The effects of roughage type on the daily patterns of feed intake and eating behaviour in young sheep - PDF Document

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  1. EATING BEHAVIOUR IN SHEEP AND ROUGHAGE TYPE 503 The effects of roughage type on the daily patterns of feed intake and eating behaviour in young sheep E. S. POLAT1*, B. COSKUN1, E. GURBUZ1, T. BALEVI1 1Department of Animal Nutrition, Faculty of Veterinary Medicine, Selcuk University, 42250, Konya, Turkey. *Corresponding author: SUMMARY RESUME Effets du type de fourrage sur le comportement alimentaire et la consommation des aliments chez le jeune mouton The effects of roughage type on the daily patterns of feed intake and eating behaviour were investigated in young sheep, individually housed. A total of 24 young sheep were allotted in 4 equal groups according to the roughage type (barley straw, corn silage, alfalfa hay and sugar beet pulp) distributed ad libitum 6 times a day in 4 hours meal intervals. Roughage intake and eating behaviour were analysed using a camera recording system for 24 hours for 7 days. The intake of barley straw (characterized by the highest crude fiber and NDF contents) was significantly depressed compared to the other roughages leading to a significantly decreased body weight and sheep spent significantly less time and low frequently eating and they have presented significantly longer resting periods than others. Sheep have eaten significantly more alfalfa hay (crude fiber: 30.1% and NDF: 50.0%) than the other roughages, have spent frequently and long time eating and have rested frequently. In the group fed with sugar beet pulp (crude fiber: 17.5% and NDF: 46.0%), animals have preferred shorter but more frequent meals than with corn silage (crude fiber: 25.2% and NDF: 64.0%) and alfalfa hay including after midnight whereas sheep from the other groups were sleeping. These results show that the NDF and moisture contents of the roughage directly affected the ingestibility leading to some changes in the eating behaviour, particularly in the frequency and quantity of meals and in the duration of resting periods. Les effets du type de fourrage sur les modalités d’ingestion des aliments et sur le comportement alimentaire ont été étudiés chez de jeunes moutons parqués individuellement. Au total, 24 animaux ont été répartis en 4 groupes égaux en fonction du type de fourrage (paille d’orge, ensilage de maïs, foin de luzerne et pulpe de betterave sucrière) distribué à volonté 6 fois par jour à intervalle de 4 heures. La consommation de fourrage et le comportement alimentaire ont été analysés sur une période de 7 jours en enregistrant sur une caméra 24 heures sur 24 les activités de chaque animal. La consommation de paille d’orge (caractérisée par des taux maximaux de fibres totales et de NDF (Neutral detergent fiber)) a été significativement plus faible que pour les autres fourrages, ce qui a également conduit à un poids vif significativement plus faible, et les moutons ont passé moins de temps à manger, ont mangé moins fréquemment que ceux des autres groupes et ont présenté des périodes de repos plus longues. Les animaux ont consommé significativement plus de foin de luzerne (fibres totales : 30.1%, NDF : 50.0%) au travers de repas longs et fréquents et ils se sont aussi fréquemment reposés. Les moutons nourris avec de la pulpe de betterave sucrière (fibres totales : 17.5%, NDF : 46.0%) ont préféré des repas plus courts mais plus fréquents qu’avec l’ensilage de maïs (fibres totales : 25.2%, NDF : 64.0%) ou le foin de luzerne y compris après minuit alors que les animaux des autres groupes dormaient. Ces résultats montrent que les taux de NDF et d’humidité des fourrages affectent directement leur ingestibilité, ce qui conduit à des modifications du comportement alimentaire notamment dans la fréquence et la quantité des repas et dans la durée des périodes de repos. Keywords: sheep, roughage intake, eating behaviour, barley straw, alfalfa hay, sugar beet pulp, corn silage. Mots-clés : mouton, consommation de fourrage, comportement alimentaire, paille d’orge, foin de luzerne, pulpe de