Behavior Of Steers Research Articles

Effects of a live yeast in natural-program finishing feedlot diets on growth performance, digestibility, carcass characteristics, and feeding behavior.

Effects of live yeast (Saccharomyces cerevisiae) in steam-flaked corn-based diets fed to natural-program beef cattle on growth performance, total tract apparent digestibility, carcass characteristics, and feeding behavior were evaluated in a randomized block design experiment. Steers (n = 144; 341 ± 7.03 kg) were blocked by initial BW and assigned randomly to 1 of the 3 treatments (n = 12 pens per treatment with 4 steers per pen). Treatments included the following: 1) control (CTL; no yeast); 2) low yeast (LY; 1.5 g/animal daily [3 × 1010 CFU]); and 3) high yeast (HY; 3.0 g/animal daily [6 × 1010 CFU]). Technologies such as implants, ionophores, and antibiotics were not used, and the steam-flaked corn-based finishing diets were fed to provide ad libitum access to feed. Yeast was included in a cottonseed meal-based premix as 1% of the dietary DM. Spot fecal samples (twice daily for 5 consecutive days) and diets were composited by pen and analyzed for acid insoluble ash to estimate apparent total tract digestibility of nutrients. Cattle were slaughtered on days 183 (4 blocks) and 204 (8 blocks). Dry matter intake (P ≥ 0.29), ADG (P ≥ 0.17), and G:F (P ≥ 0.33) did not differ among treatments. The percentage of Premium Choice (P < 0.01) carcasses increased linearly with increasing yeast inclusion in the diet. A quadratic response was observed for total tract apparent digestibility, in which steers fed LY had greater digestibility (P < 0.01) of DM by 5.4%, OM by 4.8%, NDF by 15.2%, ADF by 20.2%, CP by 6.2%, and ether extract (EE) by 2.5% compared with steers fed CTL. Feeding behavior was not affected (P = 0.28) by treatments. Live yeast improved digestibility of DM, OM, CP, EE, and fiber, without changing feeding behavior and growth performance of natural-program steers fed steam-flaked corn-based finishing diets.

Ingestive behaviour and forage intake responses of young and mature steers to the vertical differentiation of sugarcane in pen and grazing studies

SUMMARYSugarcane is an important forage resource in sub-tropical and tropical areas as it is used during the winter or dry season when the growth rate of pastures is significantly reduced. The current research study assessed the effect of four vertical sections of sugarcane in a pen trial and the level of sugarcane utilization in a grazing trial on the ingestive behaviour and forage intake of two age groups of steers (1 and 2 years old). The pen trial was comprised of two simultaneous 4 × 4 balanced Latin square designs (one for each age group of animals) of four periods, four animals and four feeding treatments, which consisted of four equal vertical sections of sugarcane. Dry matter (DM) and digestible DM (DDM) intake per kilogram of metabolic weight declined gradually from top to bottom of the sugarcane, with no significant differences between the age groups of steers. This difference in intake was associated with a decline in intake of neutral detergent fibre (NDF) as a proportion of the liveweight of the animal and an increase of total chewing time per kilogram of DM or NDF from top to bottom of the sugarcane. It was concluded that the toughness of plant material played a significant role regulating intake, which was higher for the top sections of sugarcane. In the grazing trial, steers of both age groups grazed down sugarcane in three plots over 9 days. Steers grazed up to four distinctive grazing strata. Digestible DM intake (DDM intake) was high at low levels of horizontal utilization of the top grazing stratum but DDM intake started to decline sharply when this stratum was removed in 0·92 of paddock area (i.e. equivalent to 0·08 of the pasture area remaining un-grazed). It was concluded that the proportion of un-grazed area of the pasture can be used as a grazing management strategy to control forage intake for sugarcane.

乳用種去勢牛の放牧行動 : V.牛群の行動と天候(1)

乳用種去勢牛の放牧行動 : V.牛群の行動と天候(1)

Correlation between production performance and feeding behavior of steers on pasture during the rainy-dry transition period.

