Forage Dry Matter Intake Research Articles

Evaluation of different feed intake models for dairy cows

The objective of the current study was to evaluate feed intake prediction models of varying complexity using individual observations of lactating cows subjected to experimental dietary treatments in periodic sequences (i.e., change-over trials). Observed or previous period animal data were combined with the current period feed data in the evaluations of the different feed intake prediction models. This would illustrate the situation and amount of available data when formulating rations for dairy cows in practice and test the robustness of the models when milk yield is used in feed intake predictions. The models to be evaluated in the current study were chosen based on the input data required in the models and the applicability to Nordic conditions. A data set comprising 2,161 total individual observations was constructed from 24 trials conducted at research barns in Denmark, Finland, Norway, and Sweden. Prediction models were evaluated by residual analysis using mixed and simple model regression. Great variation in animal and feed factors was observed in the data set, with ranges in total dry matter intake (DMI) from 10.4 to 30.8kg/d, forage DMI from 4.1 to 23.0kg/d, and milk yield from 8.4 to 51.1kg/d. The mean biases of DMI predictions for the National Research Council, the Cornell Net Carbohydrate and Protein System, the British, Finnish, and Scandinavian models were −1.71, 0.67, 2.80, 0.83, −0.60kg/d with prediction errors of 2.33, 1.71, 3.19, 1.62, and 2.03kg/d, respectively, when observed milk yield was used in the predictions. The performance of the models were ranked the same, using either mixed or simple model regression analysis, but generally the random contribution to the prediction error increased with simple rather than mixed model regression analysis. The prediction error of all models was generally greater when using previous period data compared with the observed milk yield. When the average milk yield over all periods was used in the predictions of feed intake, the increase in prediction error of all models was generally less than when compared with previous period animal data combined with current feed data. Milk yield as a model input in intake predictions can be substantially affected by current dietary factors. Milk yield can be used as model input when formulating rations aiming to sustain a given milk yield, but can generate large errors in estimates of future feed intake and milk production if the economically optimal diet deviates from the current diet.

Effect of supplementation frequency on intake, behavior and performance in beef steers grazing Marandu grass

Eighteen Nellore steers, with an average initial body weight (BW) of 312±10.6kg, grazing Brachiaria brizantha cv. Marandu were assigned to three experimental treatments consisting of different supplementation frequencies (daily [DAI], Monday through Friday [M–F] and Monday, Wednesday and Friday [MWF]). The supplement was offered at a rate of 35.0gkg−1 BW per week and contained 565gkg−1 corn gluten meal-60, 235gkg−1 dry sugarcane yeast, 140gkg−1 citric pulp and 60gkg−1 mineral premix. Animal performance (ADG), dry matter (DM) intake, DM digestibility, daily grazing time and pattern of supplement intake were evaluated in the steers from February to May. The forage DM intake was estimated using the alkane pair C32:C33 and the DM apparent digestibility using the alkane C35 as an internal marker. A reduction in supplementation frequency did not affect animal performance, with an average weight gain of 0.69kg/d. Supplementation frequency did not affect (P>0.05) forage and total (forage+supplement) DM intakes or DM digestibility. However, forage and total DM intakes and DM apparent digestibility decreased significantly (P<0.01) from March to May, whereas grazing time during the day (from 06:00h to 18:00h) increased by 22% in the same period. The animals receiving infrequent supplementation (M–F and MWF) spent a greater portion of the day grazing when not given the supplement compared to days on which they received the supplement. Reducing the frequency of supplementation from 7 to 3d per week is a viable method to reduce labor and equipment utilization costs as this reduction did not affect intake, digestibility or animal performance in the present study.

Effects of cooked molasses licking block supplementation pre- and post-partum on feed intake, suckling lamb performance, milk yield and milk quality in dairy sheep. Part 1

