Seasonal variation in testes size in Polish Merino rams and its relationship to reproductive performance in spring

Observations relating testes size to body weight in growing and adult Polish Merino rams were performed during 3 consecutive years in a flock of 1700 pedigree ewes. October-born ram lambs were measured for testis diameter (TD), scrotal circumference (SC), and body weight (BW) at 100 (January), 150 (March), 180 (April), 240 (June), 365 (October), and 480 d (February) of age. In adult rams (n = 63 to 73 per year) BW and SC were measured in March, May (prior to breeding), August and October. Semen quality was evaluated before each breeding season, and the results of controlled reproductive performance (2 natural services to designated rams) were analyzed. Indices were applied to relate testis size to body weight: TD BW , SC BW and TW BW . Heritability estimates of testes indices in ram lambs at 100 to 240 d and at 480 d of age ranged from 0.21 to 0.36 (SE = 0.067 to 0.090). In adult rams SC measurements within months in consecutive years were repeatable (r = 0.55 to 0.68; P相似文献   

Scrotal circumference measurements in purebred Dorset, Hampshire and Suffolk lamb and yearling rams

Purebred Suffolk, Hampshire and Dorset lamb and yearling rams (n=753), underwent performance testing from 1986 to 1989. Scrotal circumference, birth date and entry weight were recorded for each ram entering the test station. Mean age in days at entry, weight (lbs), and scrotal circumference (SC; cm) were greatest for the Hampshire rams. For all rams combined (Dorset, Hampshire and Suffolk), the mean SC by month of age revealed rapid growth from 2 to 6 mo, with a 3- to 6-mo mean SC significantly (P0.05) for mean SC measurement and a less rapid increase in SC diameter. Between 12 and 13 mo a significant increase (P相似文献   

Sexual maturational changes circulatory inhibin concentration in relation to FSH concentration and testicular size in Suffolk and DLS rams

Developmental patterns in immunoactive inhibin and FSH concentrations in peripheral blood were determined for Suffolk and DLS (Dorset x Leicester x Suffolk) rams born in January Blood samples were taken every 3 to 4 wk when testes were developing during puberty (5 to 44 wk of age) and redeveloping in early adulthood (17 to 23 months of age). Suffolk lambs had a greater average daily gain (195 vs. 143 g/day, P<0.01), and they developed larger testes (P<0.01) than DLS lambs. Inhibin and FSH concentrations peaked at about the same pubertal (8 wk) and early adult (19 or 20 months) ages in both breeds. Elevations in FSH were greater (P< 0.05) in Suffolk than DLS rams at each stage of development. The pubertal inhibin peak was nearly 70% larger (P<0.01) in DLS than Suffolk rams, and the early adult peak was comparable in rams of both breeds, but much smaller (P<0.01) than the pubertal peak. Nonetheless, inhibin was positively correlated (r=0.48 to 0.57) with FSH in both breeds during each developmental stage. Inhibin and testicular size were negatively correlated in Suffolk (r=-0.74) and DLS (r=-0.86) rams during puberty, and positively correlated in DLS rams (r=0.46) in early adulthood. We conclude that 1) inhibin concentrations are higher in juvenile rams at the time Sertoli cell numbers are being established than in adult rams during testicular recrudescence and 2) rises in FSH concentration participate in regulating corresponding rises in inhibin concentration in both stages of testicular development.     

Adipocyte cellularity in different adipose depots in bulls of seven Spanish breeds slaughtered at two body weights

The influence of body weight (BW) at slaughter and genotype on adipocyte size and number in the omental (OM), perirenal (PR), subcutaneous (SC) and intermuscular (IM) adipose tissues was studied in 168 bulls of Spain's local Asturiana, Avileña, Morucha, Parda Alpina, Pirenaica, Retinta, and Rubia Gallega cattle breeds. The young bulls were slaughtered at two BWs, 320 and 540 kg. The results obtained showed the higher amounts of lipids that accumulated between 320 and 540 kg BW (P < 0.001) to be ascribable primarily to adipose cell hypertrophy, i.e. larger adipocyte size, in the OM and PR depots (P < 0.001). In addition to hypertrophy, there was also an increase (P < 0.001) in the number of adipose cells, i.e. hyperplasia, in the SC and IM adipose depots. Significant differences were observed when comparing the different genotypes, with the Morucha, Retinta and Avileña breeds having the highest amount of adipose tissue and the largest adipocytes. The Asturiana and Rubia Gallega breeds had the lowest amount of adipose tissue and the smallest adipocytes. The Pirenaica and Parda Alpina breeds had intermediate values in between the two groups identified above. In short, the results were indicative of different lipid deposition patterns in the different breeds depending on the individual growth and maturation rates in each. Similar findings were made when comparing the different adipose tissue depots, with adipocyte hypertrophy being the main factor responsible for lipid accumulation in the OM and PR depots, as opposed to adipocyte hyperplasia in the SC and IM depots.     