betterave sucrière, ensilage de maïs intake become more and more important to be expressed in detail. There have been a lot of studies pointing on these properties which make forages interesting as a feed in animal nutrition. Quantitatively accurate prediction of feed intake by ruminants is still an unresolved problem and experimental researches on eating behaviour in ruminants are required. For that, camera monitoring systems are advantageous for monitoring-recording-validation processes by investigators and also less disturbing to animals [1]. Introduction In ruminant nutrition, roughage based feeding regimes; choice of basal diet is the main aspect of forage consumption. However, efficient utilization of roughages and control of animal’s approach on fiber sources need knowledge of what determines feeding behaviour and dietary choices. Feed factors such as nutritional composition, fiber content and maturity [12], species [3, 14], cut size [2, 10], method of processing, chemical treatment [7] and conservation methods influence eating behaviour, dietary choices and ultimately nutrient intake in sheep. Chemical composition is the key factor to assume the quality of fiber source and consumption amount. Impression of cell wall constituents’ amount and form as Acid Detergent Fibre (ADF) and Nitrous Detergent Fibre (NDF) are the major parameters but animals’ behaviours for feed selection and voluntary Harvested grain forages are produced in high amounts but are generally with low quality; better quality forages such as legume hay, corn silage or non fibrous fiber sources like sugar beet pulp (a very common industrial by-product which is well accepted by the animals) would be extended. Revue Méd. Vét., 2013, 164, 11, 503-510

  2. 504 POLAT (E. S.) AND COLLABORATORS The objective of this study was to examine the effect of common fiber sources such as barley straw (BS), corn silage (CS), alfalfa hay (AH) and sugar beet pulp (SBP) on feed intake and ingestive manners of young sheep, when given in divided equal meals of 6 times a day. ether extract (EE) according to AOAOC [27], and for crude fiber according to the CRAMPTON and MAYNARD’s method [8]. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined with the ANKOM 2000 Fiber Analyser (ANKOM Technology, Fairport, NY) as described by GOERING and VAN SOEST [18]. Non Fiber Carbohydrates (NFC) was calculated using the following formula: NFC = DM - (ASH + EE + CP + NDF) [24]. Materials and Methods EXPERIMENTAL CONDITIONS, ANIMALS AND DIETARY REGIMES Animal behaviour was recorded on PC by commercial hardware 3D-Eyes Video card (3D EYES. PCC Electronics LTD. Kadikoy, Istanbul, Turkey), using four video cameras placed at the top of fixed pens of each group, each 4 m high, for 24 hours a day. Each camera was able to cover 6 animals in every group. The border of each group was marked at 3 cells in 2 rows and intervals made clearly visible with white pegs. Records of each experimental group and individual eating behaviour, the duration of the eating, standing and resting between meals were monitored during 24hours for one week after an adaptation period of 7 days to both pens, feeds and feeding regime and analyses of these observations. The study was carried out in Turkey, Central Anatolia, Selcuk University, Faculty of Veterinary Medicine, in the experimental farm station’s sheep house. The sheep house was a well ventilated building with wooden grated floor. During the trial, the day length was approximately 14.5- 15 hours and building was artificially illuminated after the sunset and the temperature was maintained between 18°C and 22°C night and day. To avoid animal disturbance during feed service process, a radio played 24 hours a day tuned to a station which broadcast mainly people talking. Twenty four of 12 weeks old weaned male young sheep in an average starting live weight of 27.0 kg have been used in the experiment as randomly selected from a Merinos land originated herd, homogenously allocated. Experiment took place for 2 weeks with an adaption period of 7 days plus 7 days of observation. Sheep were individually housed (78x118 