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Attempted protection of bighorn sheep (Ovis canadensis) from pneumonia using a nonlethal cytotoxic strain of Pasteurella haemolytica, biotype A, serotype.

Between February and April, 1994, we tested the hypothesis that bighorn sheep (Ovis canadensis canadensis) inoculated with a cytotoxic isolate of Pasteurella haemolytica biotype A, serotype 11 (A11) could withstand challenge inoculation with a cytotoxic strain of P. haemolytica A2 of domestic sheep origin known to cause lethal pneumonia in bighorn sheep. On experimental day O, two bighorn sheep were inoculated intratracheally with 6 x 10(9) colony forming units (cfu) of a cytotoxic strain of P. haemolytica A11 (group 1); two bighorn sheep were inoculated intratracheally with 6 x 10(9) cfu of a noncytotoxic P. haemolytica A11 (group 2), and two control bighorn sheep were inoculated intratracheally with a similar volume of brain heart infusion (BHI) broth (group 3). After inoculation, all bighorn sheep remained healthy. On experimental day 16, group 1 bighorn sheep each were given the same intratracheal inoculation as on day O, and groups 2 and 3 bighorn sheep each were inoculated with BHI broth at the same volume as group 1. All bighorn sheep remained healthy following inoculations. On experimental day 42, bighorn sheep in groups 1 and 3 each were challenged with an intratracheal inoculation of 6 x 10(9) cfu of P. haemolytica A2 of domestic sheep origin known to be lethal in bighorn sheep. Group 2 sheep each were inoculated intratracheally with BHI broth at the same volume as groups 1 and 3. The four bighorn sheep in groups 1 and 3 that received the challenge inoculation died from acute bronchopneumonia within 72 hours after challenge inoculation, and cytotoxic P. haemolytica A2 was isolated from the four dead bighorn sheep. Both cytotoxic or noncytotoxic strains of P. haemolytica A11 were not lethal and did not cause pneumonia in the experimentally inoculated bighorn sheep. However, previous inoculation with cytotoxic P. haemolytica A11 did not protect the bighorn sheep against later experimental challenge inoculation with a known lethal strain of cytotoxic P. haemolytica A2 under the conditions defined in these experiments.

Animals↗

Cyclic nucleotides of lung lavage following acute antigen exposure in chronically exposed sheep.

In the sheep model of chronic allergic airway disease, we measured sequentially for 7 h following antigen exposure (Ascaris suum) histamine and the cyclic nucleotides cAMP and cGMP in bronchoalveolar lavage (BAL) fluids. Results in the six sheep with chronic allergic airway disease (reactive sheep) were compared to those of three sheep chronically exposed to antigen but without acute or chronic airway response (nonreactive sheep). Histamine levels in BAL fluids were not modified after antigen exposure in reactive and nonreactive groups. Before acute challenge, cAMP in BAL was 10.4 +/- 1.0 pmol/ml in reactive sheep and 16.4 +/- 1.0 in nonreactive sheep; cGMP was 0.16 +/- 0.01 pmol/ml in reactive sheep and 0.18 +/- 0.06 in nonreactive sheep. Antigen exposure did not change the lung lavage levels of cAMP or cGMP for up to 7 h in the nonreactive sheep. In the reactive sheep, antigen exposure induced a significant gradual fall in cAMP to 49% of the preexposure level and a rapid and sustained increase of cGMP to 200% of the preexposure level (P less than 0.05). Prechallenge lung resistance was increased in reactive sheep compared to nonreactive sheep. Antigen challenge further increased lung resistance in reactive sheep during the first hour without any change in nonreactive sheep. Reactive sheep BAL eosinophils increased to 900% of the values of nonreactive sheep at 4 and 7 h following challenge. These observations suggest that histamine does not have a major role in allergic response in the chronic sheep asthmatic model; furthermore, cyclic nucleotide modifications could reflect sympathoadrenergic imbalance and/or increase of inflammatory reaction following antigen exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Differential effects of GH stimulation on fasting and prandial metabolism and plasma IGFs and IGF-binding proteins in lean and obese sheep.

