A STUDY OF DIURNAL TEMPERATURE PATTERNS IN SHEEP

The effects of some factors on the time to first successful stand up and sucking of native lambs after parturition

The study aimed to identify the effects of birth time, birth weight, and the time to first grooming on the time to first successful stand up and sucking of the pure and crossbred native lambs. Data were recorded from pure (22 B-Bafra and 20 AKK-Akkaraman) and crossbred (19 BA F₁ (B × AKK) and 13 BA B₁ (B × F₁)) lambs during the first 3 h after delivery. The time to first successful stand up of lambs was significantly affected by the birth time (P = 0.045), the time to first grooming (P = 0.000), and the time to first successful sucking (P = 0.000). Genotype significantly affects the time to first successful stand up of the lambs born at night (P = 0.000), low birth weight (P = 0.042), the time to first grooming (short, P = 0.001, and prolonged, P = 0.019), and the time to first successful sucking (early, P = 0.041, and late, P = 0.005). Data demonstrated that the time to first successful stand up affected the time to first successful sucking. The time to first successful stand up was longer for the lambs born at night, with low birth weight, and was affected by the time to first grooming, especially for the B lambs. Consequently, it should be given particular importance to the care of lambs born at night with low weight and exposed to mismothering.

[Flock status - sheep flock assessment - Ressource and management related welfare indicators]

The welfare status of sheep flocks may be assessed via animal-, resource-, and management-related indicators. The benefits of multiple-choice questionnaires are however impaired by the diversity of sheep breeds and husbandry. From a veterinary flock health management point of view, the presented review describes the influence of environment, climate, supervision as well as additional factors under consideration of legal regulations. The improvement of welfare is a common concern of all players in the field of farm animal husbandry. Based on this, challenges as well as possibilities for improvement exist for legal and administrative institutions as well as pharmaceutical industry.

A comparison of different vaccination schemes used in sheep combining inactivated bluetongue vaccines against serotypes 4 and 8

Eight different vaccination schemes using four commercially available inactivated Bluetongue vaccines against serotypes 4 and 8 in three different combinations (setting 1-3) were tested under field conditions for their ability to generate a measurable immune response in sheep. Animals of setting 1 (groups A-D) were simultaneously vaccinated using either individual injections at different locations (groups A & D) or double injection by a twin-syringe (groups B & C). For both application methods, a one-shot vaccination (groups C & D) was compared to a boosted vaccination (groups A & B). Sheep of setting 2 (groups E-G) were vaccinated in an alternating, boosted pattern at fortnightly intervals starting with serotype 4 (groups E & F) or vice versa (group G). Group H of setting 3 was vaccinated simultaneously and vaccines were injected individually as a one-shot application. Each group consisted of 30 sheep. The immunogenic response was tested in all sheep (n = 240) by ELISA (IDScreen®Bluetongue Competition), while serum neutralisation tests were performed in five to six sheep from each group (n = 45). All vaccine combinations were well tolerated by all sheep. Of all vaccines and schemes described, the simultaneous double injected boosted vaccination of setting 1 (group B) yielded the highest median serotype-specific titres 26 weeks after the first vaccination (afv) and 100% seropositive animals (ELISA) one year afv. In setting 1, there were no relevant significant differences in the immunogenic response between simultaneously applied vaccines at different sites or at the same injection site. Importantly, a one-shot vaccination induced comparable immunogenicity to a boosted injection half a year afv. Low serotype-specific neutralising antibody levels were detected in settings 2 and 3 and are attributed to diverse factors which may have influenced the measured immunogenicity.

Rhythmic control of activity and sleep by class B1 GPCRs

Members of the class B1 family of G-protein coupled receptors (GPCRs) whose ligands are neuropeptides have been implicated in regulation of circadian rhythms and sleep in diverse metazoan clades. This review discusses the cellular and molecular mechanisms by which class B1 GPCRs, especially the mammalian VPAC2 receptor and its functional homologue PDFR in Drosophila and C. elegans, regulate arousal and daily rhythms of sleep and wake. There are remarkable parallels in the cellular and molecular roles played by class B1 intercellular signaling pathways in coordinating arousal and circadian timekeeping across multiple cells and tissues in these very different genetic model organisms.