The aim of this study was to evaluate the correlation between production performance and feeding behavior of steers reared on pasture during the rainy-dry transition period. Twenty-two ½ Holstein-Zebu crossbred steers at an average age of 10months and with an average initial body weight of 234.5±16.0kg were distributed in a completely randomized design with two types of supplementation and eleven replications. Pearson's linear correlation analysis was performed between behavioral variables and weight gain and feed conversion. Correlation coefficients were tested by the t test. The time expended feeding at the trough was positively correlated (P<0.05) with average daily gain (ADG) and with the number of periods of permanence at the trough. Bite rate and the number of bites per day were positively correlated (P<0.05) with ADG and negatively (P<0.05) with feed conversion, unlike the number of bites per swallow, which was negatively correlated (P<0.05) with ADG. There was a positive correlation (P<0.05) between feed efficiency in dry matter and neutral detergent fiber and ADG. Feeding behavior characteristics have little association with the production performance of cattle on pasture receiving mineral or energy-protein supplementation.

Effect of concrete slats, three mat types and out-wintering pads on performance and welfare of finishing beef steers

BackgroundThe objective was to investigate the effect of placing mats on concrete slatted floors on performance, behaviour, hoof condition, dirt scores, physiological and immunological variables of beef steers, and to compare responses with animals on out-wintering pads. Continental crossbred beef steers [n = 360; mean (±SD) initial live weight 539 kg (42.2)] were blocked by breed and live weight and randomly assigned to one of five treatments; (1) Concrete slats alone, (2) Mat 1 (Natural Rubber structure) (Durapak Rubber Products), (3) Mat 2 (Natural rubber structure) (EasyFix), (4) Mat 3 (modified ethylene vinyl acetate (EVA) foam structure) and (5) Out-wintering pads (OWP’s).ResultsAnimals on the OWPs had a greater (P < 0.05) live weight gain (P < 0.05) compared with the slat and Mat 2 treatments: results for Mat 1 and Mat 3 were the same (P > 0.05) as the other treatments. Animals on the OWPs had reduced lying percentage time compared with all the other treatments. Dry matter (DM) intake was greater for animals on the OWPs compared with all the other treatments. Carcass weight, kill out proportion, carcass fat score, carcass composition score, FCR and physiological responses were similar (P > 0.05) among treatments. No incidence of laminitis was observed among treatments. The number of hoof lesions was greater on all mat types (P < 0.05) compared with concrete slats and OWP treatments. Dirt scores were greater (P < 0.05) for animals on OWPs when measured on days 42, 84, 105, 126 and 150 compared with animals on slats.ConclusionsUnder the conditions adopted for the present study, there was no evidence to suggest that animals housed on bare concrete slats were disadvantaged in respect of animal welfare compared with animals housed on other floor types. It is concluded that the welfare of steers was not adversely affected by slats compared with different mat types or OWPs.

Effects of increasing inclusion of sodium hydroxide treatment on growth performance, carcass characteristics, and feeding behavior of steers fed 50% DDGS

Effects of increasing inclusion of sodium hydroxide treatment on growth performance, carcass characteristics, and feeding behavior of steers fed 50% DDGS

Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of steers fed finishing diets.

Crossbred beef steers fitted with a ruminal cannula were used to study the effects of silage type (BH 8895 corn or AF7401 sorghum) and level of inclusion (10 or 20%) in beef cattle finishing diets on digestibility of nutrients, ruminal kinetics, in vitro methane production, and feeding behavior. A 4 × 6 unbalanced Latin square design was used (6 steers; 363 ± 23 kg; 4 diets: corn silage [CS] or sorghum silage [SS], both at 10 or 20% inclusion, DM basis). Each period consisted of 14 d of adaptation and 7 d of collection. Steers were fed once daily at 1000 h. An additional study evaluated the ruminal degradability of intact ensiled sorghum grain ruminally incubated in 3 steers (547 ± 56 kg BW), using the same hybrids from the main study from 10 laboratory experimental silos. The GLIMMIX procedures of SAS were used for statistical analyses. Steers fed SS had greater NDF intake ( < 0.01) compared with the ones fed CS. The magnitude of the NDF intake change depended on the level of inclusion ( < 0.01), which was 6 and 16% for 10 and 20% inclusion, respectively. Regardless the level of inclusion, CS diets promoted greater ( ≤ 0.01) apparent total tract digestibility of nutrients evaluated (DM, OM, NDF, ADF, hemicellulose, and starch) compared with SS diets. Steers fed SS diets tended to chew 1.1 h/d more ( = 0.07) than steers fed CS diets. The level of inclusion increased ( = 0.02) the chewing time per day by 1.3 h. No major differences were observed in any of the ruminal pH and in vitro gas production variables evaluated for silage type and inclusion level ( ≥ 0.09). The CS-fed steers had 12% greater total VFA concentration and an 18.5% lower ( < 0.01) acetate-to-propionate ratio compared with SS-fed steers. The acetate-to-propionate ratio was 16% greater ( < 0.01) when steers were fed SS compared with when steers were fed CS. The CS samples were more extensively ruminally degraded ( < 0.01) than the SS samples. Greater ( < 0.01) NDF ruminal disappearance was observed in ruminal environments containing 20% silage compared with those containing 10% silage. After 96 h inside the rumen, intact ensiled sorghum grain degradability of DM reached only 51.7%. Replacing CS with SS in beef finishing diets (low roughage inclusion) requires adjustments to balance dietary energy. Sorghum material induced a desirable roughage effect in feeding behavior but also offered the potential for improved regarding fiber digestibility and intact grain ruminal degradability.

