The Influence of Age and Winter Environment on Protein Block Intake Behavior of Beef Cattle Winter Grazing Mixed-Grass Rangelands

This study evaluated the influence of cow age and temperature adjusted for windchill (Twindchill) on supplement intake behavior of cattle winter grazing rangelands. A mixed-age herd of Angus-based cows (291 and 316 in year 1 and 2, respectively) were classified by age (1-, 2-, 3-, 4-, 5–7-, and ≥8-year-old) and grazed rangeland pasture (329-ha) for two consecutive winters. Cows were provided free-choice access to supplement protein blocks in a SmartFeedPro self-feeder system. An Onset HOBO Weather Station collected data throughout the grazing period. Supplement intake (expressed as kg∙d−1 and g∙kg body weight−1), the coefficient of variation in supplement intake and intake rate (g∙min−1) displayed Twindchill × cow age × year interactions (p ≤ 0.02). In general, cow age displayed a quadratic effect on all supplement intake variables (p ≤ 0.04), where 3- to 4-year-old cattle had the greatest supplement intake with the least variation, while yearling cattle had the least amount of supplement intake and the greatest variation. In conclusion, winter environmental conditions interacted with cow age to affect cattle supplement intake behavior and, consequently, the efficacy of nutrient delivery systems for beef cattle winter grazing on rangelands.

285 Supplement intake variation, weight, and body condition change in yearling heifers grazing late-summer dryland pastures with Rumax BoviBox versus Rumax BoviBox HM protein supplements

The objectives of this study were to evaluate Rumax BoviBox versus Rumax BoviBox HM protein supplements on supplement intake behavior, body weight (BW), and body condition score (BCS) change of yearling heifers grazing dryland pastures during late summer. Fifty-nine yearling commercial Angus heifers (428 kg) were stratified by BW and randomly assigned to one of two supplementation treatments: 1) free-choice access to Rumax BoviBox protein block supplement (30% CP, 23% salt; n = 29); and 2) free-choice access to Rumax BoviBox HM high magnesium protein block supplement (28.7% CP, 23% salt; n = 30). Individual supplement intake, time spent at the feeder, and intake variation were measured throughout the study. On d 0, 42, and 84 heifers were weighed and assigned a BCS following a 16-h shrink. Additionally, forage was sampled every 14 d throughout the study. Supplement intake (kg ∙ d-1) displayed a treatment × period interaction (P < 0.01). However, within period, treatment differences were not observed with intakes averaging 0.15 and 0.34 kg ∙ day-1 for d 0 – 42 and 42 - 84, respectively. Heifers spent more time at the feeder in period 2 than in period 1 (P < 0.01), averaging 7.67 vs 4.00 min per day, respectively. Supplement intake rate (g ∙ min-1) also displayed a treatment effect (P < 0.01) indicating that heifers in the Rumax BoviBox treatment had lower intake rate compared to Rumax BoviBox HM supplemented heifers. In conclusion, there were only minor differences in intake behavior and animal performance with the Rumax BoviBox and Rumax BoviBox HM supplement treatments. However, supplement intake increased and variation in intake decreased with declining forage quality and quantity.

113 Mineral Supplementation Effects in Stocker Cattle Performance Grazed on Wheat Seeded Native Pastures

One way to extend the grazing season in the southeast United States is to plant cool-season forages into native pastures to provide additional forages for the winter and spring grazing. The objective of this study was to evaluate the effects of two different medicated (Monensin) supplementation types, with or without protein, on stocker calves grazing native pasture overseeded with wheat through the months of February to May. Cross-bred steers (n = 36; BW = 291.76 kg ± 29.92) and heifers (n = 29; BW = 288.17 kg ± 25.22), sired primarily by Hereford bulls, were assigned to two treatment groups at two locations blocked by sex and weight. All mineral supplementation was provided ad libitum. The first supplementation consisted of a commercial loose mineral (Advanced Mineral Performance Technology (AMPT); ADM; Quincy, Illinois), and the second was a commercial protein block (MoorMan’s, Mintrate Blonde Block RU; ADM; Quincy, IL) containing 42.0% Crude Protein. Average Daily Gain was compared using PROC MIX with the main effects: treatment, pasture, gender, and their interactions. The starting weights of the treatment groups were not different (P = 0.996). No significant interactions (P < 0.05) were detected and only the main effects will be reported. Steers gained more (P < 0.0001) than heifers (1.25 kg ± 0.025 kg vs. 0.96 kg ± 0.029 kg, respectively). ADG for the mineral was 1.14 kg ± 0.027 kg, compared to 1.06 kg ± 0.028 kg for the protein block (P < 0.05). Differences in ADG was observed between pastures (P < 0.07). At 124 days the final body weight of heifers averaged 119.56 kg and the steers averaged 154.70 kg. These results indicate that the mineral improved ADG over the block supplementation.

PDB-2-PBv3.0: An updated protein block database

Our protein block (PB) sequence database PDB-2-PBv1.0 provides PB sequences and dihedral angles for 74,297 protein structures comprising of 103,252 protein chains of Protein Data Bank (PDB) as on 2011. Since there are a lot of practical applications of PB and also as the size of PDB database increases, it becomes necessary to provide the PB sequences for all PDB protein structures. The current updated PDB-2-PBv3.0 contains PB sequences for 147,602 PDB structures comprising of 400,355 protein chains as on October 2019. When compared to our previous version PDB-2-PBv1.0, the current PDB-2-PBv3.0 contains 2- and 4-fold increase in the number of protein structures and chains, respectively. Notably, it provides PB information for any protein chain, regardless of the missing atom records of protein structure data in PDB. It includes protein interaction information with DNA and RNA along with their corresponding functional classes from Nucleic Acid Database (NDB) and PDB. Now, the updated version allows the user to download multiple PB records by parameter search and/or by a given list. This database is freely accessible at http://bioinfo.bdu.ac.in/pb3 .

