Mineral Feeders Research Articles

92 Rearing system influenced the performance, GI-parasite burden, and immune profile of pregnant does during winter

Abstract Small ruminants in the Southeast are predominantly raised outdoors, regardless of seasons and associated weather conditions. Severe weather in winter can decline the performance of pregnant animals and compromise their performance and immunological states. Indoor raising of pregnant animals during winter may minimize the adverse effect of cold stress; however, such potential has not been evaluated. This study hypothesized that performance, GI-parasite burden, and immune response would differ between pregnant does raised outdoor and indoor during winter. The objective of this study was to evaluate the performance, GI-parasite burden, and hematological, biochemical, and immunological parameters of pregnant does raised outdoor and indoor in winter. The study was conducted from late January to early April 2023. Sixteen pregnant Kiko does were divided into outdoor and indoor groups. Outdoor group was kept in one grazing plot consisting of mobile shelters, mineral feeders, hay feeders, and watering troughs. Indoor group was kept in individual pens consisting of containers for water, minerals, hay, and grain. Both groups were given corn and soybean mixed in 3:2 ratio (0.8% of animal body weight), ad libitum hay, minerals, and water. Daily ambient temperature and relative humidity (RH) data were collected for both sites, and temperature-humidity index (THI) was calculated. Animal performance data [body weight, body condition score (BCS), and FAMACHA score] and fecal samples were collected on d 1, weekly during the study, and at the end of the study. Fecal samples were analyzed for the type and quantity of GI parasites using the McMaster technique, and parasite eggs per gram of animal feces (EPG) was calculated. Blood samples were collected on d 1, 34, and 69 and analyzed for hematological, biochemical, and immunological parameters. Data on weather, animal performance, and hematological, biochemical, and immunological parameters were analyzed using the GLM procedure and EPG data were analyzed using the Wilcoxon Rank-Sum test in SAS 9.4. Indoor temperature was higher (7%, P < 0.01), RH was lower (8%, P < 0.05), and THI was higher (5%, P < 0.01) vs. outdoor. Overall, indoor does had better FAMACHA by 9% (P < 0.05) and greater EPG by 35% (P < 0.05). Eosinophils were reduced by 73% (P < 0.05), calcium was increased by 11% (P < 0.01), and total bilirubin was greater by 86% (P < 0.05) in indoor does at the end of the study (P < 0.05) vs. outdoor does. Results showed that performance, GI-parasite burden, and biochemical and immunological parameters of pregnant does were influenced by the rearing system during winter.

82 Effects of a red-clover containing mineral on heifer behavior and fertility

Abstract Heat stress reduces reproductive efficiency in beef cattle. Recent evidence suggests that supplementation of red clover can alleviate the physiological impacts of fescue toxicosis which could decrease heat stress. Our objective was to determine the effect of supplementing heifers grazing endophyte-infected tall fescue (E+ TF) with a conventional mineral containing red-clover leaf. We hypothesized that heifers supplemented with the red-clover leaf mineral would have greater conception rates to AI (CRAI) in times of possible heat stress compared with heifers supplemented with conventional mineral. A grazing study was conducted from May – August in 2021, 2022, and 2023. Yearling beef heifers (n = 32, 36, 40 heifers yr-1, respectively) were blocked by body weight, hair coat score and color into 4 grazing blocks that were assigned to 1 of 2 treatments (2 blocks treatment-1): 1. conventional non-medicated loose mineral control (0%-RC), or 2. conventional loose mineral + 20% wt/wt red clover leaf (20%-RC). Mineral treatments were provided in ground, 3-compartment mineral feeders ad libitum. Each grazing block was assigned to four, 0.8- ha. pastures consisting of predominantly E+ TF and were rotationally managed over the course of the study. Each year estrus was synchronized suitable for fixed time AI in May and all heifers resynchronized in June. In addition, each heifer was fitted with an ear-tag sensor (CowManager SensOor, Agis Automatisering BV, Harmelen, the Netherlands) for continuous behavioral monitoring (including high activity and activity). The CRAI were analyzed with the GLIMMIX procedure of SAS using the binomial distribution link logit function (v.9.4., SAS Inst. Inc., Cary, NC). Total daily activity and high activity reported by CowManger during May and June were analyzed by the MIXED procedure with repeated measures of SAS. The CRAI were similar for 20%-RC (67.30 ± 9.80%) and 0%-RC (60.70 ± 9.80%) heifers following the first service of AI (P = 0.51) during a thermoneutral period in May. In contrast, CRAI was greater (P = 0.02) for 20%-RC heifers (48.67 ± 13.47%) than CM (15.10 ± 13.47%) in June when temperatures increased to potential heat stress levels. Overall, conception rate after two rounds of AI for 20%-RC (78.30 ± 9.30%) heifers tended to be greater (P = 0.08) than CM (62.20 ± 9.30 %). While high activity (associated with estrous behavior) reported by CowManager did not differ between treatments (20%-RC: 203.94; 0%-RC: 213.90; SEM: 8.65 min d-1; P = 0.25), normal daily activity of 20%-RC heifers (150.69 ± 10.40 min d-1) tended to be greater (P = 0.06) than CM (126.33 ± 8.65 min d-1). Results of this study suggest supplementing red-clover containing mineral may mitigate negative effects of consuming E+ TF including decreased conception rates during times of heat stress.