Effects of increasing inclusion of sodium hydroxide treatment on growth performance, carcass characteristics, and feeding behavior of steers fed 50% DDGS.

Objectives were to determine the dietary inclusion level of NaOH in a dried distillers grains with solubles (DDGS)-based diet needed to improve growth performance and carcass characteristics of feedlot steers, and to determine the effects of NaOH treatment of DDGS on pattern of feed intake. Based on previous research regarding the acidity of DDGS, we hypothesized that using NaOH in cattle fed 50% DDGS-based diets to neutralize the acidity inherent in DDGS would improve growth performance of cattle but shift intake patterns. Angus-cross steers (120 total) were blocked into 2 BW blocks (light, initial BW = 211 ± 27 kg; and heavy, initial BW = 261 ± 27 kg) and allotted randomly within block to 20 pens (6 steers per pen; = 30). Pens within block were assigned randomly to 1 of 4 dietary treatments: 1) 50% DDGS, untreated; 2) 50% DDGS, treated with 0.5% NaOH (DM basis); 3) 50% DDGS, treated with 1.0% NaOH (DM basis); or 4) 50% DDGS, treated with 1.5% NaOH (DM basis). The remainder of the diets contained 20% dry-rolled corn, 20% corn silage, and 10% mineral and vitamin supplement, on a DM basis. Cattle were fed in a GrowSafe system. There were no effects ( ≥ 0.21) of increasing NaOH inclusion on final BW, ADG, or G:F. Increasing NaOH in the diet increased meal duration (linear; = 0.02) and tended to increase meal size (linear; = 0.06), but did not affect overall number of meals per day (linear; = 0.21) or overall DMI ( ≥ 0.40) for the course of the trial. Relative to cattle fed DDGS treated with 0, 0.5 or 1% NaOH (DM basis), steers fed DDGS treated with 1.5% NaOH consumed a larger proportion of their meals in the afternoon. However, regardless of treatment, all steers consumed 78% or more of their feed in the first 12 h post-feeding. There were no effects ( ≥ 0.19) of increasing NaOH inclusion on HCW, LM area, dressing percentage, KPH, back fat thickness, and marbling. There was a linear ( = 0.02) decrease in USDA Yield Grade (YG) 3 and a tendency ( = 0.09) for a quadratic response in carcasses grading USDA YG 4 as NaOH concentration increased in the diets; however, there were no other YG differences. The quality grade response followed marbling score and was not different ( ≥ 0.11) among treatments. Thus, there were no effects of feeding DDGS treated with NaOH on growing cattle performance or carcass characteristics. However, NaOH inclusion shifted the pattern of intake slightly to the afternoon hours, and increased meal duration without increasing the total number of meals per day.