The effect of body condition per se on plasma IGFs and IGF-binding proteins (IGFBPs) and the whole-body metabolic responses to recombinant DNA-derived bovine GH (rbGH) in both the fed and the fasted state were determined in lean and dietary obese sheep (n = 6/group). Sheep at zero-energy balance and equilibrium body weight were injected s.c. for 12 days with 100 micrograms/kg rbGH immediately before their morning feeding. Before GH treatment, fasting plasma concentrations of insulin (17.0 +/- 1.9 vs 7.5 +/- 0.7 microU/ml), IGF-I (345 +/- 25 vs 248 +/- 10 ng/ml), glucose (52.6 +/- 1.1 vs 48.3 +/- 0.7 mg/dl), and free fatty acid (FFA) (355 +/- 45 vs 229 +/- 24 nmol/ml) were greater (P < 0.05) and those of GH (1.1 +/- 0.2 vs 2.6 +/- 0.3 ng/ml) were lower (P < 0.05) in obese than in lean sheep. Fasting concentrations of IGF-II and glucagon were not affected (P > 0.05) by obesity. GH concentrations were increased equivalently by 6-9 ng/ml in lean and obese sheep during GH treatment. GH caused an immediate and a marked fivefold increase in the fasting insulin level in obese sheep but only minimally affected insulin concentration in lean sheep. The increment in fasting glucose during GH treatment was greater (P < 0.05) in obese (8-12 mg/dl) than in lean (2-5 mg/dl) sheep. Frequent measurements in the first 8 h after feeding and injection of excipient (day 0) or the first (day 1) sixth (day 6) and twelfth (day 12) daily injection of GH showed that prandial metabolism in both groups of sheep was affected minimally by GH. However, GH treatment on day 1 (not days 6 or 12) acutely attenuated the feeding-induced suppression of plasma FFA in both groups of sheep and this effect was significantly greater in obese than in lean sheep. Although obese sheep were hyposomatotropic, the basal and GH-induced increases in plasma IGF-I concentrations were greater (P < 0.05) in obese than in lean sheep. Plasma IGF-II was unaffected by obesity and was not increased by GH stimulation. Western ligand blotting showed that IGFBP-3 accounted for approximately 50-60% of the plasma IGF-I binding capacity in sheep respectively both before and during GH treatment. Basal plasma levels of IGFBP-2 were lower (P < 0.05) and those of IGFBP-3 greater (P < 0.05) in obese compared with lean sheep. GH increased the level of IGFBP-3 equally in lean and obese sheep, but suppressed the expression of IGFBP-2 more (P < 0.05) in lean than in obese sheep. We concluded that the diabetogenic-like actions of GH in sheep were exaggerated markedly by obesity, and were expressed more during the fasted than the fed states. The effects of GH stimulation on the endocrine pancreas may be selective for beta-cells and preferentially enhanced by obesity. GH regulation of IGF-I and the IGFBPs differs in lean and obese sheep.

Analysis of Variance↗

Effect of high levels of insulin on glucose utilization and glucose production in pregnant and nonpregnant sheep.

The present study was conducted to test the hypothesis that pregnancy in sheep alters the effects of insulin on glucose utilization and glucose production. Euglycemic, hyperinsulinemic glucose clamp experiments were performed in chronically catheterized, unstressed, fed or 24-hr fasted, nonpregnant sheep and fed, pregnant sheep. Endogenous glucose production rate for the whole sheep and glucose utilization rate of the uterine and nonuterine maternal tissues were measured in control and high-insulin periods by tracer technique using [6-3H]glucose. Control glucose utilization rate in the fed, nonpregnant sheep was significantly (P less than 0.05) greater than that in the fasted, nonpregnant sheep, 2.29 +/- 0.17 and 1.86 +/- 0.11 mg/min/kg, respectively, and also in the nonuterine maternal tissues of the pregnant sheep (1.71 +/- 0.18 mg/min/kg). Insulin stimulated glucose utilization 116.4 +/- 14.8% in the fed, nonpregnant sheep but only 82.8 +/- 11.0% in the fasted, nonpregnant sheep and 94.2 +/- 14.3% in the nonuterine tissues of the fed, pregnant sheep. Also, insulin suppressed endogenous glucose production to 53.2 +/- 5.6% in the fed, nonpregnant sheep, to 3.9 +/- 3.1% in the fasted, nonpregnant sheep, and to 9.0 +/- 3.7% in the fed, pregnant sheep. In the pregnant animals, uterine glucose uptake and uterine glucose utilization were not different and were not altered by changes in maternal insulin concentration. The results indicate that during late pregnancy glucose utilization is reduced and resistance to the effect of insulin to enhance glucose utilization is present in the nonuterine maternal tissues compared with nonpregnant, fed sheep. In contrast, the effectiveness of insulin to suppress glucose production in the pregnant sheep is greater than that in nonpregnant, fed sheep. These results also demonstrate that differential changes in the effect of insulin can exist simultaneously between peripheral (glucose consuming) and central (glucose producing) tissues. The changes in glucose utilization and in insulin effect in the pregnant sheep are both qualitatively and quantitatively similar to those of the nonpregnant sheep when fasted, suggesting that similar substrate and/or hormonal factors may be involved.