PSIV-29 Performance and Resiliency Against Gastrointestinal Parasites of Pregnant Does and Ewes Raised Indoor and Outdoor During the Winter Season

Abstract Small ruminants in the southeast USA are mostly raised on pastures (outdoor) irrespective of seasons and associated weather conditions. During the extreme weather conditions, such as that occur in winter, animals may perform better while kept indoors. However, literature is scant on the benefits of keeping animals indoors during winter. The objective of this study was to assess the performance and resiliency against gastrointestinal (GI) parasites of pregnant does and ewes raised indoor and outdoor in winter. The experiment was conducted for 45 days from late January to mid-March 2023. Sixteen pregnant Kiko does, and eighteen pregnant Katahdin-St. Croix cross ewes were divided into two uniform groups. Group-1 animals (8 does and 9 ewes) were kept outdoors in a grazing plot that consisted of mobile shelters, mineral feeders, hay feeders, and watering troughs. Group-2 animals (8 does and 9 ewes) were kept indoors in individual pens with consisting of containers for providing water, minerals, hay, and grain. Both groups were given ad libitum hay, minerals, and water as well as corn-soybean mixed in 3:2 ratio at the rate of 0.8% of animal live weight. Ambient temperature and relative humidity (RH) were measured for both systems. Animal performance data [body weight, body condition score (BCS), and FAMACHA score] and fecal samples were collected on Day 1, weekly during the study, and at the end of the study. Fecal samples were analyzed for the type and quantity of GI parasites using the McMaster technique, and parasite eggs per gram of animal feces (EPG) was calculated. Weather data and animal performance data were analyzed using the GLM procedure and EPG data using the Wilcoxon Rank-Sum test in SAS 9.4. Temperature was higher (13.3%, P < 0.01) while RH was lower (6.25%, P < 0.01) in the indoor system. Ewes showed greater BCS (4.86%, P < 0.01) and does showed better FAMACHA score (8.5%, P < 0.01) in indoor system compared with outdoor ewes and does, respectively. Haemonchus contortus was found to be the major GI parasite affecting animals kept in both systems. Indoor ewes showed greater EPG than outdoor ewes (89.8%, P < 0.05). Results suggest that indoor rearing of pregnant does and ewes during winter can enhance their performance. Further research is needed to determine the possible reasons for greater EPG in pregnant ewes raised indoor vs. outdoor.

Use of radio-frequency identification technology to assess the frequency of cattle visits to mineral feeders.

Three experiments were conducted to evaluate the frequency of visits to a mineral feeder equipped with radio-frequency identification (RFID). In Exp. 1, twelve heifers (Braford, Brahman, and White Angus; n = 4/breed) were fitted with RFID ear tags and placed into a pasture with access to a RFID-equipped mineral feeder. Number of visits were greater (P ≤ 0.05) during daytime than the night period. Brahman and Braford heifers favored (P ≤ 0.05) daytime than night period. White Angus heifers did not display a specific period preference (P = 0.32). In Exp. 2, Black Angus and Brahman cows (n = 15 and 19, respectively) were placed into a pasture with access to a RFID-equipped mineral feeder. Brahman cows made more (P < 0.01) visits to the mineral feeder than Black Angus cows. There were no breed differences on the number of visits during the morning (P = 0.25) and night (P ≤ 0.25) periods, but Brahman cows made more (P ≤ 0.05) visits to the mineral feeder in the afternoon period than Black Angus cows. In Exp. 3, the location of the mineral feeder was tested using 3 groups of Bos indicus-influenced heifers (n = 12/group). The mineral feeder was moved weekly within pasture. The number of visits to the mineral feeder differed for each location (P < 0.001) with visits being greatest when mineral feeder was placed near supplement and water, followed by center of the pasture, and lastly in the shade.

Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow-calf pairs grazing native range.

