Evaluating the impact of breed, pregnancy, and hair coat on body temperature and sweating rate of hair sheep ewes in the tropics.

The objective of this study was to evaluate the effect of pregnancy, breed, and hair coat on body temperature and sweating rate (SR) of hair sheep. St. Croix White (STX; = 9) and Dorper × STX (DRPX; = 9) ewes (3.6 yr of age) were evaluated over 4 d at 126 d of gestation (PREG) and over 4 d at 46 d postpartum (OPEN) in the shade and sun and in the morning (AM; 0900 to 1200 h) and afternoon (PM; 1300 to 1600 h) after a 20 min acclimation to each condition on each day. Data loggers recorded vaginal temperature (VT) at 10-min intervals for 96 h. Rectal temperature (RT) was measured using a digital veterinary thermometer, and respiration rate (RR) was measured as breaths per minute (bpm). Sweating rate was calculated from measured air properties passing over a shaved (300 cm) and unshaved area of the ewes' body using a portable calorimeter. Data were analyzed using GLM procedures of SAS (SAS Inst. Inc., Cary, NC) with breed, pregnancy status, sun exposure, and time of day as main effects. Mean temperature, relative humidity, temperature-humidity index, wind speed, and solar radiation on the days of data collection were 28.2°C, 82.8%, 80.3, 4.2 km/h, and 237.5 W/m, respectively. There was no difference ( > 0.10) in RT, RR, and SR between DRPX and STX ewes. The PREG ewes had lower RT ( < 0.007) and SR ( < 0.0001) and higher RR ( < 0.007) than OPEN ewes (38.5 ± 0.2 vs. 39.1 ± 0.2°C, 70.2 ± 3.1 vs. 88.3 ± 3.1 g⋅m⋅h, and 79.5 ± 2.2 vs. 72.1 ± 2.2 bpm, respectively). During the PM, RR, RT ( < 0.05), and SR ( < 0.006) were higher than in the AM. In the sun, RR ( < 0.001) and SR ( < 0.0001) were higher than in the shade, but there was no difference ( > 0.10) in RT. There was no difference in SR ( > 0.10) between the shaved and unshaved area of the ewe. The DRPX ewes had higher ( < 0.0001) VT than STX ewes. The PREG ewes had higher ( < 0.001) VT than OPEN ewes during the night time and lower VT than the OPEN ewes during the day time ( < 0.0001). The OPEN ewes had a greater ( < 0.009) daily range of VT than PREG ewes did (2.5 ± 0.4 vs. 1.1 ± 0.4°C, respectively), but there was no breed difference ( > 0.10). Hair coat did not have an influence on the SR of the ewes, and PREG ewes appeared to use increased respiration as opposed to sweating to help control RT. The narrower range of body temperature, measured as VT, of PREG compared to OPEN ewes may be a protective mechanism for the developing fetus.

Effect of weaning age on hair sheep lamb and ewe production traits in an accelerated lambing system in the tropics.

This study was designed to evaluate the impact of weaning age on lamb and ewe productivity in an accelerated lambing system. St. Croix White (STX) and Dorper × St. Croix White (DRPX) lambs were assigned at birth based on breed, gender, and litter size to be weaned at 63 (Early-1; 106 lambs and 68 ewes) or 90 d of age (Late-1; 99 lambs and 60 ewes) in Exp.1 or at 63 (Early-2; 77 lambs and 57 ewes) or 120 d of age (Late-2; 75 lambs and 56 ewes) in Exp. 2. After weaning, lambs were weighed weekly and fed a concentrate ration (2% BW·lamb·d) while grazing guinea grass pastures. In Exp. 1, weaning weight was greater ( < 0.0001) for Late-1 lambs than for Early-1 lambs (14.6 ± 0.3 vs. 11.0 ± 0.3 kg, respectively) and greater ( < 0.008) for DRPX lambs than for STX lambs (13.9 ± 0.4 vs. 11.5 ± 0.4 kg, respectively). Litter weaning weight was greater ( < 0.004) for Late-1 ewes than for Early-1 ewes (20.9 ± 0.8 vs. 17.4 ± 0.8 kg, respectively). Ewe efficiency ([ewe BW at weaning/litter weaning weight] × 100) was greater ( < 0.004) for Late-1 ewes than for Early-1 ewes (50.7 ± 1.9 vs. 42.3 ± 1.8%, respectively). Lamb weight gain between 63 and 90 d of age was lower ( < 0.03) for Early-1 lambs than for Late-1 lambs (2.7 ± 0.2 vs. 3.6 ± 0.3 kg, respectively). In Exp. 2, weaning weight was greater ( < 0.0001) for Late-2 lambs than for Early-2 lambs (18.7 ± 0.4 vs. 11.8 ± 0.4 kg, respectively) and greater ( < 0.008) for DRPX lambs than for STX lambs (16.9 ± 0.5 vs. 13.3 ± 0.5 kg, respectively). Litter weaning weight was greater ( < 0.0001) in Late-2 ewes than in Early-2 ewes (27.2 ± 1.0 vs. 17.5 ± 0.9 kg, respectively). Ewe efficiency was greater ( < 0.0001) for Late-2 ewes than for Early-2 ewes (68.1 ± 2.2 vs. 41.9 ± 2.0%, respectively). Lamb weight gain between 63 and 120 d of age was not different ( > 0.06) between Early-2 and Late-2 lambs (5.1 ± 0.2 vs. 5.6 ± 0.3 kg, respectively). In Exp. 1 and 2, ewe BW at breeding and lambing and weaning and lambing rate were not different among weaning ages of lambs ( > 0.17). The Early-1 ewes exhibited estrus earlier than Late-1 ewes (10.9 ± 0.9 vs. 13.9 ± 1.0 d, respectively) but there was no difference ( > 0.63) between Early-2 and Late-2 ewes. Weaning hair lambs at 90 or 120 d of age can be done in an accelerated lambing system with no detrimental effect on lamb or ewe productivity. Late weaning resulted in a decreased number of days that lambs received high-cost, imported feed without a reduction in growth, resulting in savings of US$6 to $15 per lamb.

