Kg Of Forage Research Articles

PSIV-20 The Effect of Silage Additives on Male Sterile Sorghum Fermentation Heat Production and Feed-Out Stability

Abstract The objective was to compare the effect of applying silage additives to male sterile sorghum hybrids on temperature production during ensiling time (30 d) and at feed-out period after 30 or 90 d of ensiling period. Two male-sterile sorghum hybrids; F430 and F465, with and without BMR12 trait, respectively (Richardson Seed Ltd.); were randomly allocated in plots blocked by irrigation section in a dairy farm in West Texas. During harvest, duplicate samples from each plot were obtained, placed on plastic trays, and transported to one of three stations to be treated with chemical silage preservative (SG, SiloGuard), heterofermentative bacteria inoculant with mold inhibitor solution (SM, Silage Maker 250) or distilled water (DW, control). Treatments were applied with spray bottles following a protocol that consisted of two sets of 5 sprays (1.1 mL each and 11 mL total) followed by mixing of the forage. Personnel applying the treatment were blind as to which treatment they were applying and all spray bottles, trays and tables from each station were color coded to prevent cross contamination. After treated, 3.63 kg of forage was packed in three consecutive steps using a manual press on 4.7L buckets (Uline) and a temperature data logger was placed in the center of each of the 30 d mini silos. The amount of material packed was estimated to achieve a 230 kg of DM/m3 compaction at 30% DM of the forage. At opening, the material from each silo was moved to a tray and mixed to be homogenized and exposed to oxygen. Then, the material was added back to its correspondent bucket until it filled up to the border without compressing. Heat production during the feed-out period and air-stability were assessed for both ensiling periods, whereas fermentation heat production during ensiling period was only assessed for 30 d silos. Statistical analysis was performed using mixed linear regression models (GLIMMIX procedure of SAS) with ensiling period, hybrid, treatment and the interaction of day and treatment included in the model as independent variables. Fourth root and natural log transformation were performed to obtain a normal distribution of residuals, back transformed LSM and 95% CI are reported in Table 1. Treatment effected the silage temperature during the feed-out period (P < 0.0001) and air-stability test (P = 0.02). Whereas a tendency was observed for daily heat production during the ensiled period (P = 0.07). Male-sterile sorghum silage treated with SG had the least temperature during the ensiling period and longer air-stability than SM.

A new method for green forage production: Energy use efficiency and environmental sustainability

In recent decades, hydroponic fodder has been widely used for livestock feed. Studying the energy indicators and life cycle assessment (LCA) of the hydroponic fodder can result in applying the best method for higher production with less environmental impacts. Hence the aims of this study are to evaluate energy and water use and environmental indicators for hydroponic fodder production in central region of Iran. Data collected using oral questionnaire from hydroponic fodder greenhouses in Isfahan province. The results demonstrated that total energy for production of one ton hydroponic fodder is 5060.40 MJ. Also energy ratio (ER) and energy productivity (EP) were calculated as 0.33 and 0.20 kg MJ −1 , respectively. The water productivity (WP) was about 287 kg m −3 which indicates that about 287 kg of forage is produced per each m 3 of water consumed. The results also showed that despite the many benefits of hydroponic fodder on livestock nutrition, its greenhouse cultivation imposes many adverse effects on the environment . Human health damage categories was calculated as 0.00434 DALY t −1 which was much more than other similar products. Cumulative exergy demand (CExD) results showed that the percentage of Non-renewable, fossil for hydroponic fodder production mainly result from electricity which can be decreased via using renewable energy (RE) technologies.

Yield, nutrient composition, and horse condition in integrated crabgrass and cool-season grass rotational grazing pasture systems.

