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.

Organic livestock production in Europe: Aims, rules and trends with special emphasis on animal health and welfare

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In Europe, organic farming has increased during the last decade. However, the market share is still relatively low. The needs of animals are better met in organic farming systems than in conventional systems. The goal of organic farming is to ensure high standards of product quality, animal health and welfare. As a result, there are high demands on management qualifications. However, there are no guarantees that the high standards will be maintained. The development of quality assurance programs has been suggested in order to ensure that standards are maintained. The criteria for sustainability can only be realized if the standards for animal health and welfare and product quality and environmental security are maintained.

Relationship between Prenatal Survival Rate at 70 days of Gestation and Morphometric Parameters of Vagina, Uterus and Placenta in Gilts

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Swine uterine capacity affects litter size, and it could be used as a selection parameter of reproductive performance. Although there are some controversial results, evidences show that the catheter penetration length is positively correlated with litter size, and it could be used as a tool for predicting selection methods. The aim of this study was to determine whether there is any association between the prenatal survival rate and placental size at 70 days of gestation, the vaginal length [catheter penetration length during artificial insemination (AI)] and the uterine capacity in a homogeneous group of gilts. Sixty-six commercial-line gilts in pre-pubertal phase had their oestrus induced by hormonal treatment [600 UI of Equine Chorionic Gonadtrophin (eCG) i.m. and after a 72-h period 5 mg of luteinizing hormone (LH) i.m.], but only 40 gilts showed cyclicity after induction. The AI catheter penetration length was tested on these 40 gilts at the moment of AI using a
calibrated AI catheter. Four gilts returned to oestrus and the other 36 were killed at around day 69 of pregnancy. The uterine length and weight showed a significant and positive correlation with the prenatal survival rate (p < 0.05). The catheter penetration length was unable to predict the conceptus survival rate on 70 days of gestation; however, the uterine size influenced the survival rate positively. The mean placental area was positively correlated with the mean placental weight (p < 0.0001), and both with the mean foetal weight (p < 0.0001 and p < 0.001, respectively). The analysis of the results obtained showed that neither did the catheter penetration length measurement during AI, nor the prenatal survival rate on day 70 of pregnancy predict the uterine capacity, but the uterine and placental size had a significant influence on the prenatal survival and foetus weight, respectively.

Weaning Litters from Hyper-prolific Sows

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A hyper-prolific sow can produce 60+ piglets in her lifetime. It requires good management practice to obtain the 27+ weaned pigs per sow per year. New gilts brought into the herd must be managed to obtain maximum reproduction. Proper estrus stimulation should be performed with a mature boar for a minimum of 10 minutes per day. Gilts should be bred at 16 mm back fat at 210 days of age and no less than 125 kg. This prevents breakdown of body reserves for energy. These gilts should be kept on a gilt developer diet rather than a regular gestating sow diet. Regular techniques can be followed for service timing and management of wean to estrus interval. Movement and mixing of gilts should be minimized, and back fat should be measured at breeding, 60 days into gestation, and 110 days into gestation. The sow should have 19 mm at breeding, and if not the sows feeding should be changed to alter body condition. Targets at lactation should be no more than a 3 mm loss of back fat and for the piglets to gain 240 g/day for 21 days. Gilts and sows should be grouped by farrowing history and/or body condition. There should be a hygienic farrowing kit kept on hand with lube, a cord, hibitane, a dish, and O.B. sleeves. Oxytocin wrapped in ice packs and needles/syringes should also be included. At entrance into the farrowing room they should not be overfed so that feed intake during lactation can be maximized. Heat lamps should be provided in the rooms to avoid chilled piglets, but adequate fresh airflow is necessary. Individual sow cards help to monitor each sow in the room. Farrowing assistance should be given to sows that are having difficulties to avoid a lot of stillbirths (hygienic procedures should be adhered to). Fresh born piglets should be dried, put on a dry mat underneath a heat lamp, and fed colostrum immediately. If a sow or gilt appears to be nervous and unease, place the piglets in a ring under the lamp and only release them once the sow has calmed down. After farrowing, oxytocin should be given to clear the sow of any more debris. Hyper-prolific sows require a great deal of attention to reach maximum potential. Cross fostering should be done within the first 24 hours. Split suckling can help the smaller piglets to catch up if they are in a large litter. Nurse sows should have adequate body condition to support the fall-behind piglets.

Canadian Swine Identification and Traceability

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The purpose of the traceability system in Canada is to allow movement of pigs to continue at the occurrence of a major disease outbreak. The reason this system came about was because of the scare of the 2002 European outbreak of Foot & Mouth Disease. It brought about the realization that Canada’s high health status is not well equipped to deal with a catastrophic outbreak. The initial objectives of this system were to reduce response time of a foreign animal disease outbreak, address the OIE’s guidelines for zoning, and to identify alternatives to these objectives. The principles of this system are to control disease, eradicate disease, enhance producers risk management programs, simplicity, producer-driven, and more. Geo-referencing provides information about where livestock and buildings are and what types and numbers of livestock are in the buildings. All livestock farms in Canada must be geo-referenced and data needs to be collected each time pigs change locations. Development, implementation of regulation, and readjustments are slated to begin in 2005-2006.

Prevalence and Characterization of Shiga Toxin-Producing Escherichia coli in Swine Feces Recovered in the National Animal Health Monitoring System’s Swine 2000 Study

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Genetic correlations between reproduction and production traits in swine

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