Optimizing Phosphorus Characterization in Animal Manures by Solution Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy

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A Theory of Packer Self Production in the Swine Industry

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Effects of stall width and sow size on behaviour of gestating sows

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It is recommended that gestating sows of various weights should be kept in different sizes of stalls. However, the proper size of stall has not been well defined. A study was conducted to evaluate stall width by assessing the interaction between stall width and sow size on behaviour. As stall width decreased, sows spent less time standing, more time sitting, and their udders extended into the adjacent stall more frequently. Using udder extension during less than 50% of lateral lying as a criteria for stall width, a 65 cm (26”) stall is adequate for gilts and small sows, but a 70 cm (28”) stall is required for larger sows if in stalls for the entire gestation period.

Managing Grow-Finish Pigs in Large Groups

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Keeping animals in groups of 100 or more has the potential of reducing housing costs (i.e. – penning) and giving producers more flexibility in building design and management. Managing pigs in large groups of 100 or more will result in a reduction of average daily gain, usually during the first 2 to 4 weeks after the group is formed. This is the only area that needs improvement because other aspects of productivity show little or no difference between large and small groups. Any loss in productivity appears to be small and is compensated for by facility costs and flexibility of management. Aggression is lowered in large groups because pigs tend to develop a tolerance to strange pigs. These animals may even adapt better to group housing systems in the breeding herd. Producers should not redesign partial-slat floors from small to large group housing as this may lead to poor dunging patterns. Surprisingly, investigation of animals and feeders takes less time in large group pens than small group pens. Treating them is easier than one may think because the pigs are more approachable in large groups. Hallways need to be larger and doorways need to be wider for large groups to move through. Automatic or electronic sorters are useful in replacing manual sorting of pigs. Scales are set up at the entrance to a feeding area and pigs move through the scale and are sorted to a light or a heavy side. Continuous sorting is the better method as it is less stressful for the pigs and requires less labour. Pigs need to be trained in order to adapt to this system though. The use of these automatic sorters can be useful for incorporating new management possibilities such as phase feeding and grid sensitive marketing.

The accuracy of dual energy x-ray absorptiometry (DXA), weight, and P2 back fat to predict half-carcass and primal-cut composition in pigs within and across research experiments

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Lying behaviour and adrenocortical response as indicators of the thermal tolerance of pigs of different weights.

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Optimal temperature ranges of fattening pigs at different weights were assessed by examining the behavioural and adrenocortical responses of pigs to a range of ambient temperatures. Cortisol concentration was analyzed by taking saliva samples from the pigs. Behaviours measured included lying behaviour. Depending on ambient temperature, pigs chose different areas for resting. When temperature increased, pigs would lie in the dung area away from penmates more often. Heavier pigs lied without contacting their penmates more often than their lighter counterparts. Lying without penmate contact occurred 5 to 7 °C lower than lying in the dung area. As temperature decreased, huddling behaviour increased. As pig weight increased, huddling occurred more at lower temperatures. For pigs over 85 kg body weight, there was a significant increase in cortisol levels when ambient temperature increased. The results of the present study indicated that, for pigs weighing 25 to 35 kg and housed on partially slatted floors, temperature range within the thermal tolerance of pigs was 19 to 21 °C. At 50 to 70 kg body weight, the range was 10 to 17 °C. For pigs over a body weight of 85 kg, temperature range within their thermal tolerance was 5 to 17 °C.

The effect of rearing regime on the development of the mammary gland and claw abnormalities in high genetic merit Holstein-Friesian dairy herd replacements.

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The effect of rearing regime on mammary gland development and claw abnormalities was assessed using Holstein-Friesian heifers. Treatments included 1) heifers reared to calve at 540 kg and offered grass-silage based diets during the winter and grass-based diets during the summer; 2) heifers reared to calve at 620 kg and offered grass-silage based diets during the winter and grass-based diets during the summer. They also received additional supplements; 3) heifers reared to calve at 620 kg and were offered a straw/concentrate diet during the winter and a grass-based diet during the summer; 4) heifers reared to calve at 620 kg and fed a straw/concentrate diet in both the winter and summer and were housed. By increasing the plane of nutrition, the weight of dissected udder fat increased, but there was no effect on the weight or chemical composition of dissected udder parenchyma. Fat deposition in the udder was reduced and the proportion of parenchyma in the udder was increased by offering straw- compared with silage-based diets. There were no effects on weight of fat when heifers were housed during the first summer and offered straw-based diets compared with those heifers turned out to grass, although there was a tendency towards a reduction in the proportion of parenchyma in the udder. Values for heel height, lateral claw length and heel erosion scores were lower for heifers reared on a low plane of nutrition. A higher plane of nutrition increased live weight/sole area, although it was only significantly higher for treatment 3 compared with treatment 1 heifers. Housing heifers the first summer increased the incidence of feet lesions in the white line and solear area relative to turning heifers out to grass that first summer.

