Digestible Dry Matter Content Research Articles

Nutrient Management for Optimizing Fodder Production of Sorghum – A Review

An area under cultivation of fodder crops has almost remained static (8.3 million ha) for the last 3 decades and area under permanent pastures has been declining over the years. Whereas, uncontrolled overgrazing reduced productivity of permanent pastures. Overgrazing also affect the soil bio-physic-chemical properties. The situation is further aggravated due to increasing human population and preferential need for food and growing commercial crops. In India, supply of forage has always been a limiting factor for enhancing livestock production. Demand of green and dry fodder continuously increasing as enhancing country’s livestock population. The gap in feed and forage supply, however, can effectively be reduced through integrated crop management practices with greater emphasis on nutrient management in forage crops. Application of nitrogen increases crude protein, digestible dry matter content and metabolic energy. Growth attributes with respect to plant height, stem diameter, Leaf Area Index (LAI) and number of basal node tillers increased with increase of phosphorus application levels. Application of micronutrients improves enzymatic activities and it leads to increase growth and yield of the fodder sorghum. Review regarding the use of adequate and optimum dose of nutrients especially nitrogen, phosphorus and micronutrients are of prime concern for the fodder sorghum crop in India. Keeping these points in view, the literature reviewed pertaining to the nitrogen, phosphorus and micronutrients in this crop to obtain higher biomass and good quality fodder production.

Feed-value of post-harvest quinoa plant sections grown by different cultural applications

The aim of the study, the grains of the quinoa plant grown in the Kahramanmaraş region, Turkey, which was sown at different times (March 26, April 2, 13 and 26, and May 11) in various row spacing applications (20, 40 and 60 cm) was separated, and the feed-worthiness of the remaining plant sections were analyzed. The study findings demonstrated that crude protein content was 9.70-19.30%, dry matter ratio was 86.18-88.20%, acid detergent fiber content was 42.95-55.95%, neutral detergent fiber content was 51.23-64.27%, acid detergent insoluble protein content was 0.88-1.37%, digestible dry matter content was 45.3-55.4%, drymatter intake rate was 1.87-2.34%, relative feed value was 66.88-96.49%, and quality standard value varied between III and V. Mineral content was determined as follows: Ca: 0.96-1.96%, K: 1.47-2.08%, Mg: 0.17-0.74%, P: 0.18-0.37%, Tetany: 1.51-1.99, milk fever: 3.69-9.49. It was determined that the sowing time with the highest feed values for quinoa straw was May 11, while the ideal row spacing was 40 cm. Thus, a feed with higher protein and mineral content but low indigestible nutrient content could be obtained. However, it was concluded that it would be more adequate to employ the feed in composite form with other feed plants for feed quality.

Defoliation height and potassium fertilization of Mulato II grass

A pot trial in greenhouse conditions was carried out to identify at which defoliation height Mulato II grass (Urochloa hibrida cv. Mulato II) should be managed and to determine whether potassium fertilization is necessary in soil with high potassium content. The experiment was carried out in a greenhouse in a randomized block design with six treatments and five replications. Treatments consisted of a 3 × 2 factorial arrangement, with three defoliation heights (50, 65, and 80 cm) and with or without potassium maintenance fertilization. The production characteristics and chemical composition of the forage plant were evaluated. There was no interaction effect between defoliation height and fertilization with or without potassium on any of the analyzed variables, except for mineral content in Mulato II grass. The tillers and leaves number, shoot dry matter, leaf+sheath, root system, and residue were influenced by defoliation heights and potassium fertilization, except for the leaf blades and root dry matter, leaf blade/stem+sheath ratio, and leaves number, which were not influenced by potassium fertilization. Higher shoot dry matter was observed at the heights of 65 and 80 cm; however, comparing these two heights, leaf + sheath dry matter was lower at 65 cm. Regarding the grass’s chemical composition, there was an increase in neutral and acid detergent fiber and indigestible neutral detergent fiber contents as the defoliation height increased, which resulted in lower production of potentially digestible dry matter, which can compromise the potential use of the forage by animals. Among evaluated treatments, Mulato II grass defoliation is recommended for a maximum height of 65 cm. Potassium fertilization increases the yield and the potentially digestible dry matter content of Mulato II grass, even when cultivated in soil with high potassium content.

