Lower NDF Content Research Articles

Production and chemical composition of pasture forbs with high bioactive compounds in a low input production system in the Pacific Northwest

Pasture forbs are increasingly being incorporated in pasture systems for their high nutritive value and biologically active secondary compounds as our understanding of their functional roles advances. A 2-year study investigated the effects of varietal differences and companion legume species on forage dry matter (DM) production, nutritive value, and plant secondary composition of two chicory (Cichorium intybus L.) cultivars (Antler and Grasslands Puna) grown in monoculture and in binary mixtures with red clover (Trifolium pratense L.) or birdsfoot trefoil (Lotus corniculatus L.). Antler chicory out-yielded Grasslands Puna chicory in the 2017/2018 growing season but the superiority of Antler was not consistent in 2018/2019. Binary mixtures of chicory and red clover consistently provided greater DM yield and higher nutritive quality forage than chicory monocultures. Intercropping birdsfoot trefoil with chicory cultivar Grasslands Puna yielded more DM in 2018/2019 and had lower NDF content in summer compared to chicory monocultures, but not when intercropped with Antler. Intercropping led to increased condensed tannin (CT) concentrations in forages as compared to monocultures. Antler chicory contained 7.3 times more (CT) compared to Grasslands Puna, but there was no significant difference in their anthocyanin concentrations.

Nutritive value of improved populations Brachiaria ruziziensis

A low number of Brachiaria ruziziensis (Syn. Urochloa) cultivars available on the market and a lack of information about its forage potential have made it difficult to expand its cultivated area, and have therefore made it necessary to implement a breeding program for this species. Thus, the objective of this work was to evaluate the nutritional value of ten improved populations of Brachiaria ruziziensis (Syn. Urochloa) and two controls (B. ruziziensis cv. Kennedy and B. brizantha cv. Marandu). The experimental design was a randomized block design with three replications in five sections. The data were submitted to analysis of variance in the subdivided plot in which the primary factors were the populations and the secondary cuts. The Tukey test was used at 5% of significance for the comparison of means. The genotypes used came from the third recurrent selection cycle of Embrapa dairy cattle, originating from the interbreeding of clones which had been identified as superior. The height of the cuts was 10 cm in relation to the ground. The material was cut and weighed in the field to obtain the sample weights to determine the nutritional forage value. After drying, the samples were ground in 1 mm sieves for chemical analyzes and in vitro digestibility. The best CP, ADF and NDF levels observed in IV populations (lower levels of ADF and NDF at 93 days of cut interval and lower NDF contents at 35 and 41 days of cut interval), population VI (higher CP content in the interval of 93 days, lower DM content at 64 and 93 days of cut interval, and lower NDF content at 35 and 64 days of cut interval) showed that these populations can be evaluated under grazing even at an advanced maturation stage. The objective of these selections was to evaluate the nutritional value of improved populations of Brachiaria ruziziensis (Syn. Urochloa) in order to obtain more homogeneous populations for implantation of grazing experiments.

Nutritive value of improved populations Brachiaria ruziziensis

A low number of Brachiaria ruziziensis (Syn. Urochloa) cultivars available on the market and a lack of information about its forage potential have made it difficult to expand its cultivated area, and have therefore made it necessary to implement a breeding program for this species. Thus, the objective of this work was to evaluate the nutritional value of ten improved populations of Brachiaria ruziziensis (Syn. Urochloa) and two controls (B. ruziziensis cv. Kennedy and B. brizantha cv. Marandu). The experimental design was a randomized block design with three replications in five sections. The data were submitted to analysis of variance in the subdivided plot in which the primary factors were the populations and the secondary cuts. The Tukey test was used at 5% of significance for the comparison of means. The genotypes used came from the third recurrent selection cycle of Embrapa dairy cattle, originating from the interbreeding of clones which had been identified as superior. The height of the cuts was 10 cm in relation to the ground. The material was cut and weighed in the field to obtain the sample weights to determine the nutritional forage value. After drying, the samples were ground in 1 mm sieves for chemical analyzes and in vitro digestibility. The best CP, ADF and NDF levels observed in IV populations (lower levels of ADF and NDF at 93 days of cut interval and lower NDF contents at 35 and 41 days of cut interval), population VI (higher CP content in the interval of 93 days, lower DM content at 64 and 93 days of cut interval, and lower NDF content at 35 and 64 days of cut interval) showed that these populations can be evaluated under grazing even at an advanced maturation stage. The objective of these selections was to evaluate the nutritional value of improved populations of Brachiaria ruziziensis (Syn. Urochloa) in order to obtain more homogeneous populations for implantation of grazing experiments.