Integration of warm-season grasses into traditional cool-season pastures can increase summer forage for grazing cattle. The aim of this study was to determine impacts of this practice on yield and nutrient composition of equine rotational pasture systems as well as horse body condition. Two 1.5 ha rotational systems (6 to 0.25 ha sections/system) were evaluated: a control system (CON) (all sections mixed cool-season grass [CSG-CON]) and an integrated rotational grazing system (IRS) (three CSG sections [CSG-IRS] and three Quick-N-Big crabgrass [Digitaria sanguinalis (L.) Scop.; CRB-IRS]). Three horses per system grazed in three periods: EARLY (mid-May to mid-July), SLUMP (mid-July to mid-September), and LATE (mid-September to mid-November). Herbage mass (HM) was measured prior to each rotation and samples were collected (0800 to 1000 h) for nutrient analysis. Grazing days were tracked to calculate carrying capacity (CC). Horse condition measures were assessed monthly. Over the full grazing season, 9,125 kg of forage was available for grazing in IRS versus 6,335 kg in CON. The CC was 390 horse d for IRS, while only 276 horse d for CON. Total HM/section did not differ during EARLY when CRB was not available (CSG-IRS: 2,537 ± 605; CSG-CON: 3,783 ± 856 kg/ha), but CC was greater in CSG-IRS (220 ± 37 horse d/ha) than CSG-CON (92 ± 26 horse d/ha; P = 0.03). In SLUMP, both HM and CC were greater in CRB-IRS (HM: 4,758 ± 698 kg/ha; CC: 196 ± 31 horse d/ha) than CSG-IRS (HM: 1,086 ± 698 kg/ha; CC: 32 ± 31 horse d/ha) or CON (HM: 970 ± 493 kg/ha; CC: 46 ± 22 horse d/ha; P < 0.02). While HM did not differ by section type in LATE (1,284 ± 158 kg/ha), CC was greater in CSG-CON (84 ± 9 horse d/ha) versus CRB-IRS (32 ± 13 horse d/ha; P = 0.03) and CSG-IRS (40 ± 13 horse d/ha; P = 0.06). During SLUMP, water-soluble carbohydrates (WSC) were lower in CRB-IRS (4.46% ± 0.80%) than CSG-CON (7.92% ± 0.90%; P < 0.04), but not CSG-IRS (5.93% ± 1.04%); however, non-structural carbohydrates (NSC) did not differ (7.05% ± 0.62%). There were no differences in WSC (6.46% ± 0.54%) or NSC (7.65% ± 0.54%) by section type in LATE. Horses in IRS maintained a body condition score (BCS) of 5.78 ± 0.48, but BCS did not differ by system (CON: 6.11 ± 0.48). Thus, integrated grazing increased summer pasture yield and provided adequate nutrition to maintain horse condition, but further research is needed to improve late-season production. Integrated grazing may not, however, provide an advantage in limiting dietary NSC, as NSC remained low for all pasture sections.

Extremely Elevated Total Mercury and Methylmercury in Forage Plants in a Large-Scale Abandoned Hg Mining Site: A Potential Risk of Exposure to Grazing Animals.

Ninety-five wild forage plants (belonging to 22 species of 18 families) and their corresponding rhizosphere soil samples were collected from wastelands of a large-scale abandoned Hg mining region for total Hg (THg) and methylmercury (MeHg) analysis. The forage plant communities on the wastelands were dominated by the Asteraceae, Crassulaceae, and Polygonaceae families. The THg and MeHg concentrations in the forage plants varied widely and were in the range of 0.10 to 13mg/kg and 0.19 to 23μg/kg, respectively. Shoots of Aster ageratoides showed the highest average THg concentration of 12 ± 1.1mg/kg, while those of Aster subulatus had the highest average MeHg concentrations of 7.4 ± 6.1μg/kg. Both the THg and MeHg concentrations in the aboveground plant parts exhibited positive correlations with the THg (r = 0.70, P < 0.01) and MeHg (r = 0.68, P < 0.01) concentrations in the roots; however, these were not correlated with the THg and MeHg concentrations in their rhizosphere soils. The species A. ageratoides, A. subulatus, and S. brachyotus showed strong accumulation of Hg and are of concern for herbivorous/omnivorous wildlife and feeding livestock. Taking the provisional tolerable weekly intake (PTWI) values for IHg recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA in Summary and conclusions of the seventy-second meeting of the joint FAO/WHO expert committee on food additives Rome, Italy, 2010) for human dietary exposure of 4ng/g into account, the daily intake of IHg by a 65kg animal grazing on 1.0kg of forage (dry weight) would be between 190 and 13,200μg, three to five orders of magnitude higher than the permitted limit, suggesting a potential risk of exposure.

