not affect the phytase stability. In Exp. 3, treatments were arranged in a 5 × 3 × 2 factorial with main effects of cooling method (none, heat diffusion, experimental fan cooler, experimental counterflow cooler, or freezer), storage condition (ziplock/ ambient, ziplock/frozen, and vacuum/frozen), and storage time (1 or 3 wk.). The diet was steam conditioned for approximately 45 s at 185°F and pelleted using a pellet mill (California Pellet Mill model Cl-5, Crawfordsville, IN) equipped with 0.16- × 0.50-in die. The diet was pelleted at a production rate of 2.2 lb/min by holding the feeder at a constant speed setting. The pellet mill was run 3 separate times to provide 3 replicates for each treatment. The result of Exp. 3 demonstrated that there were no three-way and two-way interactions among cooling method, storage condition, and storage time (P \u3e 0.686). The cooling method, storage condition, and storage time did not impact phytase stability (P \u3e 0.348). Therefore, freeze-drying, vacuum sealing, and freezing were not required when the feed samples were analyzed within 3 weeks of production. However, conditioned mash and hot pellet samples should be dried prior to sending the samples to the lab to prevent mold growth

Effect of Added Water, Holding Time, or Phytase Analysis Method on Phytase Stability and Pellet Quality

The addition of water to the mixer prior to pelleting is sometimes necessary to reach the target moisture content at the end of the conditioning process. However, there are limited data to demonstrate the impact of water addition in the mixer on phytase stability during the pelleting process. In addition, the variation of phytase analysis method may lead to incorrect or biased conclusions for research on industrial phytase stability. Therefore, the objective of this experiment was to determine the effect of water added in the mixer, feed holding time, and phytase analysis method on phytase stability and pellet quality. Treatments were arranged in a 2 × 2 × 2 factorial with main effects of added water (0% or 1%), holding time (0 or 2 h), and phytase analysis method (ELISA or EN ISO), respectively. For the 0% added water treatment, a 210-lb basal feed and 0.03-lb phytase were mixed for 5 min. For the 1% added water treatments, a 208-lb basal feed and 0.03-lb phytase were mixed for 120 s followed by the addi­tion of 2-lb water and then the mixture was mixed for 180 s wet mix time. The water was applied to dry feed in the mixer using a hand-held sprayer (Country Tuff model 26329, Sedalia, MO) with a flat spray tip nozzle (TeeJet model TP11006, Glendale Heights, IL). After the diets were mixed, treatments were immediately pelleted or held in a closed container for 2 h before pelleting. Treatments were steam conditioned at 185°F for approximately 30 s and pelleted using a pellet mill (California Pellet Mill Co. model Cl-5, Crawfordsville, IN). The pellet mill was equipped with a 0.16 × 0.87 in die. Samples were collected during discharge of the mixer, after conditioning and after pelleting. The conditioned mash and pelleted samples were cooled for 10 min using an experimental counterflow cooler. There were 3 replicates per treatment. Data were analyzed using the GLIMMIX procedure of SAS. The results demonstrated that there was no evidence of three-way or two-way interactions among added water, holding time, and analysis method on phytase stability for mash samples, conditioned mash samples, and pellets. The added water and holding time did not impact phytase stability for mash samples, conditioned mash samples, and pellets. The ELISA method had greater (P = 0.004) phytase activity than the EN ISO method for the pellet samples. The phytase activity was similar between the two analytical methods for mash samples and conditioned mash samples. For pellet quality, there was no evidence of interaction between added water and holding time. Added water and holding time did not impact pellet durability index. Therefore, the stability of phytase produced by a strain of Trichoderma reesei was not affected when feed was stored in a bin up to 2 h prior to pelleting. The added water in mash feed did not affect the degradation of Trichoderma reesei phytase when the feed moisture did not exceed 13%. Additionally, the ELISA or EN ISO method could be used in the laboratory to determine Trichoderma reesei phytase stability. Increasing moisture content of mash feed by 0.6% did not improve pellet quality

Effects of Grinding Corn with Different Moisture Concentrations on Subsequent Particle Size and Flowability Characteristics