Animals↗

Phylogenetic relationships of sheep populations from coastal areas in East Asia.

Using the method of random sampling in typical colonies of the central area of the habitat and several electrophoresis techniques, the variations of 12 structural loci encoding blood protein of 60 Small-tailed Han sheep were examined and compared with those of four other sheep populations from coastal areas in East Asia to explore their phylogenetic relationships. Average heterozygosity of the five populations was: Kharkhorin sheep 0.3447, Ulaanbaatar sheep 0.3285, Small-tailed Han sheep 0.3157, Hu sheep 0.3884, and Cham Tribe sheep 0.2300. The earlier researchers' conclusion through documentary research, indicating that Small-tailed Han sheep and Hu sheep both evolved from Mongolian sheep, was further verified by the results of this study. Hu sheep, Small-tailed Han sheep, and Cham Tribe sheep were decreasingly affected by the bloodline of Mongolian sheep. A 1partial founder population, i.e., Mongolian sheep forming current Small-tailed Han sheep, possibly made a contribution to the bloodline of Cham Tribe sheep.

Animals↗

Selective allergy to sheep's and goat's milk proteins.

BACKGROUND: Cow's milk proteins are amongst the most common causes of food allergy in infants, and caseins are probably the main allergens. The existence of a high degree of cross-reactivity between milk caseins from different animals has been reported. We describe a 2-year-old boy who experienced allergic reactions after eating and touching sheep's cheese, but who tolerated cow's milk and cow's milk dairy products. He had never ingested milk or milk derivatives from sheep or goat. METHODS: Skin prick tests were carried out using whey fractions of cow's milk, whole milk and casein from goat, sheep and cow. We also performed skin prick tests with enzymes used in cheese production. Prick-by-prick tests with cheese made from cow, sheep and goat and their corresponding whole milk were also performed. Total serum IgE and specific IgE to cow's milk proteins, whole cow's milk and sheep's milk were determined. Specific IgE against casein and whole milk from the three different species were determined by ELISA. Inhibition of IgE binding to bovine casein was tested for casein and whole milk from all three species. The proteins of three types of casein and whole milk from cow, sheep and goat were separated by SDS-PAGE and were incubated with the patient's serum. RESULTS: Skin tests were positive to sheep's milk and goat and sheep casein and were negative to all cow's milk proteins and whole cow's and goat's milk. Prick-by-prick tests were positive to goat's and sheep's cheese and were negative to cow's cheese. In ELISA-inhibition, sheep's milk and goat and sheep casein were able to inhibit > 50 % of specific IgE binding to sheep casein. The results of immunoblotting showed that the patient's circulating IgEs recognized only one band in the lanes corresponding to sheep and goat casein. CONCLUSIONS: We report a patient with allergy to sheep's and goat's milk proteins but not to cow's milk proteins. Sheep casein was probably the main allergen causing sensitization in this patient. The results suggest that sheep casein shows a high degree of cross-reactivity with goat casein but not with cow casein. Our patient presented allergic symptoms caused by sheep and goat milk and cheese proteins. However, he was able to tolerate cow's milk and cow's milk dairy products without any ill effects.

Animals↗

[PCR-SSCP analysis on growth differentiation factor 9 gene in sheep].