Nutrient Adequacy Evaluation of Aceh Cattle Fed with Concentrate for Forage Substitution and Performance Improvement

This study aims to evaluate nutrient adequacy based on the nutrient requirement and intake of Aceh cattle fed by concentrate as a substitution for forage to improve their performance and productivity. The study was conducted from May to July 2018 at Livestock Breeding and Forage Center for Excellence (BPTU-HPT) of Indrapuri, Aceh. Twenty heads of selected male and healthy Aceh cattle aged 1.5-2.5 yo with a weight of ±160 kg were divided into four treatment groups based on different forage and commercial concentrate feed levels, i.e. T1 as a control (fed with 25 kg of forage without any additional concentrate feed), T2 (fed with 20 kg of forage plus 1 kg of concentrate feed), T3 (fed with 15 kg of forage plus 2 kg of concentrate feed), and T4 (fed with 10 kg of forage plus 3 kg of concentrate feed). The data observed were ADG, feed consumption, and nutrient intake, requirement, and balance. Data were analyzed using one-way ANOVA and continued by DMRT. The difference in the amount of forage consumption was very significant (P <0.05), directly proportional to the amount of forage provided. Dry matter intake significantly increased with provision of concentrate (P <0.05). Increases in DM, CP, and TDN intakes were 0.75, 0.16, 0.40 kg/d, respectively. A negative balance was found in almost all nutrients and treatment groups, and there was only one positive balance, i.e. protein in T4 group. T3 group had met the DM requirement, but did not meet protein and TDN requirements, and also had the highest ADG (P <0.05) compared to the other groups. This study concludes that the use of concentrate as a substitute for forage improves nutrient intake of male Aceh cattle. Feeding of 2 kg of concentrate and 15 kg of forage can meet nutrient requirements of dry matter and provide the highest ADG.

Modulation of rumen pH by sodium bicarbonate and a blend of different sources of magnesium oxide in lactating dairy cows submitted to a concentrate challenge

With the objective of evaluating the potential effects of sodium bicarbonate or a magnesium-based product on rumen pH and milk performance of dairy cattle exposed to a dietary challenge, 30 lactating Holstein cows (648 ± 67 kg of body weight; 44.4 ± 9.9 kg/d of milk yield; 155 ± 75 d in milk) were blocked by parity (9 primiparous and 21 multiparous) and randomly distributed to 3 treatment groups. One group received a total mixed ration (TMR) that acted as a control (CTR), a second group (SB) received the same TMR but with an additional supplementation of 0.8% of sodium bicarbonate, and a third group (MG) received the same TMR as CTR but an additional supplementation of 0.4% of a magnesium-based product (pHix-Up, Timab, Dinard, France). After 1 wk of exposure to this TMR, all 3 rations were supplemented with 1 kg/d of barley, which was then increased 1 kg/wk until reaching 3 kg/d of barley during wk 4 of the study. Every kilogram of barley replaced 1 kg of forage in the diet. Individual feed intake and behavior were monitored using electronic feed bins. Seven cows per treatment were equipped with an intraruminal bolus that recorded pH every 15 min. As the severity of the barley challenge increased, dry matter intake decreased, but this decrease was more pronounced in SB cows than in MG cows, with an intermediate response for CTR cows. The MG cows produced more milk when challenged with 2 or 3 kg/d of additional barley than when challenged with 1 kg/d, whereas CTR cows produced less milk with the 3 kg/d challenge compared with 1 or 2 kg/d, and the SB cows maintained milk production. Milk fat content decreased with barley challenges, with CTR cows experiencing a more severe decrease than SB cows, which maintained stable butterfat values throughout the study, and MG cows showed a decline in milk fat content only with the 3 kg/d of additional barley. Meal size was also reduced as the severity of barley challenge increased, and this reduction was more modest in MG cows than in SB cows. The number of daily meals consumed by SB and MG cows was more constant than that recorded in CTR cows. Cows on the CTR and SB treatments showed a marked decrease in rumen pH with the 3 kg/d of additional barley, whereas MG cows maintained stable rumen pH during the barley challenges and had greater average rumen pH (5.93 ± 0.04) than CTR cows (5.83 ± 0.04) with the 3 kg/d of additional barley; SB cows showed intermediate values (5.85 ± 0.04). Last, MG cows spent less time (32.3 ± 6.1%) with rumen pH ≤5.8 when exposed to the 3 kg/d of barley challenge than CTR and SB cows (50.7 ± 5.02%). In conclusion, supplementation with MG prevents the decline in dry matter intake and milk production induced by a rumen challenge, whereas supplementation with SB prevents the decay in milk production but does not prevent the decrease in feed intake. These changes were probably due to the ability of the MG treatment to prevent a reduction in rumen pH when challenging cows with 3 kg/d of additional barley in the ration.