The objective of this study was to determine the effects of whole corn moisture and hammermill screen size on subsequent ground corn moisture, particle size, and flow- ability. Whole yellow dent #2 corn was used for this experiment. Treatments were arranged as a 2 × 2 factorial design with two moisture concentrations (as-received and high) each ground using 2 hammermill screen sizes (1/8 and 1/4 in). Corn was ground using a laboratory scale 1.5 HP Bliss Hammermill (Model 6K630B) at 3 separate time points to create 3 replications per treatment. Increasing initial whole corn moisture was accomplished by adding 5% water and heating at 55°C for 3 hours in sealed glass jars using a Fisherbrand Isotemp Oven (Model 15-103-051). Ground corn flowability was calculated using angle of repose (AOR), percent compressibility, and critical orifice diameter (COD) measurements to determine the composite flow index (CFI). There was no evidence for a screen size × corn moisture interaction for moisture content, particle size, standard deviation, or flowability metrics. Grinding corn using a 1/8 in screen resulted in decreased (P \u3c 0.041) moisture content compared to corn ground using the 1/4 in screen. There was a decrease in particle size from the 1/4 in screen to the 1/8 in but no evidence of difference was observed for the standard deviation. There was a decrease (P \u3c 0.03) in percent compressibility as screen size increased from 1/8 to 1/4 in. Angle of repose tended to decrease (P \u3c 0 .056) when corn was ground using a 1/4 in screen compared to a 1/8 in screen. For the main effects of moisture content, high moisture corn had increased (P \u3c 0.0001) ground corn moisture content compared to as-received corn. As-received corn resulted in decreased (P \u3c 0.029) particle size and an increased standard deviation compared to the high moisture corn. Increased moisture content of corn increased (P \u3c 0.038) CFI and tended to decrease (P \u3c 0.056) AOR and COD. In conclusion, decreasing hammermill screen size increased moisture loss by 0.55%, corn particle size by 126 μm, and resulted in poorer flowability as measured by percent compressibility and AOR. High moisture corn increased subsequent particle size by 89 μm, therefore improving flowability as measured by CFI

Evaluation of Conditioning Temperature and Die Specifications on Nursery Pig Performance

The objective of this study was to determine the effects on growth performance in nursery pigs that is linked to the conditioning temperature and die specifications used during the feed pelleting process. A total of 315 barrows (DNA; 200 × 400; initial BW 13.2 lb) were used in a 35-d growth trial. Upon arrival, pigs were weighed and assigned to pens in a completely randomized design with 5 pigs per pen, and each pen was randomly assigned to 1 of 7 dietary treatments with 9 replications per treatment. Treatments consisted of a mash control (MC) and 6 pelleted diets manufactured using 2 different pellet dies (length/diameter [L:D]: 6.7 and 2.7) and 3 different conditioning temperatures (low, medium, high). Conditioning temperatures for Phase 1 diets pelleted using the 6.7 L:D die were 80, 100, and 120°F and for the die with a L:D 2.7 were 100, 120, and 140°F for the low, medium, and high, respectively. Phase 2 condi­tioning temperatures for diets pelleted using the die with a L:D of 6.7 were approxi­mately 120, 140, and 160°F and for the 2.7 L:D die were 140, 160, and 180°F for the low, medium, and high, respectively. Diets were fed in three phases as follows, Phase 1: d 0 to 10, Phase 2: d 10 to 25, and Phase 3: d 25 to 35. During Phase 3 all pigs were fed a common mash diet. Overall from d 0 to 35, similar ADG was observed for pigs fed the MC or pelleted diets with the exception of the diet pelleted at the low conditioning temperature using the 6.7 L:D die, which had decreased (P \u3c 0.05) ADG compared to MC. When pelleting diets using the 2.7 L:D die, there was a tendency for increased (quadratic, P = 0.077) ADG in pigs fed diets conditioned at increasing temperatures, with the medium temperature having the greatest ADG. There was a tendency for increased (P = 0.088) ADG in pigs fed diets pelleted using the 2.7 L:D die compared to the 6.7 L:D die. Pigs fed pelleted diets, with the exception of the medium temperature on the 2.7 L:D die, had decreased (P \u3c 0.05) ADFI compared to the MC. However, diets pelleted using the 6.7 L:D die as well as the diet manufactured at the medium conditioning temperature on the 2.7 L:D die had improved (P \u3c 0.05) F/G compared to the MC diet. Additionally, pigs fed diets manufactured using the 6.7 L:D die had decreased (P = 0.030) ADFI compared to those fed diets pelleted using the 2.7 L:D die. In summary, pelleted diets showed poorer ADG but decreased ADFI and improved F/G, and no differences in final BW compared to the MC. Additionally, there was a numerical decrease in pellet quality when treatments were manufactured on the 2.7 L:D die; however, these differences did not result in a growth performance response due to conditioning temperature or die. Overall increasing conditioning temperature decreased the available lysine, and pigs fed pelleted diets had poorer ADG but decreased ADFI and improved F/G compared to those fed the MC