Growth differentiation factor 9 (GDF9) is a growth factor secreted by oocytes in growing ovarian follicles, which is essential for growth and differentiation of early ovarian follicles. The polymorphism of GDF9 gene in Small Tail Han sheep, Hu sheep, Dorset sheep and Suffolk sheep was analyzed by PCR-SSCP. The results indicated that there were three genotypes (AA, AB and BB) detected by primer 1. AA genotype was detected in four sheep breeds. AB genotype was detected in Hu sheep, Dorset sheep and Suffolk sheep. BB genotype was only detected in Suffolk sheep. Frequency of A allele was obviously higher than frequency of B allele in four sheep breeds. There were two genotypes (AA and AB) detected by primer 2. AA genotype was detected in four sheep breeds. AB genotype was detected in Hu sheep, Dorset sheep and Suffolk sheep. BB genotype was not detected in four sheep breeds. Frequency of AA genotype was the highest, and frequency of A allele was obviously higher than frequency of B allele in four sheep breeds. The polymorphic fragments amplified by primer 1 were cloned and sequenced. The sequencing results showed that there was one single nucleotide mutation: A-->G at cDNA 152 of GDF9 gene in sheep, and this mutation resulted in an amino acid change: asparagine-->aspartic acid.

Animals↗

[Study on BMP15 and GDF9 as candidate genes for prolificacy of Small Tail Han sheep].

Bone morphogenetic protein 15 (BMP15) gene and growth differentiation factor 9 (GDF9) gene which control the fecundity of Belclare and Cambridge ewes were studied as candidate genes on the prolificacy of Small Tail Han sheep. Single nucleotide polymorphism of GDF9 gene and BMP15 gene was detected in both high fecundity sheep breeds (Small Tail Han sheep and Hu sheep) and low fecundity sheep breeds (Dorset sheep, Texel sheep and German Mutton Merino sheep) by PCR-RFLP. The results showed that the G8 mutation (C --> T) of GDF9 gene and the B4 mutation (G --> T) of BMP15 gene were not detected in five sheep breeds. There was the same B2 mutation (C --> T) of BMP15 gene in Small Tail Han sheep as that in Belclare and Cambridge ewes. The same B2 mutation did not exist in other four sheep breeds. Concerning the B2 mutation of BMP15 gene, AA and AB genotypes were detected in Small Tail Han sheep, frequency of A allele was 0. 734, frequency of B allele was 0.266. The BMP15 B2 genotype distributions were high significantly different (P < 0.001) between Small Tail Han sheep and other four sheep breeds. The ewes with heterozygous mutant AB had 0.62 (P < 0.01) lambs more than those with wild homozygous type AA in Small Tail Han sheep. These results indicated that the B2 mutation of BMP15 gene had significant effect on the fecundity of Small Tail Han sheep and ruled out the possibility that the fecundity of Small Tail Han sheep was affected by the G8 mutation of GDF9 gene and the B4 mutation of BMP15 gene.

Animals↗

Consequences of long-term feeding with condensed tannins on sheep parasitised with Trichostrongylus colubriformis.

Naive wethers were used to investigate the long-term effects of dietary condensed tannins from Quebracho extract, during an intestinal parasitic infection in sheep. Sheep were allocated to eight groups; seven groups were daily infected with 3000 L(3) Trichostrongylus colubriformis for 10 weeks and the eighth group was the uninfected control. The 10-week experiment was divided into two periods; Period 1 (P(1), week 1-5) corresponded to high worm establishment and acquisition of immunity, whereas Period 2 (P(2), week 6-10) to the established worm population and expression of host immunity. Three experimental foods with similar composition were formulated: Q0, Q3 and Q6. Their difference was in the content of Quebracho extract which was 0, 30 and 60 g per kg fresh matter, respectively. All foods were offered at an allowance of 3.5% of sheep liveweight. During P(1), parasitised sheep were offered one of the three experimental foods and during P(2) they either remained on the same food or changed food according to the design (P(1)-P(2)): Q0-Q0, Q0-Q3, Q0-Q6, Q3-Q0, Q3-Q3, Q6-Q0, Q6-Q6. Control sheep were offered the allowance of Q0 throughout. Sheep that consumed Q3 and Q6 reduced their faecal egg counts (FEC) compared to sheep offered Q0, during both periods (P<0.05). No differences were observed in the FEC between sheep offered Q3 and Q6. The changeover from Q0 in P(1) to either Q3 or Q6 during P(2), was accompanied by a reduction in FEC (P<0.05), whereas an increase in FEC was observed when food changed from Q3 or Q6 to Q0 (P<0.05). Worm burdens and fecundity at the end of the experiment were reduced in sheep offered foods Q3 and Q6 compared to sheep offered Q0. A significant decrease in liveweight gain and in food conversion efficiency of parasitised sheep offered Q3 and Q6 compared to sheep offered Q0, was observed in P(1) (P<0.05) but not in P(2). By the end of the experiment control sheep had achieved higher liveweight and converted food more efficiently than parasitised sheep (P<0.05). In conclusion, evidence for a long-term effect of Quebracho extract, during both the initial establishment and on the established T. colubriformis population in sheep, was provided by the present study. It is suggested that the effect observed was a direct anthelmintic effect of the condensed tannins included in sheep diets.

