Low-Intensity, High-Frequency Grazing Strategy Increases Herbage Production and Beef Cattle Performance on Sorghum Pastures

We assessed the effects of high-intensity and low-frequency (HILF) vs. low-intensity and high-frequency (LIHF) grazing on herbage production and performance of beef cattle grazing sorghum pastures. The experimental design was a complete randomized block with two treatments and four replicates (paddocks), carried out in 2014/15. The management target of 50 and 30 cm for pre- and post-grazing, respectively, a LIHF grazing management strategy oriented to maximize beef cattle herbage intake per unit time, was compared with a HILF grazing management strategy of 80 and 20 cm for pre- and post-grazing, respectively, aiming to maximize herbage accumulation and harvest efficiency. Sixteen Brangus steers of 15-month-old and 265 ± 21 kg of live weight (LW) were randomly distributed to paddocks (experimental units). The LIHF resulted in shorter rest periods when compared with the HILF. The greater leaf lamina mass in LIHF allowed greater sward light interception at post-grazing, resulting in greater total herbage production than HILF (7581 and 4154 kg DM/ha, respectively). The average daily gain (ADG) of steers was greater for the LIHF than for the HILF treatment (0.950 and 0.702 kg/animal, respectively); however, even with a greater stocking rate in the HILF, there was no difference for LW gain per ha, with an average of 4 kg LW/ha/day. Our findings demonstrated that the LIHF strategy that is based on offering to the animals an optimal sward structure to favor the maximum herbage intake rate fosters greater herbage production, harvesting efficiency, and ADG without compromising LW gain per area of beef steers, despite the lower herbage harvested per stocking cycle.

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.

Effect of Post-grazing Sward Height on Ingestive Behavior, Dry Matter Intake, and Milk Production of Holstein Dairy Cows

Sward height is strongly related to the daily dry matter intake of grazing dairy cows, which consequently determines animal performance. Despite that, few studies have explored the potential to increase milk production by managing post-grazing sward height. An experiment was carried out to evaluate the effect of three defoliation intensities on a Lolium arundinaceum-based pasture on frequency and length of grazing meals and ruminating bouts, daily grazing and ruminating time, feeding stations and patches exploration, and dry matter intake and milk production of dairy cows. The treatments imposed were three different post-grazing sward heights: control (TC), medium (TM), and lax (TL), which were managed with 6, 9, and 12 cm of post-grazing sward heights during autumn and winter, and 9, 12, and 15 cm of post-grazing sward heights during spring, respectively. Thirty-six autumn-calving Holstein cows were grouped by parity (2.6 ± 0.8), body weight (618 ± 48) kg, and body condition score (2.8 ± 0.2) and randomized to the treatments. The pasture was accessed from 08:00 to 14:00 and 17:00 to 03:00 during spring and no supplement was involved during the evaluation period. Daily grazing time averaged 508 ± 15 min and was not affected by treatment. The reduction of post-grazing sward height increased the length of the first grazing session in the morning and the afternoon. The number of grazing sessions was greater on TL than on TM, with no difference in TC. The number of feeding stations (the hypothetical semi-circle in front of an animal from which the bites were taken without moving the front forefeet) visited was less on TC than on TL, and neither of them differed from TM. Dry matter (DM) intake was lesser on TC than on TM and TL (14.7 vs. 17.8 kg DM). Milk production during the evaluation period was 13.1, 16.2, and 18.7 kg/day for TC, TM, and TL, respectively. The milk fat, protein, and lactose content did not differ between treatments. The cows on TC exhibited a lower intake rate, although they were less selective, probably as a consequence of the sward structure of TC treatment. The cows on TM adopted a compensation mechanism which allowed them to achieve the same dry matter intake as cows on TL, but lower milk production. The cows on TL were more selective than TC and TM resulting in higher digestible dry matter intake and consequently higher milk production. The intensity of defoliation impacts on the animal-plant interaction, and constitutes a valuable management tool that can be used to boost forage intake and milk production. The new developments on information technology would allow researchers to link behavioral data with response variables (e.g., milk production, health, welfare, etc.) at different spatio-temporal scales and support short and long-term management decisions.

Feed intake, nutrient digestibility, and selected rumen parameters in feedlot bulls fed diets with different feed additives