Performance and behaviour of Nellore steers on integrated systems

This study aimed to evaluate performance and behaviour of Nellore steers (Bos taurus indicus) in integrated systems. Treatments consisted of three different systems: livestock; crop-livestock; and livestock-forestry, with triple rows of eucalyptus trees. The experiment was carried out in Sinop, MT, Brazil, in a randomised complete block design with four replicates, during two seasons (dry-rainy transition and rainy). The experimental period was from 19 September 2015 to 10 January 2016. Nellore steers used in the experiment had an average initial weight of 344 kg ± 11 kg, in continuous stocking and variable stocking rate. Forage mass accumulation rate was evaluated and, independently of the system, had the highest values recorded during the rainy season. Microclimate was evaluated through temperature and humidity index, black globe temperature and humidity index and radiant heat load. Highest values were obtained from 11:00 a.m. to 3:00 p.m. at the dry-rainy transition period for all systems. Animal behaviour was assessed every 10 min from 7:00 a.m. to 5:00 p.m., and averages were calculated for every 2 h. The longest grazing period was recorded from 9:00 a.m. to 1:00 p.m., and then after 3:00 p.m., regardless of the system. Rumination occurred more frequently from 1:00 p.m. to 3:00 p.m. during the rainy season, and also in the shade for the livestock-forestry system. Highest weight gains per area were recorded during the rainy season and for the crop-livestock system. It is concluded that the highest yields can be achieved with the inclusion of the crop component in livestock production systems, and that Nellore steers in silvopastoral systems prefer to ruminate and stay idle in the shade.

1557 Effects of thyme (Thymus vulgaris) essential oil on feed intake and feeding behavior of Nellore steers

1557 Effects of thyme (Thymus vulgaris) essential oil on feed intake and feeding behavior of Nellore steers

1495 Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of feedlot steers

1495 Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of feedlot steers

Avaliação bioeconômica de estratégias de suplementação de novilhos zebuínos mantidos em pastagens diferidas de capim-marandu no período seco

RESUMO O objetivo com este trabalho foi avaliar estratégias de suplementação sobre o consumo de suplemento, comportamento e desempenho de novilhos zebuínos mantidos em pastagem de capim-marandu (Urochloa brizantha cv. Marandu) diferido. Foi utilizado delineamento inteiramente casualizado para testar cinco estratégias de suplementação: sal mineral (SM), sal proteinado com 25% de ureia (SP) e três multimisturas (45,5% NDT) com 10% (MM10), 15% (MM 15), ou 20% (MM20) de ureia. Foram utilizados vinte novilhos com peso inicial 300±24,9kg, sendo quatro por tratamento, mantidos em cinco piquetes de 3,4ha rotacionados semanalmente, de julho a outubro de 2010. Os dados foram submetidos à ANOVA, usando o Teste de Tukey para comparar as médias (P&lt;0,05); entretanto, a análise econômica determinou a melhor estratégia. A ingestão de suplementos foi alterada (P&lt;0,05) pela estratégia de suplementação, sendo de: 106, 196, 852, 666 e 400 g/animal/dia para SM, SP, MM10, MM15 e MM20, respectivamente. O aumento do consumo de suplementos não alterou o tempo de pastejo ou ruminação/ócio (P&gt;0,05). SM resultou em perda de peso (-137 g/animal/dia). Utilizando-se o SP praticamente manteve o peso dos novilhos. Entretanto, para obtenção de ganho de peso, as multimisturas devem ser utilizadas (P&lt;0,05). Nesses casos, o ganho de peso diário chegou a 324 g/animal (MM10). Baseado nos resultados econômicos, a melhor estratégia foi MM20, seguida de MM10.

Comparison of protein and energy supplementation to mineral supplementation on feeding behavior of grazing cattle during the rainy to the dry season transition.

The aim of this study was to evaluate the effects of protein-energy or mineral supplementation on the ingestive behavior of dairy steers on pasture in the post-weaning phase during the rainy to dry season transition. Twenty-two ½ Holstein–Zebu dairy steers with an average initial body weight of 234 ± 16 kg were distributed into a completely randomized design into two groups: protein-energy supplementation and mineral supplementation offered ad libitum. The steers receiving protein-energy supplementation showed higher (P < 0.05) intake of dry matter (DM) and neutral detergent fiber (NDF) than those fed diets composed of mineral salt only. In addition, the animals that received protein-energy supplementation had longer period in grazing and spent on average more time per period eating at the trough (P < 0.05), however no significant differences were observed in the time per period in rumination and time per period in idle (P > 0.05). The supply of protein-energy supplement does not change the feeding behavior, except for an increase in the time spent feeding at the trough. The intake of protein-energy supplement improved the of DM and NDF feed efficiencies in grazing cattle during the rainy to the dry season transition.