Defoliation height and potassium fertilization of Mulato II grass

A pot trial in greenhouse conditions was carried out to identify at which defoliation height Mulato II grass (Urochloa hibrida cv. Mulato II) should be managed and to determine whether potassium fertilization is necessary in soil with high potassium content. The experiment was carried out in a greenhouse in a randomized block design with six treatments and five replications. Treatments consisted of a 3 × 2 factorial arrangement, with three defoliation heights (50, 65, and 80 cm) and with or without potassium maintenance fertilization. The production characteristics and chemical composition of the forage plant were evaluated. There was no interaction effect between defoliation height and fertilization with or without potassium on any of the analyzed variables, except for mineral content in Mulato II grass. The tillers and leaves number, shoot dry matter, leaf+sheath, root system, and residue were influenced by defoliation heights and potassium fertilization, except for the leaf blades and root dry matter, leaf blade/stem+sheath ratio, and leaves number, which were not influenced by potassium fertilization. Higher shoot dry matter was observed at the heights of 65 and 80 cm; however, comparing these two heights, leaf + sheath dry matter was lower at 65 cm. Regarding the grass’s chemical composition, there was an increase in neutral and acid detergent fiber and indigestible neutral detergent fiber contents as the defoliation height increased, which resulted in lower production of potentially digestible dry matter, which can compromise the potential use of the forage by animals. Among evaluated treatments, Mulato II grass defoliation is recommended for a maximum height of 65 cm. Potassium fertilization increases the yield and the potentially digestible dry matter content of Mulato II grass, even when cultivated in soil with high potassium content.

Yield, nutritive value and ensilage characteristics of whole-crop maize, and of the separated cob and stover components – nitrogen, harvest date and cultivar effects

SUMMARYThe objectives of the present study were to determine the effects of nitrogen (N) application rate, harvest date and maize cultivar on the yield, quality and the subsequent conservation characteristics of whole-crop, cob and stover silages. The experiment was organized in a spilt-plot design, with harvest date (15 September, 6 October and 27 October) as the main plot, and a three (maize cultivars: Tassilo, Andante and KXA 7211)×two (N application rate: 33 and 168 kg N/ha) factorial arrangement of treatments as the sub-plot, within three replicate blocks, and was conducted at Grange, Dunsany, Co. Meath, Ireland in 2009. The three harvest dates represented early, normal and late harvests, respectively, for a midland site in Ireland. Of the three maize cultivars selected, cvars Tassilo and Andante represent conventional cultivars sown by commercial livestock farmers in Ireland, while cvar KXA 7211 is categorized as a high biomass cultivar. No effect of N application rate was observed on the dry matter (DM) yield, nutritive value or ensiling characteristics of maize whole-crop or cob. Whole-crop and stover harvested on the later date had a lower digestible DM (DDM) content and the silages underwent a more restricted fermentation, compared to silages produced from herbage harvested on earlier dates. Cob silages produced from crops harvested on 15 September had lower DDM content and higher DM loss during ensiling than later harvest dates. Despite higher whole-crop DM yields, the later maturing cultivar KXA 7211 did not improve the DM yields of cob and also resulted in increased DM losses from the ensilage of cob, when compared with the other cultivars. In addition to the DM yield and nutritive value of forage maize at harvest, the subsequent fermentation profile during ensilage influences the optimum choice of cultivar and date for crop harvest in a maize silage production system.