Morphological and biochemical indicators of geese blood by deworming with brovermektin and by adding to the ration macleaya cordata and vegetable sources of bioflavonoids

One of the problems connected with the process of geese growing up is infectious diseases (infectious and parasitic), which hurt the fowls’ organisms and are in for economic lesion. As some helminths (caryocolum tetrameris and echinuria uncinata) have transitional carriers who live in the aquatic environment (water flea, freshwater shrimp and asellus aquaticus) and can infect geese in the process of grazing. Another problem of antiparasitic actions is parasits’ resistance to the majority of preparations. The perspectives of this field is determined by the usage of antihelminthics of broad spectrum which include derived avermectins, which is presented by local medication such as «Brovermektin» 1% which consists of 10.0 mg of ivermectin. The article highlights data connected with the analysis of morphological and biochemical indicators of geese blood by adding after the process of deworming: Brovermektin 1% «E-selen», chalked steamed of macleaya cordata, powder of unprocessed buckwheat grains, onion and buckwheat husks as the source of rutin and its precursor such as quercetin and proanthocyanidin. The research has shown that adding to the geese ration of Brovermektin 1% only (second testes group) leads to significant increase of the quantity of erythrocytes, concentration of hemoglobin and activation of diagnostic enzymes of alkaline phosphatase, alanine transaminase, aspartate transaminase and γ-glutamyltransferase that testifies negative influence of preparation which is had on the liver and the development of hypoxic condition. At the same time adding one-time Brovermektin 1% with «E-selen» in dose of 0.01 cm3 per fowl, vegetable additives of macleaya cordata in dose of 0.563 g/10 kg of forage, «green buckwheat» in quantity of 2 g/10 kg of body weight was leading to decrease of indicators’ activity of liver ferments and to normalization of the quantity of erythrocytes and geese blood hemoglobin – are the indicators of hepatoprotective activity of these preparations in mentioned doses.

522 Evaluation of oats incorporated into annual ryegrass on performance of beef cattle

Forty crossbred beef steers (204.1 + 18.9 kg BW) were used in a randomized complete block to determine the effects of incorporating oats (Avena sativa) into annual ryegrass (Lolium multiflorum) pastures. Ten warm-season perennial pastures (1.21 ha) were killed with glyphosate and then burned, after which pastures were scratched with a disk. Pastures were randomly assigned to 1 of 2 treatments: 1) oats drilled into the pasture at a depth of 2.54 cm, at a rate of 90 kg/ha, after which annual ryegrass was broadcast at the rate of 56 kg/ha (OATS) or 2) annual ryegrass broadcast at the rate of 56 kg/ha (RG). Fertilization rates and application were similar across both treatments. When pastures had sufficient forage to support 4 beef cattle (5 kg forage DM/kg of BW), cattle were weighed and then moved into pastures. Forage biomass was determined weekly with the use of a rising plate reader, and when forage became limiting (less than 5 kg of forage DM/kg of BW), cattle were weighed and then removed. Between forage grazing periods, cattle had access to a commercial feed supplement and dormant forage. Pasture cost of establishment per hectare was greater for OATS (P= 0.001; US$332.5 and $219.7 for OATS and RG, respectively). Average daily gain did not differ (P= 0.90) between treatments (1.00 vs. 0.99 kg/d for OATS and RG, respectively. Pastures planted with OATS had more grazing days (124 vs. 98) and overall greater gain per pasture (P= 0.003; 383.8 kg compared with 291.6 kg for OATS and RG, respectively). Pasture-only cost of gain was similar (P= 0.24) for both OATS and RG; however, when the cost of supplementation (when not grazing) was factored into the overall cost of gain, OATS had a more economical cost of gain compared with RG (P= 0.002). Results suggest incorporation of a small grain such as oats may increase the winter grazing period and reduce cost of gain.