Relationship among eye and muzzle temperatures measured using digital infrared thermal imaging and vaginal and rectal temperatures in hair sheep and cattle.

Digital infrared thermal imaging (DITI) using a thermal camera has potential to be a useful tool for the production animal industry. Thermography has been used in both humans and a wide range of animal species to measure body temperature as a method to detect injury or inflammation. The objective of these experiments was to compare the temperature of the eye (EYE) or muzzle (MUZ) measured using DITI to vaginal (VT) and rectal temperature (RT) as measures of core body temperature in hair sheep and beef cattle. In Exp.1 EYE, VT and RT were measured in lactating, multiparous hair sheep ewes (St. Croix White, n = 10, and Dorper × St. Croix White, n = 10) in a non-febrile state 5 times over a 48-h period. Data loggers were used to measure VT and a digital veterinary thermometer was used to measure RT. There was a high correlation (P < 0.001) between VT and RT (r = 0.95), EYE and RT (r = 0.76) and EYE and VT (r = 0.77). In Exp. 2 EYE, MUZ, VT and RT were measured in multiparous, lactating ewes (St. Croix White, n = 2, and Barbados Blackbelly, n = 12) at -12, -1, 0, 1, 2, 3, 4, 6, 12, 24, 36, and 48 h after being administered lipopolysaccharide (LPS; n = 7; 0.2 µg/kg BW, i.v.) or saline (n = 7; 0.5 mL, i.v.). Data loggers were used to measure VT and a digital veterinary thermometer was used to measure RT. When data were combined across treatments (LPS and saline) there was a high correlation (P < 0.001) between VT and RT (r = 0.96), EYE and RT (r = 0.82), MUZ and RT (r = 0.72), and EYE and VT (r = 0.93). In Exp. 3 EYE, MUZ, VT and RT were measured in multiparous, non-lactating, pregnant Senepol cattle (n = 44) between 0900 and 1200 h on a single day. A digital veterinary thermometer was used to measure both VT and RT. There was a high correlation (P < 0.001) between VT and RT (r = 0.78), a moderate correlation (P < 0.001) between VT and EYE (r = 0.52), RT and EYE (r = 0.58) and EYE and MUZ (r = 0.48). There was no correlation (P > 0.10) between RT or VT and MUZ. The findings of these three studies indicate that temperature of the eye, measured using DITI, can be used as an indicator of core body temperature in hair sheep and beef cattle as an alternative to using vaginal or rectal temperature.

The effect of a split feeding regimen and breed on body temperature of hair sheep ewes in the tropics.

Lactating St. Croix White and Dorper×St. Croix White ewes were used to evaluate the effect of breed and feeding a split ration on body temperature during the cool (March-April) and warm (July-August) seasons in the U.S. Virgin Islands. Within each season ewes were assigned to treatments (n=8/treatment) based on breed, age, and number of lambs. Treatments consisted of individually feeding ewes daily 0.9 kg concentrate (16.4% CP and 68% TDN) in the morning (AM) or afternoon (PM), 0.45 kg in the morning and afternoon (AM-PM), or no feed (Control) for 56 d beginning on d 7 (lambing=d 0). Ewes were fitted with intravaginal temperature data loggers, set to record vaginal temperature (VT) at 5-min intervals, for 48 h in wk 2 (d 8-14), 5 (d 29-35), and 8 (d 50-56) postpartum. Repeated measures analysis of VT was conducted using a model including treatment, season, and breed as fixed effects. There was no effect of season so data were pooled across season. The interaction of breed with treatment or season was not significant so breed comparisons were made using data pooled across treatments and season. The mean temperature, relative humidity, and temperature-humidity index during the cool and warm seasons were 25.8°C, 85.9%, and 76.1 and 28.3°C, 86.7%, and 80.6, respectively. There was no effect of season or the breed×treatment×season interaction on VT (P>0.10) so all data were pooled across season and breed for analysis of the treatment effect. During wk 2 there was no difference (P>0.10) in VT among treatment groups. During wk 5 the AM-PM ewes had higher (P<0.01) VT than AM, PM, or Control ewes. During wk 8 the AM-PM and PM ewes had higher VT (P<0.01) than either the AM or Control ewes. To evaluate breed effect, data were pooled across treatments and seasons and analyzed using breed as the single main effect. Dorper×St. Croix White ewes had higher (P<0.0001) VT than St. Croix White ewes. The results show that body temperature of ewes can be influenced by time of feeding and breed. The local breed of sheep, St. Croix White, had a lower body temperature than Dorper×St. Croix White sheep. Ewes that were fed in the afternoon for an extended time during the postpartum period developed elevated body temperatures, which could make them more susceptible to heat stress.