Effect of duration of cold stress on plasma adrenal and thyroid hormone levels and immune responses in chicken lines divergently selected for antibody responses.

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There is increasing evidence that stress affects various immune processes. Some of these changes are due to hormonal changes involving corticosterone (CORT), triiodothyronine (T3), and thyroxine (T4). Effects of stress depend on the nature of specific stressors (e.g., thermal extremes, diet, pollutants), stress-modifiers (e.g., genetic make-up, duration and severity of the stressors). This study examined the effects of a specific stress (cold stress) with stress-modifiers (duration of stress and genotype of the bird) on immune responses and plasma adrenal and thyroid hormone levels in 3 layer-type chicken lines. Two lines were divergently selected for high (H line) or low (L line) antibody responses to SRBC, and the third line was a randombred control (C). Growing chicks of the 3 lines were feed-restricted at 80% of ad libitum consumption, and subjected to cold stress (CS) at 10oC continuously for 7, 5, 3, 1 or 0 d before immunization with keyhole limpet hemocyanin (KLH). Specific antibody titers to KLH, and in vitro lymphocyte proliferation (LP) upon mitogen stimulation were measured. In addition, adrenal and thyroid hormone levels were measured in the plasma samples collected at the end of CS. No significant effect of duration of CS on specific antibody titers was found in the 3 lines. A significant enhancing effect of CS was found on LP. A significant dose-dependent suppressive effect of CS was found on plasma CORT levels. The authors concluded that CS does not affect specific antibody responses, but may have a modulating effect on cellular immunity and plasma CORT levels, depending on the duration of stress. This is the first study that reveals an absence of significant differences in adrenal and thyroid hormone levels in the described selection lines.

Complexity of behavioural sequences and their relation to stress conditions in chickens: a non-invasive technique to evaluate welfare.

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This study examined the use of behavioural complexity as a potential to assess the stressfulness of an animal’s environment. Chickens were videotaped for 0.5 hr periods and the changes in behaviour analysed to yield a complexity value. This technique was then used to determine the effects on behavioural complexity when birds were exposed to different potential stressors. Differences were found in the behavioural complexity of locomotor and resting behaviours when birds were exposed to food restriction, social crowding through the addition of more birds, and when sand was provided. The direction of these changes was not consistent for all stressors, however, the authors conclude that behavioural complexity is a non-invasive means to assess different housing conditions.

Are cows that consistently enter the same side of a two-sided milking parlour more fearful of novel situations or more competitive?

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This study attempted to find a relationship between the consistency that a cow enters a one of two sides of a milking parlour with her behaviour in a novel environment and her ability to attain fed in a competitive situation. Two groups of twelve cows were chosen from a group of 70. Cows that demonstrated a preference for entering only one side of the parlour were classified as high consistency (HC) cows and entered in the preferred way, on average, 91% of the time. Cows that did not show a strong preference for either entry entered one side 60% of the time and were classified as low consistency cows (LC). For fifteen-minute period after milking, a cow was housed in a new empty pen and her behaviour was observed. Immediately after that set of observations, another cow was introduced to the pen and feed was provided in the bucket. The behaviour of the cow was recorded for 15 minutes or until the two cows stopped feeding or interacting with one another. When HC cows were introduced to the empty pen, they stood motionless longer than LC cows. However, HC and LC cows showed similar amounts of exploratory behaviours (time spent sniffing the pen, number of steps taken, number of vocalizations) when moved into the pen. The authors interpreted the difference in activity as indicating that HC cows were more fearful of the new environment. When a new cow and feed was introduced to the pen the HC cows were began to eat the food sooner and maintained control of the bucket longer than LC cows. HC cows were involved in more aggressive interactions and tended to push the other cow more than LC cows. During the feed competition test, the HC cows stood inactive longer than the LC cows. All cows likely develop some sort of a routine. There is, however, a difference in the social strategies between cows with strong and weak preferences. Those cows that are able to demonstrate a preference may be more capable of successfully executing their social strategy.