Crossbred Angus cow–calf pairs (n = 28 pairs) at the Central Grasslands Research Extension Center (Streeter, ND) were used to evaluate an electronic feeder to monitor individual mineral intake and feeding behavior and their relationship with growth performance and liver mineral concentrations. Cows and calves were fitted with radio frequency identification ear tags that allowed access to an electronic feeder (SmartFeed system; C-Lock Inc., Rapid City, SD) and were provided ad libitum minerals (Purina Wind and Rain Storm, Land O’Lakes, Inc., Arden Hills, MN). Mineral intake, number of visits, and duration at the feeder were recorded over a 95-d monitoring period while pairs were grazing native range. Liver biopsies were collected from a subset of cows on the final day of monitoring and analyzed for mineral concentrations. Data were analyzed with the GLM procedure in SAS for mineral intake and feeding behavior with age class (cows vs. calves), intake category (high vs. low), and the interaction between class and category in the model. Correlations were calculated among cow feeding behavior and calf intake and growth performance with the CORR procedure, and a comparison of liver mineral concentrations among cows of high (>90 g/d; average 125.4 g/d) and low (<90 g/d; average 33.5 g/d) mineral intake was performed using the GLM procedure. High-intake calves (>50 g/d; average 72.2 g/d) consumed greater (P < 0.001) amounts of minerals than low-intake calves (<50 g/d; average 22.2 g/d) intake calves. Cows and calves attended the mineral feeder a similar (P = 0.71) proportion of the days during the experiment (overall mean of 20%, or once every 5 d). On days calves visited the feeder, they consumed less (P < 0.01) minerals than cows (222 ± 27 vs. 356 ± 26 g/d, respectively). Over the grazing period, calves gained 1.17 ± 0.02 kg/d, whereas cows lost 0.35 ± 0.02 kg/d. Calf mineral intake was correlated with cow duration at the mineral feeder (r = 0.403, P = 0.05). Cows with high mineral intake had greater (P < 0.01) concentrations of Se (2.92 vs. 2.41 ug/g), Cu (247 vs. 116 ug/g), and Co (0.51 vs. 0.27 ug/g) compared with low mineral intake cows, but liver concentrations of Fe, Zn, Mo, and Mn did not differ (P ≥ 0.22). We were able to successfully monitor individual mineral intake and feeding behavior with the electronic feeder evaluated, and the divergence in mineral intake observed with the feeder was corroborated by concentrations of minerals in the liver.

PSIX-37 Considerations for using game cameras for on-farm behavior of beef cattle

Abstract On-farm studies provide an opportunity to build relationships with clientele while answering applied science questions. Further, game trail cameras are a low-cost technology that may be an alternative to visually observing livestock for behavior data. An on-farm study involving eight county Extension agents and producers investigated game cameras to capture cattle visitation to mineral feeders. Three different models of Browning game trail cameras (Prometheus Group LLC, Birmingham, AL) each with timelapse feature were utilized. A three-page document provided background and methodology for the study. Details for placement of the trail camera were provided to provide consistency across farms. Cameras were pre-programmed to settings for image capture. A video for camera setup was also provided in the event that cameras reset to default settings due to battery failure. Timelapse feature was utilized providing image capture from sunrise to sunset at 2 min intervals. Several observations were noted to improve data capture in the future. Differences existed in battery utilization between camera models with one model only capturing images for approximately 2 of the 7 d periods while others had more than 80% battery life remaining after 7 d. Cameras were to be oriented facing south to avoid sun glare. Sun glare occurred at sunrise on most cameras and was particularly bad when dew was present on the camera lens. Mineral feeders need to be secured in place as livestock may move feeders out of the frame of the images captured. Still photos are insufficient in assessing behavior and short video clips are expected to improve interpretation especially when multiple animals visit the feeder at the same time. Utilization of human observation was not useful unless observation was performed at sunrise. Game trail cameras have the potential to be a cost-effective tool in capturing on-farm data of cattle behavior.

PSVII-13 Mineral feeder design impacts frequency of use in grazing beef cattle

Abstract Trace minerals are essential for many biological and metabolic processes and often supplemented ad libitum to grazing beef cattle. However, research has shown large variations in individual intakes. The objective of this study was to examine the impact of mineral feeder design on visitations and intake. In a crossover experimental design, beef cattle operations (n = 5) were randomly assigned to treatment sequence (lid status) and each evaluation period occurred for 5 – 7 days. Browning game trail cameras (Prometheus Group LLC, Birmingham, AL) were used to record time lapse pictures at 2-minute intervals from sunrise to sunset. Time was categorized as morning (≤10:00), mid-day (10:01 – 14:00), afternoon (14:01 – 18:00) and evening (&amp;gt;18:00). Activity was categorized as eating mineral, standing, lying or other within 0.5 m of feeder. Effects of farm, treatment, and time were analyzed using the GENMOD procedures of SAS 9.4 and mineral intake data were analyzed using PROC GLM. There were significant effects of farm (P &amp;lt; 0.001), treatment (P &amp;lt; 0.007), time (P &amp;lt; 0.001), and the treatment by time interaction (P &amp;lt; 0.001) for the numbers of cows and calves eating. Different herd sizes likely contributed to the significance of farm. Data were further analyzed using PROC FREQ. Of the animals eating, more cows and calves were observed eating with the lid removed (59.1% and 61.7%, respectively). However, average mineral disappearance did not differ (P = 0.57) by treatment (50.4 kg vs. 42.0 kg). Regardless of treatment, more cows were observed eating during the morning and afternoon (35% and 34.8%, respectively) than in the evening (10.3%). Similarly, more calves were categorized as eating in the morning and afternoon (29.3% and 41.3%, respectively) than in the evening (14.1%). These preliminary results indicate that feeder design may impact visitation of cows and calves but not average mineral disappearance.