Administration of 6-methoxybenzoxazolinone (MBOA) does not augment ovulatory responses in St. Croix White ewes superovulated with PMSG.

The objective of this investigation was to examine the effects of 6-methoxy-benzoxazolinone (MBOA), a plant compound that resembles melatonin and alters ovarian function in rodents, in combination with PMSG on superovulatory responses in the cycling ewe. In Experiment I, St. Croix White ewes (n = 44) were synchronized (intra-vaginal progestin sponge) for 14days followed by hCG (750 IU) at 1 day after sponge removal (day 0). Ewes were assigned to one of six treatments administered on day -1: Control (no PMSG or MBOA; n = 7); PMSG (1000 IU i.m.; n = 7); Low MBOA (0.43 mg/kg i.m.; n = 7); High MBOA (1.15 mg/kg i.m.; n = 7); Low MBOA + PMSG (n = 8); High MBOA + PMSG (n = 8). In Experiment II, St. Croix White ewes (n = 24) were synchronized (progestin CIDR) for 14 days followed by hCG on day 1 after CIDR removal (day 0). Ewes were assigned to one of three treatments administered on day -1: Control (n = 8); PMSG (n = 8); Low MBOA+PMSG (n = 8). Laparoscopy was performed on day 9 to assess numbers of corpora lutea (CL) and visible follicles on each ovary. Blood samples were collected on day -13, -1, 0, 1, and days 6 or 7-12 for analysis of serum progesterone (P4) by RIA. Treatment groups receiving PMSG (alone or with MBOA) exhibited greater (P < 0.05) serum concentrations of P4 post-synchrony than Control and MBOA-only groups. Ovulation rate was lower (P < 0.05) for Control and MBOA-only treated ewes than ewes receiving PMSG. Ovulation rate in ewes treated with MBOA alone was similar (P > 0.10) to Controls, and PMSG treatment alone did not differ (P > 0.10) from MBOA + PMSG treatment. Ewes treated with PMSG alone did not differ (P > 0.10) in follicle number from High MBOA + PMSG treated ewes, however, Low MBOA + PMSG treated ewes had greater numbers of follicles at day 9 (P < 0.05) than the PMSG or High MBOA + PMSG groups in Experiment I; although, this was not replicated in Experiment II with numbers of follicles in the Low MBOA + PMSG group being similar (P > 0.10) to PMSG alone. In summary, the addition of MBOA in combination with PMSG as part of a synchronization-superovuation protocol in the ewe did not increase ovulation rate.

Breeding soundness evaluations of Senepol bulls in the US Virgin Islands.

The breeding soundness evaluation (BSE) was used to evaluate Senepol (Bos taurus) bulls (n = 495) on St. Croix over a 7-year period. Young, unproven bulls (10-26 months of age) and breeding bulls (16 months to 8.5 years) were tested prior to sale or use in breeding. Inbreeding coefficients were determined for a subset of bulls (n = 290). The percentage of bulls passing the BSE increased (P < 0.0001) with age. Bulls that passed had a higher percentage (P < 0.0001) of normal and motile sperm as well as a larger (P < 0.0001) scrotal circumference than bulls that failed. No bulls failed the BSE for physical soundness traits or other health reasons. The incidence of testicular hypoplasia was 2.5 and 3.3% and the incidence of cryptorchidism was 1.4 and 0.9% in 12- and 16-month-old bulls, respectively, with no occurrence in bulls >20 months. The proportion of all bulls that failed the BSE and received an Unsatisfactory rating for scrotal circumference or sperm motility decreased (P < 0.0001) from >90 to <25% with age. The proportion of all bulls that failed the BSE and received an Unsatisfactory rating for sperm morphology decreased (P < 0.0001) from 99 to 83.3% with age. The inbreeding coefficient was higher (P < 0.03) in bulls that failed the BSE than in those that passed (2.24 +/- 0.19% versus 1.40 +/- 0.32%, respectively). There was a tendency for bulls with testicular hypoplasia or cryptorchidism to have a higher (P = 0.09) inbreeding coefficient than bulls with normal testes (2.90 +/- 0.46% versus 2.13 +/- 0.11%, respectively). In conclusion, Senepol bulls raised under tropical conditions had a low probability of passing the BSE at young ages, but the passing rate increased with age. Older Senepol bulls were more likely to fail the BSE due to abnormal sperm morphology than due to inadequate testicular size or sperm motility. To prevent unnecessary culling, a BSE should not be performed on Senepol bulls <16 months old.