Animal Feed↗

Studies on the role of mucus and mucosal hypersensitivity reactions during rejection of Trichostrongylus colubriformis from the intestine of immune sheep using an experimental challenge model.

Nematode-naive sheep and sheep immunised by truncated infections with Trichostrongylus colubriformis were fitted with intestinal cannulae to allow administration of challenge infection and collection of intestinal fluids. Sheep were slaughtered at various times after challenge and the distribution of larvae along the small intestine was determined. Results showed that immune sheep had significantly fewer larvae in their intestines and that some sheep could expel the challenge infection within 2 h. Mucus samples from immune sheep contained increased parasite-specific antibody, histamine and anti-parasite activity as measured by larval migration inhibition assay. Higher levels of antibody and histamine were seen in intestinal fluids of immune sheep after challenge. Immunisation of sheep by truncated infections stimulated serum IgE and resulted in significantly higher numbers of IgE-positive cells in gut tissue sections before challenge and at 2 h and 24 h after challenge. Immune sheep also had greater numbers of mucosal mast cells and globule leucocytes after challenge, compared with naive sheep. When challenge larvae were mixed with mucus from immune sheep and infused back into naive recipient sheep, there was a distinct displacement of the larval population towards the distal part of the intestine, compared with the profile of larval establishment after infusion with mucus from naive sheep. These results are further evidence for an immediate hypersensitivity reaction in the intestine of immune sheep, where challenge larvae are expelled within 2 h and confirm the direct anti-larval properties of mucus. The cannulated-sheep challenge model described here will be a useful tool to unravel the mechanism of larval rejection from immune sheep and could lead to novel therapies.

Animals↗

Immunologic responses of domestic and bighorn sheep to a multivalent Pasteurella haemolytica vaccine.

The efficacy of a Pasteurella haemolytica vaccine (serotypes A1, A2, and T10) to induce humoral antibodies and alter colonization of the upper respiratory tract by related P. haemolytica spp. strains was evaluated in 10 bighorn (Ovis canadensis canadensis) and 10 domestic (Ovis aries) sheep. Sheep of each species were divided into five pairs based on age and history of respiratory disease. One sheep in each pair was vaccinated twice 2 wk apart with 2 ml of vaccine (VAC group) and the remaining animals (NV group) were injected with 2 ml of sterile saline. Mild, transient lameness was the only observed adverse effect. Blood sera from the sheep were tested for agglutinating antibodies against whole cells of A1, A2, and T10 and for leukotoxin neutralizing antibodies. Antibody titers were expressed as the reciprocal log2 of the highest reactive dilutions. Domestic sheep > 1-yr-old and two bighorn sheep with a history of A1 infection had higher titers throughout the study against A1 cells than domestic sheep < 1-yr-old and bighorns without a history of A1 infection. Both domestic and bighorn sheep had log2 titers of 8 to 12 against A2 cells and 6 to 12 against T10 cells during this time. Bighorn sheep in the VAC group had 2 to 32 fold titer increases for A1 cells by 2 wk post-vaccination (PV) compared to 0 to 2 fold increases in VAC domestic sheep. Two to 16 and 0 to 8 fold increases in antibodies titers to A2 and T10 cells, respectively, were detected in sera of both VAC groups. Sera of bighorn sheep with a history of respiratory disease and all domestic sheep had log2 leukotoxin neutralizing antibody titers of 4 to 14 in contrast to < or = 2 in sera of bighorn sheep without a history of respiratory disease. Neutralizing antibody titers of two bighorns without a history of respiratory disease in the VAC group increased from log2 0 to 5 in one and from 0 to 9 in the other 2 wk PV. Antibody increases in these animals were no longer evident at 16 wk PV while titers of animals with histories of disease remained relatively stable. The types and numbers of Pasteurella spp. isolated from nasal and pharyngeal swabs varied throughout the study without conclusive evidence of suppression of colonization. Although the animals were not experimentally challenged to determine the efficacy of the vaccine, one VAC and one NV bighorn sheep died following introduction of an A2 P. haemolytica strain when leukotoxin neutralizing antibodies had returned to pre-vaccination levels. This vaccine appeared to be safe for use in bighorn sheep and stimulated moderate but transient increases in antibody levels which should provide some protection against naturally occurring disease. A vaccine which would induce production of high and maintained antibodies against multiple strains of P. haemolytica would be valuable for use in bighorn sheep maintained in captivity or when captured for relocation.