Replacement of wheat bran with spineless cactus in sugarcane-based diets for steers

The effect of replacing wheat bran with spineless cactus (0, 25, 50, 75, and 100%) in sugar cane-based diets on the intake of nutrients, feeding behavior, and rumen digestibility of steers was assessed using digested samples collected from the omasum. Five crossbred steers (1/2 Holstein-Zebu) were fitted with cannulas in the rumen and then assigned to a 5 × 5 Latin square design. Samples of omasal digesta were collected for three days. Rumen was evacuated via the rumen cannula to determine the rumen pool of dry matter (DM), neutral detergent fiber (NDF), indigestible NDF (iNDF), intake (ki), passage (kp) and degradation (NDF) rates, and the passage of iNDF (kpi). Nutrient intake displayed a quadratic effect, with maximum intakes of DM (5.73 kg d−1), non-fiber carbohydrates (NFC, 4.63 kg d−1), and digestible organic matter (DOM, 3.45 kg d−1) estimated at the replacement levels of 54.63, 60.00, and 43.17%, respectively. The replacement levels showed no effect on feeding, rumination, or idle times. There was a linear increase in the total apparent and ruminal digestibility of CP as the spineless cactus content in the diet was increased. There was no effect on total and partial digestibilities of OM and NDF or on intestinal digestibility of CP. No effect was observed on the rumen pool of DM, NDF, or iNDF. Furthermore, ki, kp, NDF degradation, and iNDF passage rates displayed a quadratic effect, with higher concentrations estimated for replacement levels of 56.07, 56.12, 59.00, and 55.20%, respectively. Replacing 55% wheat bran with spineless cactus in sugar cane-based diets is recommended.

Feeding behavior and productive performance of steers fed pearl millet grain-based diets containing proportions of babassu mesocarp bran

The objective of this study was to evaluate the feeding behavior and feedlot productive performance of dairy-origin steers fed for 84 days ground pearl millet grain-based diets with 0, 120, 240, 360, and 480 g kg-1 of babassu mesocarp bran (BMB) and a standard diet based on ground corn. Thirty Holstein-Zebu steers with average initial body weight of 371.02±27 kg were used. The experimental design was completely randomized, with five replications. Dry matter intake showed better fit with the quadratic regression equation with the inclusion of BMB, reaching a maximum value in diets with 360 g of this by-product. There was no difference for dry matter intake between pearl millet- and corn-based diets. There was no difference in total digestible nutrients intake between diets. The digestibility coefficient of organic matter decreased linearly with the increase in the dietary level of BMB. The digestibility coefficient of organic matter was not different between corn and millet diets. There was no difference in feeding time between diets. Total requirement of metabolizable energy increased linearly with inclusion of BMB. However, total requirements of metabolizable energy did not differ between the corn- and pearl millet-based diets. Average daily gain decreased linearly with the increase in BMB, with adjustment forced by the sharp decline of this variable in diets with 480 g of BMB. There was no difference in average daily gain between corn- and pearl millet-based diets. The inclusion of levels above 360 g of babassu mesocarp bran in pearl millet-based diets reduces the supply of metabolizable energy and the productive performance of feedlot dairy steers.

The effects of concentrate supplementation on growth performance and behavioral activities of cattle grazed on natural pasture.

The study was conducted in Manyara Region, to determine the effect of concentrate supplementation on growth performance and foraging behavior of zebu steers. Twenty zebu steers were distributed equally into two dietary groups: pasture + concentrate (PS) and natural pasture alone (NP). The animals' body weight and body condition scores were estimated every 2 weeks. The focal observation technique was used to determine grazing behavior. The average daily gain (ADG) was significantly higher (P ≤ 0.05) in the PS than in the NP. Significant less time (P ≤ 0.05) was spent in feeding by animals in the PS than those in the NP. Significant less bite rates (P ≤ 0.05) were also observed in the PS than in the NP. The most highly abundant forage species exhibited low CP contents but were most frequently eaten by the focal animals. Strategic supplementation with locally available concentrates is recommended for profitable ruminant productivity and environmentally friendly grazing strategy.