Plasma LH, FSH, testosterone, and age at puberty in ram lambs actively immunized against an inhibin alpha-subunit peptide.

Active immunization against inhibin has been shown to advance puberty and increase ovulation rate in ewe lambs; but in ram lambs, effects on puberty and sperm production are equivocal. The objective of the present study was to determine whether active immunization against an inhibin alpha-subunit peptide advances the onset of puberty in ram lambs. St. Croix hair sheep ram lambs were assigned to inhibin-immunized (n = 7) and control (n = 8) treatment groups. Lambs in the inhibin-immunized group were immunized against a synthetic peptide-carrier protein conjugate, alpha-(1-25)-human alpha-globulin (halpha-G), and control lambs were immunized against halpha-G. Lambs were immunized at 3, 7, 13, 19, 25, 31, and 37 weeks of age. On the day of immunization a blood sample was collected and lambs were weighed. Another blood sample was collected 1 week following each immunization. At 20 weeks of age additional blood samples were collected at 20 min intervals for 8h. Beginning at 20 weeks of age and at weekly intervals thereafter, scrotal circumference (SC) was measured and semen was collected using electroejaculation. A subsequent ejaculate was collected 1 week following onset of puberty, which was defined as the week of age when an ejaculate first contained > or =50 x 10(6) sperm cells. In control lambs, plasma alpha-(1-25)-antibody (Ab) was nondetectable. In inhibin-immunized lambs, alpha-(1-25)-Ab titer increased from 7 to 25 weeks of age and then plateaued at a level that varied (P<0.001) among animals. Body weight and SC of control and inhibin-immunized lambs were similar at the onset of puberty. At pubertal onset inhibin-immunized lambs were older than control lambs (31.9+/-0.5 vs. 29.5+/-0.7 weeks of age, P<0.05). Plasma FSH concentrations were similar in control and inhibin-immunized lambs from 3 to 38 weeks of age. Plasma LH levels were lower (P<0.01) in inhibin-immunized than control lambs. During the 8-h blood sampling period at 20 weeks of age, LH and testosterone concentrations were lower (P<0.05) in inhibin-immunized than control ram lambs, and the LH pulse frequency was similar in the two groups of animals. The decreased LH secretion is consistent with the immunoneutralization of a putative inhibin alpha-subunit-related peptide that stimulates LH secretion in ram lambs. Present findings show that active immunization against an inhibin alpha-peptide delays rather than advances puberty in ram lambs.

Effect of supplemental nutrition around lambing on hair sheep ewes and lambs during the dry and wet seasons in the U.S. Virgin Islands.

Pregnant St. Croix White and Barbados Blackbelly hair sheep ewes were used to evaluate the effect of supplemental nutrition around the time of lambing on ewe and lamb performance during the dry and wet seasons on St. Croix. Beginning 14 d before expected day of lambing (d 0) and for 21 d postpartum, one group of ewes was fed a pelleted supplement in addition to grazing guinea grass pasture (FEED). Other ewes in the flock grazed pasture only (CONTROL). This study was conducted during the dry season (June through September; FEED n = 14 and CONTROL n = 15) and during the wet season the next year (October through January; FEED n = 11 and CONTROL n = 12). The 24-h milk production of each ewe was measured on d 7, 21, 35, 49, and 63. Ewes were exposed to sterile rams equipped with marking harnesses to detect estrus during the postpartum period. The FEED ewes lost less weight postpartum during both seasons (P < 0.0001) and had higher milk production (P < 0.009) than CONTROL ewes during the dry season. During the dry season, the time to the first postpartum estrus did not differ (P > 0.10) between FEED and CONTROL ewes (46.9 +/- 2.7 vs 52.9 +/- 2.6 d, respectively). During the wet season, the time to first postpartum estrus was less (P < 0.07) in FEED than in CONTROL ewes (33.0 +/- 3.1 vs 41.1 +/- 2.9 d, respectively). The FEED ewes had higher lamb birth weight (P < 0.04) and weaning weight (P < 0.05) than CONTROL ewes (3.2 +/- 0.1 and 12.2 +/- 0.5 vs 2.9 +/- 0.1 and 10.9 +/- 0.5 kg, respectively) during the dry season. In the wet season, lamb birth weight and weaning weight were similar (P > 0.10) between FEED and CONTROL (3.2 +/- 0.1 and 15.5 +/- 0.7 vs 3.1 +/- 0.1 and 15.3 +/- 0.6 kg, respectively). Lambs born during the wet season had higher (P < 0.0001) ADG than lambs born during the dry season (194.4 +/- 5.9 vs 127.7 +/- 4.7 g/d, respectively). Strategic nutritional supplementation of hair sheep ewes may provide a method for increasing the weight of lambs produced during the dry season in the tropics, but it does not seem to be beneficial during the wet season.

Behavioral and endocrine responses of hair sheep ewes exposed to different mating stimuli around estrus.