Agglutination Tests↗

Sheep do not have a major role in bovine herpesvirus 1 transmission.

With regard to BHV1 eradication programs in cattle it is important to know whether sheep can be a reservoir of BHV1. We therefore performed an experiment that consisted of three phases. In phase 1, 10 sheep were inoculated with high doses of BHV1 and kept in close contact with 5 sheep and 5 calves. All inoculated sheep excreted BHV1 between 8 and 15 days post inoculation and seroconverted. Although BHV1 was isolated from the nasal mucosa of 3 out of 5 sentinel sheep, none of the sentinel sheep produced antibodies against BHV1. One sentinel calf excreted BHV1 through days 12-17; the remaining 4 calves excreted BHV1 between days 18 and 24 suggesting that the first calf was infected by sheep and the remaining 4 sentinel calves were infected by that calf and not by sheep. The bacic reproduction ratio (R0) of BHV1 between sheep and calves was estimated at 0.1, and among calves it was estimated at > or = 9. In phase 2, all inoculated sheep were treated with dexamethasone and kept in close contact with 5 sheep and 5 calves. All dexamethasone treated sheep re-excreted BHV1 over a 6- to 9-day period. None of the sentinel animals seroconverted. In phase 3, the sentinel sheep and calves of phase 1 were kept in two groups and were treated with dexamethasone. None of the sentinel sheep re-excreted BHV1, whereas 3 out of 5 sentinel calves did. It is concluded that while BHV1 infection in sheep is possible, BHV1 does not spread from sheep easily to cattle.

Animals↗

The influence of previous salt ingestion on the renal function of sheep subjected to intravenous hypertonic saline.

1. Sheep, which had access to a solution containing 1.3% sodium chloride as their sole source of drinking water for 6 months or more, were infused with a hypertonic solution (10%) of sodium chloride, and their ability to tolerate this salt load was compared with that of a similar group of sheep which drank only rain water.2. The sheep which drank the rain water were often affected by the infusion and exhibited signs resembling potassium deficit. No such signs were apparent in the animals which consumed saline water.3. Glomerular filtration rates were increased in all sheep by the hypertonic saline infusion, the increases being greater in the sheep which were maintained on the saline water. Effective renal plasma flow rates, though extremely variable, behaved in a similar manner.4. Plasma values for sodium and chloride were increased in all sheep, but remained at a higher level for a longer period in the sheep which consumed rain water. The diuresis produced by hypertonic saline appeared to persist for a longer period in the sheep which drank rain water, while the excretion of sodium and chloride tended to be greater in the sheep maintained on saline water.5. Plasma potassium was reduced in all sheep and urinary excretion of potassium increased. The latter response was more pronounced in the sheep which drank the rain water.6. Filtered loads of sodium, chloride and potassium were greater in the sheep which were accustomed to drinking saline water. However, the amounts of potassium excreted were greater than those filtered in the rain water sheep and less than those filtered in the sheep which drank saline water. It therefore seems that secretion of potassium into the kidney tubules predominated in the former group and reabsorption prevailed in the latter.7. Reabsorption of free water in excess of solute was greater in the kidney tubules of the sheep which drank saline water.8. Increased blood volume and greater dilution of plasma proteins occurred in the sheep which drank rain water.

Analysis of Variance↗

[The developmental patterns of GH-R, IGF-1 and IGF-IR gene expression in sheep skin].

