Demand-feeding behaviour and diel pattern of feeding activity in Oncorhynchus mykiss held under different photoperiod regimes

1992 ◽  
Vol 40 (4) ◽  
pp. 535-544 ◽  
Author(s):  
T. Boujard ◽  
J. F. Leatherland
Keyword(s):  
Oncorhynchus Mykiss ◽  
Feeding Behaviour ◽  
Feeding Activity ◽  
Diel Pattern

Adaptive changes in the appetite, growth and feeding behaviour of pony mares offered ad libitum access to a complete diet in either a pelleted or chaff-based form

2002 ◽  
Vol 74 (3) ◽  
pp. 517-528 ◽  
Author(s):  
C. McG. Argo ◽  
J. E. Cox ◽  
C. Lockyer ◽  
Z. Fuller
Keyword(s):  
Body Weight ◽  
Feeding Behaviour ◽  
Feeding Activity ◽  
Average Daily Gain ◽  
Nutrient Digestibility ◽  
Crude Fibre ◽  
Period 2 ◽  
Complete Diet ◽  
Gross Energy ◽  
Ad Libitum

AbstractSeven, 3-year-old pony mares (~230 kg) were used in a cross-over study to compare the appetite, energy and nutrient digestibilities, growth rate and feeding behaviour, when a complete diet was offered ad libitum in either the original loose-chaff mix (C), or as a more convenient, milled and pelleted preparation (P). Ad libitum access to the study diet (gross energy = 17·2 MJ/kg dry matter (DM)) was attained over 2 weeks. In the following 4 weeks, groups 1 (no. = 3) and 2 (no. = 4) received pelleted and chaff-based diets respectively. Dietary forms were exchanged during week 5 and ad libitum provision continued for a further 4 weeks. Behaviour and apparent nutrient digestibilities were assessed in weeks 3 and 4 of each period. Pelleted food had a lower proportion of water (P, 0·12; C, 0·22), but relative proportions of oil (0·04), crude protein (0·08), crude fibre (0·29), neutral-detergent fibre (NDF; 0·53) and gross energy (GE) were neither altered by food processing nor time. Apparent digestibilities (DM, 0·49; GE, 0·50; NDF, 0·40 in period 1) of the pelleted and chaff-based diets were similar within periods but decreased (P 0·01) to a similar extent for both diet types (proportional changes: DM, –0·14; GE, –0·16; NDF, –0·28) in period 2. Overall, mean intakes of digestible energy (DE) for chaff-fed animals during period 1 were 0·73 (P 0·001) of pellet DE intake (DEI). Mean DEI of pellets increased (P 0·001) during period 1 to attain 1·76 (s.e. 0·25) MJ/kg M0·75 on day 25. Following transfer from pellets to chaff, DEI decreased (P 0·001) to 0·68 (s.e. 0·07) MJ/kg M0·75 by the end of period 2. In contrast, DEI of animals which progressed from chaff to pellets remained relatively constant between periods. Oestrous behaviour caused no detectable change in the appetite of individual mares. Irrespective of differences in DEI, average daily gain (ADG) in body weight and condition score (CS) did not differ between groups. Overall, mean ADG decreased (P 0·01) from 1·54 (s.e. 0·17) kg/day in period 1 to 0·26 (s.e.0·08) kg/day in period 2. Changes in body weight were associated with CS (R2 = 0·72). Each CS point represented a 53·4 (s.e. 4·8) kg gain in body weight. Chaff meals were longer (30·6 (s.e. 1·6) min, P 0·001), less frequent (23·8 (s.e. 1·4) per day, P 0·001) and associated with a lower bite rate (3·8 (s.e.0·2) per min, P 0·001) and increased chewing requirement (23 (s.e. 1·2) per bite, P 0·001), which decreased the rate of DM intake (17·0 (s.e. 0·9) g/min, P 0·0.01). Overall, chaff-fed animals spent more time feeding (0·50 (s.e. 1·3) of the time; P 0·0.01), primarily at the expense of non-feeding activity and rest. The ad libitum feeding regime enabled stabled ponies to re-establish natural feeding patterns and offers a viable alternative to meal and forage feeding. The more slowly ingested chaff form maximized time spent feeding and limited changes in DEI during the introductory period. Although CS and ADG increased over the first 4 weeks, growth and appetite returned to near maintenance values within 9 weeks in association with a decrease in dietary energy intake and nutrient digestibility.