Hair sheep ewes were used to evaluate the influence of various levels of mating stimuli on the duration and timing of estrus and LH concentrations around estrus. Ewes were treated with PGF2alpha (15 mg, im) 10 d apart. At the time of the second PGF2alpha treatment (Day 0) ewes were placed in groups and exposed to different types of mating stimuli. One group of ewes (n = 16) was exposed to an epididymectomized ram (RAM), a second group of ewes (n = 16) was exposed to an epididymectomized ram wearing an apron to prevent intromission (APRON) and a third group of ewes (n = 17) was exposed to an androgenized ovariectomized ewe (T-EWE). Jugular blood samples were collected from ewes at 6-h intervals through Day 5. Plasma was harvested and LH concentration was determined by RIA. The ewes were observed at 6-h intervals to detect estrus. A ewe was considered to be out of estrus when she no longer stood to be mounted by the teaser animal. There was no difference (P > 0.10) in the proportion of ewes expressing estrus (79.6%) or having an LH surge (85.7%) among the treatments. Neither the time to estrus nor the duration of estrus were different (P > 0.10) among APRON, RAM or T-EWE groups (41.6+/-3.8 vs 43.6+/-3.6 vs 46.1+/-3.6 h, respectively, and 26.5+/-2.2 vs 24.8+/-2.3 vs 30.5+/-2.2 h, respectively). The time to LH surge was similar (P > 0.10) among APRON, RAM and T-EWE groups (51.2+/-4.5 vs 51.2+/-4.7 vs 52.7+/-4.5 h, respectively). The magnitude of the LH surge was similar (P > 0.10) in the T-EWE, APRON and RAM ewes (99.7+/-4.9 vs 87.2+/-4.9 vs 85.8+/-5.0 ng/mL, respectively). The time from estrus to the LH surge was not different (P > 0.10) among APRON, RAM or T-EWE ewes (10.1+/-2.2 vs 9.8+/-2.3 vs 11.6+/-2.3 h, respectively). These results show that the expression and duration of estrus are not influenced by different types of mating stimuli in hair sheep ewes. In addition, the timing and the magnitude of LH release does not appear to be influenced by mating stimuli around the time of estrus.

Estrus synchronization and artificial insemination of hair sheep ewes in the tropics

Hair sheep ewes (St. Croix White and Barbados Blackbelly) were used to evaluate 3 methods of estrus synchronization for use with transcervical artificial insemination (TAl). To synchronize estrus, ewes (n=18) were treated with PGF2alpha (15 mg, im) 10 d apart, with controlled internal drug release (CIDR) devices containing 300 mg progesterone for 12 d (n=18), or with intravaginal sponges containing 500 mg progesterone for 12 d (n=18). On the day of the second PGF2alpha injection or at CIDR or sponge removal, sterile rams were placed with the ewes. Jugular blood samples were collected from the ewes at 6-h intervals until the time of ovulation, and daily for 16 d after estrus (Day 0). Plasma was harvested and stored at -20 degrees C until LH, and progesterone concentrations were determined by RIA. There was no difference (P>0.10) in time to estrus among the CIDR-, PGF2 alpha- or sponge-treated ewes. All of the ewes in the CIDR group and 94.4 percent of the sponge treated ewes exhibited estrus by 36 h after ram introduction, while only 72.2 percent of PGF2alpha-treated ewes showed signs of estrus by this time (P<0.06). The time from ram introduction to ovulation was not different (P>0.10) among CIDR, PGF2alpha- or sponge-treated ewes. The time to preovulatory LH surge was similar (P>0.10) among treatment groups. Hair sheep ewes (n=23) were synchronized using PGF2alpha and bred by TAI using frozen-thawed semen 48 h after the second injection. The conception rate to TAI was 2/23 (8.7 percent) and produced 3 ram lambs. In a subsequent trial, 17 ewes were synchronized with CIDR devices and bred by TAI using frozen-thawed semen 48 h after CIDR removal, resulting in a conception rate of 52.9 percent (9/17). It is possible to synchronize estrus in hair sheep using either CIDRs, sponges or PGF2alpha. Even though there were no significant differences in the timing of ovulation or the LH surge among the treatment groups, a higher concentration rate was achieved in ewes synchronized with CIDR devices during the second trial. This may reflect an increase in the skill level of the TAI technician.(AU)

Estrus synchronization and artificial insemination of hair sheep ewes in the tropics.

