Behavioural and physiological responses to an acute stressor in crib-biting and control horses

Posted in: Welfare by admin on January 1, 2003 | No Comments

It was observed through video-recordings that crib-biting horses perform the stereotypy for 10.4 to 64.7 % of their stabling time. Crib-biting and non-crib-biting horses (controls) were exposed to an arousal-inducing stimulus in order to study the similarities and differences in their response. For the first two days of the experiment, the horses received food from a special bucket. On day three, the food bucket was presented but the horses were not allowed to feed. During and after presentation of the food stimulus, arousal behaviour and crib-biting intensity were studied, as was plasma cortisol concentration, heart rate at rest, and heart rate variability at rest. Heart rate and arousal behaviour in crib-biters and in controls increased in response to the stimulus, but crib-biting frequency decreased. Upon examination of heart rate variability at rest, it was determined that crib-biters had a lower vagral tone (high frequency component) and a higher sympathetic tone (low frequency component) than controls. This lower basal parasympathetic activity may be indicating why crib-biting horses showed neither a significant increase in the high frequency component during presentation of the food stimulus, nor decrease in the high frequency component after presentation of the stimulus, when compared with control horses. Therefore, there may be differences in the tuning of the autonomous nervous system and in the stress reactivity of crib-biting and non-crib-biting horses. The experimental results suggest that crib-biting horses are more stress sensitive than non-crib-biting horses, and they are also physiologically and psychologically less flexible than the non-crib-biting horses.

A laser-based method to measure thermal nociception in dairy cows: Short-term repeatability and effects of power output and skin condition.

Posted in: Welfare by admin on | No Comments

Exposure to acute stress can lead to changes in nociceptive thresholds. Laser technique has been used successfully to measure nociceptive thresholds in cattle. This paper presents data from three experiments examining whether: 1) the method is valid as a measurement of nociceptive threshold in dairy cows; 2) there is an acceptable repeatability within 15 min (the duration of most experimental acute stressors); and 3) skin condition (intact vs. naked) affects nociceptive threshold and its variability in dairy cows. Three experiments were performed to observe the behavioural responses to a computer-controlled CO2 laser beam applied to the skin on the caudal aspect of the metatarsus. In experiment 1, effects of power output on nociceptive responses were examined on dairy cows kept and tested in tie stalls. Increasing the power output affected the latencies to respond, types of response, and behaviour during (increasing frequency of tail flicking) and between single laser exposures (increasing frequency of kicking). Therefore, behavioural responses to a laser stimulus seem to be a valid measure of nociception in dairy cows. Repeatability within 15 minutes was investigated in experiment 2. The variables’ latency to move the exposed leg and frequency of tail flicking during laser exposure showed the highest level of repeatability. Effects of power output and skin condition were examined in experiment 3. Increasing the power output and shaving off hair led to increased responses as seen by shorter latencies to respond, less non-responding, and increased kicking. In conclusion the results of these experiments suggest that behavioural responses to laser stimulation are a valid and reliable measure of nociception in dairy cows, especially when applied on naked skin.

Effects of qualitative and quantitative feed restriction on the activity of broiler chickens.

Posted in: Welfare by admin on | No Comments

Diurnal patterns and time courses of activity were investigated in groups of fast-growing broilers subjected to different levels of qualitative and quantitative feed restrictions. Eight groups of 225 female Ross 208 broiler chickens were reared from 1 to 57 days of age in straw-bedded floor pens (18.9 m2) equipped with drinking nipples and six circular feed troughs. The lighting schedule consisted of 7 h and 10 min of darkness preceded by 30 min dusk. Groups were fed one of two feeds (Control and Diluted), where the latter was the control feed diluted with 15% ground oat hulls. All groups were fed ad libitum between 0-7 days of age and 43-56 days of age. During the in-between period four groups were fed ad libitum and four groups were fed twice a day (meal-fed). The meal-fed groups were fed 58 and 67% of the ad libitum groups on control and diluted, respectively, calculated on a weekly basis. Activity was logged every half-a minute throughout the experimental period using passive infrared detection (PID). Number of birds feeding was counted in all groups every 4 min during 90 min after the morning meal (08.00 h) and 90 min around the afternoon meal (14.00 h). Quantitative, but not qualitative, feed restriction affected activity levels, with meal-fed chickens being more active throughout the light period. An increase in the proportion of meal-fed birds feeding following each meal was observed. Across the meal-feeing period the meal-fed chickens appeared to learn about food availability and adjusted their behaviour accordingly. General activity of the chickens peaked at 21 days for all groups. An activity increase during the dark period was found to reflect night feeding as well as the growth of the birds. The potential welfare benefit to the birds of increased activity caused by quantitative restriction was in the present experiment overshadowed by the concomitant extended periods of hunger.