Circadian and seasonal variation of the body temperature of sheep in a tropical environment

Nychthemeral and annual rhythms of the rectal temperature were determined for Corriedale sheep in a tropical climate. The minimum rectal temperature averaged 39.55 degrees C at 0500 hours in summer, and 38.87 degrees C at 0600 hours in winter. The maximum was 40.03 degrees C in summer (1700 hours) and 39.33 degrees C in winter (1830 hours). Annual cycle of the rectal temperature showed a minimum in July and maximum in December.

Effect of Lactation on Diurnal Temperature Patterns of Dairy Cattle in Hot Environments

Vaginal temperature patterns were obtained from 15 Holstein cows through radiotelemetry. Animals were divided into three groups with five animals per group: 1) cows in early lactation, less than 100 days postpartum, 2) cows in late lactation, greater than 240 days postpartum, and 3) dry cows. Animal temperatures, dry bulb, wet bulb, and black globe temperatures were monitored every 15 min for 17 days. Analysis of variance showed no significant difference for daily mean vaginal temperature between lactation groups. However, on hotter days, lactating cows had higher temperatures than dry cows. Daily mean vaginal temperatures of cows in early lactation were correlated with daily mean dry bulb temperature, black globe temperature, and relative humidity. Comparison of group temperature patterns isolated differences to specific times of day. In groups with early and late lactations, temperatures were lower in either group after milking. Vaginal temperatures were higher in lactating cows than in dry cows through most of the day. Results were 1) diurnal temperature patterns differ among groups; 2) lactating cows are sensitive to environmental changes; and 3) animal management can affect patterns of animal temperature.

The influence of the nasal mucosa and the carotid rete upon hypothalamic temperature in sheep

1. In chronically-prepared sheep, intracranial temperatures were measured in the cavernous sinus among the vessels of the carotid rete and at the circle of Willis extravascularly, and in the preoptic area and in other brain stem regions. Extracranial temperatures were measured intravascularly in the carotid or internal maxillary arteries and on the nasal mucosa and the skin of the ear.2. At 20 degrees C ambient temperature, shifts in temperature of the hypothalamus and of other brain sites paralleled temperature shifts in the cerebral arterial blood which was cooler than central arterial blood. During periods of arousal and of paradoxical sleep, vasoconstriction of the nasal mucosa and the ear skin occurred and temperatures at the cerebral arteries and in the brain rose without a comparable rise in central arterial blood temperature.3. Anaesthetic doses of barbiturate abolished the temperature oscillations in the cerebral arterial blood and the brain. When air was blown rapidly over the nasal mucosa in anaesthetized animals, temperatures dropped precipitously in the cavernous sinus, at the cerebral arteries, and in the brain, while central arterial temperature fell only slightly. Injections of latex into the facial venous system demonstrated a venous pathway from the nasal mucosa to the cavernous sinus.4. When sheep were exposed to 45-50 degrees C ambient temperature, respiratory rate increased 5-10 times and the temperature gradient between central and cerebral arterial blood widened.5. It is concluded that venous blood returning from the nasal mucosa and the skin of the head to the cavernous sinus cools the central arterial blood in the carotid rete. This is an important factor in the maintenance of hypothalamic temperature in the wool-covered, long-nosed, panting sheep and undoubtedly affects hypothalamic thermoreceptors and temperature regulation in artiodactyls.

Thermal response of intravascular and rectal tissue to temperature changes and chemical conditions in the rumen of sheep

1. Experiments were conducted with two wether sheep which were fitted with rumen cannulae and chronically implanted intravascular thermocouples. An attempt was made to study the thermal response of intravascular and rectal tissue to temperature changes and chemical conditions in the rumen.2. When ice or hot water were placed in the rumen there was an immediate fall or rise in the intravascular temperature accompanied by a similar change in rectal temperature. The intravascular temperatures returned to their precooling or preheating level of 40 degrees C within 130 min, the rectal temperatures required 6-8 hr to return to their pretreatment values.3. When 0.5 M acetic acid was infused into the rumen there was a marked rise in the intravascular temperature, over and above the diurnal rhythm but not in rectal temperatures. Infusion of mixtures of acetic plus propionic or acetic plus n-butyric acids caused an intravascular temperature rise on feeding within the range of the diurnal pattern. In fasted animals, infusions of volatile fatty acids resulted in no rise in intravascular temperature.