Hair sheep ewes (St. Croix White and Barbados Blackbelly) were used to evaluate 3 methods of estrus synchronization for use with transcervical artificial insemination (TAI). To synchronize estrus, ewes (n = 18) were treated with PGF2alpha (15 mg, im) 10 d apart, with controlled internal drug release (CIDR) devices containing 300 mg progesterone for 12 d (n = 18), or with intravaginal sponges containing 500 mg progesterone for 12 d (n = 18). On the day of the second PGF2alpha injection or at CIDR or sponge removal, sterile rams were placed with the ewes. Jugular blood samples were collected from the ewes at 6-h intervals until the time of ovulation, and daily for 16 d after estrus (Day 0). Plasma was harvested and stored at -20 degrees C until LH, and progesterone concentrations were determined by RIA. There was no difference (P>0.10) in time to estrus among the CIDR-, PGF2alpha- or sponge-treated ewes. All of the ewes in the CIDR group and 94.4% of the sponge treated ewes exhibited estrus by 36 h after ram introduction, while only 72.2% of PGF2alpha-treated ewes showed signs of estrus by this time (P<0.06). The time from ram introduction to ovulation was not different (P>0.10) among the CIDR-, PGF2alpha- or sponge-treated ewes. The time to the preovulatory LH surge was similar (P>0.10) among CIDR, PGF2alpha and sponge treated ewes. Progesterone levels through Day 16 after the synchronized estrus were not different (P>0.10) among treatment groups. Hair sheep ewes (n = 23) were synchronized using PGF2alpha and bred by TAI using frozen-thawed semen 48 h after the second injection. The conception rate to TAI was 2/23 (8.7%) and produced 3 ram lambs. In a subsequent trial, 17 ewes were synchronized with CIDR devices and bred by TAI using frozen-thawed semen 48 h after CIDR removal, resulting in a conception rate of 52.9% (9/17). It is possible to synchronize estrus in hair sheep using either CIDRs, sponges or PGF2alpha. Even though there were no significant differences in the timing of ovulation or the LH surge among the treatment groups, a higher conception rate was achieved in ewes synchronized with CIDR devices during the second trial. This may reflect an increase in the skill level of the TAI technician.

Plasma-derived proteins in airway defence, disease and repair of epithelial injury.

One significant characteristic of the airway mucosa in vivo, that cannot easily be mimicked in vitro, is its microcirculation, which generates a highly dynamic, biologically active milieu of plasma-derived molecules that may pass to the airway lumen in vivo. New data on the mechanisms of airway mucosal exudation indicate that the protein systems of circulating plasma may contribute significantly to the biology and immunology of the lamina propria, its surface epithelium and the luminal surface, not only in injured airways, but also in airways that are activated but display no sign of oedema, epithelial disruption, or increased absorption capacity. We suggest that present knowledge of the mechanisms of plasma exudation, together with rapidly emerging information (not detailed herein) on receptors, target cells and cellular responses to the plasma-derived molecules, must be considered in any realistic model that investigates "immuno-inflammatory" mechanisms of the airway mucosa.

Evaluation of sexual behavior of hair sheep rams in a tropical environment.

We evaluated sexual behavior of St. Croix White (SC; n = 5) and Barbados Blackbelly hair (BB; n = 4) rams under two environmental conditions in the tropics. Sexually naive rams were individually exposed for 15 min to a restrained, ovariectomized ewe, three times during a 3-wk period in June, in a pen with shade (SHADE; 33.1+/-.3 degrees C) or without shade (SUN; 38.3+/-.3 degrees C). Rectal temperature (RT) of rams was measured before and after each test. Sexual behaviors were recorded by observers outside the pens. The number of mounts and ejaculations were similar (P > .10) between the SUN (12.1+/-2.8 and 3.6 +/-.5, respectively) and SHADE (10.7+/-2.9 and 3.4+/-.4, respectively) tests. There was no breed x test pen interaction for any of the behaviors recorded (P > .10). The BB rams mounted the ewe more (P < .04) than did the SC rams (15.7+/-2.8 vs 7.3+/-2.7 mounts, respectively). The overall level of activity (foreleg kicks, attempted mounts, mounts, and ejaculations) was similar (P > .10) between BB and SC rams (64.9 +/-8.5 vs 45.4+/-8.5 events, respectively). Rectal temperature before testing was similar (P > .10) in BB and SC rams (39.4+/-.1 vs 39.4+/-.1 degrees C, respectively). The change in RT of rams was not different (P > .10) between SUN and SHADE tests (.6 +/-.1 vs .8+/-.1 degrees C), but BB rams had a greater (P < .02) change in RT than SC rams (.9+/-.1 vs .5+/-.1 degrees C, respectively). The change in RT was positively correlated with time to first service (r = .39, P < .01) and number of mounts (r = .52, P < .001) and negatively correlated with number of services (r = -.47, P < .0008). These results show that under tropical conditions, hair sheep rams exhibit a full repertoire of sexual behaviors. There does not seem to be a negative influence of elevated ambient temperature during testing on the level of sexual behavior of these rams.

The effect of ram exposure on uterine involution and luteal function during the postpartum period of hair sheep ewes in the tropics.