Heritability estimates and genetic correlations for body weight and scrotal circumference adjusted to 12 and 18 months of age for male Nellore cattle

Heritability estimates and genetic correlations were obtained for body weight and scrotal circumference, adjusted, respectively, to 12 (BW12 and SC12) and 18 (BW18 and SC18) months of age, for 10 742 male Nellore cattle. The adjustments to SC12 and SC18 were made using a nonlinear logistic function, while BW12 and BW18 were obtained by linear adjustment. The contemporary groups (CGs) were defined from animals born on the same farm, in the same year and birth season. The mean heritability estimates obtained using the restricted maximum likelihood method in bi-trait analysis were 0.25, 0.25, 0.29 and 0.42 for BW12, BW18, SC12 and SC18, respectively. The genetic correlations were 0.30 ± 0.11, 0.21 ± 0.13, 0.21 ± 0.11, -0.08 ± 0.15, 0.16 ± 0.12 and 0.89 ± 0.04 between the traits BW12 and BW18; BW12 and SC12; BW12 and SC18; BW18 and SC12; BW18 and SC18; and SC12 and SC18. The heritability for SC18 was considerably greater than for SC12, suggesting that this should be included as a selection criterion. The genetic correlation between BW18 and SC12 was close to zero, indicating that these traits did not influence each other. The contrary occurred between SC12 and SC18, indicating that selection using one of these could alter the other. Because of the mean magnitudes of heritabilities in the various measurements of weight and scrotal perimeter, it is suggested that the practice of individual selection for these traits is possible.     

Relationship of scrotal circumference and testicular volume to age and body weight in the swamp buffalo (Bubalus bubalis)

Scrotal circumference (SC) and testicular volume (TV) were measured in 65 swamp buffalo bulls ranging in age from 7 to 60 months and weighing 130 kg to 560 kg. Ages and body weight (BW) were recorded for each male at the time of measurement to find out if they correlated with SC and TV. SC and TV increased linearly and correlated significantly with age and BW (SC vs age: r = 0.74, p<0.01; SC vs BW: r = 0.88, p<0.01; TV vs BW: r = 0.82, p<0.01). SC measurements ranged from 15.1 +/- 1.1 cm to 24.0 +/- 0.4 cm for ages ranging from 10.0 +/- 0.6 to 48.5 +/- 6.3 months, revealing that testicular size in swamp buffaloes was very much smaller than domestic cattle. The SC norms distributed with age would be useful in the evaluation of swamp buffalo males for breeding soundness.     

Effect of different husbandry systems on the reproductive development of post-weaning ram lambs under tropical conditions

Two groups of three-to four-month-old weaning ram lambs were studied for 20 months, beginning with weaning at between three and four months. Group 1 was comprised of nine ram lambs which were reared under an intensive husbandry system, and given standard nutrition and mineral supplements throughout the study. Group 2 was comprised of nine rams which were reared under the traditional nomadic/extensive management system, in which the only source of feed was the available pasture. The reproductive traits studied include: age, weight and scrotal circumference at puberty and at all corresponding ages up to 23 months, libido and sexual dexterity and semen characteristics at puberty and all corresponding ages. In the intensively managed rams, the average age at puberty was 6.4+/-0.5 mos. The averages of the other parameters at puberty were: body weight (BW), 21.7+/-2.5kg; scrotal circumference (SC), 18.5+/-1.3cm; libido score, 1.7+/-0.7 and sexual dexterity, 1.7:0.8. In the extensively managed rams, the average age at puberty was 7.8+/-0.3 mos. The average values of the various parameters at puberty were: BW, 17.3+/-1.2kg; SC, 15.2+/-1.4cm; libido score, 3.2+/-0.6 and sexual dexterity, 3.2:1.8. The inter- and intra-group variations in all the parameters at puberty and at all corresponding ages were significant. The average morphological sperm cell abnormalities at puberty were: 25.2+/-3.4% and 31.6+/-8.3% for rams reached puberty and at all corresponding ages than the extensively reared flock. Certain factors that influence post-weaning reproductive development and performance are discussed.     