Relationships Between Social Dominance and Feeding Behaviour in Lactating Heifers During Periods of Heavy Competition

1993 ◽  
Vol 1993 ◽  
pp. 150-150
Author(s):  
A.D. Kenwright ◽  
J.M. Forbes
Keyword(s):  
Social Interaction ◽  
Social Dominance ◽  
Feeding Behaviour ◽  
Feeding Activity ◽  
Dairy Herds ◽  
Agonistic Interactions ◽  
High Ranking ◽  
The Way

Previous research has shown that social dominance in dairy herds can be measured using replacements of one cow by another at feed stations (Rutter et al,1987). When there is competition for feed or space, the motivation to engage in physical and non-physical agonistic interactions will be stronger than if resources are freely available. When resources are limited, social dominance becomes very important and high ranking animals have priority.This becomes especially important after cows are returned from milking and/or when fresh feed is added when the number of cows is far greater than the number of feeding spaces (Campling and Morgan, 1981). This experiment aimed to further investigate the way in which social interaction between cows affects the feeding behaviour, particularly at times of peak feeding activity.

Comparison of feeding behaviour and performance of weaned pigs given food in two types of dry feeders with integrated drinkers

1999 ◽  
Vol 68 (1) ◽  
pp. 35-42 ◽  
Author(s):  
M. Laitat ◽  
M. Vandenheede ◽  
A. Désiron ◽  
B. Canart ◽  
B. Nicks
Keyword(s):  
Feeding Behaviour ◽  
Feeding Activity ◽  
Weaned Pigs ◽  
Multifactor Analysis ◽  
Daily Water ◽  
The Mean ◽  
The Difference ◽  
And Performance ◽  
Almost All ◽  
Type V

AbstractPerformance of 80 (tests 1 and 2) or 60 (tests 3 and 4) weaned pigs were compared when using ‘Tubetype’ feeder (T), allowing the animals to mix meal and drinking water, or another type (V) where drinking and eating places are separated. The difference in growth rate was not significant but the mean daily water consumption (1 per pig per day) was higher with T than with V in each test but significantly only in tests 1 and 3 (1·84 v. 1·40, and 2·11 v. 1·26, P < 0·01).Feeding behaviour was assessed during tests 2 and 4. Multifactor analysis of variance revealed effects (P < 0·01) of feeder, group size and period of the day on the occupation time and the average number of animals using the feeders simultaneously. These two variables were higher for V than for T (test 2: 23·4 per 24 h v. 21·5 per 24 h and 4·5 v. 3·7, P < 0·05; test 4: 20·0 per 24 h v. 18·2 per 24 h, P< 0·01). In each test, both feeders were used for a longer time and by more piglets during the ‘day’ than during the ‘night’ (P < 0·01). When grouping 40 pigs, animals used both feeders during almost all the day period (V: 15·9 per 16 h and T: 15·8 per 16 h). During the night period, this was only true with V (V: 7·4 per 8 h; T: 5·8 per 8 h). The use of feeder V in crowded conditions thus prevented preferential diurnal feeding activity, commonly described in pigs. In conclusion, even if productivity is not affected, feeding behaviour and thus eventually welfare are influenced by the type of feeder, especially with high numbers of animals.

Feeding behaviour and grazing impacts of a Euplotes sp. on attached bacteria

1998 ◽  
Vol 44 (7) ◽  
pp. 623-629 ◽  
Author(s):  
J R Lawrence ◽  
R A Snyder
Keyword(s):  
Image Analysis ◽  
Feeding Behaviour ◽  
Feeding Activity ◽  
Grazing Pressure ◽  
Bacterial Populations ◽  
Grazing Impacts ◽  
Feeding Effort ◽  
Attached Bacteria ◽  
Biofilm Bacteria ◽  
Time Series Images

The locomotory and feeding responses of a Euplotes sp. to attached populations of Vibrio natriegens and Pseudomonas fluorescens in a continuous flow system were analyzed by computer image analysis of video microscopy recordings. Upon entry into the chamber, the ciliates moved in long continuous arcs 300 µm in length during which time no bacteria were consumed. As feeding began, the average path length shortened, the arcs became tighter, and the ciliates changed direction more frequently. The feeding activity of the Euplotes appeared to be gregarious, being concentrated in patches within the biofilm of attached bacteria. It was also noted that the feeding effort targeted patches previously visited by other Euplotes, despite reduced bacterial density relative to the surrounding field of attached bacteria. This focused and intense feeding activity resulted in localized zones of nearly complete clearance within the attached bacterial populations. Loss of bacteria and averaged ciliate presence within feeding patches were determined from digitized time series images and discrimination thresholds for particle size. These data were used to determine grazing rates indicating that Euplotes sp. removed 120 V. natriegens cells·ciliate–1·h–1 and up to 882 P. fluorescens cells·ciliate–1·h–1. However, surface clearance rates for Euplotes sp. grazing on V. natriegens and P. fluorescens were 0.02 and 0.03 mm2·ciliate–1·h–1, respectively, indicating that surface grazing pressure was fairly consistent within the patches of intense feeding activity. The effect of such intense localized feeding behaviour on attached or biofilm bacteria would be to increase spatial and temporal heterogeneity within biofilms. Key words: digital image analysis, Euplotes, grazing, biofilms.