EVALUATION OF FRIESIAN HOLSTEIN GRADE COWS FERTILITY BASED THE LEVEL OF MILK UREA

This study was conducted to evaluate fertility grade of Friesian Holstein cows based on milk urea levels. A number of eight cows which fulfill the criteria of not pregnant and in second to sixth lactation, produced milk of 2.5 liters/day, and body weight ranging from 400-450 kg were used in this research. The cows were given fodder that consisted of 30 kg of forage and 10 kg of a mixture of concentrate (pollard, pulp out, and molasses), in the morning and afternoon. Milk and blood samples were taken once a week for five weeks in the morning before fed. Milk urea levels were measured using the urea FS (DiaSys) and blood samples were tested using enzyme linked immuno-sorbent assay (ELISA) with the progesterone hormone kit (DRG, Germany). The variables measured were pregnancy rate, service per conception (S/C), days open, and progesterone levels. Reproduction and milk urea levels data were analyzed by linear regression to determine the relationship between two variables. Progesterone data were analyzed descriptively. The results showed that the average calving interval, days open, and S/C were 607.5±170.27 days; 341.25±187.65 days; and 2.41±2.32 days, respectively. The average of milk urea levels was 14.16±2.55 mg/dL. Regression analysis showed a significant effect (P0.05) and negative correlation between milk urea level and S/C. The average of non-pregnant progesterone hormone level was 12.04±7.13 ng/mL. In conclusion, the fertility grade of Friesian Holstein cows decreased when the milk urea level at 14.16 mg/dL and non-pregnant progesterone at 12.04±7.13 ng/mL.

Nitrogen Fertilizer Effects on Nitrous Oxide Emission from Southwest Brazilian Amazon Pastures

Beef production is one of the most important agricultural activities in Brazil. In order to increase production without increasing deforestation, farmers are intensifying breeding and pasture improvements. The main technique for increasing pasture improvement is the application nitrogen fertilizer, but this action can result in emission of nitrous oxide (N2O). We assessed the impact of nitrogen fertilizer application on GHG emissions and pasture yield in a pasture located at Southwest Brazilian Amazon. Agronomic recommended rates of nitrogen fertilizer (NF) and higher rates, as two times (2NF) and four times (4NF) the recommended rate were applied. A control treatment with no fertilizer was also analysed. The experiment had 30 days duration, where we observed the baseline emissions from all treatments, including control. Nitrogen fertilizer application resulted in high N2O emissions. We found no differences between NF and 2NF treatments, but all treatments were different from control. The higher forage yield leads to low N2O emission per kg of forage in 4NF treatment. According to our study, the best (agro-environmental benefits) practice is the application of 100 kg N ha-1 (2NF treatment) in the region studied

The effect of presenting forage in multi-layered haynets and at multiple sites on night time budgets of stabled horses

The aim of this study was to explore the efficacy of multi-layered haynets and multiple presentation of haynets to increase time spent on feed intake behaviour at night (13h observation). For preliminary assessment two horses performing the oral stereotypy of crib-biting were included. Six horses received the same amount of forage during a 22-day, cross-over study where treatment consisted of either forage presentation in a single small-holed haynet (SH) or the forage was divided between 3 haynet combinations hung up simultaneously=multiple haynets (MH). The three haynets presented simultaneously consisted of (a) MH single haynet (same as SH), (b) MH double layered haynet and (c) MH triple layered haynet. Multiple haynets were presented, in random order, on three sides of the stable. Horses were filmed using a video surveillance camera with infrared light source. Behaviour was observed for at least 4 nights per treatment (one night during the acclimatisation period [nights 2–4] and three nights during the end period [nights 7–11]). The observation period commenced at 16.30–17.00h (point of haynets being presented) until 06.00h (all horses) or 9.00h (2 crib-biting horses) the next morning. Data were analysed for normal distribution and ANOVA between haynets, paired t-tests between treatments and Pearson correlation were used (SPSS. 17.00; 2012). There was a significant effect of type of haynet (p<0.001) on intake time per kg forage (min/kg for SH: 39; MH all (data combined): 51; MH Single: 27; MH Double: 67; MH Triple: 78; overall sem. 8.9). The overall time budget (minutes per observation hour) showed a significant difference between treatments for eating from haynet, standing still, locomotion and drinking. Horses finished eating from SH haynets at around 01.38am (±1.05h s.d.), were last observed at the double net at 03.00am and at the triple net at 05.12am (±1.25h s.d.). Based on these results, providing 6kg of forage in 3 double-layered, 2.5cm haynets spread around the stable could potentially lead to an increased feeding time of 2h per night compared to a single 2.5cm holed haynet containing 6kg. From the continuous observation data a clear visual difference in crib-biting pattern and therefore motivation to perform crib-biting emerged between the two stereotypic horses.