cm2) and separate roughage, concentrate feed and water were supplied. At the end of the experiment, the camera records of every individual concentrate and roughage consumption, standing without eating and resting periods have been inspected. The continuous positions and activities of each animal were monitored from the records by scan sampling at 30 second intervals throughout each 4 hours meal and also on the whole observation session. Two observers sat in front of computer screen, one identified the activity of individual sheep on each occasion and the other was recording to a worksheet page. They were used for all the observations and observed each group the same number of times. The behaviour of every individual sheep and groups on each occasion was determined by time and length by an adapted computer program with activated macros in Microsoft Excel. The investigated parameters of animal behaviours were the meal period (roughage consumption was recorded after the first 2 hours and at the end of the period of continuous 4 hours), the time spent eating (time (in minutes) in which roughage eating longer than 1 minute was observed), the eating bouts (times) (corresponding to animals eating phase which does not end before 1 minute), the roughage intake (g) (amount of roughage consumed by animal throughout one meal period), the concentrate intake (g) (amount of concentrate consumed by animal throughout one day), the standing period (time (in minutes) in which animals were standing without any other activity) and the resting period (time (in minutes) in which animals were laying down). Water was always freely available to animals, inside the pens. Animals were fed individually 6 times a day, with roughage ad libitum in 4 hour intervals plus concentrate 300 g/head (Metabolisable Energy (ME): 2.8 Mcal/kg of dry matter (DM), Crude proteins (CP): 17.5 %) once a day at 14:00 o’clock. Feed consumption was determined at the commencement of the experiment and 15-20% more roughage offered in every meal bout. Types and amounts of roughages offered to animal groups (6 sheep per group) in every meal on raw basis were; Barley Straw (BS) 160g/meal, Sugar Beet Pulp (SBP) 1200 g/meal, Corn Silage (CS) 800 g/meal and Alfalfa Hay (AH) 300 g/meal. In every meal period, feed offered and refused were weighed and recorded in every two hours. Weigh backs were discarded and fresh feed was provided. All roughages were in similar dimensions like 2-3 cm lengths. Such dimensions were found resulting in higher intake of dry matter for sheep fed with hay [22], corn silage and sugar cane pulp [13]. The experimental protocol was approved by the ethics Committee of the Faculty of Veterinary Medicine, Selcuk University. Animals have been weighed at the beginning and at the end of the experiment and empty body weights of animals have been recorded. CHEMICAL AND BEHAVIOURAL ANALYSES STATISTICAL ANALYSIS The feed samples were analyzed for dry matter (DM), crude protein (CP), crude ash (ASH) and crude fiber (CF), The data obtained from different roughages of four in 6 different periods of a complete day have been modelled in Revue Méd. Vét., 2013, 164, 11, 503-510

  3. EATING BEHAVIOUR IN SHEEP AND ROUGHAGE TYPE 505 Barley straw Corn silage Alfalfa Sugar beet pulp Concentrate Dry Matter (%) Crude Protein (%) Ash (%) Ether Extract (%) Crude Fiber (%) ADF (%) NDF (%) NFC (%) 93.7 3.8 11.3 1.2 38.4 48.9 74.0 9.4 24.7 7.3 9.8 2.6 25.2 34.0 64.0 16.5 89.6 18.0 11.3 1.6 30.1 34.3 50.0 19.3 19.7 11.9 4.0 1.5 17.5 25.5 46.0 36.6 92.7 19.7 8.4 3.5 13.0 11.1 22.9 38.2 ADF: Acid Detergent Fiber, NDF: Nitrous Detergent Fiber, NFC: Non-fibrous carbohydrates. Table I: Chemical compositions of different roughages consumed by young sheep. Roughage intake (g) Time spent eating (min) Eating bouts (number) Standing periods (min) Resting periods (min) Barley straw (n = 6) 06h00-10h00 10h00-14h00 14h00-18h00 18h00-22h00 22h00-02h00 02h00-06h00 Total Corn silage (n = 6) 06h00-10h00 10h00-14h00 14h00-18h00 18h00-22h00 22h00-02h00 02h00-06h00 Total Alfalfa hay (n = 6) 06h00-10h00 10h00-14h00 14h00-18h00 18h00-22h00 22h00-02h00 02h00-06h00 