Influence of supplemental copper, manganese, and zinc source on reproduction, mineral status, and performance in a grazing beef cow-calf herd over a 2-year period

This experiment evaluated the effects of Cu, Mn, and Zn source on mineral status, reproduction, and performance of grazing beef cattle in eastern Colorado. Crossbred (Angus and Angus × Hereford; n = 261) 3-yr-old beef cows were stratified by expected calving date, BW, BCS, and liver Cu status and randomly assigned to 1 of 6 replicates. Replicates were then assigned to 1 of 2 treatments (n = 40–45 cows per replicate), resulting in 3 replicates per treatment for the 2-yr experiment. Treatments consisted of (1) inorganic–organic trace mineral combination (IOC; 75% of Cu, Mn, and Zn from sulfate forms and the remaining 25% from organic AA complexes) and (2) hydroxy trace minerals (HTM; 100% from hydroxychloride forms). Replicates were rotated among pastures approximately every 28 d to minimize pasture effects. Free-choice mineral feeders were used to provide NASEM (2000) recommended concentrations of Cu, Mn, and Zn continuously for 2 yr. Blood samples and liver biopsies were obtained from every cow before the initiation of the experiment and then from a subgroup of animals (20 random animals per replicate) at the end of yr 1 (d 335 of the experiment) and 2 (d 638 of the experiment). Over the 2-yr experiment, mineral intake, cow BW, BCS, pregnancy rate to AI, and overall pregnancy rate did not differ across treatments. Calf weaning weights were also not affected by trace mineral source. At the end of yr 1 and yr 2, liver Cu concentrations were greater ( P ≤ 0.05) in HTM- compared with IOC-supplemented cows. Liver Zn concentrations were greater ( P < 0.05) in cows receiving HTM at the end of yr 1 and tended ( P < 0.06) to be greater at the end of yr 2. Liver Mn concentrations were not affected ( P > 0.05) by trace mineral source. Overall productivity of grazing beef cows and their calves over a 2-yr period were similar in cattle supplemented with hydroxy or a combination of sulfate and organic trace minerals. Liver Cu and Zn concentrations were greater in cows fed HTM.

Blood plasma concentrations of chlortetracycline achieved by administration of a mineral formulation to adult beef cows

ABSTRACT Objective Our study objectives were to characterize steady-state plasma chlortetracycline (CTC) concentrations achieved by adult beef cows treated with a commercial, CTC-containing mineral supplement under 2 conditions, where intake was controlled and under conditions when intake was uncontrolled, as in a pasture setting typical of production practices for anaplasmosis control. Materials and Methods Thirty cows were allocated to 3 individually administered treatment groups: nonmedicated control (NM-F), medicated mineral administered via gelatin capsule (M-C), or medicated mineral fed in a small amount of grain (M-F). After a washout period, 15 of the original cows received an intended CTC dose of 1.1 mg·kg of BW−1·d−1 administered via a mineral feeder in a pasture setting (M-P). Blood samples were collected at multiple time points, and plasma chlortetracycline concentrations were quantified. Results and Discussion Mean plasma chlortetracycline concentrations for M-C and M-F treatments were 20.2 and 19.3 ng/mL, respectively, with no differences in mean, minimum, or maximum plasma concentrations. Conversely, differences in both median and minimum plasma concentrations were detected when the dose was controlled (M-C or M-F) compared with when the dose was administered via mineral feeder in a pasture setting (M-P). Implications and Applications Future CTC studies can be designed using individual intake in grain because administration by gelatin capsule offers no advantage in dosage consistency. The assumption that mean consumption from a mineral feeder will achieve the same plasma CTC concentrations as individual or bunk-fed experiments should be further analyzed. The pharmacodynamic parameters associated with efficacy were not evaluated in this study and remain unknown.

Regionalisation of nitrate leaching on pasture land in Southern Manitoba

Nitrogen is a key agricultural input which is crucial for crop growth, development, and yield. However, an excess application of nitrogen may result in the nitrate contamination of groundwater. This research focused on the estimation of nitrate leaching fluxes upon the application of pig slurry on pasture land in Southern Manitoba using physical based modeling and to further spatially disperse the point estimates of nitrate leaching fluxes at the field scale. The field site was located in Southeastern Manitoba. Grazing livestock tended to concentrate near areas such as mineral feeders, water troughs and shelters causing higher deposition density of urine and feces, resulting in six bare earth areas in the study site. HYDRUS-1D was used to determine continuous recharge and nutrient leaching estimates. The simulated leaching estimates were spatially dispersed using Cokriging. The difference in simulated and observed nitrate concentrations in groundwater was expressed in terms of RMSE between 0.023 and 5.12 mg NO3−-N L-1, NSE between 0.66 and 0.96 and the ME between −1.03 mg NO3−-N L-1 and 1.05 mg NO3−-N L-1. Simulation results suggested that two years of pig slurry application to the hay pasture on a coarse sandy soil did not cause significant accumulation of nitrate in the shallow groundwater since the maximum nitrate leaching flux were below 11 kg ha-1 resulting in NO3− concentration in groundwater below 1.2 mg L-1. In contrast, nitrate concentrations five times above the drinking water threshold were simulated in bare earth areas. Leaching of large amounts of nitrate occurred in these areas. Overall, HYDRUS-1D can be considered a useful tool in quantifying nitrate leaching estimates for pasture in a cold climate such as southeastern Manitoba, and Cokriging can be considered a reliable method for a study site where cross-correlations between variables are important to consider for carrying out interpolation.

