Eating Behaviour in Large Groups: Learning How Pigs Perceive Their Environment

Posted in: Prairie Swine Centre by admin on January 1, 2008 | No Comments

As we studied how finisher pigs perform in large groups we have also studied their eating behaviour. Our reasons for this extend beyond our interest in feed intake, to questions we have on how pigs perceive their environment and the impact that could have on our management. For example, when we first started working with larger groups, in this case 80 pigs in a pen, two theories existed for how pigs interacted with this large space. One theory was that to avoid unfamiliar pigs and aggression, the animals would restrict their movement to a limited area of the pen. We would call this a territory. We used 8 feeders in the pen of 80 pigs, and spaced these evenly along one of the long walls of the rectangular pen. Of 60 pigs that we observed, 80% visited all 8 of the feeders during a 24-hr period. All of the pigs ate from at least 6 of the feeders. This eating behaviour demonstrated that the pigs were not territorial, but used the entire pen. The implication was that resources, such as feed and water, did not have to be located throughout the pen, but could be concentrated, perhaps in a food-court.
We continued our studies with slightly larger groups (108 pigs/pen) but retained the spacing of feeders equidistantly along the length of the pen. The eating behaviour of pigs in large and small (18 pigs/pen) groups was remarkably similar with the exception of the first week after group formation. While pigs in large and small groups spent similar amounts of time eating during the first week, those in large groups visited feeders more often (35 times/day) than did those in small groups (25 times/day). As with the pigs in the previous study, the pigs in large groups were sampling many feeders each day. The first week after the groups were formed we saw both a reduction in average daily gain and an increase in feeder visits (but not total eating time) in large groups compared to small. We hypothesize that the need to investigate the entire pen during the first days in a large group led to many feeder visits, and contributed to a reduction in growth.
Moving on from our finding in the first study that pigs would use the entire pen, our next experimental set-up placed the feeders in the large group together near one end of the pen. Unlike the previous studies, pigs in the large group would have to travel farther from their lying area to the feeder than did the pigs in small groups. The eating behaviour of pigs in large groups changed. When the cost (effort) to get to a resource (feeder) increases, we would predict that animals would visit the resource less often, but the visits would be longer to compensate. This is what we saw in large groups. The pigs in large groups ate fewer (9.2 vs 11.7 meals/day) but longer meals (7.4 vs 5.3 min/meal), so that the total time spent eating in a day (60.4 vs 55.7 min/day) and total feed intake (2.78 vs 2.82 kg/day) were similar in large and small groups. In this same study we superimposed a crowded treatment (k = 0.025) on the group sizes. Crowded pigs also reduced the number of visits to the feeder each day, but they did not increase the length of their visits or maintain their total eating time and feed intake. The crowded pigs demonstrated a loss of appetite compared to the pigs in large groups, even though both conditions resulted in fewer meals.
Our studies on eating behaviour of pigs in large groups have demonstrated that pigs make use of the entire pen, visiting most if not all feeders regularly. The inquisitiveness leading to this extensive use of the pen is evident in a large number of feeder visits during the first week, and may contribute to poor initial growth in the system. When feeders are concentrated in one area of the pen, making it more difficult to get to a feeder, pigs in large groups reduce their number of meals, but compensate by having longer meals. The adaptability of pigs in large groups allows us to broaden the scope of our management options to include not only large groups, but also concentrated feeding areas within the pen.

Influence of extruded linseed on growth, carcass composition, and meat quality of slaughtered pigs at one hundred ten and one hundred sixty kilograms of liveweight

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The objective of this experiment was to determine the effects of dietary extruded linseed, an n-3 PUFA on growth performance, carcass composition, meat quality, and oxidative stability of pigs slaughtered at 111 kg and 160 kg approximately. This was done because there has been much interest in ways to manipulate the fatty acid composition of meat as the Western diet is characterized by a high intake of SFA relative to PUFA, and the consumption of n-3 PUFA is decreased realtive to n-6 PUFA. This study shows that the inclusion of linseed in swine diets may in fact improve the fatty acid profile of pork without significantly affecting oxidation or color stability. Thus, this type of feeding practice may improve human health based on the n-6:n-3 PUFA ration recommended for the human diet.

How pigs are handled on the farm can affect meat quality

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Proper nutrition and proper on-farm handling affect
meat quality.
Those are two firm outcomes of a three-year study led
by Prof. Peter Purslow, acting Associate Dean (Research and
Innovation) for the Ontario Agricultural College and Professor,
Department of Food Science, University of Guelph.
The study, which will be completed this summer with a final
look at nutrition, included 648 slaughter pigs from 27 groups
of pigs representing a large number of commercial operations
and processing days, as well as some pigs from research farms.