St. Croix White hair sheep ewes lambing in July (n = 20) or November (n = 26) were used to evaluate the effect of ram exposure on uterine involution and postpartum luteal function. Ewes were exposed to an epididymectomized ram (EXPOSED) beginning on d 7 after lambing (d 0) or kept isolated from rams (CONTROL) through d 63. The width of each uterine horn was measured using transrectal ultrasonography at 3.5-d intervals beginning within 3 d after lambing. Jugular blood samples were also collected at these times, and plasma was harvested for progesterone (P4) analysis. Days to first estrus postpartum was not different (P > .10) between EXPOSED ewes that lambed in July or November (39.3 +/- 3.1 vs 44.2 +/- 3.8 d, respectively). Cross-sectional area of uterine horns was not different (P > .10) between EXPOSED and CONTROL ewes, ewes bearing one or two lambs, or ewes that lambed in November or July. Cross-sectional area of uterine horns in EXPOSED and CONTROL ewes had decreased to < 30% of initial values by 28 d postpartum (P < .0001). Ewes exposed to rams had a P4 concentration greater than 1 ng/mL sooner postpartum (P < .006) than CONTROL ewes (32.4 +/- 2.4 vs 42.1 +/- 2.3 d, respectively). The P4 concentration in the first sample greater than 1 ng/mL was greater (P < .06) in EXPOSED ewes than in CONTROL ewes (3.3 +/- .4 vs 2.3 +/- .4 ng/mL, respectively). In July, ewes exposed to rams had greater (P < .03) P4 concentrations than CONTROL ewes during the 63 d after parturition, but this difference was not apparent (P > .10) in ewes that lambed in November. Ram exposure did not hasten uterine involution in hair sheep ewes in the tropics. Luteal function, determined by plasma P4 concentrations, was enhanced by ram exposure during July but not during November. The lack of seasonality of hair sheep in the tropics does not seem to totally inhibit the response of ewes to ram exposure.

Human airway epithelial tight junctions.

The flux of fluid, ions, macromolecules, and inflammatory cells across airway epithelium depends in part upon the integrity of its apico-lateral tight junctions. Without the correct balance of fluid and ions, the normal functioning of mucociliary clearance and the neural responsiveness of the airways cannot take place. Freeze-fracture electron microscopy has been used to investigate the structure of human airway tight junctions and their morphology comprehensively characterised at two airway levels (main and lobar bronchi). Further data is needed to establish if the fall in transepithelial electrical resistance found across progressively proximal disparate airway generations is correlated with an alteration in tight junction morphology. Altered epithelial permeability is associated with the development of the airway conditions: asthma, chronic bronchitis, and cystic fibrosis. However, few data have been published on the structure of tight junctions in asthma and chronic bronchitis. In patients with cystic fibrosis, airways obtained at transplantation and postmortem show a basal extension of the apico lateral tight junctional belt. This change is not unique to cystic fibrosis airways as it also occurs in non-respiratory systems postmortem. However the functional relevance of these changes remains uninvestigated and recently developed in vitro models may help answer this question. The data demonstrate that tight junctions are highly dynamic structures capable of rapid alterations in disease and in response to functional stress.

A comparison of two methods of oestrous synchronisation of hair sheep in the tropics.

Two trials were conducted to evaluate the efficacy of oestrous synchronisation procedures in St. Croix White, Barbados Blackbelly hair and Florida Native wool ewes. In Trial 1 (conducted in June), 27 ewes were treated with controlled internal drug release (CIDR) devices for 12 days (CIDR1) and 29 untreated ewes served as controls (CONT). The CIDR devices were removed on the same day that intact rams equipped with marking harnesses were placed with the ewes. Time to oestrus after ram introduction was shorter (P < 0.0001) in CIDR1 than CONT ewes. Within 3 days of ram introduction 100% of CIDR1 ewes but only 37.9% of CONT ewes had been in oestrus (P < 0.0001). Conception rate at first oestrus after ram introduction was 74.1% overall, with no effect (P > 0.10) of treatment, but days to conception were shorter (P < 0.001) in CIDR1 than CONT ewes. Ovulation rate at first oestrus after ram introduction was not different (P > 0.10) between CIDR1 and CONT ewes. The CIDR1 ewes lambed earlier (P < 0.004) in the lambing season than CONT ewes, but there was no difference in the number of lambs born per ewe (P > 0.10). In Trial 2 (conducted in October), 14 St. Croix White ewes were treated with CIDRs as in Trial 1 (CIDR2) and 14 St. Croix White ewes were given two i.m. injections (15 mg) of prostaglandin F2 alpha (PGF) 10 days apart. Intact rams were introduced on the day of CIDR removal or the second PGF injection. The CIDR2 ewes exhibited oestrus earlier (P < 0.01) than PGF treated ewes. The conception rate to breeding at the synchronised oestrus was similar (P > 0.10) between CIDR2 and PGF treated ewes. Progesterone concentration on Day 10 after the synchronised oestrus was not different (P > 0.10) between CIDR2 and PGF treated ewes. These results indicate that oestrous synchronisation procedures can be used in sheep in the tropics without adversely affecting fertility. Due to a lack of seasonal anoestrous these procedures have the potential to be used during all times of the year.

Artificial insemination, hybridization and pregnancy detection in sika deer (Cervus nippon ).