The Effect of Pellet Mill Production Rate and Knife Distance on Pellet Quality

Longer pellet lengths may lead to decreased pellet breakage, resulting in increased pellet durability index (PDI). Thus, the objective of this experiment was to determine the effects of production rate and knife distance on pellet length and subsequent pellet quality. Treatments were arranged in a 2 × 3 factorial with two production rates (16 and 33 lb/min) and three knife distances (0.25, 0.50, and 0.75 in). All diets were conditioned at 185°F and pelleted using a CPM pellet mill (Model 1012-2 HD, California Pellet Mill Co., Crawfordsville, IN) equipped with a 0.19 in × 1.25 in die. The production rate (PR) and knife distance (KD) were randomized to minimize the effects of pelleting and sampling order. There were 3 replicates per treatment. Samples were analyzed for pellet length, percentage fines, and PDI using the standard and modified tumble box method (STD and MOD, respectively) and Holmen NHP100 (TekPro Ltd, Norfolk, UK) with a 60-sec run time. Data were analyzed using the GLIMMIX procedure of SAS (v. 9.4, SAS Inst. Inc., Cary, NC). There was no evidence for an interaction between PR and KD for all analyzed variables (P \u3e 0.24). The 16 lb/min PR yielded a longer pellet (P ≤ 0.05) compared to the 33 lb/min PR. The PR had no effect on percentage fines (P \u3e 0.10); however, decreasing the PR tended to increase PDI regardless of analytical method (P ≤ 0.10). Increasing KD resulted in longer (P \u3c 0.01) pellets and decreased (P \u3c 0.01) percentage fines. Reducing KD to 0.25 in reduced PDI compared to 0.50 in and 0.75 in treatments, which yielded similar PDI. In conclusion, pellet quality can be improved by increasing the pellet length from 0.19 to 0.34 in (KD 0.25 and 0.75 in, respectively)

Evaluating Soybean Meal Quality Using Near-Infrared Reflectance Spectroscopy

The objective of this study was to establish a range of soybean meal quality to evaluate the correlations between official analytical methods and near-infrared reflectance spectroscopy (NIRS). Crushed soybean white flakes (Mark Hershey Farms, Lebanon, PA) exposed to mechanical oil extraction, but not heat processing, were used in this experiment. Ground samples (500 g) were put into cotton bags and autoclaved at 262°F for 0, 5, 10, 15, 30, 45, and 60 min at 29 PSI. This was done to simulate varying degrees of heat processing. A total of 2 samples per treatment were autoclaved in 3 separate blocks. The duplicate samples were divided and analyzed using NIRS and official analytical analysis (wet chemistry). Crude protein (CP), total lysine (Lys), Lys:CP, available Lys, available Lys:total Lys, protein solubility in potassium hydroxide (KOH), trypsin inhibitor activity (TIA), urease activity index (UAI), individual amino acids (AA), and total AA were analyzed to determine the degree of processing using official analytical methods. The correlation coefficient (R) and coefficient determination (r2) between NIRS and official analytical methods were established for CP, total Lys, available/reactive Lys, Lys:CP and available/reactive Lys:total Lys. Data were analyzed using the SAS (v. 9.4, SAS Institute Inc., Cary, NC) GLIMMIX procedure and the CORR procedure to determine the degree of association of NIRS and official analytical analysis. When measured using official analytical methods, CP, total AA, Ala, Asp, Glu, Gly, Iso, Leu, and Val decreased (linear, P \u3c 0.05), whereas available/reactive Lys:total Lys, Lys:CP, available Lys, KOH, trypsin inhibitor, urease, Lys, and Cys decreased (quadratic, P \u3c 0.05) with increasing exposure time to the autoclave. There was a positive correlation between official analytical and NIRS results for CP, Lys:CP, available Lys:total Lys, total AA, Ala, Cys, Lys, and a negative correlation for Thr. A linear model was best fit (P = 0.011, r2 = 0.489) to predict CP using NIRS. A quadratic model was best fit to use NIRS total Lys (P = 0.011, r2 = 0.969), reactive Lys (P = 0.001, r2 = 0.988), and their ratio (P = 0.001, r2 = 0.981) to predict official analytical results. In conclusion, increasing soybean autoclave exposure time decreased soybean meal quality as measured by crude protein, total Lys, Lys:CP, available Lys, available Lys:total Lys, KOH solubility total AA, and additional AA. In addition, regression models were successful at using NIRS for Lys, reactive Lys, Lys:CP, and reactive Lys:total Lys to predict official analytical results

Effect of Mill Type and Particle Size Variation on Growth Performance and Carcass Characteristics of Finishing Pigs