Aspects of the sexual development of Brahman versus Angus bulls in Florida

Postweaning growth and reproductive traits were studied in 10 Brahman and 12 Angus bulls from 8 through 20 months of age. Brahman bulls reached puberty at 15.9 +/- .4 months of age, weighed 432 +/- 16 kg, had a scrotal circumference (SC) of 33.4 +/- 1.2 cm, and plasma testosterone of 3.96 +/- 1.03 ng/ml. Breed differences in SC averaged over the entire study were not significant. However, the breed x day interaction (BxD) (P<.01) showed that, initially, the Brahman SC was smaller than the Angus SC; however, by the end of the study, the Brahman SC was larger than the Angus. When SC was adjusted for body weight, breed differences (P<.01) and BxD (P <.01) for SC/body weight (BW) reflected the later age and heavier weight at which the Brahman bull reached puberty. Plasma testosterone differed between breeds (Angus > Brahman, P< .01) and increased at a linear (P< .01) rate with age. There was no BxD in plasma testosterone. No breed differences in sperm concentration were observed. However, other semen traits were different (P< .01), i.e., rate of forward movement, sperm motility, total abnormalities and semen volume. A BxD (P< .01) was also evident for breed differences in these semen traits. Sexual development of the Brahman bull occurred at a later chronological age and in a nonparallel pattern to that of the Angus. Between animal variation in SC within the Brahmans and differences between this study and other reports suggest that differences in SC exist for various populations of Brahman bulls and should provide opportunities for progress in selection for this trait.     

Utilization of frozen-thawed epididymal ram semen to preserve genetic diversity in Scrapie susceptible sheep breeds

The European Union has introduced transmissible spongiform encephalopathy (TSE) resistance breeding programmes for several sheep breeds to cope with the genetic susceptibility to Scrapie infections. Due to the different allele frequencies among breeds, strong selection for ARR alleles is associated with a loss of genetic diversity in small populations and in larger populations with unfavourable ARR allele frequencies. To ensure maintenance of genetic diversity, an adhoc cryopreservation programme was initiated employing epididymal sperm from 109 rams representing 16 different breeds within one breeding season. Epididymal semen was chosen for this adhoc programme because time consuming training of rams for ejaculated semen collection via an artificial vagina was not possible. Prior to freezing, average sperm motility was 79.7% and acrosome integrity was 93.7%. After freezing, these levels were decreased to 60.5 and 72.8%, respectively. An insemination trial using frozen-thawed epididymal semen resulted in a lambing rate of 87.5%. Results show that this semen preservation method is robust and efficient and associated with high fertility. It may also be useful for other animal species.     

Seasonal cycles in the blood plasma concentration of FSH, inhibin and testosterone, and testicular size in rams of wild, feral and domesticated breeds of sheep

Seasonal cycles in testicular activity in rams were monitored in groups of wild (mouflon), feral (Soay) and domesticated breeds of sheep (Shetland, Blackface, Herdwick, Norfolk, Wiltshire, Portland and Merino) living outdoors near Edinburgh (56 degrees N). The changes in the blood plasma concentrations of FSH, inhibin and testosterone, and the diameter of the testis were measured every half calendar month from 1 to 3 years of age. There were significant differences between breeds in the magnitude and timing of the seasonal reproductive cycle. In the mouflon rams, the seasonal changes were very pronounced with a 6-15-fold increase in the plasma concentrations of FSH, inhibin and testosterone from summer to autumn, and a late peak in testicular diameter in October. In the Soay rams and most of the domesticated breeds, the seasonal increase in the reproductive hormones occurred 1-2 months earlier with the peak in testicular size in September or October. In the two southern breeds (Portland and Merino), the early onset of testicular activity was more extreme with the seasonal maximum in August. In cross-bred rams, produced by mating Soay ewes (highly seasonal breed) with Portland or Merino rams (less seasonal breeds), there was a seasonal reproductive cycle that was intermediate compared to that of the parents. A comparison between all 11 breeds showed a significant correlation between the timing of the seasonal cycle in plasma FSH concentration and testicular diameter (time of peak FSH vs testis, r = 0.95). The overall results in the rams are consistent with a primary role of FSH in dictating the seasonal cycle in testicular size and the secretion of inhibin. The earlier seasonal onset in the testicular cycle in the southern breeds of domesticated sheep, and the differences from the wild type, are taken to represent the effects of genetic selection for a longer mating season.     