Efficacy of mineral supplementation to growing cattle grazing winter-wheat pasture in northwestern Oklahoma.

Two experiments were conducted to evaluate the efficacy of mineral supplementation to cattle grazing winter-wheat pasture. In experiment 1 (fall), 120 steers and heifers (body weight [BW] = 232 ± 11.4 kg) were assigned randomly to four blocks of replicated pastures during the second week of November in 2008 and 2009 and all herds (6 animals/pasture; 4.9 ha/pasture) were allowed to graze for 84 d. In experiment 2 (spring), 216 steers (BW = 248 ± 7.9 kg) were assigned randomly to five blocks of replicated pastures during the second week of February in 2009 and 2010 and all herds (12 or 6 animals/pasture; 4.9 ha/pasture) were allowed to graze for 84 d. Half the pastures in both experiments received a free-choice mineral mixture (Wheat Pasture Pro; Land O'Lakes Purina Feed, LLC; St. Paul, MN; Ca, 16% and P, 4%); mineral feeders were weighed weekly to determine mineral intake. All pastures were planted in early September of each year (67 kg of seed/ha) and fertilized with 50 kg of urea-N/ha. Standing herbage dry matter was determined midway between weigh dates by clipping wheat forage to the ground along 122 cm of drill rows at 10 locations/pasture. Data were analyzed by ANOVA, with treatment as the fixed effect and pasture, animal sex (experiment 1), and block as random effects. In experiment 1, cattle offered minerals had a 43% faster average daily gain (ADG; P = 0.02, 0.73 kg) than cattle not offered minerals (0.51 kg); hence, supplemented cattle weighed 6% more (P = 0.04; 286 kg) after 84 d than nonsupplemented cattle (271 kg). In experiment 2, cattle offered the mineral supplement had a faster ADG (20% increase; P = 0.04; 1.00 kg) than cattle not offered minerals (0.83 kg). Further, supplemented cattle weighed 4% more (P = 0.03; 326 kg) after 84 d than nonsupplemented cattle (312 kg). In both experiments, daily standing herbage dry matter averaged 1,381 kg/animal and never differed (P ≥ 0.47) between treatments. Mineral intakes averaged 135 (experiment 1) and 124 (experiment 2) g/d, resulting in a cost of supplement to kilogram of added BW gain of $0.53 and $0.64, respectively (assuming a mineral cost of $0.88/kg). Overall, supplementing an appropriate mineral mixture to cattle grazing winter-wheat pasture increased ADG in a cost-effective manner.

Assessment of Variability in Yearlong Relative Loose Mineral Intake and Range Cow Productivity in North American Northern Great Plains