An experiment was conducted to evaluate the feed intake, nutrient digestibility and selected rumen parameters in feedlot bulls fed diets containing different feed additives. Six rumen-cannulated Nellore bulls (age = 8 ± 1.0 months; initial BW = 225 ± 13.2 kg) were distributed in a 6 × 6 Latin square design. Six experimental diets based on 30% corn silage and 70% concentrate on a dry matter (DM) basis were evaluated. Diets differed in feed additive on a DM basis, as follows: 1.4% bicarbonate and magnesium oxide in 3:1 ratio (BOX); 36 ppm lasalocid sodium (LAS); 30 ppm monensin sodium (MON); 25 ppm virginiamycin (VIR); 30 ppm monensin sodium plus 25 ppm virginiamycin (MV); and 3.15% commercial mineral supplement containing D-limonene and exogenous α-amylase (EOA). The experiment lasted 144 d, with six periods of 24 d. Each period consisted of 14 d for dietary adaptation, 3 d for feces and urine collection, and 7 d for omasal and ruminal digesta collection. Bulls fed the BOX diet showed greater (P < 0.05) intake of DM, organic matter (OM), neutral detergent fiber (apNDF), crude protein (CP), and starch compared to the other diets. Diets with LAS, MON, VIR, MV, or EOA did not influence (P > 0.05) the DM, OM, apNDF, CP, or starch intake of feedlot bulls. Bulls fed the EOA diet showed greater (trend; P = 0.09) ruminal digestibility of starch compared to the other diets. The feed additives did not affect (P > 0.05) the intestinal or total tract digestibility of starch, rumen pH, microbial efficiency, total rumen fluid, dilution rate, rate of intake, rate of degradation, or passage rate of the DM, OM, apNDF, and starch. In conclusion, LAS, MON, VIR, MV, and EOA diets reduced nutrient intake compared to BOX. Although all feed additives presented similar effects on rumen pH, temperature, and kinetics the presence of exogenous α-amylase in the EOA diet may increase ruminal starch digestibility and apparent total tract digestibility of DM and OM.

Impact of salt intake on inflammation markers in cardiovascular disease: a retrospective observational case-control study

Background. Salt intake currently poses a serious threat due to the cardiovascular challenge incurred by excessive sodium consumption.Objectives. The identification of markers associated with high salt intake in hypertensive patients.Methods. A retrospective observational case-control study surveyed 251 persons, including 194 hypertensive patients with stable salt intake. The intake was assessed in the “Charlton: SaltScreener” questionnaire. General, biochemical blood panels and interleukin levels (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-18) were evaluated in the outcome of medical examination. Statistical data processing was performed with R using the RStudio software.Results. The mean patient age in survey was 72.47 ± 9.8 years, women prevailed in the selected cohort (n = 151, 60.1%). All patients were assigned in cohorts by the daily salt intake rate, ≤5 g (n = 12), 6–10 g (n = 144), >10 g salt per day (n = 38). The largest cohort (74.2%) united patients consuming 6–10 g salt per day, whereas only 6.2% patients consumed salt <5 g/day. Final analysis included patients consuming ≥6 g/day and having a C-reactive protein (CRP) level <20 mg/L. The analysis elicited an association between the monocyte count, CRP and salt intake towards the statement that higher salt intake leads to higher monocyte counts at CRP <20 mg/L in blood. Modelling revealed a close monocyte count–salt intake relationship, with a low-to-high intake transition sharply increasing the probability of elevated absolute monocyte count in blood provided the CRP level is <20 mg/L.Conclusion. The study infers a direct relationship between salt intake >10 g/day and blood monocyte count. However, its significance ceases at CRP rising to ≥20 mg/L.

14 Genome-wide Association Studies of Disease Resilience Traits from a Natural Polymicrobial Disease Challenge in Pigs

Infectious diseases cause tremendous financial loss in the pork industry, emphasizing the importance of disease resilience, which is the ability of an animal to maintain performance under disease. The objective of this study was to identify quantitative trait loci (QTL) for disease resilience based on both univariate and bivariate genome-wide association studies (GWAS). Data used were late nursery and finisher growth rates and clinical disease phenotypes, including medical treatment and mortality rates, subjective health scores, feed and water intake traits and carcass traits, collected on 50 batches of 60 or 75 crossbred (LRxY) barrows under a polymicrobial natural disease challenge. Multiple QTL were detected for all traits. The major histocompatibility complex (MHC) region (22–25 Mb on chromosome 7) was found to be associated with multiple traits, including late nursery and finisher growth rates, average daily feed intake and intake rate, average daily water dispensed, water intake duration, and number of visits to the drinker. The MHC region explained ~13% of genetic variance for late nursery growth rate. Further fine mapping identified four QTL in the MHC region for late nursery growth rate that spanned the class I, II, and III regions. Gene set enrichment analyses found genomic regions associated with resilience phenotypes to be enriched for previously identified disease susceptibility and immune capacity QTL, for genes that were differentially expressed following bacterial or virus infection and immune response, and for gene ontology terms related to immune and inflammatory response. In conclusion, MHC and other QTL identified play an important role in host response to infectious diseases and can be incorporated in selection to improve disease resilience. Funded by Genome Canada, Genome Alberta, USDA-NIFA, and PigGen Canada.