Total Sugar beet pulp (n = 6) 06h00-10h00 10h00-14h00 14h00-18h00 18h00-22h00 22h00-02h00 02h00-06h00 Total 49.1BC 51.1B 41.3C 74.1A 55.8B 34.1D 50.9c 27.3B 30.0AB 23.0B 34.5A 29.2AB 13.3C 26.2c 2.9A 2.5AB 2.6AB 3.1A 2.1B 1.1C 2.4c 42.4A 39.0AB 39.0AB 33.5B 22.2BC 16.2C 32.0b 170.3D 171.0CD 168.1D 172.0CD 188.7B 210.5A 181.7a 123.1B 135.5B 127.9BC 140.7A 134.8B 110.2D 128.7b 42.0A 34.3B 33.5B 40.9A 39.9A 29.3C 36.6a 3.8A 2.8AB 3.1AB 3.4A 3.0AB 2.4B 3.1b 43.4A 32.6B 38.0AB 30.2B 26.9BC 22.1C 32.2b 154.6D 173.1B 158.1D 168.9C 173.2B 188.7A 171.2b 176.3B 184.4B 181.8B 191.2A 193.7A 154.1C 180.2a 42.7A 39.1A 33.9B 36.4AB 35.6AB 30.9C 36.4a 3.9A 3.5AB 3.4AB 3.5AB 3.1B 2.3C 3.3b 36.6A 27.3B 27.3B 27.6B 27.1B 18.0C 27.3c 160.8D 173.7C 166.8D 176.0B 177.3B 191.1A 176.3ab 116.8BC 114.3BC 145.9AB 156.0A 128.8B 104.2C 127.7b 30.0B 27.8BC 33.7AB 38.1A 33.9AB 26.3C 31.6b 4.0A 3.8AB 4.5A 4.2A 3.6AB 2.7B 3.8a 50.2A 34.1B 39.5AB 34.5B 37.3AB 28.2C 37.3a 159.8D 178.0B 157.2D 167.4C 168.8C 185.6A 171.1b Mean SEM SEM: standard error of the mean; Different superscripts a,b,c in the same column indicate significant differences (p < 0.05 or more) between the roughage types Different superscripts A,B,C,D in the same column indicate significant differences (p < 0.05 or more) for a given roughage type according to the recording period within day. 121.9 4.41 32.7 0.83 3.1 0.08 32.2 0.93 175.1 1.66 Table II: Roughage intake, time spent eating, number of eating bouts, standing and resting periods per day during meal intervals of 4 hours in young sheep according to the roughage types (Barley straw, Corn silage, Alfalfa hay and sugar beet pulp). Revue Méd. Vét., 2013, 164, 11, 503-510

  4. 506 POLAT (E. S.) AND COLLABORATORS General Linear 6x4 factorial design and statistically analyzed in SPSS Package Program. One Way ANOVA test has been used to compare the set of daily data among groups. The significant results have been tested in Duncan’s Test in same Package Program (SPSS 17.0). Results were considered as significant when p value was less than 0.05. 3). The roughage DMI within the day and meal periods has been summarized in Table III. Roughages were consumed in majority during daytime instead of during night and were preferentially ingested during the first 2 hours of a meal, when fresh feed was given. The pattern in the roughage consumption was similar in all groups and only the ingested quantities significantly varied among the groups (p < 0.001). Results There was no acclimation effect and familiarization to feeds and feeding activity and adaptation was complete within treatment groups at the end of the first period of 7 days. Animals responded well to their diets in all meal periods. The chemical composition of investigated roughages and concentrate are given in Table I. The dry matter content of roughages was varying between 19.7% for the sugar beet pulp and 93.7% for the barley straw. Barley straw had the highest Neutral Detergent Fiber (NDF) content and the lowest Non Fibrous Carbohydrates (NFC) while sugar beet pulp was characterized by low NDF and high NFC. Figure 1: Roughage intake in sheep fed 6 times a day during 4 hour meal periods with barley straw, alfalfa hay, corn silage or sugar beet pulp. The roughage dry matter intake, time spent eating, number of eating bouts, length of standing periods and resting periods were significantly affected according to the roughage type given to sheep as shown in Table II. Roughage DMIs (dry matter intake) during 4 hour meal periods have significantly differed according to the roughage type (p < 0.001): maximal intakes were seen with alfalfa hay whereas sheep have consumed significantly less barley straw. In the same way, the mean time spent eating during 4 hours meal intervals was significantly affected by type of roughages (p < 0.001); this time was markedly increased when alfalfa hay or corn silage were distributed to sheep and it was dramatically depressed with barley straw. It was also noted that the mean number of eating bouts per meal was significantly lowered when barley straw was used compared to the other roughages (p < 0.001) and