Smooth bromegrass pasture beef growing systems: Fertilization strategies and economic analysis

<h2>ABSTRACT</h2> In recent years, prices for N fertilizer have increased dramatically, reducing net returns of fertilized pasture systems. A 5-yr study from 2005 to 2009 was conducted to evaluate management strategies and relative differences in profitability for 3 methods of backgrounding calves on smooth bromegrass pastures. Forty-five steers were used each year for a total of 225 animals in a randomized complete block design. Treatments included pastures fertilized in the spring with 90 kg N/ha (FERT), nonfertilized pastures with calves supplemented daily with dried distillers grains plus solubles (DDGS) at 0.6% of BW (SUPP), and control (CONT) pastures that had no fertilizer or supplementation applied. Pastures were rotationally stocked and put-and-take cattle were used to maintain similar grazing pressure on all treatments. Forage production was greatest for the FERT paddocks, intermediate for SUPP paddocks, and least for CONT paddocks (P < 0.01). Stocking rates were greater for SUPP pastures compared with nonfertilized pastures because of increased forage production and replacement of approximately 0.79 kg of forage for each 1 kg of supplement fed. At the conclusion of grazing, SUPP steers were 40 kg heavier than either the FERT or CONT steers, which resulted in increased gross revenue of $44.14/steer for the SUPP treatment (P < 0.01). Net returns were greatest for SUPP at $17.55/steer (P < 0.01), whereas both the CONT and FERT treatments had negative net returns of -$6.20 and -$8.71/steer, respectively. In the future, the relationship between prices for land, N fertilizer, and DDGS will affect the net returns of all 3 treatments.

Quantitative characteristics of nutrition in free-ranging reindeer (Rangifer tarandus) and musk oxen (Ovibos moschatus) on Wrangel Island

In 2004 to 2006, studies on free-ranging reindeer and musk oxen on Wrangel island were performed to estimate the nutrient value, daily intake, and digestibility of forage in different seasons of the year. Forage digestibility was determined from the ratio between the contents of indigestible components (lignin) in forage and animal feces. Daily forage intake was calculated from data on daily feces excretion and forage digestibility. The amount of feces and parameters of life activity of individual animals were estimated by following their 24-hour tracks. The results show that the daily intake of forage (dry weight) in musk oxen amounts to 7.8 kg in the summer period and decreases to 6.1 kg in the snow period (March–April). Grazing reindeer in the snow period consume 3.9 kg of forage per day. Forage digestibility in reindeer reaches 56% in March to April and decreases to 52% in June. In musk oxen, forage digestibility in different seasons (March, June, September) varies within a similar range (53–57%). Nutrition parameters (diet composition, forage intake rate and digestibility) of reindeer and musk oxen on grazing grounds of Wrangel Island are similar. Metabolizable energy consumption in both animals during the winter period is at the maintenance level (917–930 kJ/kg0.75 body weight). In the summer period, this parameter in musk oxen increases to 1163 kJ/kg0.75 body weight to meet the energy demand of the animals.

Production and Quality of Forage and Economics of Grazing a Hay Meadow in the Spring

AbstractAn experiment was conducted to determine the effects of spring grazing on forage DM production and nutritive value, as well as the economics of spring grazing a flood-irrigated hay meadow. Two vegetation types were present: predominantly ‘Garrison’ fcreeping foxtail (Alopecurus arundinanceus Poir) and a complex mixture with both introduced and native species. With use of cages, samples of ungrazed and grazed treatments were collected before and after grazing and also in August. Eighty-eight Angus × Gelbvieh rotationally-crossed heifers (average BW = 361.3 kg) were allowed to graze from May 27 to June 8 at 5.4 heifers/ha. A sampling date effect (P < 0.0001) occurred for forage DM production. Forage DM production was not different (P = 0.90) between native species and creeping foxtail. Also, grazing treatment did not alter (P = 0.23) forage DM production. Vegetation types were not different (P . 0.19) in ash, NDF, ADF, and CP, but creeping foxtail was greater (P = 0.02) in in vitro DM digestibility than the native species group. The loss of 12,025kg of forage due to early grazing treatment, at a hay price of $0.0772/kg, resulted in a replacement hay value of $928. Forage plants were able to adequately recover from grazing despite atypical environmental conditions; however, expected improvements in quality did not occur with the early grazing treatment. It is concluded that although spring grazing by beef heifers did not affect forage production and most indices of forage quality, less harvestable nutrients in late summer were more costly than feeding harvested forage or renting pasture for the spring-grazing period.