Background: Appraisal of the effectiveness of supplementary mineral nutrition in grazing range cattle to promote growth and reproduction is lacking due to an inability of methods to measure cause and effect relationships, record variability of grazed diet mineral concentrations, evaluation of cattle presence at mineral feeder, measurement of shifting requirements due to changes in physiological stage and a lack of accurate mineral supplement intake quantification. Methods and findings: This study evaluated cattle presence at mineral feeder, relative mineral intake and its association with calf Body Weight (BW) at birth and weaning, cow BW change and calving interval (d). Cross-bred cows grazed native range with access to mineral feeders containing 34% salt, 57% macro/microminerals, 9% distillers’ grains and 1% titanium (Ti) as titanium dioxide for sixteen months from August 2010 to November 2011. Motion activated cameras were used to record ear tags of 106 cross-bred cows as their heads approached the open range mineral tub. Mineral feeder tubs were placed near water sources to promote contact of cattle with mineral supply. Rectal fecal samples were collected at 1 or 2-months interval and were analyzed for Ti content. Filtered samples were transferred to 15 ml falcon tubes for Ti analysis using inductively-coupled plasma mass spectrometry analytical technique (USFS Bozeman Fish Technology Center, Bozeman, Montana, USA). It was assumed that fecal Ti was positively related to mineral consumption. Cows were assigned to one of four fecal Ti concentration clusters based on their mean Ti concentration: (1) low (3 to 5 ppm, n=23), (2) mid-low (5 to 6 ppm, n=36), (3) mid-high (6 to 7 ppm, n=26) and (4) high (7 to 11 ppm, n=21). Data were analyzed using Proc Mixed SAS (SAS Inst., Inc., Cary, NC) and a model including Ti cluster and cow age (2 to 11 years) as a covariate. The percent of cows at mineral tub each day differed (p<0.01) by season. In late growing season (July-October), 48 ± 3.9% of herd visited the tub daily compared to 31 ± 3.4% in fall and winter dormancy (November-March) and 27 ± 4.1% during spring growth (April-June). Average consumption based on amount of mineral fed was greatest (p<0.01) during forage dormancy and spring growth (53 ± 3.8 g hd-1 d-1) and lowest during late growing season (38 ± 3.5 g hd-1 d-1). Regardless of fecal Ti concentration, all groups had similar 2011 calf BW at birth (p<0.22) and weaning (p=0.89), cow BW change (2010-2011) p=0.71 and 2010 to 2011 and 2011 to 2012 calving interval (p=0.85). In addition, mean fecal Ti in 18 non-pregnant and 88 pregnant cows were 6.22 ppm and 5.95 ppm (p=0.68), indicating no differences in mineral consumption between non-pregnant and pregnant cows. Conclusion: During the late growing season, cow activity at a mineral tub was highest but mineral disappearance from the tub was the lowest. Range in mean fecal Ti of individual cows represented a 3-fold divergence in Ti dilution indicating a magnitude difference in mineral consumption. If mineral consumption was a primary production limitation in the year of this study, then differences would be expected for the production traits evaluated influenced by predicted mineral intake.

005 Evaluation of Metal Loss through Simulated Rainfall-Induced Leaching of Salt-Based, Free-Choice Mineral Supplements: An Extension Service

Previous research identified preferential intake of Cu, Zn, and Mn-fortified supplements containing Zn and Mn hydroxychloride and basic Cu chloride vs. sulfate and organic forms of these metals among young beef calves. However, in the days following significant rainfall events, the preferential differences lessened. In addition, visual observation of the colored pooled water collecting under the raised mineral feeders suggested rainfall-induced leaching of trace minerals. Therefore, we designed a series of experiments to investigate rainfall-induced metal losses under laboratory conditions. From these efforts, a simplified laboratory procedure was established allowing benchtop evaluation of rainfall-induced leaching susceptibility from free-choice, salt-based mineral supplements. This procedure is now available as an extension service of the UF-IFAS, Range Cattle Research and Education Center. Briefly, the procedure is designed to simulate a 10.2 cm rainfall occurring over 3 separate events (3.4 cm on Monday, Wednesday, and Friday). The procedure requires a minimum of 4 kg of mineral supplement being tested, which is divided into 4, 1 kg subsamples. A single pre-leaching sample (250 g) is collected from each of the subsamples and the remaining 750 g of sample is placed into Buchner funnels (177 cm2) on 20 to 25 µ pore filter paper. Deionized water (pH adjusted to 5.6) is poured over the mineral and the leachate collected into volumetric flasks. Along with the original pre-leaching sample, the remaining leached mineral is dried, weighed and analyzed for Cu, Zn, and Mn concentration using inductively coupled plasma spectroscopy techniques. Metal loss is estimated by calculating the difference between the total metal in the initial pre-leached sample less the metal remaining in the leached sample. Results are presented as percent metal loss ± SD of the 4 replications. The service is offered for $350 per sample with a turnaround time of approximately 14 d. In addition to leaching loss of trace metals, the analysis also provides important comparison between labeled nutrient specifications and actual chemical analysis. Results provide both manufacturers and producers with an understanding of the potential for essential nutrient losses due to rainfall interactions with free-choice, salt-based mineral and assist in evaluating the economic advantages of increased frequency of supplementation, use of weathering agents, and investment in rainfall-protected mineral feeders.

006 Use of Radio-frequency Identification Technology to Assess the Frequency of Cattle Visits to Mineral Feeders

006 Use of Radio-frequency Identification Technology to Assess the Frequency of Cattle Visits to Mineral Feeders

The effect of season on supplemental mineral intake and behavior by grazing steers

An experiment was conducted to compare individual, free-choice loose mineral intake and feeding behavior by steers grazing pasture during late spring to summer (SS) and fall (FS). Each season was divided into 4 periods of 8 to 9 d. Two 1.5-ha paddocks were equipped with a feeder that measured individual mineral consumption. Forage availabilities in both seasons were maintained above 2,000 kg of DM/ha. No differences were observed (P > 0.05) for average mineral intakes (g/d) between seasons (96.3 vs. 85.4 g/d for SS and FS, respectively). Differences among animals and days within each period were observed (P 0.05) was detected. Expressing intake as grams per day is confounded due to differences in animal weight, but when expressed on a metabolic weight basis (MBW), daily mineral intakes differed (P 0.05) were detected between mineral intakes (expressed as either g/d or g/kg of MBW) and available forage nutritional composition or IVDMD of clipped forage. In addition, no significant correlations (P > 0.05) were detected between steer ADG, temperature, or rainfall and mineral consumption. Steer attendance at the mineral feeder appeared to be related to intensity of daylight and daily temperatures according to differences in feeder attendance patterns between SS and FS. Results indicate higher mineral supplement intakes and lower CV during SS when expressed on a MBW basis when forage availability was maintained above 2,000 kg/ha.