it was remarkably increased with sugar beet pulp (Table II). Figure 2: Roughage intake in sheep fed 6 times a day during 4 hour meal periods with barley straw, alfalfa hay, corn silage or sugar beet pulp. In addition, maximal roughage intakes whatever the type were recorded particularly at 18h00-22h00 (and also at 22h00-02h00 for the alfalfa hay) whereas roughage intakes declined at 14h00-18h00 (except with sugar beet pulp) and were the lowest at 02h00-06h00 in all groups (p < 0.001) (figure 1). Similarities were observed in the variations of time spent eating according to the meal periods (figure 2): basically animals in all groups have spent longer times to eat at sunrise (06h00-10h00) and at sunset (18h00-22h00) than in other meal periods, they have not spent much time eating roughage (except with sugar beet pulp) during the period 14h00-18h00 and the eating activity was quite depressed at 02h00-06h00 (p < 0.001). In parallel, the eating bouts also significantly cumulated at sunrise (06h00-10h00) and at sunset (18h00-22h00) excepted in the group fed with sugar beet pulp in which they culminated at 14h00-18h00 (figure Figure 3: Numbers of eating bouts in sheep fed 6 times a day during 4 hour meal periods with barley straw, alfalfa hay, corn silage or sugar beet pulp. In agreement, when considering the daily averages of roughage DMI, time spent eating and number of eating bouts (Table IV), it was found that the overall roughage intakes Revue Méd. Vét., 2013, 164, 11, 503-510

  5. EATING BEHAVIOUR IN SHEEP AND ROUGHAGE TYPE 507 BS CS AH SBP SEM p-value Roughage DMI (g/day) Feed consumed During the first 2 hours of meals In g In % During the last 2 hours of meals In g In % During daytime (06h00-20h00) In g In % During nighttime (20h00-06h00) In g In % 305.5c 772.0b 1081.4a 765.9b 61.9 < 0.001 212.2c 68.7% 574.8b 73.9% 788.9a 72.6% 468.1b 60.5% 48.4 < 0.001 NS 93.3c 31.3% 197.2b 26.1% 292.8a 27.4% 297.8a 39.5% 19.3 < 0.001 NS 193.7c 62.8% 487.5b 63.1% 676.0a 62.3% 470.7b 61.2% 39.1 < 0.001 NS 111.7c 37.2% 284.5b 36.9% 405.5a 37.7% 295.2b 38.8% 23.7 < 0.001 NS DMI: Dry matter intake; BS: Barley straw; CS: Corn silage; AH: Alfalfa hay; SBP: Sugar beet pulp; SEM: standard error of the mean Different superscripts a,b,c in the same row indicate significant differences (p < 0.05 or more) according to the roughage type. Table III: Distribution of the quantity of feed consumed during a meal and the overall 24 hours period in young sheep (n = 6 per group) according to the roughage types (Barley straw, Corn silage, Alfalfa hay and sugar beet pulp). BS CS AH SBP SEM p-value Time spent eating (min/day) Time spent eating concentrate (min/day) Number of eating bouts (time/day) Roughage DMI (g/day) Roughage DMI (g/min) Roughage DMI (g/bout) Body weight (kg) Roughage DMI (% of BW) Total DMI (% of BW) 157.2b 9.6 14.4c 305.5c 2.1c 16.0c 28.4b 1.1c 2.1c 219.8a 12.0 18.4b 772.0b 3.6b 35.9b 33.4a 2.3b 3.2b 218.5a 9.9 19.7ab 1081.4a 5.1a 76.1a 32.8a 3.3a 4.2a 189.7ab 10.5 22.7a 765.9b 4.2ab 42.2b 32.1a 2.4b 3.2b 9.1 0.4 0.9 61.9 0.3 4.9 0.6 0.2 0.2 < 0.05 NS < 0.01 < 0.001 0.001 < 0.001 < 0.05 < 0.001 < 0.001 DMI: Dry matter intake; BW: body weight; BS: Barley straw; CS: Corn silage; AH: Alfalfa hay; SBP: Sugar beet pulp; SEM: standard error of the mean; NS: not significant. Different superscripts a,b,c in the same row indicate significant differences (p < 0.05 or more) according to the roughage type. Table IV: Daily averages of roughage intake, time spent eating and number of eating bouts and weight growth in young sheep (n = 6 per group) according to the roughage types (Barley straw, Corn silage, Alfalfa hay and sugar beet pulp). expressed in g/day greatly varied according to the roughage given (p < 0.001), the daily maximal and minimal consumed amounts being obtained with alfalfa hay and barley straw, respectively. Although the daily time spent eating and the daily number of eating bouts were not only highly elevated in the group receiving alfalfa hay but also in groups fed with corn silage (for time spent eating, p < 0.05) or with sugar beet pulp (for number of eating bouts, p < 0.01), the