Comparative evaluation of effect of legume type on feed intake among dairy cows fed maize (Zea mays) stover treated with groundnut (Arachis hypogea) and soybean (Glycine max) stover

This study evaluated the use of maize, groundnut and soybean stover in cattle feeding. The study assessed the value of upgrading the quality of crop residues. The study involved evaluation of palatability of maize stover improved using urea (U), chopped groundnut stover (cGS), chopped soybean stover (cSS), mineralized groundnut stover solution (mGS) and mineralized soybean stover solution (mSS). In the feeding trial, twelve (12) crossbred dairy cows in their second parity were used as experimental units. A 22 factorial experiment within a Completely Randomised Design (CRD) was used. Maize stover was chopped before being mixed with urea, chopped legume stover and mineralized legume stover solutions. The effect of supplementation using maize stover upgraded with U, cGS, cSS, mGS and mSS was studied for supplement intake levels. Urea Ensilage Treatment (UET) was used as the novel therapy in the study. Both legume type and processing method had influence on supplement intake of maize stover. Groundnut stover had significantly (p˂0.05) higher (0.99kg/day, se=0.04) effect on supplement intake of maize stover than soybean stover(0.83kg/day, se=0.04). The use of mineralized legume stover solution proved significant (p˂0.05) to the use of chopped legume stover in improving the intake of maize stover. Results have indicated that intake was highest (1.01kg/day, s.e=0.04) for mineralised groundnut stover solution and lowest (0.67kg/day, s.e=0.04) for Urea Ensiling Treatment.

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.

Lutein and Zeaxanthin Distribution in the Healthy Macula and Its Association with Various Demographic Factors Examined in Pseudophakic Eyes

The macular pigment consisting of lutein (L) and zeaxanthin (Z) protects photoreceptors via its antioxidative and barrier activities. This study aimed to determine L and Z distribution in the healthy macula and their association with various demographic factors. Macular pigment optical density (MPOD) was measured using fundus autofluorescence spectroscopy in 352 pseudophakic eyes with no fundus diseases. Pseudophakia was chosen to avoid the influence of cataract in the measurement of fundus autofluorescence. The mean patient age was 72.3 ± 8.6 years. MPOD was analyzed separately in three zones, i.e., A: a central area within a radius of 0.5°, mainly containing Z; B: a ring area with radii from 0.5° to 1.3°, containing Z and L; C: a ring area with radii from 1.3° to 9°, containing L. Multivariate analyses were performed with MPOD as the dependent variable and sex, supplement intake, smoking habits, glaucoma, diabetes, age, body mass index (BMI), skin carotenoid levels, retinal thickness, retinal volume, axial length as the independent variables. The mean total MPOD volume within 9° eccentricity was 20,121 ± 6293. Age was positively associated with MPOD in all zones. Supplement and BMI were positively and negatively associated with MPOD in zones B and C. Smoking was negatively associated with MPOD in zone A. This study revealed the standard MP values of aged Japanese, which resulted to be higher than the previously reported values in other races. Age was found to have a positive association with MP values. L in the outer foveola was affected by BMI and supplements, but Z in the foveola was not. The amount of Z in the Müller cell cone may not be changed easily by factors such as hunger and satiety in the context of preservation of homeostasis in the human body, but tobacco had a negative effect on Z.

Impacts of Rumen Degradable or Undegradable Protein Supplementation with or without Salt on Nutrient Digestion, and VFA Concentrations