Metabolismo nitrogenado em bovinos suplementados a pasto durante a transição águas seca

Objetivou-se com este estudo avaliar o consumo, a fermentação ruminal, síntese de proteina microbiana, balanço dos compostos nitrogenados e comportamento ingestivo de suplemento de novilhos mantidos a pasto, suplementados com níveis crescentes de proteína bruta. Foram utilizados 4 novilhos mestiços, com idade média de 24 meses, peso corporal médio de 400 kg, providos de cânula ruminal. Os animais foram mantidos em piquetes individuais, em delineamento quadrado latino 4 x 4. Os suplementos experimentais foram constituídos por diferentes níveis de proteína: T00= Suplemento mineral (controle); T20= Su-plemento concentrado com 20 % de PB; T40= Suplemento concentrado com 40 % de PB; T60= Suplemento concentrado com 60 % de PB. Não foi observado efeito sobre o consumo de matéria seca. Foi observado efeito sobre as concentrações de valerato, porém não foram observadas respostas lineares ou quadráticas. O tratamento T60 apresentou menor velocida-de de ingestão de suplemento em relação aos demais. Os níveis de suplementação proteica não influenciaram o consumo de matéria seca, síntese de proteína microbiana e balanço de compostos nitrogenados, porem influenciaram as concentrações de ácidos graxos de cadeia ramificada e a velocidade de consumo de suplemento proteico.

Behavioural characterisation of Holstein steers in three different production systems

The objective of the present study was to characterise the behaviour of Holstein steers in three different production systems. Forty-eight castrated Holstein males were randomly divided into three groups and allocated to the following three outdoor treatments: (T1) animals confined in a yard with an area of 210 m2, (T2) animals confined in a similar-sized yard but with 6 h of access to a pasture plot, (T3) animals maintained throughout the experiment on a pasture plot. Behaviour was recorded by scan sampling, 12 h a day (from 0700 hours to 1900 hours), 3 days per week, for 4 weeks evenly distributed from Week 7 to Week 16 of the experiment. So as to assess their patterns of behaviour, a negative binomial regression, correspondence analysis and logistic regressions were performed. Grazing was the predominant behaviour among Groups T2 and T3, while ‘eating hay’ was the most frequent behaviour among Group T1. For all treatments, lying was the second-most frequent behaviour. Despite animals in T2 having access to pasture for only half of the time with respect to those in T3, there was no difference between both treatments in the time spent grazing. Correspondence analysis of behaviour as a function of weather conditions showed that several behaviours were close to certain weather conditions, e.g. ‘standing’ and ‘ruminating while standing’ were closer to light rainy weather, while ‘lying’ or ‘ruminating while lying’ were more related to sunny weather.’Lying’ tended to increase along the day in all treatments, while ‘eating hay’ increased along the day within Group T1, but decreased within Groups T2 and T3. It is concluded that the management conditions associated with the systems that were studied produced different behavioural patterns in the steers. Grazing behaviour is important for the animals, and the permanent or restricted possibility to perform it, determined by the production system, meant that the patterns of other behaviours changed to give priority to pasture intake.

Correlation between Ingestive Behavior and Digestibility Coefficients of Supplemented Grazing Steers, with or without Addition of Propolis Extract (LLOS®)

Correlation between Ingestive Behavior and Digestibility Coefficients of Supplemented Grazing Steers, with or without Addition of Propolis Extract (LLOS®)

Ingestive behavior of grazing steers fed increasing levels of concentrate supplementation with different crude protein contents.

This study aimed to evaluate the ingestive behavior of steers on Brachiaria brizantha pasture fed diets with increasing levels of concentrate supplementation. Thirty-two crossbred steers in the finishing phase with average weight of 420 ± 8kg were distributed in a completely randomized design with four treatments and eight replicates per treatment. Their behavior was assessed every 5min for 24h, in the middle of the experimental period. Variance and regression analyses at 0.05% probability were adopted. The times spent grazing and ruminating reduced linearly (P <0.05), whereas the times spent at the trough (eating) and on other activities increased linearly (P <0.05) as the supplementation levels were elevated. The total feeding and chewing times decreased linearly (P <0.05) as the concentrate levels in the diet were elevated. By increasing the supplementation levels, the number of bites per day decreased linearly (P <0.05), and the feed efficiency of dry matter increased quadratically. Rumination efficiency of dry matter increased linearly (P <0.05) with increasing levels of concentrate supplementation. Grazing and rumination activities are reduced when the time devoted to other activities and at the trough are increased, as a result of the substitution effect.