roughage intakes per eating time and per eating bouts were the highest in animals receiving alfalfa hay (p < 0.001). By contrast, the daily eating activity (characterized by roughage intakes, time spent eating and number of eating bouts) was dramatically decreased in sheep fed with barley straw, leading to a significant decrease in the body weight at the end of the experiment (p < 0.05). Consequently, the efficiencies (expressed in % of body weight) of roughage intake and of total dry matter intake (including the consumption of concentrate which was consumed rapidly without any significant difference on eating time) were also markedly increased in the group fed with alfalfa hay and considerably depressed in those fed with barley straw (p < 0.001). The duration of the standing and resting periods of animals during meal periods and complete day (Table II) has significantly varied according to the roughage type (p < 0.001): the standing periods lasted longer when sheep received sugar beet pulp and they were significantly shortened when animals were fed with alfalfa hay whereas the longest resting periods were recorded in sheep receiving barley straw and the shorter ones were observed in animals fed with sugar beet pulp or corn silage. Animals fed with sugar beet pulp spent longer time of standing especially after midnight while other Revue Méd. Vét., 2013, 164, 11, 503-510

  6. 508 POLAT (E. S.) AND COLLABORATORS animals were mainly resting. For all groups, standing periods were the longest during sunrise meal (06h00-10h00) and the lowest ones were noted at 02h00-06h00. By contrast, sheep have reduced eating activity (decreased roughage intakes, time spent eating and number of eating bouts) throughout the night (02h00-06h00) and have preferred resting. In addition, a slight increase in the resting periods was noted before midnight (at 10h00-14h00) except in animals fed with barley straw. This difference in the behaviour observed in the group fed with barley straw was significant with the others (interaction roughage type x periods: p < 0.01) (figure 4). animals 6 times a day may reduce the exacerbated feed intake immediately following distribution and improve roughage intake during other periods such as sunrise and sunset in which the number of eating bouts were more frequent as described in the present trial. During the 4 hours meal period, most of the roughage was consumed during the first half of the meal (60.5-73.9%) and the rest was consumed in the second half. As it was described in material and method, feed was taken away before the animals came and it was weighed in the middle of the meal and same feed was put back for another 2 hours until the end of meal. This weighing activity (disappearance of meal for a few minutes) did not motivate animals for further eating. Resting period (min) In addition, sheep generally prefer the feeds they can eat faster [23]. The balance between motivation to eat, satiation which directly regulates feed intake and dietary choices act in combination for controlling eating behaviour at short-term in adequate term with body homeostatic regulation [16]. Feed factors operate mainly on the short-term control for feed intake [4] and roughage ingestibility is defined as the maximum quantity of the feed that can be eaten by the animal when it is supplied ad libitum. The decrease in ingestibility with roughage character is the result of the increase in its fill effect [3, 4]. When given indoors, ingestibility of forage depends mainly on their nutritive value and fill effect in rumen limits the feed intake in ruminants [20]. Plant tissue lignification and fiber fractions e.g. amount and composition of cell walls (NDF and ADF) increases the undegradable fraction of feed and decreases the degradation rate of diet consumed [19]. Barley straw 220 210 Alfalfa hay 200 Corn silage 190 180 Sugar beet pulp 170 160 150 06-10 10-14 14-18 18-22 22-02 02-06 hour Figure 4: Duration of the resting periods in sheep fed 6 times a day during 4 hour meal periods with barley straw, alfalfa hay, corn silage or sugar beet pulp. Discussion In this study different