Feed Grains and Livestock: Impacts on Meat Supplies and Prices

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In this article we attempt to explain what is happening to feed costs, including the likely consequences of the recent ethanol boom on these costs and how the different sectors—beef, dairy, pork, and poultry—are adjusting to higher costs. Importantly, speed of adjustment will vary significantly as industries with shorter production cycles, such as poultry, are able to respond in a matter of months whereas adjustments in industries with longer production cycles, such as beef, can take a period of several years.

Effect of dietary soybean oil and soybean protein concentration on the concentration of digestible amino acids in soybean products fed to growing pigs

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The apparent ileal digestibility (AID) of amino acids by growing pigs is increased if oil is added to the diet (Li and Sauer, 1994; Albin et al., 2001). Standardized ileal digestibility values (SID) for crude protein and amino acids take into account the amino acid contributions of endogenous origins, and values for SID are more accurate estimates of the digestibility of amino acids in a feed ingredient compared with values for AID (Stein et al., 2007). However, there is limited information about the effect of dietary oil on the SID of amino acids in soybean products fed to pigs. It has been suggested (NRC, 1998) that the digestibility of amino acids in full-fat soybeans (FFSB) is less than in soybean meal (SBM) and soy protein concentrate (SPC). This is surprising because full-fat soybeans contain more oil than SBM and SPC (Cromwell, 2000; Zarkadas and Wiseman, 2005), and it would, therefore, be expected that the digestibility of amino acids in FFSB is greater than in defatted soybean products. Because increased protein concentration in soybeans is often accompanied by a reduced concentration of oil (Yaklich, 2001), the digestibility of amino acids in high-protein soybean varieties may be different from the digestibility in conventional varieties. The objective of this experiment was to measure the effect of oil addition to SBM and SPC on AID and SID of crude protein and amino acids by growing pigs and to compare these values to the AID and SID for crude protein and amino acids in FFSB. The second objective was to compare the digestibility of amino acids and the concentration of digestible amino acids in a new high-protein variety of FFSB (FFSB-HP) to values obtained in conventional sources of FFSB (FFSB-CV), SBM, and SPC. Four diets were prepared using each soybean product as the sole source of crude protein and amino acids in 1 diet. Two additional diets were formulated by adding soybean oil (7.55 and 7.35%, respectively) to the diets containing SBM and SPC. A nitrogen-free diet was also used to measure basal endogenous losses of crude protein and amino acids. The 2 sources of FFSB were extruded at 150°C before being used in the experiment. Seven growing barrows (initial BW = 26.2 kg) were prepared with a T-cannula in the distal ileum and allotted to a 7 × 7 Latin square design. Ileal digesta were collected from the pigs on day 6 and 7 of each period. All digesta samples were lyophilized and analyzed for DM, crude protein, amino acids, and chromium, and values for AID and SID of crude protein and amino acids were calculated. The addition of oil improved (P < 0.05) the SID of most indispensable amino acids in SBM and SPC. The SID for 6 of the indispensable amino acids in FFSB-HP were greater than in FFSB-CV, and the SID for all indispensable amino acids except Met was greater in FFSB-HP than in SBM. However, the SID for most amino acids in FFSB-HP was similar to SBM with oil and SPC, but these values were lower than in SPC with oil. In conclusion, the addition of oil improved the SID of most amino acids in SBM and SPC fed to growing pigs, and the SID of amino acids in FFSB-HP were greater than in SBM and similar to the SID of amino acids in SBM with oil and in SPC.

For more information the full article can be found at http://jas.fass.org/

Comparing fogging strategies for pig rearing using simulations to determine apparent heat-stress indices

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Strategies to reduce the apparent heat-stress indices inside a growing pig building were compared. Two fogging strategies were studied, fogging with the necessary water evaporating to give the same: (i) duration of heat-stress, ‘FDuration’, and (ii) intensity of heat-stress, ‘FIntensity’, as when using evaporative pads, ‘EPads’. For the whole 5-month period (May–September) under Greek summer conditions strategy ‘FIntensity’ was significantly better than strategy ‘FDuration’ in terms of heat-stress duration (Po0.05; reduction 45.1%) and heat-stress intensity (Po0.01; reduction 70.7%). Also, during the hottest day (Julian 176) it resulted in: (i) a lower daily average inside temperature (28.5 vs. 31.8 1C; reduction 10.4%), (ii) a smaller daily inside dry-bulb temperature variation (8.7 vs. 10.3 1C; reduction 15.5%)
and (iii) a higher reduction of peak outside temperature (36.8 1C at 14:00 h), namely 2.9 vs. 0.2 1C, respectively. For both strategies and heat-stress indices July was the most stressful month and May the mildest. In areas characterised by high outside temperatures and scarce water resources strategy ‘FIntensity’ should be implemented with caution as larger water quantities, in comparison to strategy ‘FDuration’, need to evaporate.