Influence of age and scrotal circumference on breeding soundness examination of range rams

Breeding soundness examinations (BSE) were conducted on 3,167 range rams on New Mexico sheep ranches during 1982, 1983 and 1984. Age and scrotal circumference (SC) were recorded for each ram and based on SC, rams were further classified as small (<30.8 cm), medium (31-37 cm) or large (>37.8 cm). Scrotal circumference increased with age (P < 0.05) up to 7 yr of age. Rams rated as satisfactory by BSE had a large (P < 0.05) SC, averaging 34.4 cm for all ages combined. Most rams classed as small (P < 0.01) were also rated unsatisfactory. There was no difference (P > 0.10) in BSE rating of rams classified by SC as medium or large. Results of this study suggest that SC is influenced by age, and this trait should be considered within age groups. Rams with an SC of <30 cm are more likely (P < 0.05) to be rated unsatisfactory by BSE.     

Sperm output and hormone concentrations in Finn and Dorset rams exposed to long- and short-day lighting

Seasonal changes in photoperiod have a substantial effect on sexual behavior and reproduction in rams. Little information is available on sperm output from high libido versus average libido rams subjected to intensive semen collection while being exposed to controlled short versus long photoperiods. Six Finn and six Dorset rams were compared in a reversal design, which allowed rams of both breeds to be exposed to 8 h versus 16 h of light. During each of two 84-d periods rams were subjected twice to an initial depletion of epididymal sperm reserves by collecting up to 26 ejaculates of semen in 3 d, followed by up to 10 ejaculates per day, 1, 3, 5, and 7 d after the initial depletion. A total of 2673 semen samples were collected. Nearly twice as many ejaculates (63.6% of the total) were obtained from Finn rams as from Dorset rams during both the initial and subsequent 3-d sperm depletion periods. This difference in libido was associated with obtaining 33.6 +/- 3.1 x 10(9) sperm from Finn rams versus 10.0 +/- 2.2 x 10(9) sperm from Dorset rams during the initial depletion period (P<0.05). Changes in photoperiod did not affect sperm output (P>0.05) in Finn rams, but may have affected Dorset rams. With 16 h of light, prolactin was significantly (P<0.05) increased in both breeds, particularly in Finn rams. Testosterone in both breeds followed an endogenous rhythm, not affected by the change in controlled photoperiods.     

Libido and scrotal circumference of rams as affected by season of the year and altered photoperiod

Two trials were conducted to evaluate the influence of season of the year and altered photoperiod on libido and scrotal circumference (SC). A 30-minute serving-capacity test was used to measure ram libido. the measures of libido were reaction time (RT), time from entry into the pen to first mount and/or service, total mounts (M), and total services (S). The serving-capacity test was conducted by placing a ram with four estrus-induced ewes and measuring RT and counting M and S. Prior to each serving-capacity test, SC was measured for each ram. Rams were tested every two weeks. In Trial I, eleven two-year-old Rambouillet rams from each of three selection lines -a high line (four rams; selected on the basis of high prolificacy), a low line (three rams; selected on the basis of low prolificacy) and a random bred control line (four rams) - were used in a one-year study. Rams were exposed to ambient conditions throughout the year. Rams were more active during the short days of fall and winter, i.e. normal breeding season, as evidenced by a greater number of total mounts and services plus a shorter reaction time. Selection line affected reproductive parameters measured, with the high line having more M and S and a shorter RT than the low line. However, SC was larger in the low line. In Trial II twelve rams were divided into two groups of six. The control group was exposed to ambient conditions from April 18 through July 24. The treated group was exposed to eight hours of light and 16 hours of darkness (8L:16D) from April 18 through July 24, simulating short days of fall and winter. Total services (S) in the 30-minute test interval were higher for rams subjected to the 8L:16D treatment (P<0.01; 2.7+/-0.2 vs 1.6+/-0.2 for 8L:16D and control, respectively). SC was 31.7+/-0.2 vs 30.2+/-0.2 for 8L:16D and control, respectively (P<0.01). Total mounts in 30 minutes were not affected by treatment (6.9+/-0.8 vs 5.7+/-0.8 for 8L:16D and control, respectively; P>0.10). No significant differences in any of the reproductive parameters between treatment groups were observed during the first 28 days. However, there were significant differences (P<0.05) observed between 8L:16D rams and control rams for SC during 42 to 84 days and S between days 42 to 70, respectively. Serving-capacity tests carried out about one month following the end of altered photoperiod trial showed no significant differences between treated and control rams, thus indicating that treatment had no carry-over effect.     