총체맥류 주요품종의 봄 파종에 따른 생육, 수량 및 사료가치 비교

본 시험은 청보리, 밀, 호밀, 트리티케일, 귀리 등 총체맥류 주요 품종에 대하여 봄 파종시 출수 여부, 생육, 수량 및 사료가치 등을 적기 파종과 비교하고자 2008/2009년에 충남농업기술원(예산) 밭 사료포에서 수행되었다. 시험초종 및 품종은 청보리(영양, 파성 I), 밀(금강, 파성 II), 호밀(곡우, 파성 III 추정), 트리티케일(신영, 파성 III 추정), 귀리(삼한, 파성 II 추정)이었고, 파종기는 가을 적기파종(10월 18일)과 봄 파종(2월 23일, 3월 10일)을 두었다. 출수기는 봄 파종시 가을 적기 파종에 비하여 청보리, 밀, 호밀, 트리티케일 등은 약 16~20 일, 귀리는 약 9일 늦었다. 봄 파종시 수확시기는 영양 보리(황숙기) 6월 8일, 곡우 호밀(출수 후 10일) 5월 25일, 금강 밀(황숙기), 신영 트리티케일(유숙기) 및 삼한 귀리(유숙기)는 6월 17일경 이었다. 봄 파종은 가을 파종에 비하여 출현기부터 출수기까지의 적산온도의 감소가 컸고, 파종기~출현기, 출수기부터 성숙기까지의 적산온도는 큰 차이가 없었다. 전체 경수에서 출수된 이삭수의 비율은 영양 보리, 금강 밀, 신영 트리티케일, 삼한 귀리 등은 62.0~73.1% 로서 정상적으로 출수되었고, 곡우호밀은 56.0%로서 출수되지 않는 분얼이 많았다. 봄 파종시 건물수량은 삼한 귀리> 신영 트리티 케일> 영양 보리> 금강 밀> 곡우 호밀 순으로 많았고, 가을파종에 비하여 영양 보리 71.7%, 금강 밀 60.6%, 곡우 호밀 46.2%, 신영 트리티케일 70.2%, 삼한 귀리 110.9% 수준이었다. 총체맥류를 봄에 파종하면 가을 파종에 비하여 ADF 함량, NDF 함량 및 조단백질 함량이 증가하는 것으로 나타났고, 가소화건물함량과 상대사료가치는 낮아졌다. 봄 파종시 평균 가소화 건물수량은 삼한 귀리> 신영 트리티케일> 영양 보리> 금강 밀> 곡우 호밀 순으로 높았고, 가을에 파종한 것에 비하여 영양 보리, 금강 밀, 곡우 호밀, 신영 트리티케일은 모두 감수되었고, 삼한 귀리는 증수되었다. 따라서 예취시기 등을 고려하지 않는다면 봄 파종은 귀리가 가장 알맞은 것으로 나타났고, 다음은 신영 트리티케일, 영양 보리 순이었으며, 곡우 호밀은 부적합한 것으로 판단되었다. 또한 총체 맥류의 봄 파종 및 재배는 파성을 소거할 필요가 있으므로 2월 말(경칩 전) 얼음이 풀리는 대로 가능하면 빨리 파종하여 낮은 지온으로 종자 상태에서 춘화처리가 되도록 할 필요가 있었다. Few spring sowing have been conducted on winter cereal crops for whole-crop silage use. Experiments were conducted during 2007 and 2008 at the Chungnam Agricultural Research & Extension Services. The objectives of this study were compared the spring sowing with the optimum season's sowing on growth, yield and feed quality in five winter cereal crops. The treatments consisted of 5 winter cereal crops, Youngyang (Barley, Spring habit I), Keumkang (Wheat, Spring habit II), Gogu(Rye, Spring habit estimated III), Shinyoung (Triticale, Spring habit estimated III), Samhan(Oat, Spring habit estimated II), and 3 planting dates, 18 October (optimum season's sowing), 23 February and 10 March in spring. Heading days as affected by spring sowing compared to optimum season sowing were delayed by 16~20 days in barley, wheat, rye and triticale, and 9 days in oat. The clipping dates at the optimal harvesting stage of each crop for round-baled silage in spring sowing was 8 June (yellow ripe stage) in barley, 25 May (10 days after heading) in rye, and 17 June in wheat (yellow ripe stage), triticale (milky stage) and oat (milky stage). The accumulative temperature from emergence to heading was significantly decreased as affected by spring sowing compared to optimum season's sowing, but that of sowing to emergence and that of heading to maturing was similar. The rate of spikes per tillering surveyed at each clipping date was 62.0-73.1 percent in barley, wheat, triticale and oat, and 56.0 percent in rye compared to that of optimum season sowing. The dry matter yield in spring sowing compared to 18 October was obtained about 71.7 percent in barley, 60.6 percent in wheat, 46.2 percent in rye, 70.2 percent in triticale and 110.9 percent in oat. It were increased in acid detergent fiber (ADF), neutral detergent fiber (NDF) and crude protein content, but decreased in digestible dry matter content(DDM) and relative feed value (RFV). The yield of DDM by spring sowing was decreased in barley, wheat, rye and triticale, but increased in oat. The yield of dry matter and DDM were higher in oat and triticale than that of barley, wheat and oat. So, regardless to clipping dates and cropping system, the appropriated crop for spring sowing was oat, and subsequently triticale and barley. It was not adopted for spring sowing in rye because of low rate of no. of spikes per tillers and yield. It was necessary eliminated winter growing nature by earlier sowing at the late of February after overwinter.