Effect of Variety and Plant Protection Method on Chemical Composition and in Vitro Digestibility of Faba Bean (Vicia Faba) Seeds

Abstract The aim of the work was to determine the effect of faba bean varieties and plant protection method on their yield of seeds and protein, chemical composition, in vitro true digestibility (IVTD) and nutritive value for ruminant feeding. The study was carried out on four cultivars of faba beans grown in similar environmental conditions in a two-factorial field experiment. The variation between cultivars, modified by the plant protection method, in chemical composition and IVTD of seeds may suggest that there would be a need to estimate its real nutritive value used for diet formulation instead of one common value for faba bean species read from feed tables. It was shown that lowtannin varieties are characterized by slightly higher CP and lower NDF content and significantly (P<0.01) higher IVTD digestibility compared to traditional or terminal inflorescence varieties. Regardless of type of faba been variety, the highest seed and protein yields were found when insecticides were applied, with minor effect on chemical composition and the nutritive value of seeds.

Seasonal heat production and energy balance of grazing yaks on the Qinghai-Tibetan plateau

A study was conducted to measure the energy balance of free-ranging yak during the four annual seasons in order to elucidate the factors constraining energy utilization by grazing yak. The heat production (HP, kJ/day) of grazing non-lactating female yaks was calculated as the product of heart rate (HR, beats/min) and the amount of O2 delivered to the body at every heartbeat (O2P, μl), and by the constant value of 20.47kJ/l of O2 consumed. Heart rates were recorded continuously over 4 days, using modified heart rate monitors. Individual daily fecal output was measured using Cr2O3 as an external marker. Daily herbage dry matter (DM) intake was calculated from fecal output and digestibility of the forage determined in vitro. The greatest herbage mass was measured in August (496kg DM/ha), and the least in December and May (208 and 226kg DM/ha). However, the herbage present in both May and August had higher crude protein contents and lower NDF contents than those sampled in October and December. Daily average HR (beats/min) was greater in summer (August) than during the other three seasons (78 vs. 49–52). The greatest O2P was recorded in May. The highest metabolizable energy intake (MEI) (1120kJ/kg BW0.75 per day) was measured in August when yaks grazed on lush green forage. HP was higher in August than in October and December (715, 548 and 400kJ/kg BW0.75 per day, respectively), but did not differ significantly from that measured in May (640kJ/kg BW0.75 per day). The animals were in positive energy balance only during August (energy retention (ER)=405kJ/kg BW0.75 per day). Energy balance did not differ between the other seasons: −111 (October), −91 (December) and −13 (May) kJ/kg BW0.75 per day, respectively. HP and ER were highly correlated with MEI (R2=0.73 and 0.88, respectively). The formulas calculated through the regression of HP and ER on MEI were used to estimate fasting heat production (FHP=341kJ/kg BW0.75 per day) and maintenance ME requirements (MEm, 545kJ/kg BW0.75 per day) of the free grazing yaks. The results showed that free-ranging yaks expended much more energy to resist harsh environmental and sward conditions compared with confined yak or cattle and grazing cattle in low land area.

Feeding Brassica juncea or Brassica napus canola meal at increasing dietary inclusions to growing-finishing gilts and barrows