Effects of mineral-supplement delivery system on frequency, duration, and timing of supplement use by beef cows grazing topographically rugged, native rangeland in the Kansas Flint Hills1,2

The effects of mineral-supplement delivery system on patterns of supplement use by grazing beef cows were measured in 2 studies. Study 1 was conducted on 4 pastures grazed by pregnant, mature beef cows (BW = 562 ± 38 kg) from February to May. Study 2 was conducted on 4 pastures grazed by lactating beef cows (BW = 579 ± 54 kg) and their calves from May to September. Treatments were mineral delivered in salt-based, granular form (salty) or mineral provided in a low-protein, cooked, molasses-based block (sweet); both were fed ad libitum. The salty supplement was supplied to cattle via a covered mineral feeder; the sweet supplement was supplied via an open-topped barrel. Both salty and sweet supplements were deployed in each pasture. No additional salt was supplied to cattle. Forage use in the vicinity of each supplement-deployment site and the frequency and duration of herd visits to each supplement-deployment site were measured during four 14-d periods during study 1 and seven 14-d periods during study 2. Supplements were moved to new locations within pastures at the beginning of each period. Consumption of the sweet supplement was greater than salty during each data-collection period in study 1; however, relative differences in consumption diminished over time (treatment × time, P = 0.03). In study 2, sweet consumption was greater than salty in periods 1, 6, and 7 but was not different from salty during periods 2, 3, 4, and 5 (treatment × time, P < 0.01). Increased consumption of the sweet supplement in study 1 translated to greater frequency of herd visits to supplement-deployment sites compared with the salty sites (2.82 vs. 2.47 herd visits/d; P = 0.02) and longer herd visits to supplement-deployment sites compared with the salty sites (125.7 vs. 54.9 min/herd visit; P < 0.01). The frequency of herd visits to mineral feeding sites in study 2 was similar (P > 0.10) between treatments for periods 1 through 6; however, herds visited the sweet sites more often than salty during period 7 (P < 0.01). Herd visits to the sweet sites were longer than those to the salty sites in study 2 (83.8 vs. 51.4 min/herd visit; P < 0.01). Forage disappearance within 100 m of supplement-deployment sites was not influenced (P ≥ 0.54) by treatment in either study. Results were interpreted to suggest that the sweet supplement influenced the location of grazing cattle more strongly than the salty supplement and may be more effective for luring cattle into specific areas of pasture during the winter, spring, and early fall but not during summer.

Long-term effect of cow congregation zone on soil penetrometer resistance: implications for soils and forage quality

Higher degree of soil penetrometer resistance can reduce forage yields and can lead to water and soil quality degradation due to increased runoff and soil structure destruction. The inability of roots to penetrate in soils with high penetrometer resistance will result in decreased yield. With less root penetration into the soil, root mass is reduced and plant’s ability to take up nutrients is reduced. To test whether cattle congregation sites typical on most forage-based cow-calf ranches, such as mineral feeders, water troughs, and shaded areas are more compacted and have greater soil penetrometer resistance than in other pasture locations under Florida conditions, soil penetrometer resistance data around and beneath three cattle congregation sites in established (>10 yr) grazed beef cattle pastures were collected in 2004, 2005 and 2006. Penetrometer readings were collected from two soil depths (0–20 and 20–40 cm) at different locations around the cattle congregation sites following radial (every 90 degrees: north, south, east, and west direction) sampling patterns at 0.9, 1.7, 3.3, 6.7, 13.3, 26.7 and 53.3 m away from the approximate center of cattle congregation sites. Results showed that area around or near cattle congregation sites tended to have higher soil penetrometer resistance values than in other locations within pasture field because of the frequent concentration of cattle around the different cattle congregation sites. Soil penetrometer resistance decreases linearly with distance away from the center of mineral feeders and water troughs; however, soil penetrometer resistance at the shaded areas was showing slight increase with distance away from the center. The least soil penetrometer resistance in all years were observed from shaded areas (1 200 × 103 Pa) while soil penetrometer resistance at water troughs was about 1 600 × 103 Pa and at mineral feeders of 1 800 × 103 Pa. These values were in the “fair” range of root penetration. Penetrometer resistance of soils can be a good predictor of root system performance and especially useful in predicting root extension into the deeper regions of the root zone at the congregation zone and grazing zone in pasture.