PSI-27 Excretion of purine derivatives and rumen microbial protein synthesis in Nelore steers supplemented with low-moisture, sugarcane molasses-based block and fed low-quality forage

The objective of this study was to determine the effects of supplementation of low-moisture, sugarcane molasses-based block (LMB) on steers fed low quality forage in the excretion of purine derivatives and in the synthesis of ruminal microbial protein. Six rumen cannulated Nellore steers steers (23 months, 350 ± 10 kg) were distributed in a 3 × 3 double Latin square design. The treatments were composed of Brachiaria brizantha ‘Marandu’ hay ad libtum as an exclusive source of bulky (93.65% DM, 3.97% CP and 81.76% NDF) and supplements: complete mineral blend with urea [UR, (urea, salt, mineral-vitamin premix)], a commercial protein supplement [PS, (corn grain, soybean meal, urea, salt and mineral-vitamin premix)] or low-moisture, cooked sugarcane molasses-based protein block [LMB, (cane molasses, cottonseed meal, soybean oil, urea, salt and mineral-vitamin premix)]. Each experimental period lasted 21 days (14 days of adaptation and 7 days of data collection). The total urinary volume was measured for five days in each experimental period. The urine was collected in rubber funnels fixed by elastic loops on the backs of the animals. The urine was conduct through hoses connected to a 20 L polyethylene bucket containing 250 mL of 20% H2SO4 solution. Every 24 hours, the collected urine was homogenized and the total excreted volume was measured. The data were analyzed using Software R, having as fixed effect the treatments and as animal random effect, period, Latin square and error. Supplementation with LMB lead to greater excretion of allantoin (P = 0.046), microbial nitrogen flow (P = 0.023) and higher microbial crude protein (P = 0.023) into the intestine compared to UR and PS. While no effect was observed on total purines and purines absorbed (P > 0.05). Thus, LMB supplementation for rumen cannulated Nellore steers fed low quality forage was effective to improve metabolizable protein supply.

PSI-28 Effect of supplementation with low-moisture, sugarcane molasses-based block on intake and ruminal volatile fatty acid profile on steers fed low quality forage

We evaluated the effects of supplementation of molasses based on low moisture molasses (LMB) on steers fed low quality forage in DM intake and ruminal VFA. Six rumen cannulated Nellore steers (23 months, 350 ± 10 kg) were distributed in a 3 × 3 double Latin square design. The treatments were composed of Brachiaria brizantha cv. Marandu ad libtum as an exclusive source of bulks (93.65% DM, 3.97% CP and 81.76% NDF) and supplements: complete mineral blend with urea [UR, (urea, salt, mineral-vitamin premix)], a commercial protein supplement [PS, (corn grain, soybean meal, urea, salt, and mineral- vitamin premix)] or protein block based on low-moisture cooked sugarcane molasses [LMB, (cane molasses, cottonseed meal, soybean oil, urea, salt and mineral-vitamin premix)]. Before subsequent feeding, samples of orts were collected to monitor the daily intake. After 14-d adaptation period, rumen fluid samples were collected in each experimental period at 0, 2, 4, 6, 8, 10, 12 and 14 h after feeding, to evaluate concentrations of VFA, which was determined by gas chromatography. The data were analyzed using Software R, with measures repeated in time for VFA and having as fixed effect the treatments and as animal random effect, period, Latin square and error. The intake of hay (P = 0.024), total DM (g/day, P = 0.001), NDF (P = 0.027) and supplement (P < 0.001) was higher for animals supplemented with PS. The total VFA and acetate ratio were not affected by the treatment (P > 0.05). The propionate ratio was higher for LMB (P = 0.016). The butyrate ratio (P = 0.005), valerate (P = 0.010) and A:P ratio (P = 0.017) was higher when the animals were supplemented with PS. The results indicate that the use of LMB improves propionate ratio and decrease the acetate:propionate ratio for steers fed low quality forage.

PSII-3 Effect of molasses-based block supplementation on cattle fed endophyte-infected Tall Fescue (Festuca arundinacea) seed

Ergot-alkaloid toxicosis induces persistent vasoconstriction in cattle, interfering with efficient thermoregulation. Our objective was to evaluate impact of cooked molasses-based block supplements (MBS) on performance and physiological measurements in cattle fed ergot-containing Tall Fescue seed (TFS). Crossbred steers (n = 95; 287 ± 6.4 kg) were blocked by body weight, randomly assigned to individual indoor feeding pens and treatments consisting of: Negative Control (NC; prairie hay only); Positive Control (PC; hay plus TFS); and molasses block treatments fed hay and TFS with ad libitum access to a 38% protein block (CB); 38% protein block containing 0.3% crystalline menthol (MB); or a 38% protein block containing a proprietary blend of mannan oligosaccharide and capsaicin (AB). The TFS was mixed with molasses (9:1), and amount fed was increased gradually at 3-d intervals from 45 to 520 g/animal daily by day 42. Temperature differential between ocular conjunctiva and ear tip (ΔT) was determined weekly using thermographic imaging. Coccigeal vein diameter (CVD) was measured with Doppler ultrasound imaging (DU) on days 63 and 84. Data were analyzed as mixed models with block as a random effect and treatment, time, and treatment by time interaction as fixed effects. Block intakes did not differ among MBS treatments (P > 0.05). Cattle fed MBS had greater ADG, DMI, gain:feed (P < 0.01) compared to NC and PC. For the second half of the study MBS treatments had lower ΔT (P < 0.05). Supplementing cooked molasses-based block supplements low-moisture molasses block can improve performance and potentially enhance peripheral blood irrigation in cattle consuming ergot-infested feeds.