중부지역에서 총체맥류의 예취시기별 사료가치 변화

청보리, 밀, 호밀, 트리티케일, 귀리 등 5종의 총체맥류에 대하여 중부지역에서 답리작 재배시 월동 후인 3월 15일 부터 6월 15일까지 10일 간격으로 10회에 걸쳐 예취한 후 각 작물별 예취시기에 따른 사료가치를 비교하였다. ADF 함량은 5종의 총체맥류 모두 월동 후 증가하다가 각 작물별로 최고점에 도달한 후 성숙이 진행됨에 따라 감소되는 2차원적인 경향을 보였고, NDF 함량은 월동 후 점진적으로 증가하다가 대체로 어느 일정시기 이후에는 정체되거나 다소 감소되는 경향을 보였으며, 조단백질 함량은 잎이 풍부한 월동 직후에 높았다가 생육단계가 진행됨에 따라 점진적으로 감소되는 경향을 보였다. 가소화건물(DDM) 함량은 총체맥류 5종 모두 월동 후 생육이 진전될수록 낮아지다가 출수기 이후 종실이 충실해짐에 따라 다시 증가되는 경향을 보였고, 상대사료가치(RFV)는 월동 후 잎이 풍부한 생육초기에 높았다가 생육이 진전됨에 따라 감소되었으며, 출수기 이후에 종실이 충실해지면서 다시 증가되는 경향을 보였다. 맥종별로 보면 청보리인 영양보리는 다른 총체맥류에 비하여 출수기 이후 ADF와 NDF 함량이 낮았고, 가소화건물 함량과 상대사료가치(RFV)가 높았다. 금강밀은 다른 총체맥류에 비하여 단백질 함량이 높았고, 출수기 이후 가소화건물 함량과 상대사료 가치가 곡우호밀, 신영트리티케일, 삼한귀리에 비하여 상대적으로 높았다. 곡우호밀은 다른 총체맥류에 비하여 내한성과 내재해성이 강하지만 월동 후 성숙기 까지 ADF와 NDF 함량이 높고, DDM 함량과 상대사료가치 (RFV)가 낮은 조사료 작물에 해당하였다. 신영트리티케일은 영양보리 또는 금강밀과 곡우호밀의 중간적인 특성을 보였으며, 생육후기로 갈수록 가소화건물 수량이 직선적으로 증가하였다. 삼한귀리는 출수 전까지 ADF와 NDF 함량이 낮고 단백질이 풍부하였지만, 출수 후 성숙이 진행될수록 다른 총체맥류에 비하여 변화가 적었다. The objectives of this study were to evaluate the different cutting dates on the changes of feed quality among five cereals (barley, wheat, rye, triticale and oat) for whole crop silage. Field trials were conducted at paddy field in Yesan, Chungnam Province and the aerial parts were clipped 10 days from 15 March to 15 June. Changes of acid detergent fiber (ADF) content in relation to different cutting dates was described by a quadratic curve for 5 winter cereals crops. ADF content reached a maximum at 5 days after heading in barley cultivar 'Youngyang', 7 days in wheat 'Keumkang', 18 days in rye 'Gogu', 1 days in triticale 'Shinyoung' and 10 days in oat 'Samhan'. Neutral detergent fiber (NDF) content were linearly increased as growing after overwintering and stagnated or slightly decreased after heading. The crude protein were linearly decreased throughout the growth period of 5 whole crop cereals. Digestible dry matter (DDM) content were decreased from early stages to heading and subsequently increased as grain filling. Relative feed value (RFV) for 5 crops were decreased as growing and subsequently increased as grain filling after heading. Barley cultivar for only forage use 'Youngyang' were lower at ADF and NDF content and higher at DDM and RFV after heading than those of other cereals for forage use. So, barley for whole crop silage was a good crop with high feed quality and high proportion of spikes compared with other winter cereal crops. Wheat cultivar for grain 'Keumkang' were higher at crude protein than those of other four cereals from overwintering to maturing and were higher at DDM and RFV after heading than those of rye, triticale and oat. Rye cultivar with cold tolerant and high fresh yielding 'Gogu' were highest at ADF and NDF content and lowest at DDM content and RFV. So, rye was a crop with low quality for forage use compared to other winter cereal crops. Triticale cultivar with flourishing and high yielding 'Shinyoung' was intermediated between barley and rye, and were linearly increased at DDM yield by different cutting dates. Oat cultivar with cold tolerant and high tillering 'Samhan' were lower at ADF and NDF content and higher at crude protein before heading, but after heading, there are not especially advantages compared to barley, wheat or triticale.