This study tested the nutritional benefit of a supplement offered freely to dairy sheep over a period from 60 days before lambing to 60 days after lambing, at stall and grazing. Thirty Sarda dairy sheep on Day 90 of gestation, homogeneous for age, parity number, bodyweight (BW) and body condition score (BCS), were allocated to one of two groups: control (Ctr) or treated (Cry). Over 120 days, both groups received ryegrass hay and concentrate indoors. After weaning, the ewes also had access to pasture for 6 h/day. Throughout the experimental period, the Cry group had ad libitum access to a cooked molasses licking block. No significant differences were observed between the groups in forage, concentrate and total DM intake. During the experiment, the reduction in BCS in early lactation tended to be slower in the Cry than in Ctr group (Ptrend &lt; 0.09), whereas no significant effects were seen on BW. Lamb performance tended to be improved by Cry in terms of liveweight of litter size per sheep (9.65 vs 8.22 kg for Cry and Ctr, respectively; P &lt; 0.07), whereas no significant effects were observed on milk yield and composition, except for a trend for increased fat content in the Cry versus Ctr group (6.15% vs 5.95%, respectively; P &lt; 0.08). Cry ewes had higher blood cholesterol concentrations than did Ctr ewes (1.96 vs 1.63 mmol/L; P &lt; 0.01). Because there were no differences between feed intake at stall and the estimated total DM intake at stall and during grazing between the two groups, the better performance of the Cry group could be explained by an increase of feed use efficiency at the digestive and/or metabolic level.

Correlation between intake and ingestive behavior of pasture-grazed heifers

Objetivou-se com este estudo, avaliar a correlação entre o consumo e comportamento ingestivo de novilhas mestiças em pastagem tropical. O experimento foi conduzido na Fazenda Princesa do Mateiro, na cidade de Ribeirão do Largo, Bahia. Foram utilizadas 20 bezerras com a composição genética de 5/8 de Guzerá Leiteiro e 3/8 de Holandês, idade média de 18 meses e peso corporal de 187 ± 13,1 kg. O experimento durou 224 dias e os animais mantidos em sistema de pastejo rotacionado com Brachiaria brizantha cv. Marandú. O tempo de pastejo não correlacionou com nenhuma das variáveis associadas com a ingestão. O tempo de ruminação mostrou correlações positivas com a ingestão de matéria seca da forragem (CMSF) e fibra em detergente neutro (CFDN). Variáveis associadas ao tempo gasto em alimentação no cocho, alimentação em geral e mastigação total, não foram correlacionados com a ingestão (P&gt;0,05). Houve correlação positiva entre o número de períodos de pastejo (NPP) e os períodos de ruminação (NPR) e consumo de MS total (CMST), matéria orgânica (CMO), forragem ( CMSF), fibra em detergente neutro (CFDN), carboidratos totais (CCHOT), extrato etéreo (CEE). O consumo de proteína bruta (CPB) foi positivamente correlacionado com NPP e NPR. A taxa de bocado foi positivamente correlacionada com CMST, CMO, CMSF, CFDN, CCHOT, CEE e CPB. O tempo médio por bolo ruminado foi negativamente correlacionada com CMST, CMO, CFDN, CHOT e CEE. Correlações positivas foram observadas entre o número de bocados por dia e CMST, CMO, CMSF, CFDN, CHOT e CEE. O número de mastigações por bolo mostraram correlações negativas com CMSS e CPB. O tempo por bolo ruminado foi negativamente correlacionada com a ingestão de proteína bruta. O número de mastigações por bolo mostrou correlações positivas com os consumos de matéria seca e fibra em detergente neutro. O número de bolos por dia mostraram correlações positivas com CMSF e CCHOT. O tempo de mastigação não mostrou correlação significativa com o consumo. Em conflito com a literatura nacional e internacional, o tempo de pastejo não foi correlacionada com a ingestão por novilhas mestiças em pastejo. O número de atividades, o tempo gasto e a taxa de bocado, tem demostrado ser altamente correlacionados com as variáveis de consumo e pode, por conseguinte, compor equações para predizer o consumo a partir da avaliação do comportamento ingestivo. O número de bocados realizados por dia contribui para a ingestão de novilhas em pastagem.

Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage

Nutrient composition and organoleptic properties of milk can be influenced by cow diets. The objective of this study was to evaluate the forage type effects on volatile organic compounds, fatty acid (FA) profile, and organoleptic properties of milk. Timothy grass was fed as hay, pasture, or silage during a period of 27 d to a group of 21 cows in a complete block design based on days in milk. Each cow also received 7.2kg/d of a concentrate mix to meet their nutrient requirements. Forage dry matter intake averaged 13.9kg/d and was not different among treatments. Milk yield was higher for cows fed pasture, intermediate for cows fed silage, and lowest for cows fed hay. However, milk fat content was higher for cows fed hay and silage, compared with cows fed pasture. As a result, fat-corrected milk and fat yield were not different among treatments. Increasing the supply of dietary cis-9,cis-12 18:2 (linoleic acid) and cis-9,cis-12,cis-15 18:3 (α-linolenic acid) when feeding pasture enhanced the concentration of these 2 essential FA in milk fat compared with feeding hay or silage. Moreover, the ratio of 16:0 (palmitic acid) to cis-9 18:1 (oleic acid), which is closely related to the melting properties of milk fat, was lower in milk from cows on pasture than in milk from cows fed hay or silage. Cows fed hay produced milk with higher levels of several free FA and γ-lactones, but less pentanal and 1-pentanol. More dimethyl sulfone and toluene were found in milk of cows on pasture. Cows fed silage produced milk with higher levels of acetone, 2-butanone, and α-pinene. Results from a sensory evaluation showed that panelists could not detect a difference in flavor between milk from cows fed hay compared with silage. However, a significant number of assessors perceived a difference between milk from cows fed hay compared with milk from cows fed pasture. In a sensory ranking test, the percentage of assessors ranking for the intensity of total (raw milk, fresh milk, and farm milk), sweet (empyreumatic, vanilla, caramel, and sugar), and grassy (grass, leafy vegetable, and plant) flavors was higher for milk from cows fed pasture compared with hay and silage. Using timothy hay, pasture, or silage harvested at a similar stage of development, the current study shows that the taste of milk is affected by the forage type fed to cows. More research is, however, needed to establish a link between the sensory attributes of milk and the observed changes in volatile organic compounds and FA profile.

Effects of replacing grass silage with either maize silage or concentrates during late pregnancy on the performance of breeding ewes fed isonitrogenous diets

A study was undertaken to investigate the performance of breeding ewes fed a range of forage and concentrate-based diets in late pregnancy, balanced for supply of metabolizable protein (MP). For the final 6 weeks before lambing, 104 twin-bearing multiparous ewes were offered one of four diets: ad libitum precision-chop grass silage + 0.55 kg/day concentrates (GS); ad libitum maize silage + 0.55 kg/day concentrates (MS); a 1 : 1 mixture (on a dry matter (DM) basis) of grass silage and maize silage fed ad libitum + 0.55 kg/day (GSMS); or 1.55 kg/day concentrates + 50 g/day chopped barley straw (C). The CP content of the concentrates was varied between treatments (157 to 296 g/kg DM) with the aim of achieving a daily intake of 130 g/day MP across all treatments. Compared with ewes fed GS, forage DM intake was higher (P < 0.05) in ewes fed MS (+0.21 kg/day) and GSMS (+0.16 kg/day), resulting in higher (P < 0.001) total DM intakes with these treatments. C ewes had the lowest total DM intake of all the treatments examined (P < 0.001). C ewes lost more live weight (LW; P < 0.001) and body condition score (BCS; P < 0.05) during the first 3 weeks of the study but there were no dietary effects on ewe LW or BCS thereafter. The incidence of dystocia was lower (P < 0.01) in C ewes compared with those offered silage-based diets (7.5% v. 37.4% ewes), and was higher (P < 0.01) in ewes fed MS compared with GS or GSMS (50.7%, 34.7% and 26.9%, respectively). There were no significant dietary effects on the plasma metabolite concentrations of ewes in late pregnancy, pre-weaning lamb mortality, weaned lamb output per ewe or on lamb growth rate. The results of this study demonstrate that both maize silage and all-concentrate diets can replace grass silage in pregnant ewe rations without impacting on performance, provided the supply of MP is non-limiting. The higher incidence of dystocia in ewes fed maize silage as the sole forage is a concern.