PSXV-8 The study of feeding behavior traits in connection to feed efficiency in duroc boars bred in Russia

The study of feeding behavior is of particular interest because it is directly related to efficiency of feeding. The aim of our study was to determine the genetic parameters of the feeding behavioral traits in Duroc boars (n = 766) in relation to the feed efficiency based on the analysis of variation components. Genstar and Shauer feeders were used to collect the behavioral data, including daily feed intake (DFI), total daily time spent in feeder (TPD), number of daily visits to feeder (NVD), average duration of each visit (TPV), feed intake per visit (FPV), and feed intake rate (FR). Genetic and environmental variabilities were determined by the mixed model equation using the REMLF90 program. Multiple regression analyses were used to adjust feed conversion rate (FCR) for the duration of the testing period, initial and final body weight, and average daily gain. The average initial body weight was 35.7 kg and the duration of testing period was 78.1 days. Actual FCR values reached 2.20 kg/kg with a phenotypic variability of 26.3%. Moderate values of heritability coefficients (h2) were observed for TPV (h2=0.168), FCR (h2=0.214), and DFI (h2=0.221) traits. The heritability parameters for FPV and TPD traits were higher and accounted to 0.269 and 0.290, respectively. The highest value of h2 was observed for NVD (0.494). Analyses of genetic correlations revealed several interesting findings. The boars, which more often visited feeding stations, spent more time in feeder (r2=+0.536 for NVD/TPD), herewith duration of each visit and feed intake rate were decreased (r2=–0.593 and –0.760 for NVD/TPV and NVD/FR, respectively). Feed conversion rate was positively correlated with TPD (r2=+0.530) and negatively correlated with FR (r2=–0,772). Our research results will be useful for development of artificial selection programs to select Duroc pigs for increased feeding efficiency. The study was supported by RFBR No19-316–90008.

Herbage mass and allowance and animal genotype affect daily herbage intake, productivity, and efficiency of beef cows grazing native subtropical grassland

The beef sector in Campos grasslands must increase animal productivity without external inputs while reducing environmental impact. The objective of this study was to estimate herbage intake [g/metabolic body weight (MBW)/d] of straightbred (Hereford/Angus) and crossbred (F1 of Hereford x Angus) beef cows grazing subtropical native grassland with High and Low herbage allowance (HA, 5 vs 3 kg DM/kg BW) during gestation and lactation and its relationship with biological efficiency of cow-calf productivity. Herbage intake (estimated via n-alkanes C32:C33 ratio) was measured during early (Ge1, -163 d prior calving) and mid to late [Gm1 (-83) and Gm2, (-90 d prior calving)] gestation and lactation (L0, L1 and L2, 60, 47 and 31d following calving) periods in 24-36 cows, selected to create 8 groups (4 per block) of HA x cow genotype treatment. Cows grazed native grassland year-round, under High and Low HA (except in winter). We analyzed the effect of cow genotype (straightbred vs. crossbred cows) and HA (High vs. Low) on herbage mass and height, daily herbage intake rate (DMI), cow body condition score (BCS), calf average daily gain (ADG) and body weight at weaning (BWW) and g of calf weaned/kg DMI. High allowance improved DMI during lactation periods (High 115.6 vs Low 94.1±5.3 P&lt;0.05 g/MBW/d). Crossbred cows decreased DMI during gestation (crossbred 81 vs. straightbred 94±4.3 P=0.05 g/MBW/d) compared to straightbred cows. Crossbred and High HA improved biological efficiency, 40.0 vs. 26.2 and 36.0 vs. 29.7 g of calf/kg DMI respectively. High allowance increased herbage mass and sites with greater canopy height which allow greater DMI, positively associated with cow BCS at weaning, calf ADG, BWW, and g of calf/kg DMI. Crossbred cows reduced DMI during gestation showing no greater annual DMI. Animal productivity and biological efficiency can be improved using High HA and crossbred cows, which should decrease the environmental impact of cow-calf systems.

Supplement intake in half-marathon, (ultra-)marathon and 10-km runners – results from the NURMI study (Step 2)

The primary nutritional challenge facing endurance runners is meeting the nutrient requirements necessary to optimize the performance and recovery of prolonged training sessions. Supplement intake is a commonly used strategy by elite and recreational distance runners to meet nutritional recommendations. This study was conducted to investigate the patterns of supplement intake among different groups of distance runners and the potential association between supplement intake and sex, age, running and racing experiences.In a cross-sectional design, from a total of 317 runners participating in this survey, 119 distance runners were involved in the final sample after data clearance, assigned into three groups of 10-km runners (n = 24), half-marathoners (n = 44), and (ultra-)marathoners (n = 51). Personal characteristics, training and racing experiences, as well as patterns of supplement intake, including type, frequency, and dosage, were evaluated by questionnaire. Food Frequency Questionnaire was implemented to assess macronutrient intake. ANOVA and logistic regression were used for statistical analysis.While 50 % of total distance runners reported consuming supplements regularly, no differences between distance groups in consumption of carbohydrate/protein, mineral, or vitamin supplements were observed (p > 0.05). In addition, age, sex, running and racing experience showed no significant association with supplement intake (p > 0.05). Vitamin supplements had the highest intake rate in runners by 43 % compared to minerals (34 %) and carbohydrate/protein supplements (19 %).The present findings provide a window into the targeted approaches of long-distance runners as well as their coaches and sport nutrition specialists when applying and suggesting sustainable nutritional strategies for training and competition.Trial registration: ISRCTN73074080. Retrospectively registered 12th June 2015.