Weed management in irrigated fenugreek grown for forage in rotation with other annual crops

Fenugreek (Trigonella foenum-graecom L.) is an annual legume that has potential as a forage crop on the Canadian Prairies. Experiments were established to determine the tolerance of fenugreek to several herbicides and their efficacy on various weeds. Potentially, fenugreek could be grown in conservation tillage systems in rotation with other annual crops. Therefore, additional multi-factor experiments were conducted to determine the effect of herbicides, seeding method, and 11 previous crops on fenugreek yield. Without herbicide application, weeds contributed 37 to 86% to total dry matter production. When imazamox/imazethapyr, or combinations of imazamoz/imazethapyr or imazethapyr with ethalfluralin was applied, weed contents were about 5% of the total dry matter and the herbicides did not reduce fenugreek yield compared to the hand-weeded check. Total forage samples with a low weed content had lower fibre content and higher protein and digestible dry matter content than forages with a high weed content. When imazamox/imazethapyr was used for weed control, fenugreek yields and weed biomass were similar after direct seeding and after cultivation plus seeding. In addition, the effect of previous crop and the previous crop by seeding method interaction was not significant for fenugreek yield and weed biomass. Therefore, irrigated fenugreek can be successfully grown in conservation tillage systems in rotation with several crops provided an effective herbicide is used for weed control. Key words: Conventional tillage, crop rotation, redroot pigweed, wild oat, zero tillage

Why bears consume mixed diets during fruit abundance

In many ecosystems, grizzly bears (Ursus arctos) and black bears (Ursus americanus) feed heavily on berries and fruits in the fall. While a few birds and mammals are exclusively frugivorous, bears and most other animals consume fruit as part of a mixed diet. The mixed-diet strategy avoids potential calcium, protein, amino acid, or other nutrient deficiencies that can occur on fruit diets. However, we hypothesized that the high carbohydrate - low protein content of fruit would increase energy metabolism and force bears to use dietary mixing to meet protein requirements and, thereby, reduce energy metabolism. We examined the effects of six plant-based diets containing from 2.3 to 35% crude protein on intake, maintenance costs, and efficiency of gain of captive grizzly and black bears. In addition, the food habits of six populations of wild grizzly and black bears were analyzed, to determine the crude protein and digestible dry matter content of their diets. Efficiency of gain (0.53 ± 0.02 (±SD) g gain/g digestible dry matter intake) did not differ across diets. However, maintenance costs differed, ranging from 24 g·(kg0.75·day)-1 (120 kcal (1 cal = 4.1868 J) digestible energy (DE)·(kg0.75·day)-1) on the 35% protein pelleted diet to 80 g·(kg0.75·day)-1 (340 kcal DE·(kg0.75·day)-1) on fruit diets containing 2.3-5.6% protein (P = 0.0001). Supplementation of the fruit diet with additional protein increased mass gain but did not completely reverse the growth-depressing effect of the fruit-only diet. Protein limitations or other characteristics of fruit diets that increase energy metabolism and intake may be strategies that also directly benefit plants, by increasing either seed dispersal or propagation.

Why bears consume mixed diets during fruit abundance

In many ecosystems, grizzly bears (Ursus arctos) and black bears (Ursus americanus) feed heavily on berries and fruits in the fall. While a few birds and mammals are exclusively frugivorous, bears and most other animals consume fruit as part of a mixed diet. The mixed-diet strategy avoids potential calcium, protein, amino acid, or other nutrient deficiencies that can occur on fruit diets. However, we hypothesized that the high carbohydrate - low protein content of fruit would increase energy metabolism and force bears to use dietary mixing to meet protein requirements and, thereby, reduce energy metabolism. We examined the effects of six plant-based diets containing from 2.3 to 35% crude protein on intake, maintenance costs, and efficiency of gain of captive grizzly and black bears. In addition, the food habits of six populations of wild grizzly and black bears were analyzed, to determine the crude protein and digestible dry matter content of their diets. Efficiency of gain (0.53 ± 0.02 (±SD) g gain/g dig...