Consumo de forragem e desempenho de novilhas de corte recebendo suplementos em pastagem de azevém

Foram estudados o desempenho, comportamento e a ingestão de forragem por novilhas de corte em dois estádios de desenvolvimento do azevém (Lolium multiflorum Lam.): pré-florescimento e florescimento. As novilhas permaneceram exclusivamente em pastejo ou em pastejo e recebendo grão de milho ou suplemento extrusado com gordura. O delineamento experimental foi o inteiramente casualizado, em arranjo fatorial 3x2 (três sistemas alimentares x dois estádios fenológicos do azevém). A ingestão de forragem foi estimada usando o óxido de cromo como indicador da produção fecal. Os valores médios de massa de forragem e oferta de lâminas foliares foram de 1636kg ha-1 de matéria seca (MS) e 2,3kg de MS 100kg-1 de peso corporal (PC), respectivamente. Novilhas que não receberam suplemento consumiram mais pasto sem diferir das que receberam gordura. Animais exclusivamente a pasto realizaram maior número de bocados diários. As ingestões de MS do pasto e total, que foram de 2,74 e 3,01% do PC, respectivamente, são similares no pré-florescimento e florescimento do azevém. A ingestão de matéria seca total e os tempos de pastejo, ruminação e ócio de bezerras de corte recebendo suplementos são semelhantes ao uso exclusivo da pastagem de azevém, resultando em desempenho individual semelhante.

Effects of Increasing Rumen‐Undegradable Protein Supplementation Levels on Early Weaned Calves Grazing Stargrass

Early weaned beef calves (Bos spp.) grazing warm‐season grasses may benefit from increasing levels of rumen‐undegradable protein (RUP) supplementation due to the limited RUP supplied by the forage and their high nutrient requirements. The objective of this study was to test the effects of increasing levels of RUP supplementation on performance of early weaned calves grazing stargrass (Cynodon nlemfuensis Vanderyst) pastures. The experiment was conducted in Ona, FL, from May to August 2007 and 2008. Treatments were 1.5 g kg−1 body weight (BW) of three levels of supplemental RUP from soybean [Glycine max (L.) Merr.] meal (SBM) (350 g kg−1 RUP), Soyplus (SP) (600 g kg−1 RUP) (a modified expeller SBM) (West Central, Ralston, IA), or a 50:50 mixture of SBM and Soyplus (SBMSP) (475 g kg−1 RUP). Pasture size was 0.51 ha and four early weaned calves were assigned to each pasture. There was no effect of the treatments on mean herbage mass (HM; 2.7 Mg ha−1), forage crude protein (CP) (171 g kg−1), in vitro digestible organic matter (IVDOM) concentration (640 g kg−1), or calf average daily gain (0.56 kg d−1). Increased RUP supplementation did not affect forage dry matter intake (mean = 2.0% BW); however, there was a linear decrease in apparent dry matter digestibility from 640 to 600 g kg−1. Increasing levels of RUP supplementation may not increase performance of early weaned calves grazing stargrass pastures when forage CP is not limiting.

Suplementação de novilhos Nelore sob pastejo, no período de transição águas-seca

Avaliou-se o efeito da suplementação proteica sobre o consumo e o desempenho de novilhos recriados em pastagens de capim-piatã (Brachiaria brizantha cv. Piatã), durante o período de transição águas-seca. Utilizaram-se 20 novilhos Nelore, com peso médio inicial de 260kg, distribuídos ao acaso, em esquema de parcelas subdivididas. Os suplementos foram: sal mineral com ureia (controle) - ofertado ad libitum; sal proteinado - ofertado a 0,2% do peso vivo; suplemento proteico-energético - ofertado a 0,3% do peso vivo; e suplemento proteico-energético - ofertado a 0,5% do peso vivo. A suplementação teve efeito aditivo sobre o consumo de matéria seca total. O consumo médio diário dos suplementos foi de 0,167; 0,597; 0,865 e 1,469kg/animal, sendo observado ganho médio diário de 0,686; 0,761; 0,719 e 0,850kg/animal para os tratamentos controle e suplementados com 0,2; 0,3 e 0,5% do peso vivo, respectivamente. Verificou-se que as estratégias de suplementação avaliadas foram economicamente viáveis e proporcionaram desempenho semelhante sob condições de elevada oferta de forragem, sendo recomendado iniciar a suplementação proteica no período de transição águas-seca.