Seasonal cycles in testicular activity in Mouflon, Soay sheep and domesticated breeds of sheep: breeding seasons modified by domestication

The seasonal reproductive cycle in rams was monitored in Mouflon (wild-type), Soay (feral type) and a variety of domesticated breeds of sheep (Shetland, Blackface, Herdwick, Norfolk, Wiltshire, Portland and Merino) by measuring the changes in the diameter of the testes (first three years of life in all breeds) and the blood plasma concentrations of FSH and testosterone (first four to six years of life in Mouflon and Soay rams). In the Mouflon rams there was a pronounced seasonal cycle in all the reproductive parameters from one to six years of age. The plasma concentrations of FSH increased from June to September associated with redevelopment of the testes; maximum testicular size and plasma concentrations of testosterone occurred in October at the onset of the rut. In the Soay and domesticated breeds the seasonal maximum in testicular size occurred in late September or October except in two of the southern breeds (Portland and Merino) which showed an earlier peak to the sexual cycle in August. The change in size of the testes from the minimum to the maximum was less in the domesticated breeds (135–157%) compared to the Soay (171%) and Mouflon (160%). Crossbred rams produced by mating Soay ewes (highly seasonal breed) with Portland or Merino rams (less seasonal breed) had a seasonal testicular cycle intermediate in timing compared to the pattern characteristics of the parent breeds; this is consistent with the involvement of multiple genes in the mechanism controlling the sexual cycle in the ram. The earlier seasonal onset of full testicular activity in the southern breeds is assumed to be the result of selection for a prolongation of the breeding season for early lambing.     

Relationship of scrotal circumference to age, body weight and onset of spermatogenesis in goats

Scrotal circumference (SC) and body weight (BW) measurements were obtained from 122 crossbred (Saanen x Loca; Jumnapari x Local) bucks, ranging in age from 3 to 28 months. Spermatogenesis and semeniferous tubule diameters were studied from testicular biopsies in 24 bucks. The results showed that SC increased curvilinearly and was significantly correlated with age (P < 0.05). Scrotal circumference correlated more significantly with BW (P < 0.001). Spermatogenesis was completed at 6-7 months with a sudden increase in tubular diameter at the same time. Since SC is an indirect measurement of testicular size, a marked increase in testicular size indicated the onset of active spermatogenesis and, hence, the possibility of using bucks for breeding at an earlier age than normally recommended. Further, SC norms obtained in this study may become useful in the evaluation of bucks for breeding soundness.     

Adjusted 200-day scrotal size as a predictor of 365-day scrotal circumference

Data collected from 264 bulls of 13 beef breeds at the Michigan Bull Test Station was evaluated to determine if scrotal circumference (SC) adjusted to 200 d of age could be used to predict scrotal circumference at 1 yr of age. Scrotal circumference of each bull was recorded on arrival at the test station and at the time of breeding soundness examination (BSE) and was adjusted to 200 and 365 d of age, respectively. Bulls with adjusted SC>34.0 cm by 365 d of age averaged a larger SC at 200 d (P < 0.0001) and faster scrotal growth (P < 0.0001) than bulls with a 365 d adjusted SC /= 23.0 cm had a 95% probability of achieving SC > 34.0 cm by one year of age. Calves measuring < 23 cm at 200 d had a 54% probability of achieving > 34.0 cm scrotal size by one year. This information can contribute to the selection of breeding bulls that will achieve desirable scrotal size by one year of age.     