Young horses' reactions to humans in relation to handling and social environment.

Posted in: Welfare by admin on | No Comments

In this experiment Forty Danish warmblood colts were used to investigate the effect of housing and handling in the rearing period on the reactions to humans. The horses entered the experiment after weaning and were housed either individually or in groups of three. Half of the horses from each housing group were handled three times per week for a period of 10 min. Approach tests were performed in the home environment when the horses were 6, 9, 12, 18, 21, and 24 months old, and an Arena and Human Encounter test was performed in a novel environment when the horses were 12 and 24 months old. In the home environment, single-housed horses approached sooner and were more easily approached by a human than group-housed horses where no effect of handling was observed. In the Arena and Human Encounter test, single-housed horses expressed less restless behaviour, more explorative behaviour, and less vocalization than group-housed horses. Handled horses showed lower increase in heart rate during the test than non-handled horses. There was no difference between the number of times single or group-housed horses touched an unfamiliar person in the Arena and Human Encounter tests but handled horses approached sooner than non-handled horses. It is concluded that the social environment affected the way horses reacted to humans when tested in the home environment but not in a novel environment. In contrast, handling affected the reactions to humans when tested in the novel environment but not in the home environment. However, handled horses also reacted less to the novel environment in general, thus indicating that handling is a mean of avoiding potential dangerous situations.

Optimum versus maximum lysine levels for weanling pigs.

Posted in: Welfare by admin on | No Comments

Rapid improvements in lean growth potential, health status and management of the weaned pig have resulted in changes in the energy and amino acid requirements such that previous recommendations or diet formulations used in the past may no longer result in maximum performance. In addition, recent research showing increases in nursery exit weights will double by marketing places even greater importance on maximizing weight gain of the weanling pig. So, we ask the question: .How much lysine is enough and how much is too much, and how much lysine in the starter is economical? Currently, recommended lysine:energy ratios vary from as low as 2.8 to as high as 5.0 g total lysine/Mcal DE for pigs up to 25 kg. In 1998, the National Research Council (NRC) recommended 3.5 g total lysine/Mcal DE for pigs above 5 kg live weight. Two experiments were conducted to determine the optimum ratio of total lysine/ DE for the weaned pig. In experiment 1, a total of 240 pigs at weaning were fed a standard commercial SEW diet for 5 days followed by a transition diet for 8 days. Pigs were then fed the experimental diets for a 28-day period starting on day 13 postweaning. The six experimental diets contained total lysine/DE ratios of 2.7, 3.0, 3.3, 3.6, 3.9 or 4.2g total lysine/Mcal, equal to 0.95%, 1.05%, 1.16%, 1.26%, 1.37% and 1.47% total lysine, respectively. Growth rate and feed efficiency increased with increasing lysine/DE ratio. There was no effect of lysine/DE on feed intake. Because growth rate increased linearly to the highest level (4.2 g/Mcal; 1.47 % total lysine), we concluded that the required lysine/DE ratio for the weaned pig is at or above this level and thus may be higher than most literature values and recommendations. A second experiment was therefore necessary. In experiment 2, a total of 240 pigs were fed two levels of DE; low energy (LE, 3.4 Mcal DE/kg) or high energy (HE, 3.6 Mcal DE/kg), at 5 lysine/DE ratios (3.7, 4.0, 4.3, 4.6, and 4.9 g total lysine/Mcal). Thus, 10 diets, ranging in total lysine content from 1.26% to 1.76%, were investigated. The lysine/DE ratios were selected to bracket existing literature values for the weaned pig and included higher values than those used in experiment 1. Pigs were fed one of the 10 experimental diets starting on day 7 post-weaning for a 28 day period. Growth rate increased and feed efficiency improved with increased lysine:DE ratio. Overall, the level of DE did not influence growth rate. However, pigs fed the high-energy diets ate 13% less feed than those fed the low-energy diets in week 1 and had 12% lower growth rate. Overall feed intake was 4% lower on the high-energy diets, but DE intake was similar for both DE levels. The lysine:DE ratio that maximized performance was calculated from the regression equation. We concluded that for pigs growing from 7.5 to 22.5 kg, the requirement is 4.65 g total lysine/Mcal DE, equal to 1.60% total lysine. The existing recommended ratios for the weaned pig are inadequate to support its full growth potential, so the results of experiment 1 were confirmed. Increasing the lysine level of a starter diet from 1.30% to 1.60% will cost about $80 per tonne using current feed costs. With actual total feed intake of pigs on lysine:DE levels for this period, the feed cost per pig will increase by $1.86 at the optimum lysine level. Assuming this additional lysine increases nursery exit weights by 1 kg, and assuming, based on previous research at the Prairie Swine Centre, that this improvement will increase weights at 20 wk of age by 2 kg, we calculated the change in net income per pig by using ratios above 3.7 g/Mcal. The maximum benefit is obtained at 4.30 g/ Mcal (1.5%) when hog market prices are above $1.75 (Table 3), but lowers levels of 1.3% to 1.4% optimized financial returns at lower market prices. Clearly, hog market prices dictate the benefit of using optimum versus maximum lysine:DE ratio in the starter diet and provide further support for the logic that feeding programs must be developed in the context of changing economic conditions.