Novel Brassica (B.) juncea has a thinner seed coat and therefore lower fibre content than conventional B. napus canola meal (CM) and could potentially be fed at greater dietary inclusions to pigs. In a 2×2×3 factorial arrangement, 528 barrows and 528 gilts [33.6kg body weight] housed in 48 pens (22 barrows or gilts) were fed either B. juncea or B. napus CM at 100, 200 or 300g/kg of diet with up to 200g/kg wheat DDGS to slaughter weight (120kg). Compared with B. napus, B. juncea CM had 32g/kg greater CP, 12g/kg lower crude fat, 86g/kg lower ADF, and 91g/kg lower NDF content. However, aliphatic glucosinolate content was 2.7 times greater in B. juncea (11.76μmol/g) than B. napus CM (4.34μmol/g). For the entire trial (d 0–72), daily weight gain (ADG) was not affected by canola species, but feed disappearance (ADFI) was 45g/d lower (P=0.06) and feed efficiency 7g/g greater (P<0.05) for pigs fed B. juncea than B. napus CM. Carcass traits were not affected by canola species except dressing, which was 1% lower (P<0.05) for pigs fed B. juncea than B. napus CM. For the entire trial, increasing CM inclusion from 100 to 300g/kg of diet decreased ADFI (P<0.001) by 184g/d, decreased ADG by 32g/d (P<0.05), but increased feed efficiency (P<0.001) by 14g/g. Dietary CM inclusion level did not affect farm ship live weight to slaughter, carcass backfat thickness, lean yield, or index. Nonetheless, carcass weight was 0.9kg lower (P<0.05), dressing was 1% lower (P<0.001), loin depth was 1.3mm lower (P<0.01), and days to slaughter was 2.3 days greater for pigs fed 300 compared with those fed 100g CM/kg diet. In conclusion, growing-finishing pigs can be fed diets including B. juncea CM the same as conventional B. napus CM without decreasing growth performance or carcass traits. Feeding growing-finishing pigs a diet with 300 vs. 200 or 100g/kg CM with up to 200g/kg of wheat DDGS resulted in decreased weight gain and a minor decrease in carcass weight, dressing and loin depth, but increased feed efficiency.

Effects of feeding level and NDF content of grass-clover silages on chewing activity, fecal particle size and NDF digestibility in dairy heifers

The objective of this study was to assess effects of feed intake and NDF content of highly digestible grass-clover silage on chewing behavior, fecal particle size distribution and apparent digestibility in restrictively fed heifers. Four grass-clover silages (Lolium perenne, Trifolium pratense and Trifolium repens) were harvested in 2009 at different regrowth stages, resulting in silages with NDF contents of 312, 360, 371 and 446 g/kg dry matter (DM), respectively. Four rumen-fistulated Jersey heifers (343±32 kg BW) were fed silage at 90% of ad libitum levels in a 4×4 Latin square design, replicated with further restricted feeding levels (50%, 60%, 70% or 80% of ad libitum) in a balanced 4×4×4 Greco-Latin square design. Eating activity was estimated from test meal observations, while rumination activity was estimated from jaw movements logged by a jaw recorder system. Total tract digestibility was estimated from chromic oxide marker and fecal spot sampling, and fecal particle size distribution in washed and freeze-dried particulate DM was determined by dry sieving (2.36, 1.0, 0.5, 0.212 and 0.106 mm, and bottom bowl). Higher NDF content of silage stimulated longer eating time per kg DM intake (P<0.001), while reduced feeding level caused a reduction in eating time per kg DM intake (P<0.001) and NDF (P<0.001). Rumination time per kg DM intake (P<0.01) increased with reduced feeding level, with less effect of feeding level at lower NDF contents (P<0.01) and more rumination with greater NDF content (P<0.01). Relative to NDF intake, rumination time increased with greater NDF content (P<0.01), at a higher rate with reduced feeding level (P<0.05). Digestibility of potentially digestible NDF (DNDF) decreased with greater NDF content (P<0.001) and increased with reduced feeding level (P<0.05). Increasing NDF content resulted in more particulate DM in feces (g/kg DM; P<0.05) and larger mean particle size (P<0.001). In conclusion, feeding heifers with grass-clover silages of decreasing NDF content increased chewing time relative to NDF intake, reduced mean fecal particle size, and increased DNDF digestibility. Restricting feeding level made heifers eat for a shorter time period while rumination and total chewing was increased, causing the ratio between eating and rumination time to decrease with lower intake of forage fiber. Particle size reduction and digestibility depended mostly on changes in NDF content, especially the indigestible NDF content.

Meta-análise do impacto da fibra em detergente neutro sobre o consumo, a digestibilidade e o desempenho de vacas leiteiras em lactação