The objective of this experiment was to determine the effects of mill type used to grind corn and its particle size variation on diet flowability and subsequent finishing pig growth performance and carcass characteristics. A total of 200 pigs (DNA Line 241 × 600; initially 121.9 lb) were used in a 75-d growth trial. Pigs were randomly assigned to pens with either 5 barrows or 5 gilts per pen. Pens were then randomly allotted to 1 of 4 treatments balanced by weight and gender with 10 pens per treatment. Treatments were arranged as a 2 × 2 factorial with 2 mill types (3-high roller mill; RMS, Model 924 or a hammermill; Bliss, model 22115) and 2 particle size variations (standard vs. blended). Increasing corn particle size variation was accomplished by blending 30% 400 μm corn, 40% 600 μm corn, and 30% 800 μm corn. Standard treatments were accomplished by grinding corn to an average of 600 μm with either mill. On d 75, pigs were transported to a commercial packing plant for processing and determination of carcass characteristics. The average analyzed complete diet mean particle sizes and standard deviations were 497, 540, 503, and 520 μm and 2.70, 2.75. 3.35, and 3.35 for the roller mill standard, roller mill blended, hammermill standard, and hammermill blended treatments, respectively. Diet flowability was calculated using angle of repose (AoR), percent compressibility, and critical orifice diameter (COD) measurements to determine the composite flow index (CFI). The AOR were 34.2, 33.0, 35.4, and 36.2º; COD were 32.0, 31.3, 30.0, and 33.0 mm; compressibilitys were 18.7, 18.4, 17.0, and 15.7%; and CFI were 52.9, 55.4, 53.9, and 53.2 for the roller mill standard, roller mill blended, hammermill standard, and hammermill blended treatments, respectively. There were no interactions or main effects of mill type on growth performance or carcass characteristics. However, pigs fed the blended diets had marginally significant decreased (P \u3c 0.083) average daily gain (ADG) compared to those fed the standard diets. No differences were observed in total feed cost or cost per lb of gain between treatments. Pigs fed blended diets also had marginally decreased (P \u3c 0.059) gain value and income over feed costs (IOFC) compared to those fed diets that were not blended. In conclusion, mill type used to grind corn and increasing particle size variation did not impact flowability metrics of complete diets. Mill type used to grind corn did not influence performance of finishing pigs, while increasing particle size variation by blending various particle sizes of corn led to a marginal reduction in ADG, gain value, and IOFC

Effect of Steam Pressure and Conditioning Temperature During the Pelleting Process on Phytase Stability

This experiment was designed to evaluate the effects of steam pressure and conditioning temperature on the stability of microbial phytase. Treatments were arranged as a 2 × 3 factorial of steam pressure (24 and 44 psi) and conditioning temperature (170, 180, and 190°F). Phytase was added to a corn-soybean meal-based diet and mash samples were collected for phytase analysis. The diet was pelleted via steam conditioning (10 × 55 in Wenger twin staff pre-conditioner, Model 150) and using a pellet mill (CPM Model 1012-2) with a 3/16 × 1 1/4 in pellet die (L:D 6.7). Conditioner retention time was set at 30 sec and production rate was set at 33 lb/min, approximately 100% of the rated throughput for the pellet mill. All treatments were replicated on 3 separate days. For each treatment, pellet and conditioned mash samples were composited such that 2 samples of each were analyzed for phytase activity and pellet durability index (PDI). Moisture analysis was conducted on initial mash, conditioned mash, hot pellet, and cooled pellet samples. Conditioning temperature, hot pellet temperature (HPT), and production rate were recorded throughout each processing run. Data were analyzed using the GLIMMIX procedure in SAS 9.4, with pelleting run as the experimental unit and day as the blocking factor. There was no evidence (P \u3e 0.17) for a steam pressure × conditioning temperature interaction for HPT, phytase stability, moisture, or PDI. Increasing conditioning temperature from 170 to 190°F increased (linear, P \u3c 0.01) HPT. There was no evidence for difference (P = 0.80) in HPT between steam pressures. Phytase stability of conditioned mash decreased (linear, P \u3c 0.01) with increasing conditioning temperature. In cooled pellets, phytase stability decreased (linear, P \u3c 0.01) with increasing conditioning temperature. Cooled pellets tended (P = 0.08) to have greater phytase stability when steam pressure was set at 44 psi compared to 24 psi. Moisture of conditioned mash and pellets increased (linear, P ≤ 0.05) with increasing conditioning temperature, and PDI tended (linear, P = 0.06) to increase with increasing conditioning temperature. There was no evidence (P \u3e 0.35) that steam pressure affected feed moisture or PDI. Results of this experiment show that phytase stability in conditioned mash and pellets decreases linearly when the conditioning temperature rises above 170°F and HPT above 179°F. As expected, HPT increased and feed moisture tended to increase with increasing conditioning temperature. Increasing steam pressure from 24 to 44 psi resulted in tendencies for greater phytase stability in pellets and had no effect on HPT or feed moisture