Artificial insemination (AI) was performed on sika hinds (Cervus nippon ) receiving various dosages of pregnant mare serum gonadotropin (PMSG; Year 1: 0, 50 and 100 IU; Year 2: 100 and 150 IU) and using semen collected from elk and 1 2 elk x 1 2 sika stags. The time from synchronization device removal (CIDR vs norgestomet) to estrus was determined through observations of mounting activity. Methods for pregnancy detection, serum progesterone (P4), estrone sulfate (E1S), pregnancy-specific protein B (PSPB) and ultrasonography, following AI (Year 1: AI, Days 28 and 48 after AI; Year 2: AI, Days 42, 53 and 100 after AI) and a 90-d natural breeding season were investigated. From available production data, body weights were compared among sika and 1 4 elk x 3 4 sika hybrids relative to age. Pregnancy rates tended (P < 0.10) to differ relative to PMSG treatment and sire; administration of 0 IU PMSG resulted in fewer hinds becoming pregnant to AI than 50 or 100 IU of PMSG. Hinds receiving 100 IU of PMSG had higher (P < 0.05) pregnancy rates than hinds receiving 150 IU PMSG. Time to standing estrus did not differ (P > 0.10) between the CIDR and norgestomet groups. Pregnancy rates 50 d after a 90-d breeding season were similar (P > 0.10) between ultrasound (70.9%) and PSPB (61.6%). Serum P4 after 90 d in breeding groups and 50 d after stag removal were higher (P < 0.05) for pregnant than open hinds. Pregnancy rates (Year 1) 48 d after AI were similar (P > 0.10) between ultrasound (49.0%) and PSPB (37.3%). Serum P4 28 and 48 d after AI were higher (P < 0.05) for pregnant than open hinds. Serum E1S was higher (P < 0.01) for pregnant than open hinds 48 d after AI. Pregnancy rates (Year 2) 100 d after AI did not differ (P > 0.10) between ultrasound and PSPB (66.7%). Serum P4 was higher (P < 0.03) in pregnant than open hinds at 42, 53 and 100 d after AI. At 100 d after AI, pregnant hinds had higher (P < 0.002) serum E1S than open hinds. At 6 to 8 and 11 to 13 mo of age, 1 4 elk x 3 4 sika males tended (P < 0.08) to be heavier than sika males, while 1 4 elk x 3 4 sika females were heavier (P < 0.05) than sika females at all ages. In summary, this study documents the use of AI and methods for pregnancy detection in sika hinds as well as preliminary information regarding the production of elk-x-sika hybrids.

Airway and lung elastic fibre is not reduced in asthma nor in asthmatics following corticosteroid treatment.

By morphometric investigation of the relative content of elastic and collagen fibres, we have tested the hypothesis that loss of elastic fibres in the conducting airways and lung parenchyma may reduce tissue elastic recoil, resulting in increased airway maximal closure and apparent increased responsiveness. The study groups comprised: Group A (n = 11) with relatively mild atopic asthma using inhaled bronchodilators prn (i.e. short-term corticosteroids users); Group B (n = 9) with more severe asthma requiring inhaled bronchodilators regularly, and daily inhaled glucocorticosteroids (i.e. longterm corticosteroid users); Group C (n = 12) normal healthy workers. Bronchial biopsy samples were taken from three sites from the left lung. Group A biopsy samples were taken before and after a 4 wk treatment period with inhaled corticosteroids (200 micrograms b.i.d.) and the relative elastic and collagen fibre content of a subepithelial zone was determined from electron micrographs. In a parallel study, the relative proportion of elastic fibre in post mortem lung tissue samples (inner aspect of the bronchial wall, alveolar wall, and points of attachment of surrounding alveoli to intrapulmonary bronchi) from subjects suffering a fatal asthma attack (n = 11), and non-asthmatic suffering sudden death (n = 9), were determined using Miller's elastic and eosin counterstain for light microscopy. In bronchial biopsies of normal subjects, 4.6 (SEM 1.1)% of subepithelial connective tissue was elastic fibre, similar to mild asthmatic subjects, 1.9 (SEM 0.48)%. Neither short-term (4 weeks) inhaled corticosteroid (200 micrograms b.i.d.) nor long-term (< 6 months) treatment with variable doses of inhaled steroids (100-1000 micrograms b.i.d.) significantly altered the elastic or collagen content of the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

No effect of histamine on human bronchial epithelial cell permeability and tight junctional integrity in vitro.

Both animal and human studies have suggested that histamine increases airway epithelial cell permeability in vivo. In order to study the effect of histamine on paracellular epithelial permeability and tight junctional integrity, we have cultured human bronchial epithelial cells to confluency and investigated the effect of topically applied 0.1-20.0 microM histamine. Cultures were established on microporous membranes of tissue culture cell inserts and used for the assessment of: 1) transepithelial movement of radiolabelled mannitol (14C-mannitol) and bovine serum albumin (14C-BSA), in the luminal to serosal direction and 2) changes in electrical resistance of the cultures. Epithelial cell cultures were also established on plastic coverslips, in order to determine tight junction morphology by freeze-fracture electron microscopy, and to assess junctional integrity by lanthanum penetration, using thin sections. Compared with untreated control cultures, 0.1-10 microM histamine did not significantly alter the movement of either 14C-mannitol or 14C-BSA across the epithelial cultures at any time during incubation, but caused an increase in the electrical resistance of the cultures, which was maximal by 6 h of incubation. The morphology of the tight junctions revealed by freeze-fracture and junctional integrity (the latter determined by the degree of lanthanum penetration) were similar in untreated control cultures and cultures incubated with histamine. These studies indicate that histamine does not have a direct effect on paracellular bronchial epithelial permeability in vitro.