Avaliaram-se os efeitos das características químicas e da digestibilidade in vivo da FDN (DFDN) sobre o consumo, a digestibilidade e o desempenho de vacas leiteiras em confinamento utilizando-se meta-análise a partir de 285 observações de seis experimentos. Utilizaram-se dados de animais alimentados com dietas à base de silagem de milho (n = 213) ou cana-de-açúcar (n = 72). Apesar do menor teor de FDN da cana-de-açúcar (45,27% da MS) em relação à silagem de milho (54,48%), observaram-se menores consumos de MS e FDN, que refletiram em menor produção de leite. Verificou-se maior redução no comsumo de matéria seca (kg/dia) com aumento do teor de FDNf (FDN de forragem, % da MS) em dietas com canade-açúcar (332,4 g de MS para cada 1% no teor de FDNf) em relação à silagem de milho (96 g de MS para cada 1% no teor de FDNf). O maior efeito de repleção ruminal da FDN da cana-de-açúcar deve-se à fração indigestível, majoritária, apesar da maior taxa de degradação da fração potencialmente degradável da FDN em relação à silagem de milho. A produção de leite não-corrigida (PL) e corrigida para 4% de gordura (PLC) e o teor de proteína do leite reduziram linearmente com o aumento no teor de FDNf, independentemente da fonte de forragem. Porém, a PL e PLC não foram afetadas pelo nível de FDNnf (FDN de não-forragem). Os consumos de MS, FDN e NDT e o teor de gordura no leite reduziram linearmente com aumento na relação lignina:FDN, com maior amplitude em dietas à base de cana-de-açúcar em relação à silagem de milho. O consumo de MS, a produção de leite e a produção de leite corrigida reduziram linearmente e na mesma magnitude entre as fontes de forragens, com o aumento na DFDN da dieta. O efeito do teor FDN e lignina sobre o consumo, a digestibilidade e o desempenho animal depende da fonte utilizada.

Feeding behaviour of sheep fed lucerne v. grass hays with controlled post-ingestive consequences

Understanding what determines feeding behaviour in herbivores is essential to optimise the use of forages in breeding systems. Herbivores can evaluate foods by associative learning of their pre-ingestive characteristics (taste, odour, etc.) and their post-ingestive consequences. Post-ingestive consequences are acknowledged as influencing intake and food choices, but the role of pre-ingestive characteristics is still being debated. Our experiment was designed to test their separate effects on daily dry matter intake (DMI), intake patterns and short-term choices in sheep by crossing the nature of the hay orally consumed (o) ad libitum, lucerne (L) or grass (G), with the nature of the hay introduced into the rumen (r), L or G, at a rate of half the total amount of hay received the day before. We applied four treatments, Go/Gr, Go/Lr, Lo/Gr and Lo/Lr, to test the effects of (i) post-ingestive consequences with similar pre-ingestive characteristics (Go/Gr v. Go/Lr; Lo/Gr v. Lo/Lr) and (ii) pre-ingestive characteristics with similar post-ingestive consequences at the end of the feeding period (Go/Lr v. Lo/Gr). Six rumen-fistulated sheep underwent all the treatments over 11-day periods in a latin square design. Eating time was restricted to 6 h/day, intraruminal introductions were performed just before food offer and choice tests were conducted after food removal. For similar pre-ingestive characteristics, DMI increased when L hay was introduced into the rumen rather than G (P < 0.05), possibly owing to a lower fill effect of L due to its lower NDF content and higher rumen degradability. The increased DMI resulted from longer eating time when G was orally consumed (149 v. 192 min, P < 0.05), whereas it resulted from higher intake rate with L (4.8 v. 6.1 g/min, P < 0.05). For similar post-ingestive consequences at the end of the feeding period (Go/Lr and Lo/Gr), DMI were similar (P > 0.05). Pre-ingestive characteristics or palatability per se did not therefore influence daily intake, although they influenced eating patterns. Pre-ingestive characteristics also greatly influenced short-term choices in favour of the hay that was not previously consumed, independently of any post-ingestive influence. This study confirms the effects of post-ingestive consequences on daily intake, but demonstrates that these variations are obtained by different behavioural adjustments under the influence of pre-ingestive characteristics. Preference for novelty, regardless of post-ingestive consequences, thus suggests that sheep may seek a diverse diet more for pleasure than for functional purposes, with implications for animal welfare.

Management strategies to improve cow-calf productivity on meadow bromegrass pastures