The objectives of this study were to evaluate the effect of differences in protein type and delivery method on rumen dynamics and nutrient digestion. Cows were allotted to rumen degradable protein (RDP) or rumen undegradable protein (RUP) and self-fed (SF) salt-limited pressed blocks or hand-fed (HF) loose supplement, resulting in four dietary treatments. There was a delivery effect (p = 0.04) on neutral detergent fiber (NDF) intake, as the SF animals consumed more NDF than HF animals. The RDP-SF animals had greater NDF digestibility (p = 0.04) and water intake (p = 0.03) than the three other treatments. Supplement intake displayed a protein type effect (p = 0.03), as RDP-supplemented animals consumed more supplement on a g·kg body weight (BW)−1 d−1 basis than RUP animals. There was an effect of protein type (p = 0.02) and delivery method (p = 0.03) on fluid flow rate, with RUP and HF cows having greater liquid flow rates. Ruminal pH was lower (p < 0.01) in RDP-HF cows than RDP-SF cows at all hours, except 4-h post-feeding. RDP-SF animals had the greatest (p < 0.01) concentrations of ruminal ammonia. Valerate ruminal concentrations were greater (p = 0.04) in RDP supplemented animals compared to RUP supplemented animals. In conclusion, self-fed supplements containing RDP may enhance the use of low-quality forages and increase ruminal ammonia concentrations.

283 Precision versus Group Supplementation at Two Levels on Growth and Development of Replacement Heifers

Two experiments were conducted to evaluate use of the Super SmartFeeder (SSF; C-Lock, Inc.) for individual versus group supplementation of heifers grazing stockpiled, novel tall fescue. In experiment 1, Angus heifers (n = 64; 267 + 31.7 kg) had access to the SSF and were allowed 3.6 kg/d of grower supplement. Individual intake was recorded daily and analyzed to determine adoption. Twenty-four percent of the heifers did not adopt to individual SSF supplementation (P &lt; 0.05). In experiment 2, heifers (n = 64; BW= 275 + 31.3 kg) were allotted, based on adoption to SSF, to supplementation system of group feeding (n = 2 reps/level; GRP) or SSF precision feeding (n =16/level; PRE) at two levels (0.5% or 1% of BW) for 127-d in a 2 x 2 factorial. Data were analyzed using Mixed procedure. The interaction between supplementation level and feeding system tended to be significant (P = 0.10) for overall ADG. Average daily gain was greater for 1% BW than 0.5% BW (0.81 vs. 0.47 kg/d) for PRE but did not differ for GRP (0.69 kg/d). Daily supplement dry matter intake differed (P &lt; 0.05) by supplementation level and total BW gain was greater (P &lt; 0.05) by 24.3 kg for 1% versus 0.5% supplementation level. Ultrasound ribeye area and fat thickness measures were greater (P &lt; 0.05) for 1% BW supplement compared to 0.5% BW at the end of the 127d study. When PRE was analyzed independently, heifer BW differed (P &lt; 0.05) on d 91, 117 and 127 between supplement levels. The correlation between individual heifer daily supplement intake and overall ADG for PRE was 0.68 (P &lt; 0.0001). The use of technology to precisely control intake in a grazing system created greater divergence in growth by supplementation level compared to group feeding systems.

PSX-A-6 Late-Breaking: Conventional vs Heritage cattle supplement intake, weight-gains, and body condition scores on Chihuahuan desert pasture

Use of adapted beef cattle biotypes is gaining momentum as a novel management strategy for limiting the environmental footprint of ranching and adapting to climate change in the southwest. We compared supplement intake (SI), calf birthweights, cow weights, and body condition scores (BCS) of desert-adapted Brangus (BR; n = 15) vs. Raramuri Criollo (RC; n = 28) cows in four adjacent pastures (1098±85 ha) for three months (Mar 7 – Jun 9, 2020) using ANOVA for a RCBD (significance at P &lt; 0.05). Cows had ad libitum access to 18% crude protein lick tubs in all pastures, which were weighed weekly to determine SI. Brangus cows had greater SI than RC, both overall (BR: 0.21±0.04 vs. RC: 0.08±0.03 kg×cow×d-1) and on a metabolic bodyweight basis (BR: 2.31±0.09 vs. RC: 0.95±0.09 g×kg0.75). All cows were bred to Brangus bulls and calf birth weights were not different between biotypes (BR: 31.5 ± 1.0; RC: 29.6±0.9 kg). Brangus cows weighed more at the beginning (535.0±14.8 kg) and end (582.2±14.5 kg) of the study compared to RC (beginning: 345.5±11.8 kg; end: 357.0±12.0 kg). Percent of bodyweight change was not different between biotypes (BR: 8.51±2.35; RC: 2.85±1.81 %). On a 1 to 5 scale, BCS of Brangus (4.06±0.09) was greater than RC (3.18 ± 0.07) at the onset of the study, but biotypes had similar BCS at the end of the trial (BR: 4.09 ± 0.09; RC: 3.89±0.08). Our preliminary results indicate that lighter RC cows were capable of gaining bodyweight and improving BCS with reduced SI, both overall and on a metabolic bodyweight basis. This finding may reflect lower nutrient requirements, better relative efficiencies and lesser grazing impacts on desert rangelands by RC cattle. Future studies will seek to replicate these breed-comparison trials over multiple years, research sites, and supply chains, with an emphasis on overall systems production efficiency and sustainability.