Intake and digestion by wethers fed a tropical grass-based diet supplemented with increasing levels of canola meal

Eight Polwarth×Texel wethers (31±3.8kg body weight (BW)), housed in metabolic cages and offered sudangrass (Sorghum sudanense) ad libitum, were used in a replicated 4×4 Latin Square experiment to evaluate the effects of increasing levels of canola meal supplementation on intake, digestibility, duodenal flow of N compounds and on N excretion. Four of the eight wethers were fitted with duodenal cannula. Treatments included no supplement (0) or daily supplementation with 5, 10 or 15g/kg BW of a canola meal mixture (nine parts canola meal one part cracked corn grain). Forage dry matter (DM) intake decreased linearly and total DM, organic matter (OM), digestible OM and N intake increased linearly with increasing levels of supplementation. Supplementation did not affect neutral (NDF) or acid detergent fiber (ADF) digestibility whereas it tended to improve DM and OM digestibility. Fecal and urinary N excretion, as well as duodenal flow of α-amino N and non-ammonia non-microbial N increased linearly with increasing levels of supplementation. Rumen microbial protein flowing to duodenum and the efficiency of rumen microbial protein synthesis were not affected by treatments. The proportion of rumen degradable protein which was used for microbial protein synthesis decreased linearly with increasing levels of supplementation, but at a higher rate than was the reduction of the proportion of N intake which reached the small intestine as α-amino N. In conclusion, despite increasing N excretion and exerting a depressive effect on forage intake, supplementation with a high-degradable true protein source improves α-amino N and energy supply in ruminants fed tropical grass based-diets.

Liveweight gain and feed intake of weaned Bali cattle fed a range of diets in Central Sulawesi, Indonesia

Three experiments were conducted to determine liveweight (W) gain and feed and water intake of weaned Bali cattle offered a range of feed types. In each experiment, 18 weaned entire male Bali cattle were allocated to three treatment groups in a completely randomised block design, with six replicates (animals) per treatment. The dietary treatments were: Experiment 1, native grass fed ad libitum, native grass supplemented with rice bran at 10 g dry matter (DM)/kg W.day and native grass supplemented with a mixture of rice bran and copra meal in equal proportions fed at 10 g DM/kg W.day; Experiment 2, elephant grass hay fed ad libitum, elephant grass supplemented with gliricidia at 10 g DM/kg W.day, and gliricidia fed ad libitum; and Experiment 3, corn stover fed ad libitum, corn stover supplemented with gliricidia at 10 g DM/kg W.day, and corn stover supplemented with rice bran/copra meal in equal amounts (w/w) at 10 g DM/kg W.day. Each experiment was 10 weeks in duration, consisting of a 2-week preliminary period for adaptation to diets and an 8-week experimental period for the measurement of W change, feed and water intake and digestibility of the diet. Growth rates of 6–12-month-old, entire male Bali cattle fed a range of local diets ranged from 0.10 and 0.40 kg/day. Lowest growth rates occurred when the cattle were given the basal diets of native grass (0.104 kg/day), elephant grass (0.174 kg/day) and corn stover (0.232 kg/day). With the addition of supplements such as rice bran, rice bran/copra meal or gliricidia to these basal diets liveweight gains increased to between 0.225 and 0.402 kg/day. Forage DM intake was reduced with these supplements by on average 22.6% while total DM intake was increased by an average of 10.5%. The growth rate on gliricidia alone was 0.269 kg/day and feed DM intake was 28.0 g/kg W.day. Water intake was not affected by supplement type or intake. In conclusion, inclusion of small quantities of locally available, high quality feed supplements provide small-holder farmers with the potential to increase growth rates of Bali calves from 0.1 to 0.2 kg/day, under prevailing feeding scenarios, to over 0.4 kg/day.

Methane yields from Brahman cattle fed tropical grasses and legumes

In the national greenhouse inventory, methane emissions from the Australian tropical beef herd are derived from cattle fed two diets. In the experiments reported here, methane production was measured by open-circuit gas exchange from 13 Brahman cattle offered 22 diets from combinations of five tropical grass species and five legumes, with a minimum of three steers per diet. All diets were offered daily ad libitum, with the exception of three legume diets fed without grass and leucaena (Leucaena leucocephala) mixed with grass, which were offered at 15 g dry matter per kg liveweight. Diets were fed as long-chopped dried hay, with the exception of leucaena, which was harvested and fed within 2 days. For the data from cattle fed diets of grass and grass mixed with legumes, methane production could be predicted as 19.6 g/kg forage dry matter intake (residual standard deviation 12.3). Observed methane yields were not predictable from a stoichiometry, which used volatile fatty acid proportions in rumen fluid. Mean methane emission rates across all diets were equivalent to 8.6–13.4% of digestible energy intake, and 5.0–7.2% of gross energy intake. The latter values are comparable to IPCC (2006) recommendations (5.5–7.5%) for large ruminants fed low-quality crop residues and by-products. Methane yields per unit of ingested dry matter or digested organic matter were variable across diets but were related to digestibility and contents of fibre and protein. These results constitute a significant downward revision of the methane emissions attributable to the northern Australian beef herd grazing tropical pastures.