Semi-quantitative RT-PCR was applied to investigate the developmental patterns of GH-R, IGF-1 and IGF-IR mRNA expression in skin of two sheep breeds. One breed was the first filial generation (F1) of Romilly Hillys x Merino of China (Xinjiang Agricultural Reclamation line) wool sheep, and the other was Kazak hair sheep. 18S rRNA was used as the internal standard. Sheep were weighed and wool and skin samples were collected at different times. Results showed that body weight increased rapidly during 30-135 days but slowed during 135-255 days. Wool growth increased gradually during 30-135 days, degreased till 180 days of age, but rebounded thereafter. Overall, body weight and developmental patterns of wool growth was not significant different between hair and wool sheep. GH-R mRNA expression in the skin of hair sheep increased significantly during 30-90 days, peaked at 90 days of age (P<0.05), then declined signifi cantly (P<0.05). GH-R mRNA expression in the skin of wool sheep increased significantly until 135 days of age (P<0.01) and then decreased significantly (P<0.01). The peak level was higher in the wool sheep than the hair sheep. The expression of cantly IGF-1 mRNA and IGF-IR mRNA in the skin of hair sheep increased during 30-90 days, then declined significantly (P<0.01). The expression of IGF-1 mRNA and IGF-IR mRNA in the skin of wool sheep were high at birth and then reduced gradually. The IGF-1 mRNA expression in the skin of hair sheep reached its peak at 90 days of age, and was significant higher than that of wool sheep. The expression of GH-R, IGF-1 and IGF-IR mRNA in skin of hair sheep was higher than that of wool sheep before 90 days of age, but was lower after that. The results suggest that GH-R, IGF-1 and IGF-IR mRNA expression in the skin of sheep follows specific developmental patterns, and different patterns exist between the two breeds.

Animals↗

Pasteurella haemolytica cytotoxin-dependent killing of neutrophils from bighorn and domestic sheep.

Peripheral blood neutrophils from Rocky Mountain bighorn sheep (Ovis canadensis canadensis) and domestic sheep were exposed to culture supernatants from Pasteurella haemolytica isolates recovered from these two sheep species. Six culture supernatants from bighorn sheep isolates and two from domestic sheep isolates were tested for cytotoxicity as determined by the release of lactate dehydrogenase. Two of the bacterial culture supernatants from bighorn sheep were not cytotoxic, while the other four bighorn sheep culture supernatants were effective cytotoxins on both bighorn (> 95% cell death at 150 micrograms of cytotoxin) and domestic sheep neutrophils (55 to 95% cell death at 150 micrograms of cytotoxin). Two culture supernatants of P. haemolytica from domestic sheep were effective cytotoxins on both bighorn (> 95% cell death at 150 micrograms of cytotoxin) and domestic sheep (70 to 75% cell death at 150 micrograms of cytotoxin) neutrophils. Potency of cytotoxins derived from P. haemolytica isolates from bighorn sheep was three to seven-fold higher when tested with bighorn sheep neutrophils as compared to domestic sheep neutrophils. Cytotoxins derived from P. haemolytica isolates from domestic sheep were five to six-fold more potent when tested with bighorn sheep neutrophils than when domestic sheep cells were used.

Animals↗

[Cloning and sequencing of four microsatellite loci in Small Tail Han Sheep].

Small Tail Han sheep is an excellent local sheep breed in China. Small Tail Han sheep has significant characteristics of high prolificacy. The lambing percentage averaged 260 percent in Small Tail Han sheep. The genetic detection of 4 microsatellite loci OarAE101, OarHH35, BM143 and BMS2508 which were closely linked to the fecundity gene FecB in Booroola sheep was conducted in 159 sheep in Small Tail Han sheep, Dorset sheep, F1 hybzids(Dorset x Small Tail Han sheep). The results confirmed the genetic characteristics of codominance of microsatellite DNA. The PCR amplified products of microsatellites were detected by non-denatured (natural) polyacrylamide gel electrophoresis. The sequences of PCR amplification fragment of 6 clones of 4 microsatellite loci in Small Tail Han sheep were accepted by GenBank of National Center for Biotechnology Information, National Institutes of Health in USA, the GenBank accession numbers were AF394445, AF394446, AF394447, AF394448, AF394449, AF394450, respectively. The sequence homogeneity between OarAE101 in Small Tail Han sheep in this study and the ovine OarAE101 in GenBank was 98 percent. The sequence homogeneity between OarHH35 in Small Tail Han sheep in this study and the ovine OarHH35 in GenBank was 99 percent. The sequence homogeneity between BM143 in Small Tail Han sheep in this study and the bovine BM143 in GenBank was 95 percent. The sequence homogeneity between BMS2508 in Small Tail Han sheep in this study and the bovine BMS2508 in GenBank was 95 percent. OarAE101, OarHH35, BM143 and BMS2508 in Small Tail Han sheep were all perfect microsatellites. These results could provide molecular basic data for the research on the germplasm characteristics of Small Tail Han sheep.