314 Carbohydrases Enzymes Improve the Productive Performance of Grazing Nellore Bulls Fed Different Nutritional Plans During the Rainy Season

The aim with this trial was to evaluate two nutritional plans with the addition of dosages of carbohydrases enzyme blend on productive performance of grazing Nellore bulls in rainy season. One hundred and two contemporary Nellore steers (BW = 294.10 ± 3.35 kg) were equally distributed in six paddocks (17 steers/paddock) following a completely randomized design in a 2x3 factorial arrangement, being the factors two nutritional plans: mineral-proteic supplementation (Fosbovi® Proteico 30; PS) offered at 0,1% BW or mineral-protein-energetic supplementation (Fosbovi® Proteico-Energético 25; PES) offered at 0.3% BW); and three levels of enzymatic carbohydrases blend (0, 4,75 or 9,50 g/animal/day). The enzymatic blend was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme® VP and Ronozyme® WX); Both enzymes and supplemented were provided by DSM Nutritional Products Brasil S.A. Supplement intake and animal weighting were carried out daily and individually by an automatic scale system installed in each paddock. Data were analyzed using PROC MIXED of SAS and means were compared by polynomial regression. Animals that received PES had greater ADG (0.896 vs. 0.775 kg/day; P &lt; 0.001) compared to those fed PS. Intermediary level (4.75 g/day) of carbohydrate enzymes also presented the highest ADG in PES compared to 0.0 level (0.941 vs. 0.896 kg/day; P = 0.006). Still, higher enzyme levels (9.5 g/day) presented greater ADG on PS, when compared to 0.0 level (0.852 vs. 0.775 kg/day, P = 0.006). PES animals presented greater intake, compared to PS (1.112 vs. 0.432 kg/day, P &lt; 0.001). According to polynomial regression, it is recommended to include 4.75 g/day of these carbohydrases enzymes in PS and 4.39 g/day in PES for growing Nellore bulls in rainy season.

151 Intake, Growth, and Insectifugal Outcomes Associated with Free-choice Supplementation of Garlic Products to Feedlot Steers

Conflicting anecdotal accounts from producers about their cattle performance and fly-repellence outcomes while receiving garlic-infused supplements have limited feeding decisions. This study evaluated differences in animal performance and insectifugal outcomes among four groups (26 steers per group) over two years (total = 208 steers). The steers either received non-garlic mineral supplement (MS), MS+0.3% garlic oil-based premix (GOil), MS+2.5% garlic powder (LGP), or MS+5% garlic powder (HGP). A completely randomized design was implemented where each steer was assigned to each treatment group while balancing for bodyweight and breed composition. Steers received a feedlot ration and free-choice mineral supplement for 86 and 108 d in the first and second year, respectively. Individual feed and supplement consumption were measured with automatic feeding units. Fly abundance on each animal was determined using digital images collected during weekly fly surveys. The ADG, feed efficiency, ultrasound body composition, and intake-related activities were also evaluated during the study. Data were analyzed using linear- or generalized linear mixed models in SAS. A significant year and Group×year interactions were observed for daily supplement intake (P &lt; 0.02). Similar interactions (P &lt; 0.04) were observed for feeding behaviors associated with supplement intake. Fly abundance during the peak months was below the economic threshold and was not different among the groups (P = 0.25), but the year and Group×year interactions were significant (P &lt; 0.02). There were no differences among the groups for DMI (P = 0.81), ADG (P = 0.54) and gain to feed ratio (P = 0.34). The Group×year interactions were present for the change in ultrasound rib-fat-thickness. The reasons behind the differences in supplement intake are not clear but may be related to the garlic products’ phytochemical profiles. These results suggest that further studies are required to identify the specific bioactive compounds in garlic that affect supplement intake.