The effect of inclusion of lupins/triticale whole crop silage in the diet of winter finishing beef cattle on their performance and meat quality at two levels of concentrates

This study investigated the performance and instrumental meat quality of finishing beef steers offered grass silage (GS), grass silage:maize silage (GS:MS) and grass silage:lupins/triticale silage (GS:LT). The lupins/triticale silage was grown as either two separate crops in the same field and harvested together (LT1) or grown and harvested as a mixture (LT2). The silages were offered to eighty continental cross beef steers, initial live weight 530±47.7kg and 18±1.6 months of age and were supplemented with 3 or 6kg concentrates fresh/head/d. Silage was fed ad libitum with the mixtures offered at a ratio of 60 GS:40 maize silage (MS), LT1 or LT2 on a dry matter (DM) basis and concentrates were offered once (3kg) or twice (6kg) daily on top of the silage. Animals were slaughtered in three batches after 100, 117 and 124d on experiment. The LT1 and LT2 produced yields of 8.7 and 7.5kgDM/ha and the silages were poorly fermented as demonstrated by high ammonia-N concentration (182 and 173g/kg total N), low lactic acid (9g/kg DM) and high pH (5.0 and 4.7). Silage type had no significant effect on slaughter live weight, liveweight gain, carcass gain, forage DM intake (DMI), total DMI or feed efficiency expressed as kgDMI/kgliveweight gain or kgDMI/kgcarcass gain. Silage type had no effect on carcass characteristics or instrumental meat quality. The results of this study demonstrate that offering lupins/triticale silage in combination with high quality grass silage (D-value greater than 700) at a ratio of 60 grass silage:40 LT1 or LT2 on a DM basis had no effect on animal performance, carcass characteristics or meat quality parameters relative to high quality grass silage offered alone or in combination with maize silage.

Variaciones diarias de la oferta forrajera, efecto sobre la producción y calidad de la leche

RESUMENObjetivo. Determinar el efecto de las variaciones de la oferta diaria de forraje sobre laproducción y calidad de la leche. Materiales y métodos. Determinando el área de ofertadiaria mediante un sistema de posicionamiento global y empleando la técnica de doblemuestreo para medir producción de biomasa previa y posterior al pastoreo, se estimó suconsumo diario por diferencia agronómica. Se estimaron variaciones dentro y entre fincaspara los parámetros evaluados. Se estableció el grado de asociación entre las variacionesdiarias en la oferta con el consumo, el volumen y calidad de la leche. Resultados. Losresultados evidenciaron asociación entre variaciones de oferta diaria y consumo de forraje(R2=0.65) y la variación en volumen diario de leche (R2=0.45). Las variaciones en grasano mostraron relación con cambios en la oferta (R2=0.0) y sus valores fueron asociadosa la relación forraje/suplemento (R2=0.52). Las variaciones en proteína tuvieron menorasociación con las variaciones en la oferta (R2=0.17) y mayor con el consumo de materiaseca (R2=0.34). Conclusiones. Los resultados sugieren que variaciones en la ofertaforrajera explican en mayor grado las variaciones en el consumo de materia seca con unefecto directo sobre el volumen de leche y en menor grado sobre las variaciones en sucomposición.

Technical note: The use of a physical activity monitor to estimate the eating time of cows in pasture