Transgenic Approaches to Enhance the Environmental and Physiological Characteristics of Pigs and Their Impact on the Pork Industry

Posted in: Production by admin on | No Comments

Transgenic selection is the genetic modification of an organism via addition or removal of select genes. Transgenic selection can do what selective breeding is unable to do, or do it with more certainty. Success in enhancing productivity of domestic animals has been achieved by the use of injectable growth hormone. Transgenic pigs have been developed that generate phytase in the saliva in order to digest typically unavailable phosphorus, without the need of dietary phytase. This in turn results in the need to not supplement diet with phosphorus, thereby reducing phosphorus emission in wastes. Transgenic pigs have been produced in Japan that contained the plant gene FAD2 that produces an enzyme involved in the synthesis of beneficial fatty acids.

Some transgenic work has been done in other species that could prove to be beneficial in the swine industry. In cattle, the protein lactoferrin can be secreted by transgenic cows, which could help piglet immunity. Mastitis in mice could lead to a transgenic pig that creates an enzyme in the udder to break down the bacteria that cause mastitis (such as Staphylococcus aureus). Some work in mice could also lead to transgenic pigs that synthesize important antibodies. Pigs created transgenically need to be examined to make sure there is nothing that could be allergenic to humans as a result of this DNA manipulation. When transgenic pigs become available (estimate 3 to 4 years), there will be no need for production changes. They will be able to grow and thrive in current operation standards. There is a gradual change in consumer awareness of valuable characteristics of transgenic products such that by the time there are transgenic pigs ready for market there will be an informed and accepting consumer base ready to purchase transgenic pork.

Nursery Management – Big Pens

Posted in: Production by admin on | No Comments

Lately there has been interest in increasing the pen size of nursery pigs (from about 22 to 50 – 150 pigs). Ideas for a large pen design include a fully slatted floor, feeders along the length of the room and centre, and 4 pens per room. Feeders are one of the most limiting factors in this design (there MUST be adequate access to enough feeders). The advantages to large group sizes include cost, extra space utilization, savings in labour cost, less moving and mixing, and more forgiving in regards to crowding. Some of the disadvantages include difficulty in handling and age and health. To get this system up and running, 20% more feeders and drinkers, hospital pens, an alley, 80 per pen, and adequate space are all recommended.

Benefits of COOL to the Swine Industry

Posted in: Production by admin on | No Comments

It is not a wise strategy to implement a costly program to inform Americans that 89% of the pork they eat is of U.S. origin when it appears that fewer than 75% of Americans are willing to pay a premium for U.S. pork.
Basics of COOL
The 2002 Farm Bill contained a controversial provision mandating country of origin labeling (COOL) of certain unprocessed foods (beef, pork, lamb, fish, seafood, peanuts, fruits and vegetables) sold through non-small grocery stores (i.e. stores which annually sell more than $230,000 of fruits and vegetables) beginning on September 30, 2004. The basic concept of COOL appears to be popular with consumers. Much of the controversy about COOL arises from concerns that many in the livestock-red meat industry have that COOL will be a costly regulation with little or no benefit for their sector.

Feed intake, digestibility and N retention of a diet of water spinach supplemented with palm oil and / or broken rice and dried fish for growing pigs

Posted in: Production by admin on | No Comments

From Supply Push to Demand Pull : Agribusiness Strategies for Today’s Consumers

Posted in: Production by admin on | No Comments