A 4-yr experiment was conducted to determine the effects of fertilization, incorporation of a legume and use of the Rumensin®-controlled release capsules (CRC) on productivity of cow-calf pairs grazing meadow bromegrass (Bromus biebersteinii Roem &amp; Schult.). Four pasture treatments (T), alfalfa-grass fertilized (AF), alfalfa-grass unfertilized (AU), grass-only fertilized (GF) and grass-only unfertilized (GU), each replicated twice were compared. The eight 3.7-ha pastures were split into five equally sized paddocks and rotationally stocked with first-calf cows in 1995 and 1998, and with mature cows in 1996 and 1997. Half of the cows on each pasture received a Rumensin® CRC 1 wk prior to the start of the pasture season. Cow DMI was not influenced by fertilization or incorporation of a legume. However, cows treated with monensin consumed less (2.3% BW) compared to the control cows (2.5% BW, P &lt; 0.05). Incorporation of alfalfa and fertilization improved pasture quality and resulted in higher CP and lower NDF content in forage selected by the animals. Monensin improved (P &lt; 0.05) cow average daily gain (ADG, kg d-1) when grazing unfertilized grass and alfalfa-grass pastures, but did not influence gains of cows on fertilized pastures. Fertilizer application, legume incorporation and monensin administration did not affect milk yield or milk composition. Despite differences in diet quality, calf ADG for AU, AF, and GF were similar. However, calf ADG was lower for GU pastures (P &lt; 0.05), probably as a result of the high fibre and low protein content of this pasture treatment. Both incorporation of alfalfa and fertilization increased total calf gain (kg ha-1); the greatest improvement was associated with fertilization. There were, however, economic advantages to legume incorporation, as the cost of the additional gain for GF and AF pastures averaged $1.08 and $0.79 kg-1 ha-1, and no extra costs were incurred for AU. Key words: Beef cows, calves, milk yield, pasture productivity, alfalfa, meadow bromegrass

Manipulação do Corte do Sorgo (Sorghum bicolor, L. Moench) para Confecção de Silagem, Visando a Produção do Novilho Superprecoce

O experimento foi conduzido com o objetivo de estudar os parâmetros relativos ao consumo de alimentos, ganho de peso, conversão alimentar e eficiência energética de bezerros de corte em confinamento, alimentados com duas dietas, com inclusão de silagem de sorgo AG-2006 colhida em duas alturas de corte: corte baixo (14 cm) e corte alto (45 cm). Foram utilizados 12 bezerros Braford com idade média de sete meses e peso médio inicial de 208 kg. O período de confinamento foi de 126 dias, subdividido em dois períodos de 63 dias, em que a relação volumoso:concentrado, para ambas as dietas testadas, foi de 60:40 e 50:50, respectivamente, para o primeiro e segundo períodos. A silagem produzida pelo corte alto apresentou menor teor de FDN (42,57 contra 52,24%) e maior DIVMO (63,67 contra 53,59%). Não houve interação entre altura de corte e período de avaliação em confinamento para os parâmetros relativos aos consumos diários de matéria seca (CMS) e de energia digestível (CED), expressos nas diferentes formas, ao ganho de peso médio diário (GMD) e à eficiência energética (CE). A elevação da altura de corte de 14 para 45 cm das plantas de sorgo para produção de silagem não afetou o CMS (7,60 contra 7,70 kg/dia), o CED (21,62 contra 23,83 Mcal/dia), o GMD (1,233 contra 1,375 kg) e a eficiência energética (17,53 contra 17,31 Mcal/kg de PV), respectivamente. Animais que tiveram a silagem de sorgo colhida a 45 cm incluída na dieta alimentar foram mais eficientes na transformação da matéria seca consumida em ganho de peso em relação à dieta com silagem de sorgo colhida a 14 cm de altura (5,60 contra 6,17 kg de MS/kg de PV).

Enhanced Intake and Production of Cows Offered Ensiled Alfalfa with Higher Neutral Detergent Fiber Digestibility

The objective of this study was to determine the effect of forage fiber digestibility as part of a total mixed diet on intake and production of cows with intakes that were likely limited by rumen fill, using treatments that were not confounded by fiber source, concentrate, or ratio of forage to concentrate. Two alfalfa silages with similar NDF concentrations (40%) but different NDF digestibilities (40 vs. 45% after 24h of in vitro fermentation) were harvested, mixed with concentrate to achieve diets containing 35% NDF, and offered to 12 multiparous cows (13 DIM) in a two-period balanced crossover design. Samples taken during silage feeding revealed that diets differed in both NDF digestibility (3 percentage units) and NDF content (1.8 percentage units), making interpretation of results difficult. Nonetheless, milk production (36.3 vs. 38.2kg/d) and DMI (19.4 vs. 20.4kg/d) were significantly higher with the higher NDF digestibility diet. Apparent in vivo DM and NDF digestibilities, total rumen VFA after feeding, and molar percentage of propionate were also higher with this diet. Equal NDF intake between diets suggested that higher DMI was due to the lower NDF content in the more digestible NDF diet. Higher NDF digestibility might also increase DMI; further experimentation is necessary with larger unconfounded differences in fiber digestibility at the time of feeding.