Accurate eating time can be used as an index of forage dry matter intake in grazing cows. To develop a method for easily estimating the eating time of dairy cows in a pasture, 8 lactating Holstein cows were fitted with collars equipped with commercial uniaxial accelerometers; namely, the Kenz Lifecorder EX (LCEX; Suzuken Co. Ltd., Nagoya, Japan), and were allowed to graze in a pasture for 4, 8, or 20h daily for 7 d. The LCEX device recorded the intensity of the physical activity categorized into 1 of 11 activity levels ranging among 0 (no movement), 0.5 (subtle) and from 1 to 9 (1, light; 9, vigorous intensity) every 4s during the experimental period. The activities of the animals were also video-recorded for 11h and were manually classified into 7 categories (eating, searching, ruminating, standing resting, lying resting, drinking, and walking) at 4-s intervals. According to the count distribution of the activity levels for the categorized activities, 94.4% of the counts involving eating activity ranged from activity level 1 to 7. On the other hand, most of the counts were activity level 0 or 0.5 when ruminating and resting activities were observed. No records of activity level 8 or 9 were found in any activities. When activity level 1 was used as a threshold for discriminating eating from the other activities, the lowest misclassification rate of 5.5% was observed. With a threshold of activity level 1, the eating times in pasture for cows grazing for 4, 8, and 20 h/d were 142.8, 290.6, and 438.4min/d, respectively, and the proportions of the time spent in pasture that were made up of eating time were 0.66, 0.67, and 0.38, respectively [the proportion during daytime (8h of the 20-h grazing treatment) was 0.63 and that at nighttime (12h of the 20-h grazing treatment) was 0.23]. The use of the LCEX device allows for easy measurement of eating time and facilitates the determination of the pattern of eating activity in pasture for grazing cows.

Concentrate and crude protein levels in diets for dairy Gyr lineage cows grazing elephant-grass during the rainy season

The objective of this work was to evaluate the effects of three levels of concentrate (2.0, 4.0 and 6.0 kg/cow/day) and two levels of crude protein (CP) (14 and 16% total dietary dry matter), in comparison to mineral mixture (control) on the intake, apparent digestibility, milk composition and yield and on feed efficiency and use of concentrates of cows grazing elephant grass (Pennisetum purpureum, Schum) in the rainy season. Twenty-one milking Gyr cows with average body weight of 426 kg and yield of 13.0 kg of milk/cow/day at 55 days of lactation were distributed in randomized blocks design, with seven diets (treatments) in a 3 × 2 + 1 factorial arrangement and three replications, in a period of 84 days. Forage dry matter intake was not influenced by the diets, but total dietary dry matter intake increased by 45% with the inclusion of concentrate in the diet. However, milk yield increased by only 17% (1.76 kg more milk per day) with the use of concentrate. For dairy Gyr cows grazing elephant-grass during the rainy season, 2 kg of concentrate/cow/day and 14% of CP in the total diet provided the best productive response without harming body weight.

Suplementos para recria de bovinos Nelore na época seca: desempenho, consumo e digestibilidade dos nutrientes

The objective was to evaluate the effect of supplementation with intake of 0, 0.25, 0.50 and 0.75% body weight (BW) of Nellore young bulls on intake, performance and apparent digestibility of nutrients during the dry season. A total of 116 Nellore young bulls were used with an average of nine months of age and body weight of 168 &plusmn; 35 kg. The study lasted 114 days, beginning on August 4 and ending on November 25, 2007. The design was completely randomized with four treatments and 29 replications for performance and five replications to evaluate intake and digestibility, in deferred Brachiaria brizantha grazing. The animals were weighed in beginning and end of the experiment. Forage DM intake showed a quadratic effect, with low point of 0.4% BW; CP, TC and TDN intake increased linearly; DWG, TWG and final body weight showed a quadratic effect, with the maximum point at around 0.60% BW. Apparent digestibility of DM, OM, CP, TC, NFC and TDN value showed a linear increase. It is recommended to supplement levels to 0.60% BW, in which maximum point performance was obtained, and where digestibility presents a linear increase, and the percentage of supplement resulted in increases in nutrient intake.

Rumen‐Undegradable Protein Supplementation Effects on Early Weaned Calves Grazing Annual Ryegrass