For more information the full article can be found at  http://www.sciencedirect.com/science/journal/15375110

A comparison of the effects of dietary spray-dried bovine colostrum and animal plasma on growth and intestinal histology in weaner pigs

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This study was undertaken to evaluate the effects of dietary spray-dried plasma from two species (bovine and porcine) alongside spray-dried bovine colostrum in pigs weaned at 21 days of age, investigating the effect of these ingredients on small intestine histology, morphology and some indices of intestinal inflammation. It was found that compared to results from the control treatment, dietary spray-dried bovine colostrum reduced small intestine villus height at the site 25% along the small intestine, but increased it at the 75% site, whereas spray-dried bovine plasma increased villus height in the 25% and 75% sites, and spray-dried porcine plasma had no effect on villus height in any sampled region of the small intestine. Further research is needed to determine whether they are indeed functional alternatives, and where their similarities and differences may lie.

For more information the full article can be found at http://www.journals.elsevierhealth.com/periodicals/livsci

Evaluation of NutriDense low-phytate corn and added fat in growing and finishing swine diets

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This study evaluates the effects of NutriDense low phytate corn in conjunction with increasing added dietary fat on growing and finishing pig performance. The results indicate that increasing added fat improved growth performance regardless of the corn source. In addition, growth performance was similar for pigs fed NutriDense low-phytate or yellow dent corn.

Effects of neonatal iron status, iron injections at birth, and weaning in young pigs from sows fed either organic or inorganic trace minerals

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In this study second-partiy sows were fed diets containing organic or inorganic trace minerals, and their progeny were used to determine the iron (Fe) status of pigs at birth and nursing and postweaning phases. The results indicated a reduced Fe bioavailability when sows were fed the organic fe source, but this could also been because of a greater Fe need, lowered Fe status, or both, for the sow because of the greater number of pigs farrowed and heavier litter weights at parturition and weaning. It is also concludeed that Fe injection at birth may be critical to achieving maximum pig growth response to weaning. There was no apparent advantage to injecting fe at weaning when neonatal pigs received Fe injections.

The effects of R-salbutamol on behavior and physiology of finishing pigs

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Salbutamol has potential for use as a
repartioning agent in swine. The aims of this experiment
were to determine effects of salbutamol on behavior
and physiology of finishing pigs. The study used
192 pigs (88.8 ± 0.9 kg of BW) housed in groups of 6
in 32 pens and assigned to 1 of 4 treatments: 1) control—
0 mg/kg of salbutamol, 2) 2R—control diet with
2 mg/kg of the pure R-enantiomer of salbutamol, 3)
4R—control diet with 4 mg/kg of pure R-salbutamol, or
4) 8RS—control diet with 8 mg/kg of a 50:50 mixture
of the R- and S-enantiomers. All diets were offered ad
libitum for 4 wk. Salbutamol diets were replaced with
control diets 24 to 48 h before slaughter. Behavioral
responses to handling during weighing were recorded
immediately before assignment to the treatments (wk
0) and at weekly intervals over the next 4-wk period.
Behavioral and heart rate (HR) responses to a 10-min
human presence test in the home pen were measured
during wk 0, wk 1, and wk 3. Heart rate responses to
a 36-min transportation were recorded. One pig from
each pen had blood collected 4 times: during wk 0, 2, 4,
and at exsanguination. Blood was analyzed for NEFA,
creatine kinase, glucose, lactate, blood urea nitrogen,
ammonia, insulin, cortisol, norepinephrine, and epinephrine.
Data were analyzed using PROC GLM of
SAS, with pen as the experimental unit. Treatment
had no effect on time spent lying laterally, overall activity,
or time spent alert. Treatment had no effect on
handling measures (P > 0.05) or on behavioral responses
to human presence (P > 0.05), with all pigs willing
to spend similar amounts of time close to and touching
the human. However, during the human presence
test in wk 1 and wk 3, control pigs had HR around 10
peats per minute less (P < 0.05) than pigs in the other 3 treatments. During transport, overall HR were similar across treatments (P > 0.05). However, at certain 1-min
time points, control pigs had greater HR than salbutamol-
treated pigs (P < 0.05). There were no treatment differences in lactate, epinephrine, or norepinephrine concentrations at any point. During wk 4, control pigs had less creatine kinase (P < 0.02) and greater blood urea nitrogen (P < 0.005) compared with pigs fed all the salbutamol treatments. The home pen behavior, handling, human presence test, and transport results indicate that salbutamol-treated pigs do not show marked differences in home pen time budgets and behavioral and HR responses to handling and transportation compared with control pigs. Thus, salbutamol did not have a negative effect on finishing pig well-being during this study.