Temperature and Water Stress Effects on Growth of Tropical Grasses

Coastal bermudagrass (Cynodon dactylon (L.) Pers.) and Kleingrass “75” (Panicum coloratum L.) were grown under controlled environments to evaluate the effects of high growth temperaturesand water stress on forage growth. Plants were grown under a controlled environment with 14/10 hour day/night temperatures of 30/20,35/25, and 40/3W C; 2 water regimes; and 3 stages or ages of regrowth at harvest. High growth temperatures significantly (KO.05) increased dry matter yield and accelerated tiller number and the maturation rate of the plants. Significant (JYO.05) increases in leaf area, weight per tiller, and plant height were observed as growth temperatures were increased. Reduction of number of tillers per pot due to water stress reduced dry matter yields approximately 380/o. The percent leaf was greater for the water-stressed plants than for the well-watered plants, but the leaf area per plant was less due to reduction of growth and delayed maturation. Dry matter yield of water-stressed plants grown under higher temperatures increased more than corresponding wellwatered plants as a result of increased rate of stem elongation and leaf development. Though water-stressed plants were shorter and had less leaf area than well-watered plants, the relative increase in both height and leaf area at higher temperatures of stressed plants was greater than well-watered plants. Apparently supraoptimal temperature (400 C) does not have a negative effect on yield in the presence or absence of moisture stress. Reduction of digestible dry matter content has been reported for warm-season tropical grasses sampled under conditions of high temperature and water stress (Holt 1975, Pitman et al. 1981, Wilson 1981). Environmental stresses also affect growth rates and yields of grasses. Optimum temperatures for growth of tropical grasses are 30 to 35” C during the day and 25 to 30” C at night (Dirven and Deinum 1977, Ivory and Whiteman 1978). Optimum temperature results in an increased rate of stem elongation and leaf appearance (Dirven and Deinum 1977) and an increase of the number of tillers and of leaves per tiller. An increase in area per leaf and leaf area per plant also contributes to the greater production. Conversely, water stress in tropical grasses reduces yield (Ng et al. 1975, Wilson et al. 1976) slows cell enlargement and stem elongation, and reduces leaf area and the shoot/ root ratio. High temperature can accentuate the rate of water loss, plant water deficits, and water stress. Although mid-summer sampling of warm-season grasses has facilitated evaluation of the combined effects of high temperatures and water stress, the independent effects of high temperature and water stress, and their interaction, remain to be quantified in controlled environments. Henderson and Robinson (1982) reported the effects of growth temperatures on yield of tropical grasses under 2 watering regimes, but the effects on yield components were not reported. In addition, growth temperatures reported to date generally have not exceeded 35’ C in most studies, yet summer daytime temperature extremes in the Southwestern United States commonly exceed 35” C. The objective of this study was to quantify the independent effects of high growth temperature and water stress, and their interaction, on yield and growth components of Coastal bermudagrass and Kleingrass 75.

Relation of feedlot performance and certain physiological responses to the metabolizable protein and urea content of cattle diets.

An experiment was conducted to test the accuracy of the metabolizable protein system in predicting the amount of urea that would be useful in a corn-based cattle diet. Treatment diets included a basal, low-protein (7.8% CP) negative control (NC) with no supplemental N and a positive control (PC) that contained soybean meal. Urea was added to the NC diet in quantities calculated to be either 25% deficient (LU), equal to (MU) or 25% in excess (HU) of the urea fermentation potential ( UFP ). In vitro rumen fermentation studies were used to determine sequential ammonia production and digestible dry matter content of the diets. In a growth trial, 12 individually-fed Angus, Hereford and Angus X Hereford steers weighing an average of 213 kg were assigned randomly to each treatment diet. At the conclusion of the 112-d trial, rumen ammonia and jugular blood urea N (BUN) concentrations were determined on two steers from each treatment before feeding and at 1, 2, 3, 4 and 5 h postfeeding. In vitro ammonia concentrations of the NC and PC treatments were lower (P less than .05) than that of urea containing diets. In vivo rumen ammonia concentrations at 1 h postfeeding and BUN levels at 3 h postfeeding were low for both the NC and PC diets compared with urea-containing diets. Both of these values increased with each successive increase of added urea to the NC diet. During the initial 70 d of the growth trial, daily gains were improved (P less than .05) by addition of urea up to the MU level, which fulfilled the calculated UFP .(ABSTRACT TRUNCATED AT 250 WORDS)