Large-scale trophic interactions: White-tailed deer growth and forest understory

:The role that limiting factors play in population dynamics and the physical condition of animals may be easier to detect at the edge than the centre of a species’ range. We took advantage of a density cline at the periphery of distribution range of white-tailed deer to study trophic interactions between this herbivore and understory vegetation. We tested the hypothesis that the availability of summer forage in woodlands for this selective browser determines adult body size through density-dependent forage consumption during growth. We predicted 1) a change of forest composition resulting from persistent selective browsing; and 2) a negative relationship between the size of fully grown deer and the intensity of forage competition in summer. We estimated deer population density, carcass mass at maturity, and standing biomass of vegetation in 13 zones throughout the range of the deer in Québec, which covers 128,000 km2. Asymptotic carcass mass was related to body length, and to a lesser extent to percent body fat, and reflected size of fully grown deer. Plant biomass varied with respect to deer density, but the direction and intensity of the relationship depended on deer preference for various plant groups. Occurrence of preferred taxa decreased with increasing deer density. Forage competition in summer was related negatively to deer size, which declined sharply when there was < 10,000 kg of forage per deer. In the trade-off between growth and body reserves, the size of mature deer is likely adjusted to forage intake in order to balance absolute nutrient needs, a response allowing increased foraging efficiency of depleted resources.

Efeito de inoculante bacteriano sobre a qualidade da silagem e perda de matéria seca durante a ensilagem de sorgo

RESUMO - O objetivo deste trabalho foi avaliar o efeito de um inoculante bacteriano comercial, contendo Lactobacillus plantarum, Streptococcus faecium e Pediococcus acidactili, sobre a qualidade da silagem e perda de matéria seca (MS) durante a ensilagem de sorgo (Sorghum bicolor L. Moench). Os tratamentos foram constituídos por dois tipos de silagem de sorgo duplo-propósito colhido no estádio farináceo: sem (controle) e com inoculante; três posições dentro de cada silo (região do terço inicial, região central e do terço final), correspondendo a três períodos de coleta (52, 65 e 71 dias de fermentação) e três repetições em cada posição. Cada repetição foi constituída por um saco de tela plástica de malha fina, contendo aproximadamente 4 kg de forragem, sendo a parcela representada por uma amostra de aproximadamente 1 kg de forragem. A silagem com inoculante apresentou menor teor de cinza (matéria mineral), nitrogênio amoniacal e ácido láctico e níveis mais elevados de fibra em detergente neutro e fibra em detergente ácido. A silagem com inoculante não diferiu do controle em relação ao pH, à proteína bruta, energia bruta e porcentagem de perda da MS.

Effects of Cellobiose and Monensin on In Vitro Fermentation of Organic Acids by Mixed Ruminal Bacteria

The objective of this study was to determine the effects of cellobiose and monensin on the in vitro fermentation of organic acids (L-aspartate, fumarate, and DL-malate) by mixed ruminal bacteria. Ruminal fluid was collected from a steer fed 36.7kg of forage and 4.5kg of concentrate supplement once per day. Ruminal fluid was centrifuged to sediment feed particles and protozoa, and the resulting supernatant, which contained bacteria, was added (33%, vol/vol) to anaerobic media (500ml). Incubations (n = 2) were performed in batch culture at 39°C and sampled at 0, 2, 4, 6, 8, 12, and 24h. Organic acids were added to achieve a final concentration of 7.5mM. Cellobiose was added to obtain a final concentration of 5mM, and monensin dissolved in ethanol was included at concentrations of 0 or 5ppm. Addition of cellobiose to organic acid fermentations increased the rate of organic acid utilization by the mixed bacterial population. Total concentrations of volatile fatty acids were increased by the addition of cellobiose to all fermentations. A lag period (≤8h) occurred in fermentations that were treated with monensin before organic acids were utilized. Total concentrations of volatile fatty acids were increased, and the acetate to propionate ratio was decreased, by monensin treatment. When cellobiose and monensin were added together, propionate production and organic acid utilization were increased. Both cellobiose and monensin affected the in vitro fermentation of organic acids by mixed ruminal bacteria by providing a carbon and energy source and by influencing electron disposal.