Animals↗

Behavioural differences between three breed groups of hunting dogs confronted with domestic sheep.

When running free in open fields, domestic dogs occasionally display predatory behaviour towards domestic sheep. This has not yet been studied scientifically. The aim of the present study was to investigate the inclination to chase sheep in three breed groups of hunting dogs that are most frequently used in areas with grazing sheep. We studied 41 elkhounds, 29 hare hunting dogs and 68 English setters. Behaviours indicative of motivation for chasing or attacking sheep were examined in three different ways. A path test examined functional traits such as hunting ability, contact willingness, reactivity to sudden noise, and response towards a lone sheep. In a sheep confrontation test, loose-leashed dogs were observed in a fenced enclosure with sheep and given electric shocks through an electronic dog collar if within 1-2m from the sheep. A questionnaire to the dog owners supplied information on their dog's previous experience with sheep and behavioural responses to various types of novel stimuli. No significant sex differences were found. The elkhounds showed the highest interest in a lone sheep in the path test, and displayed the highest initial hunting motivation, the highest percentage of dogs starting a sheep attack, the highest attack severity, and were most frequently given el. shocks. The hare hunting dogs were intermediate, while setters showed the lowest values for these variables. Dogs reported as showing low fearfulness more frequently acted as potential sheep chasers in the tests. Dogs up to 3 years of age showed a more pronounced initial hunting motivation and more frequent attacks than older dogs, although there were no age differences in the number of el. shocks given in the test. The latter may be related to the more frequent abruption of attacks among younger dogs. The main factors predicting a high hunting motivation and attack severity were lack of previous opportunity to chase sheep, low fearfulness towards gunshots and unfamiliar people, and general interest in sheep shown when encountering them. Probability of sheep chasing differed between dog breeds and age groups. Previous experience and certain character traits were indicative of a high predatory motivation towards sheep.

Journal Article↗

Cellular and humoral elements of the lower respiratory tract of sheep. Immunological examination of cells and fluid obtained by bronchoalveolar lavage of normal lungs.

Bronchoalveolar washings were harvested from the excised lungs of 68 normal sheep of 3 different age groups (A: birth to 8 weeks; B: 6 months to 2 years; C: older than 2 years). Cells and fluid obtained were examined quantitatively and functionally. Fewer cells were present in the lavage fluids of Group A sheep compared with those of Groups B and C. Macrophages were the predominant cell type (70-80%) in all sheep, with lymphocytes being second in number. The lower proportion of lymphocytes in young sheep (Group A) was attributable to lack of B-lymphocytes. As a proportion of the lymphocyte population T-cells were in the majority (60-80%) in all sheep. The proportion of null cells was higher in young sheep than in adults. Pulmonary lymphocytes from sheep of all ages responded poorly to stimulation by the non-specific mitogens phytohaemagglutinin, concanavalin A, pokeweed mitogen and lipopolysaccharide of Escherichia coli. The proportion of neutrophils was higher in sheep over 2 years old compared with younger animals. Eosinophils were present in all age groups but their proportion was greatly increased in animals over 2 years of age. Basophils were absent in young sheep and were present in only low numbers in the lungs of adult animals. In young sheep (Group A) IgG was the predominant immunoglobulin. With age, the percentage of IgG in lung fluid decreased while that of IgA increased so that IgA became the predominant immunoglobulin in older animals (Group C). In sheep of all ages IgM was present in negligible amounts. The highest value of complement (C3) occurred in adult sheep (Group B). The total white blood cell counts and differential blood counts of all the sheep were within accepted normal ranges. As in the lungs, there was an age-associated reduction in the proportions of blood T-lymphocytes and an increase in B-lymphocytes. In contrast to lung lymphocytes, those from the blood of sheep of all ages exhibited a wide range of responses to mitogens. The lowest stimulation indices were observed in the oldest sheep (Group C). The results provide background data against which assessment can be made of changes consequent upon infection with respiratory pathogens.

Age Factors↗