Early weaned beef calves (Bos spp.) can be raised on cool‐season pastures in Florida but more information on protein supplementation is necessary to optimize the performance of those calves. The objective of this study was to evaluate the effects of three levels of rumen‐undegradable protein (RUP) supplementation on performance of early weaned calves grazing annual ryegrass (Lolium multiflorum Lam.) pastures. The study was conducted in Ona, FL in 2007 and 2008. Treatments were 1.5 g kg−1 body weight (BW) supplementation of three levels of supplemental RUP, soybean meal (SBM, 350 g kg−1 RUP), Soyplus (SP, 600 g kg−1 RUP, modified expeller soybean meal, West Central, Ralston, IA), or a 50:50 mixture of soybean meal‐Soyplus (SBMSP, 475 g kg−1 RUP). Pasture size was 0.3 ha and four early weaned calves were assigned to each pasture. There was a linear increase in herbage mass (HM, from 1.9–2.1 Mg ha−1) and herbage allowance (HA, from 1.1–1.4 kg dry matter [DM] kg−1 live weight, LW) with increasing levels of RUP. Increased RUP supplementation decreased forage dry matter intake (FDMI) and total dry matter intake (TDMI) in 2008 but there was no effect in 2007. There was no difference in average daily gain (ADG, 0.76 kg d−1) among treatments. Increasing the levels of RUP supplementation has potential to increase stocking rates of early weaned calves grazing annual ryegrass pastures.

Metabolizable protein and energy supply in lambs fed annual ryegrass (Lolium multiflorumLam.) supplemented with sources of protein and energy

SUMMARYTen Polwarth×Texel lambs (26±2·1 kg live weight (LW)), housed in metabolism cages and offered ryegrass (Lolium multiflorum)ad libitum, were used in a 5×5 Latin Square experiment to evaluate the effect of supplement type on digestion processes and on amino acid and energy supplies. Five of the 10 lambs were fitted with a rumen catheter and duodenal cannulae. Treatments included no supplement (control); 7 g/kg LW daily of cassava meal (Manihot esculenta, high-starch low-nitrogen (HS-LN)), cassava meal plus corn gluten meal (2:1, high-starch high-undegradable N (HS-UN)), cassava meal plus calcium caseinate (2·8:1, high-starch high-degradable N (HS-DN)) or corn gluten feed (low-starch high-degradable N (LS-DN)). Total intake of dry matter (DM), organic matter (OM) and N, as well as digestible OM intake were increased with HS-UN, HS-DN and LS-DN (P⩽0·050). Forage DM intake was reduced by HS-LN (P=0·030). Apparent digestibility of DM and OM was increased by HS-LN and HS-DN (P⩽0·038). Digestibility of neutral detergent fibre (NDF) and OM true digestibility were similar for all treatments. Supplementation with HS-LN decreased duodenal flux of total N, amino acid N, ammonia N and feed residual N (P⩽0·023). None of the supplements affected rumen microbial protein entering the small intestine, whereas the efficiency of rumen microbial protein synthesis (EMPS) was reduced by HS-LN and HS-DN (P⩽0·036). Ruminal degradability of dietary N (RDN) was increased by HS-LN, HS-DN and LS-DN (P⩽0·050). In conclusion, supplementing lambs fed ryegrass with degradable or undegradable high-protein concentrate increased the amino acid supply without affecting the supply of digestible energy, regardless of either the starch content or the degree of ruminal degradability of the protein source. These results indicate that supplementation of ryegrass-based diets should include both starch and protein sources.

Dry matter intake and digestibility of temperate pastures supplemented with sorghum grain in wethers and heifers

The aim of this study was to evaluate the effect of sorghum grain supplementation on total and forage dry matter (DM) intake and digestibility of wethers and heifers consuming temperate pasture. Twenty four Corriedale x Milchschaf wethers and 24 crossbred heifers fed temperate pasture were non-supplemented or supplemented with sorghum grain at 5, 10 or 15 g/kg body weight (BW). Offered and refused feed were measured for 11 days and faeces voided were recorded daily during five days. Samples of feeds and faeces were collected daily and analyzed for DM. Supplement inclusion led to an inverse response in both species. Total dry matter intake (TDMI) of supplemented wethers was 20% lower than non-supplemented ones. Forage dry matter intake (FDMI) averaged 40% less in supplemented groups than in non-supplemented ones. Heifers receiving the supplement had 23% more TDMI but 10% less FDMI than non-supplemented, and lower FDMI was observed as supplementation increased. Dry matter digestibility (DMD) was 0.69 for wethers and 0.65 for heifers, with no differences between treatments. When the results from all animals were analyzed together, no differences on TDMI, lower FDMI and higher DMD were observed for the supplemented groups. In conclusion, sorghum grain supplementation affected TDMI differently in the two species, reducing TDMI in wethers and increasing TDMI in heifers. Supplementation reduced FDMI, the reduction being higher in wethers than in heifers. Dry matter digestibility of supplemented diets was higher, probably due to grain digestibility.