Physiological effects of elevated plasma corticosterone concentrations in broiler chickens. An alternative means by which to assess the physiological effects of stress.

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

Physiological measures are often used in the assessment of animal welfare. Many of these measures involve the hypothalamo-pituitary-adrenal (HPA) axis, particularly the animals’ ability to release cortisol and the effects of cortisol release on other physiological measures. Some of these studies involve giving animals an infusion of corticosterone, but this can be a significant stressor in itself. This study was conducted to determine if it is possible to administer corticosterone by drinking water and if the effects are similar to other means of administration. The chickens were given 4 levels of corticosterone in their water (0 to 20 mg/L). Plasma corticosterone levels rose in accordance with the level in the water. Secondary responses to corticosterone, such as heterophil counts, also responded in a dose dependent manner. It is concluded that administration of corticosterone in the drinking water is an effective means of studying stress responses in chickens.

Effect of ketoprofen, lidocaine local anesthesia, and combined xylazine and lidocaine caudal epidural anesthesia during castration of beef cattle on stress responses, immunity, growth, and behavior.

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Holstein x Freisian beef cattle were monitored after castration by burdizzo (B), with or without anesthesia. Methods of anesthesia used included ketoprofen (K), local anesthesia (LA) or caudal epidural anesthesia (EPI). A control (C) treatment in which no anesthesia was used was also implemented. Effects on plasma cortisol, acute-phase proteins, interferon-ã production, growth, and behavior. K animals had a lower area under the cortisol curve against time than the other treatments. Plasma haptoglobin concentrations were lower on day 1 after castration for BK animals compared to B, BLA or BEPI animals. Haptoglobin and fibrinogen concentrations were higher in all castration groups on day 3 after castration than in group C. The same concentrations remained higher on day 7 for BLA animals than in B or C animals. Concanavalin A-induced interferon-ã production was lower on day 1 in B, BLA, and BEPI animals than in C, with no differences between C and BK treatments. ADG was lower from day 1 to 35 for B, BLA, and BEPI animals but not BK animals compared with C. There was a higher incidence of combined abnormal postures overall in B than in C, BK and BEPI animals. There was no difference between the K and EPI treatment. Conclusions stated that burdizzo castration increased plasma cortisol and acute-phase proteins and suppressed immune function and gains. Local anesthesia prolonged the increase in acute-phase proteins. Ketoprofen was more effective than LA or EPI in decreasing cortisol levels and was able to partially reverse the reduction in ADG after castration had been carried out. Pain-associated behavioral responses were decreased the most during the first 6 hours after castration with use of K or EPI rather than LA. Ketoprofen was more effective in reducing inflammatory responses associated with castration than LA or EPI.

AI Management

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The popular switch to AI has brought about new responsibilities. Breeding herd success relies on 3 general areas: semen quality, technician ability, and female fertility. Shortcomings in any one of these areas will reduce productivity. The most important responsibility for the technician is good heat detection. Purchasing from a source that has a reliable quality assurance program can ensure semen quality. The semen should be stored in a fridge 17 to 18 degrees C and rotated two times per day. Hormones emitted from a boar that is present are needed for good heat detection. Head to head contact and physical stimulation from the boar helps significantly to get the sow into a standing heat. Make sure that the boars are not housed near the sows in order to avoid habituation (sows getting used to the boars presence and becoming unresponsive to the boar). Sows who come into estrus late after weaning should be bred ASAP, and sows that come into heat early after weaning should be delayed breeding. One good, thorough heat detection per day should be sufficient for the sows (gilts should be checked twice a day regardless). A late breeding can result in reduced immunity by the sow and compromise reproduction quality. The challenge for each breeding manager is to develop an estrus detection program and an accompanying insemination schedule that results in a satisfactory level of reproductive performance.

Three Points to Watch for Optimal Productivity

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Three points to watch for optimal productivity include mouldy feed, gilt pool, and adequate number of serviced sows per week. Certain new barn equipment has areas where mouldy feed can build up. This mould build up can produce mycotoxins, which can be extremely harmful to pigs. This can affect conception, 4 to 8 week failure rate, and result in repeat estrus. Preventative measures include checking regularly for mouldy feed, graphing reproductive performance, and using a farrowing rate decision tree. The goals of any gilt program should be better sow longevity, productivity consistency across parities, and a better gilt pool predictability. Gilt pool checklists are great to normalize any gilt program. This should include gilt age at service, finisher phase diet, modified open gilt diet, consistent teaser boar, biofeedback for immunity, and proper pen space. Breeding the right number of sows per week is important to reduce variation in pig flow. This can be accomplished by using graphs and information from PigCHAMP to hit the weekly target.

Impact of Farm Size and Type on Competitive Advantage

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Financial and reproductive performance of lactating-pregnant Creole sows

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Lifetime and post-weaning determinants of performance indices of pigs

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Fertilizing Forages with Manure

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Livestock manure contains most nutrients that crops require and is frequently used as a fertilizer. This paper looks at its usefulness in relation to forages. The results showed that in general the application of hog manure resulted in significant forage yield increases when compared to the control plots in all cases. Forage stands that are kept in good condition will have a greater response to manure application than stands contaminated with weed or poorly productive grasses.
Soil type, nutrient demand of various crops and nutrient content of manure will affect the manure application rate. In order to calculate this rate correctly, nutrient analysis of the manure and soil test recommendations should be done. Factors that need to be considered when applying manure are 1) application methods, such as low-disturbance injection which provides a low-cost alternative to fertilization, 2) application timing, where spring application seems to be the most beneficial and 3) application frequency where applications made to meet a two year nutrient requirement result in good responses.
A study by PAMI (2000) indicated that application of high rates of manure resulted in a carryover of nutrients in the years following application that have contributed to a concentration of nitrates in the forage. A number of factors can influence this accumulation and it is recommended that forages (cut for hay or grazed) that have received nutrients should be tested to determine nitrate and potassium levels.

A REVIEW OF AMMONIA EMISSIONS FROM CONFINED SWINE FEEDING OPERATIONS

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Bedding and Seasonal Effects on Chemical and Bacterial Properties of Feedlot Cattle Manure

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