Diurnal and nocturnal feeding activity in Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 54 (12) ◽  
pp. 2894-2900 ◽  
Author(s):  
Anders Alanärä ◽  
Eva Brännäs
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Salvelinus Alpinus ◽  
Feeding Activity ◽  
Activity Patterns ◽  
Arctic Char ◽  
Diel Activity ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Nocturnal Feeding ◽  
Nocturnal Fish

When food is limited and competition for it is high, individual fish may adopt different diel activity patterns. We followed individual feeding activity in groups of 10 Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) using a combined self-feeding and PIT-tag system. Food was supplied at low and high rewards to five replicate groups of Arctic char and rainbow trout. Four categories were identified in both species: high-triggering diurnal (diurnal fish with the highest self-feeding activity), low-triggering diurnal, nocturnal, and nontriggering fish. On average, the photophase proportion of the total daily activity was approx 90% in diurnal and approx 20% in nocturnal individuals. Rainbow trout offered high rewards did not show any diel preferences. Diurnal Arctic char and rainbow trout with the highest self-feeding activity were initially larger and had the highest growth rates, indicating a high social position. Nocturnal fish were initially smaller and their proportion of trigger actuations much lower than the high-triggering diurnal fish. These still grew successfully whereas nontriggering fish grew significantly less. Thus, some individuals with a low social status may apply an alternative strategy to attain adequate growth by feeding at night when dominant individuals are less aggressive. This may be referred to as concurrent dualism (diurnalism and nocturnalism).

Influence of Rainbow Trout (Oncothynchus mykiss) on Density and Feeding Behaviour of a Perlid Stonefly

1989 ◽  
Vol 46 (9) ◽  
pp. 1575-1580 ◽  
Author(s):  
Blair W. Feltmate ◽  
D. Dudley Williams
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Feeding Behaviour ◽  
Predator Avoidance ◽  
Feeding Rate ◽  
Avoidance Behaviour ◽  
Substrate Selection ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Paragnetina Media

Stonefly (Paragnetina media) density was reduced in a rainbow trout (Oncorhynchus mykiss) enclosure by approximately 35%, whereas in a trout exclosure no significant changes in density occurred. Of the 35% reduction, approximately two-fifths and three-fifths were attributable, respectively to direct consumption of stoneflies by trout, and emigration by stoneflies from the predator-stressed section of stream. With trout present in laboratory aquaria, predator avoidance behaviour resulted in stoneflies remaining significantly more on dark substrate on which they were less vulnerable to trout predators. Stoneflies consumed significantly fewer prey (enchytraeid whiteworms) over 24 h, in the presence of both small (2.0–4.0 cm) and large (10.0–12.0 cm) rainbow trout in aquaria, compared with stoneflies feeding in trout-free aquaria. Feeding rate and substrate selection did not differ between well-fed and starved (5 d) nymphs.

The effect of body condition on the feeding behaviour of sheep with different times or access to food

1997 ◽  
Vol 64 (2) ◽  
pp. 239-246 ◽  
Author(s):  
A. M. Sibbald
Keyword(s):  
Body Condition ◽  
Feeding Behaviour ◽  
Food Access ◽  
Day Treatment ◽  
Feeding Activity ◽  
Latin Square ◽  
Access Time ◽  
Fresh Food ◽  
Time Spent Feeding ◽  
Access To Food

AbstractIntakes and feeding patterns were studied in two groups of 24 Scottish Blackface ewes, with initial mean body condition scores of 2·15 (thin) and 3·15 (fat). Three treatments, allowing access to a dried-grass pellet diet ad libitum for 6, 12 or 24 h/day, were applied in a Latin-square design, with each sheep receiving each treatment for one 12-day period. Food intakes were measured daily and feeding activity was recorded automatically every minute for one 24-h period during the last 5 days of each 12-day treatment period.Mean intakes were higher for thin than for fat ewes (1720 v. 1467 g dry matter (DM) per day; P < 0·001). There were no interactions between the effects of body condition and food access time and mean intakes over the last 7 days for the 6-, 12- and 24-h food access treatments were 1429, 1686 and 1805 g DM per day respectively (T < 0·001). Time spent feeding was higher for thin than for fat ewes, over the whole day (231 v. 197 mini day; P < 0·05) and in the first 6 h after the introduction of fresh food (140 v. 120 min; P < 0·05), but there were no differences between thin and fat ewes in the frequency of meals or in the rate of intake during meals. Intakes for the first 6 h were higher with restricted food access (1402, 1109 and 819 g DM per day for 6-, 12- and 24-h access; P < 0·001) but there were no differences in time spent feeding. The number of meals during the first 6 h was higher (10·4 v. 8·3; P < 0·05) and the rate of intake was higher (11·4 v. 7·8 g/min; P < 0·05) for 6-h compared with 24-h food access.It was concluded that long-term differences in intake due to body condition and short-term changes due to restricting food access time, involve different behavioural responses and this may reflect differences in the mechanisms involved in the regulation of voluntary intake. Keywords: body condition, feeding behaviour, sheep.

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