roughages were given to young sheep in divided meals and it was found out that type of roughage significantly influenced feed intake and eating behaviours. In the present study, maximal roughage DMI was obtained when sheep were fed with alfalfa hay whereas this parameter was dramatically depressed in animals consuming barley straw. DULPHY et al. [14] have also observed low barley straw intake efficiency (0.9-1.1 % of body weight) similar to the value obtained here (1.1%) whereas they have found lower alfalfa hay efficiency (2.2-2.4%) than in the present study (3.3%). This discrepancy may probably be related to the higher digestibility of the alfalfa hay in the present study characterized by a lower NDF (49.9%) compared to the roughage used by DULPHY et al. (NDF: 53.5-56.3%). In accordance with these results, NEWMAN et al. [25] have reported that sheep tend to consume more clover than grass in order to rapidly provide a high satiety level (especially through protein intake). However, the dry matter intake was not directly associated to the NDF contents of the four distinct roughages tested here. Indeed, despite various NDF contents in corn silage and sugar beet pulp, the roughage efficiency was similar in the 2 groups (2.3% and 2.4% of body weight, respectively). In addition, in the present study, sheep fed with corn silage have spent long time for eating compared to those fed with barley straw and sugar beet pulp with shorter eating bouts than those fed with alfalfa hay and sugar beet pulp, probably because of the relatively high NDF content (64.0% vs. 50% (alfalfa hay) and 46% (sugar beet pulp)) that has limited corn silage consumption. In the case As all kinds of roughages were in similar dimensions (2.5- 3.0 cm), a possible physical effect related on particle size on the roughage intake rate previously reported by VILLABA and PROVENZA [31] was ruled out in the present study. Animals generally set their major meal as sunset and consumed highest amounts. Sunset meal time was effectively long for sheep receiving sugar beet pulp and barley straw but in those fed with alfalfa hay or corn silage, the sunrise meal time was the longest. Rest of the eating was spread throughout the day. It was reported that grazing cumulates especially during sunset and sunrise [21]. THOMSON et al. [30] also observed a first important meal on the morning at 09 h and the daily maximal meal occurring at 20 h. as main grazing periods. In this study, feed consumption occurred as 33-40% of daily diet during the periods of sunrise (06- 10 hours) and sunset (18-22 hours), which is lower than previously reported as 60-80% in pasture [4]. In animals fed indoors and when feed distribution was scheduled twice per day [21], 60-80 % of daily intake was eaten during two main meals following distributions. Consequently, feeding Revue Méd. Vét., 2013, 164, 11, 503-510

  7. EATING BEHAVIOUR IN SHEEP AND ROUGHAGE TYPE 509 of barley straw, the low amount of roughage intake was linked to its high fiber content (38.4% compared to the others). Non forage fiber sources like sugar beet pulp are advantageous in ruminant nutrition leading to an increased intake due to low NDF and ADF fractions of fiber [29]. In the same way, O’DOHERTY et al. [26] have observed that sugar beet pulp added to pressed SBP enhanced daily intake from 1060 g to 1260 g compared to corn silage in late pregnant ewes in which rumen capacity was limited. Because of high moisture content in sugar beet pulp limiting its intake [6], it was observed that sheep receiving sugar beet pulp were spreading eating during the 24 hours period (the mean number of eating bouts per meal and the duration of standing periods, particularly after midnight were significantly elevated compared to the groups fed with alfalfa hay and corn silage) whereas the roughage intake per meal was significantly decreased. As a conclusion, 4 different roughages were investigated on eating behaviour of penned young sheep. Not only NDF but also moisture contents in roughages were found effective on animal intake and behaviour significantly. In such experimental studies on assessment of voluntary eating activity and behaviour, it would be necessary to apply an additional technique for monitoring ruminating activities in animal. References 1. AGREIL C., MEURET M.: An improved method for quantifying intake rate and ingestive behavior of ruminants in diverse and variable habitats using direct observation. Small Rum. Res., 2004, 54, 99-113. 