Spatial distribution of soil carbon in pastures with cow-calf operation: effects of slope aspect and slope position

Spatial distribution of soil carbon in pastures with cow-calf operation: effects of slope aspect and slope position

Características do sistema produtivo da pecuária no município de Santarém, Pará

Com o objetivo de identificar as principais falhas no sistema de produção que limitam a pecuária em Santarém, Pará, foram entrevistados, ao acaso, 21 pecuaristas (90,5% de corte - cria, recria e engorda; 9,5% de leite), proprietários de 10% da população de bovinos do município. 71,4% das propriedades tinham currais para manejo do gado, entretanto apenas 38,1% possuíam balança e 23,8% tronco de contenção. A Brachiaria brizantha estava presente em todas as fazendas, sendo usada exclusivamente em 42,9% das propriedades. A disseminação de plantas invasoras (61,9%) foi considerada a principal dificuldade no manejo das pastagens. Constatou-se que 76,2% dos pecuaristas utilizam misturas minerais com macro e micro-elementos, geralmente de formulações comerciais, enquanto que 19% utilizam apenas sal comum, enriquecido com micro-elementos. A concentração de fósforo (P) na mistura mineral estava abaixo do recomendado para bovinos de corte em 76,9% das propriedades e apenas 19% das propriedades possuía cochos para suplementação mineral adequada.

Sustainable Management of Nutrients in Forage-Based Pasture Soils: Effect of Animal Congregation Sites (5 pp)

Background, Aim and Scope Grazing animals have a dominant effect on the movement and utilization of nutrients through the soil and plant system, and thus on the fertility of pasture soils. Grazing can accelerate and alter the timing of nutrient transfers, and increase the amount of nutrients cycled from plant to soil. Long periods, position of shade, and water resources for grazing cattle can influence the spatial distribution of soil biochemical properties including soil organic carbon (C), total extractable inorganic nitrogen (TEIN), and Melich 1 extractable total phosphorus (TP). The objective of this study is to test whether cattle congregation sites typical on most Florida ranches, such as mineral feeders, water troughs, and shade areas are more nutrient-rich and may contribute more nutrients to surface and groundwater supply than in other pasture locations under Florida conditions. Materials and Methods: Baseline soil samples around and beneath three congregations sites in established (>10 yr) grazed beef cattle pastures at the United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Subtropical Agricultural Research Station (STARS), Brooksville, FL, were collected in 2003, 2004, and 2005. Results: The levels of soil TEIN and TP were significantly (p ≤ 0.001) affected by the interaction of congregation sites and distance away from the center of the sites. Mineral feeders had the highest concentration of TP followed by shades and water troughs. The concentrations of soil TP decreased almost linearly with distance (x = meter) away from the center of the mineral feeders (-5.24x + 55.10; R2 = 0.92; p ≤ 0.001) and the shades (-6.25x + 57.21; R2 = 0.85; p ≤ 0.001). However, the level of TP around the water troughs (-0.25x + 16.91; R2 = 0.09) does not appear to change significantly with distance, staying close to about 13-18 mg kg-1. The levels of TEIN decreased linearly with distance away from the mineral feeders from the center of the shades. A linear model can describe the relationship between TEIN and distance away from the center of shades: -11.3x + 78.2; R2 = 0.95; p ≤ 0.001. The shaded sites (34.25 ± 1.7 mg kg-1) had higher levels than the mineral feeders (7.22 ± 0.60 mg kg-1) or water troughs (10.06 ± 0.8 mg kg-1) sites. Discussion: The higher soil TP near and around the mineral feeders can be attributed to the presence of phosphorus in the supplemental feeds. The average level of soil TP in the mineral feeders of 34.05 ± 0.44 mg kg-1 was not high enough to be of environmental concern. Losses of soil phosphorus by overland flow are becoming a big concern when the concentrations for soil phosphorus exceeded 150 mg kg-1 in the upper 20 cm of soils. With TN, the shaded sites (34.25 ± 1.7 mg kg-1) had either higher levels than the mineral feeders (7.22 ± 0.60 mg kg-1) or water trough (10.06 ± 0.80 mg kg-1) sites. Higher TEIN content at the shade sites may have been more likely due to frequent urination of animals and lack of vegetation immediately adjacent to shades. The lack of vegetation within and/or near the shades then had no uptake mechanism for removal of inorganic nitrogen, unlike the heavy demand for inorganic nitrogen by bahiagrass in other areas of the pasture. An accumulation of TEIN immediately adjacent to shades could lead to a potential point source that would be susceptible to leaching or gaseous losses to the environment. Conclusions: Early results of the study are suggesting that cattle congregation sites in beef cattle operations in Florida are not nutrient-rich, therefore may not contribute more nutrients to surface and groundwater supply under Florida conditions. Recommendations and Perspectives: Since there is no apparent vertical build up or horizontal movement of TEIN and TP in the landscape, we can then surmise that cattle congregation sites may be considered not a potential source of nutrients at the watershed level, at least on the sand ridge soils in Florida. Further research is continuing, including sampling at cattle congregation sites at other locations in north and south Florida, which started in July 2004.