MAXIMUM LOSS OF FEED FROM NYLON BAGS IN THE RUMENS OF STEERS AS RELATED TO APPARENT DIGESTIBILITY

Nylon bags containing rolled barley or mixtures of rolled barley and finely chopped alfalfa hay in ratios of 1:1, 2:1, and 3:1 were removed from two fistulated steers 1, 2, 4, 8, 14, 24, 48, and 72 hours after placement in the rumen. The cumulative loss of dry matter and protein from the bags was described for each ration by an equation of the form X/Y = k1 + k2X. The asymptotes of the curves so calculated were taken as estimates of the theoretical maximum loss of dry matter and protein. Maximum dry matter losses were 77.4, 80.7, 82.4, and 90.5% and apparent dry matter digestibilities were 73.0, 78.3, 79.1, and 80.7% for the 1:1, 2:1, 3:1, and all-barley rations, respectively. The corresponding values for maximum protein loss were 95.3, 94.2, 94.6, and 98.8% while those for apparent protein digestibility were 76.8, 83.2, 83.7, and 82.0%. From estimates of endogenous fecal protein loss, it was calculated that fecal loss of potentially available feed dry matter accounted for 60% of the difference between the apparent and maximum digestible dry matter content of the three rations containing hay, and 89% of that of the all-barley ration. Endogenous fecal protein loss accounted for about half of the difference between maximum and apparent protein digestibility.

Curing Coastal Bermudagrass Hay: Effects of Weather, Yield, and Quality of Fresh Herbage on Drying Rate, Yield, and Quality of Cured Hay1

AbstractMoisture losses and changes in yield and quality of 64 lots of Coastal bermudagrass hay were studied during curing. Water content of grass after a day of curing was significantly influenced by initial water content, vapor pressure deficit of the air, solar radiation, and yield; there was a significant interaction of initial water content with the other three factors. Water content of the grass might increase or decrease during the night, depending upon water content at the end of the previous day, vapor pressure deficit, and yield. Dry matter yield and crude protein and digestible dry matter content decreased slightly in good curing weather and sharply in rainy weather. Carotene losses were associated with total radiation received during curing. We concluded that rain during curing would produce greater losses in quality than delaying harvest until better weather was predicted.

Effect of Age on the Chemical Composition, Palatability and Digestibility of Grass Leaves1

SynopsisYoung leaf blades from the top of heading culms of Gahi‐1 pearl millet and Georgia 337 Sudangrass were more palatable and contained more crude and true protein and less lignin than older lower leaves taken from the same culms. Eighteen successive leaves from top to bottom of the culms of late‐maturing millet plants gradually decreased from 73.9% to 58.2% in digestible dry‐matter content. Millet genotypes differed significantly in digestible dry‐matter content.

The Use of Methoxyl Groups in Forage and Fecal Materials as an Index of the Feeding Value of Forages

Summary The relationship of the methoxyl content of forage and of feces to the digestibility and to the content of crude protein, crude fiber, ether extract and nitrogen-free extract has been studied at three different growth stages of pasture herbage. The relationship of the lignin to the methoxyl content and to the contents of the proximate constituents of the plant also have been studied. The digestibility of forage dry matter was correlated negatively with the amount of lignin (−0.989) and of methoxyl (−0.991) in the forage consumed. A highly significant negative correlation (−0.974) also existed between the methoxyl content of the feces and the digestible dry matter content of the forage. The correlation (0.425) between the lignin content of the feces and amount of digestible dry matter in the forage consumed was not significant. The crude protein content of the feces also was correlated very highly with the digestible dry matter content of the forage (0.962). This study indicates that the methoxyl content of forages and/or feces may prove, with further study, to be equal or superior to the lignin content as an index of the digestibility of forages. If this should prove to be valid for all forages, the analytical task would be simplified because the procedure for the determination of methoxyl is simpler than that for lignin. In addition, when methoxyl is determined, a distinct chemical radical is measured. This is not true in the determination of lignin by present methods.