2. ALLEN M.S.: Relationship between fermentation acid production in the rumen and the requirement for physically effective fiber. J. Dairy Sci., 1997, 80, 1447- 1462. 3. BAUMONT R., DULPHY J.P., JAILLER M.: Dynamic of voluntary intake, feeding behavior and rumen function in sheep fed three contrasting types of hay. Ann. Zootechn., 1997, 46, 231-244. 4. BAUMONT R., PRACHE S., MEURET M., MORAND- FEHR P.: How forage characteristics influence behavior and intake in small rumiants: a review. Livestock Prod. Sci., 2000, 64, 15-28. 5. CHAI K., KENNEDY P.M., MILLIGAN L.P., MATHISON G.W.: Effect of cold exposure and plan species on forage intake, chewing behavior and digesta particle in sheep, chewing behavior and digesta particle in sheep. Can. J. Anim. Sci., 1985, 65, 69-76. 6. CHASE L.E.: Effects of high moisture feeds on feed intake and milk production in dairy cattle. Cornell Nutrition Conference of Feed Manufacturers, Ithaka, NY, 1979. 7. COŞKUN B., KADAK R., TUNCER Ş.D., ŞEKER E., BAYTOK E., DELIGÖZOĞLU F.: Üre ve melasla muamele edilen buğday ve mercimek samanlarının hayvan beslemede kullanımı üzerinde araştırmalar. Hayvancılık Araştırma Derg., 1991, 1, 27-33. 8. CRAMPTON E.W., MAYNARD L.A.: The relation of cellulose and lignin content to nutritive value of animal feeds. J. Nutr., 1970, 15, 383-395. 9. DAS N., MAITRA D.N., BISHT G.S.: Genetic and non- genetic factor influencing ingestive behavior of sheep under stall-feeding condition. Livestock Prod. Sci., 1999, 32, 129-136. 10. DE BOEVER J.L., DE SMET A., DE BRABANDER D.L., BOUCQUE C.V.: Evaluation of physical structure. 1. Grass silage. J. Dairy Sci., 1993, 76, 140-153. 11. DE HAER L.C.M., MERKS J.W.M.: Patterns of daily food intake in growing pigs. Anim. Prod., 1992, 54, 95- 104. 12. DEMARQUILLY C., ANDRIEU J., WEISS P.: L’ingestibilité des fourrages verts et des foins et sa prévision. In: Prévision de la Valeur Nutritive des The time spent eating per day was highly correlated with total DMI (r = 0.875, p < 0.001) and roughage DMI (r = 0.875, p < 0.001). ERHARD et al. [15] reported that the time interval (ranged from 4h to 8h) during meals has directly affected the number and the duration of eating bouts, more animals were waiting, more eating bouts were long and frequent. SCHWARTZKOPH-GENSWEIN et al. [28] assumed that differences in eating rate could strongly affect the relationship between cumulated waiting periods for meal and total DMI intake. In the present study, animals were not in a competitive situation and their eating behaviour would most likely be dissimilar to that observed in a flock setting. In a similar way, DE HAER and MERKS [11] reported that pigs housed together ate faster and consumed more feed per meal than those penned individually. In the present study, standing periods were significantly longer early in the morning and, and resting periods were longest late at night in all groups. Sheep fed with alfalfa hay have spent significantly less time standing than others whereas those fed with sugar beet pulp have stood up much longer. Particularly, these animals remained standing after midnight much longer than the others. During the trial, animals spent resting in the majority of their time (in average, approximately 3 hours per 4 hours period, i.e. nearly 75% per day), thus including rumination and sleeping. Nevertheless, it was found that sheep receiving barley straw exhibited significantly longer standing periods especially after 22h00 than the others. GILL [17] reported that sheep stay awake for 16 hours a day in pasture, 4-5 hours half sleepy and 3-4 hours asleep. In a behaviour study, DO THI et al. [13] observed that sheep spent 282 min eating and 540 min ruminating per day and CHAI et al. 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