PSXIII-3 Effects of mineral source and additive in mineral supplementation on productive performance of growing beef cattle on tropical pastures

Our objective was to evaluate the effects of mineral supplementation using the association of carboaminophosphochelates as mineral source plus Salinomycin on grazing beef cattle performance during growing phase. A total of 80 Nellore bulls (IBW = 292.72 ± 13.55 kg; Age, ~13 mo) were distributed in 8 paddocks (~2.7 hectares each) planted with Palisade Grass cv. Xaraés during the rainy to rainy-to-dry transition seasons (February to May). The experiment was a randomized complete block design (10 animals/paddock, 4 paddocks per treatment). The mineral supplementation was provided ad libitum and treatments were: Control; Mineral supplementation containing inorganic minerals, and TM+Salinomycin = Mineral supplementation containing carboaminophosphochelates (TM, Tortuga® Minerals) as minerals source (Cr, Se, Zn, Mn, S, Cu e Co) plus Salinomycin (~108 mg per animal/day). The supplement orts were removed and weighted daily to calculate supplement intake. The animals were weighed after a 14 h-fasting at the beginnig and end of the trial (84 days) to calculate weight gain. The paddock was considered the experimental unit and data were analyzed using PROC MIXED of SAS, whereby means were separated using the PDIFF statement (P &lt; 0.05). Supplement intake was similar between treatments (P = 0.13). Animals supplemented with TM+Salinomycin tended to have greater final BW (358 vs. 347, P = 0.07) and increased ADG in 22,3% (0.730 vs. 0.597 kg/d, P = 0.03) compared with animals fed Control. In conclusion, the combination of carboaminophosphochelates minerals plus salynomicin improves grazing beef cattle weight gain, with no deleterious effect on mineral supplement intake.

186 Have New Feeding Technologies Revolutionized the Way We Design Grazing Experiments?

New technologies have enabled autonomous measurement of intake and feeding behavior of pen-fed animals and this has piqued interest in utilizing similar technologies in grazing experiments. Various feeding systems are currently available, but individual supplementation and feeding experiments have been conducted for years using individual feeding stanchions, which are the lowest level of technology for measuring supplement intake. These experiments are laborious as they require animals to be trained and acclimated, gathered at each feeding, and sorted into individual stalls for supplementation—thereby disrupting the animals grazing activities. In the mid-1980s Calan Gate systems (American Calan; Northwood, NH) became popular in pasture supplementation experiments, but still have many of the same disadvantages. Newer, more automated systems, reduce labor and possibly have less disruption of the animal’s grazing behavior, but are reliant on the animal’s willingness to use the system and ability to access it when more dominant peers are present. Individuals also do not always follow the “averages”-based rules we often hold true and behave differently in groups. Recent research with automatic feeders show steers consumed average of 60% of the potential supplement with supplement intake CVs of 50 to 100%. These technologies lead many to question the paradigm of experimental units in experimental designs. The experimental unit is defined as the smallest independently assigned unit to which the treatment is applied. This definition of experimental unit is somewhat limiting when taken to the extreme, but still applies well for experiments utilizing individual animal feeding, regardless of the level of technology involved. In many cases where the aforementioned technologies are used, the individual animal can be both the observational and experimental unit. This symposia presentation will discuss attributes of different feeding options and the implications on study design, experimental power, and the designated experimental unit.