Effect of malate on in vitro mixed ruminal microorganism fermentation.

The objective of this study was to evaluate the effects of different concentrations of DL-malate (disodium salt) on the in vitro mixed ruminal microorganism fermentation of soluble starch or cracked corn. Ruminal fluid was collected from a steer fed 6.8 kg of forage and 2.3 kg of concentrate supplement once daily, and mixed ruminal microorganisms were incubated in anaerobic media (40 mL) that contained 20% (vol/vol) ruminal fluid in batch culture for 24 h at 39 degrees C. Malate was added to the incubation bottles (n = 4) to achieve final concentrations of 0, 4, 8, and 12 mM. When mixed ruminal microorganisms were incubated with only DL-malate as the substrate, final pH numerically increased, propionate and total VFA concentrations increased (P < .05), and the acetate:propionate ratio decreased (P < .05) as the concentration of DL-malate increased from 0 to 12 mM. Fermentation of cracked corn in the presence of 8 or 12 mM DL-malate resulted in an increase (P < .05) in final pH and propionate concentration. Total VFA tended to increase (P < .21), whereas final concentrations of L-lactate numerically decreased. In the case of soluble starch, 8 and 12 mM DL-malate caused a decrease (P < .05) in methane concentration. When only ruminal fluid (no added anaerobic medium) was used as the inoculum rather than 20% ruminal fluid medium, similar results for final pH, propionate, L-lactate, and total VFA were observed for soluble starch and corn incubations treated with DL-malate.(ABSTRACT TRUNCATED AT 250 WORDS)

Old World Bluestem Responses to Nitrogen Fertilization

Old World bluestem (Bothriochloa ischaemum L.) is being extensively seeded on marginal farmland in the Southern Plains. This field study was conducted in western Oklahoma to develop guidelines for efficient N fertilization of this perennial, warmseason grass established on soil depleted in plant-available N by 80 to 90 years of cultivation and erosion. Ammonium nitrate at 0, 35, 70, and 105 kg N ha-lyr-1 was broadcast on Old World bluestem stands for 5 years on Woodward sandy loam (Typic Ustocrept) and for 3 years on Pratt loamy sand (Psammentic Haplustalf). Forage production averaged 800 kg ha'lyr'1 without N fertilization. An average of 30 kg of forage was produced per kg N applied at rates of 35 and 70 kg N ha-lyr-1. The 105 kg N ha lyr'l treatment produced substantially more forage than the 70 kg N ha-lyr-1 treatment only in years with above-average precipitation or favorable precipitation distribution. Partial die-out of Old World bluestem occurred one year; N fertilization increased die-out on Pratt loamy sand. Application of 70 kg N ha-1 in April was more effective in forage production and fertilizer N use in some years than split applications of 35 kg N ha-1 in April and June. Accumulation of N in forage over 5 years, plus residual N in stem bases, roots, and the surface 0.1 m of the Woodward sandy loam was 1,040 and 1,350 kg N ha-1 for the 0 N and 70 kg N ha-lyr-1 treatments, respectively. The difference of these values, 310 kg N ha-1, suggests that most of the 350 kg N ha-1 applied over 5 years was accounted for; however, the standard error of difference between the means was large (50 kg N ha-1).

A Method for Estimating Economic Injury Levels for Control of Rangeland Grasshoppers with Malathion and Carbaryl

A theoretical “average” rangeland grasshopper weighs 81.6 mg (dry weight) in the adult stage and consumes 9,22, and 53 mg of forage/day in the 4th instar, 5th instar, and adult stages, respectively. Criteria for a computer program are presented whereby grazing pressure from grasshopper infestations can be predicted as a function of initial density and normal daily rate of survival. The benefits of a contemplated control measure may then be estimated through appropriate adjustment of the survival rate. By assigning dollar values to the worth of forage and cost of treatment, the lowest infestation that will justify control measures can be determined. The technique is demonstrated for 2 effective but dissimilar insecticides, malathion and carbaryl. By using actual treatment costs for 1981 control programs and by assuming that an AUM (364 kg of forage) saved from destruction by grasshoppers