Use of naloxone challenge to predict sexual performance of rams before the fall breeding season

Serving capacity tests (SCT) identify rams as sexually active, sexually inactive, or low sexual performers. Labor and time requirements make SCT impractical and expensive. Therefore, a hormone-based test for libido was developed using the responses of LH and testosterone (T) after naloxone. This test effectively identified sexually active and inactive rams during the breeding season (November and December). The current study evaluated the effectiveness of this method at a different time of the year. Objectives were to determine if the blood test can detect differences in libido during late July and August, and to characterize LH and T profiles up to 120 min postnaloxone treatments at this time of year. Two experiments were conducted using i.v. naloxone at 0.75 mg/kg BW. Sexually active (SA) and sexually inactive (SIA) rams were identified using SCT. In Experiment 1, 16 SA and 18 SIA rams of several breeds were identified based on SCT conducted before naloxone tests. In Experiment 2, 72 Suffolk x white face rams were given SCT after naloxone tests and were of unknown sexual activity at the time of the naloxone tests. Mixed model analyses for repeated measures with repeated factors (month and sample time) and a covariate for mean LH or T before naloxone treatment were used for LH and T data. Proc Logistics modeled probabilities that rams were sexually active. The LH response to naloxone increased but did not differ (P > 0.09) by ram class (SA or SIA) or month. The T response peaked 75-90 min after naloxone treatment and was still elevated at 120 min. Testosterone differed (P < 0.03) for ram class by month by time in Experiment I and differed (P < 0.01) between months in Experiment 2. Proc Logistics incorrectly indicated that SA and SIA rams were all sexually active. This study indicates that the naloxone challenge test cannot discriminate between SA and SIA rams during July and August. Further research is required to determine the time of year when this sire identification test for libido has significant accuracy.     

Profiles of luteinizing hormone, follicle-stimulating hormone, testosterone and prolactin in rams of diverse breeds: effects of contrasting short (8L:16D) and long (16L:8D) photoperiods

Mature rams of Polled Dorset, Finnish Landrace, Rambouillet and Suffolk breeding were maintained in a temperature-controlled environment and exposed to two consecutive cycles of short (8L:16D) followed by long (16L:8D) days. Serum hormone concentrations were determined in weekly samples and in 24-h profiles characterized at the end of each lighting schedule (i.e., 12, 24, 36 and 48 weeks). In all four breeds, the pituitary-testicular axis was more active during short days as compared with long days and the magnitudes of changes in serum luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone concentrations were greater for the two most seasonal breeds, Finnish Landrace and Suffolks. In comparison to other breeds, Finnish Landrace rams had significantly (P less than 0.05) higher mean LH levels, showed the greatest number of LH peaks/24 h, and had the highest mean testosterone levels at the end of both periods of short days, while Rambouillet rams had significantly (P less than 0.05) lower testosterone. Rambouillets also showed the smallest changes in pulsatile LH and testosterone secretion and displayed the least number of LH peaks/24 h following short days. Serum FSH levels were significantly (P less than 0.05) higher in Finnish Landrace and Suffolk rams than in Polled Dorsets and Rambouillets after 12 weeks of short days. Breed differences in serum LH, FSH and testosterone were not apparent following long days. Prolactin levels in Rambouillet rams were significantly (P less than 0.05) lower than in the other breeds following both periods of long days. These results indicate that breed differences exist in mature rams with regard to hormone secretory profiles. Breed differences in serum gonadotropin and testosterone are only apparent during short days when the hypothalamo-pituitary-testicular axis in rams is considered most active. Likewise, breed differences in prolactin are noticeable only during long days when secretion of this hormone is enhanced. Breed differences in LH, FSH and testosterone secretion in rams during short days might be related to seasonality of mating and/or fecundity of breed types.     

Biological functions as affected by summer season-related multiple environmental stressors (heat,nutritional and walking stress) in Malpura rams under semi-arid tropical environment

The study was conducted with the primary objective to establish the impact of simultaneously imposed multiple stressors (thermal, nutritional and walking) on various biological functions in Malpura rams. The study was conducted for a period of 45 days. Twenty adult Malpura rams (average BW 44.9 Kg) were used in the present study. The rams were divided into two groups, CON (n = 10; Control) and MS (n = 10; multiple stressors). Both body weight (p < 0.05) and body condition scoring (p < 0.01) were lower in MS compared with CON rams. All the scrotal measurements reduced significantly (p < 0.01) in MS rams. All the testicular measurements also reduced significantly (p < 0.01) in MS as compared to CON rams. The seminal attributes, individual motility (p < 0.05), rapid motility (p < 0.05) and curvilinear velocity (p < 0.05) were significantly reduced in CON rams. However, slowness (p < 0.05), linearity (p < 0.05) and straightness (p < 0.05) parameters significantly increased in MS as compared to CON rams. In addition, plasma testosterone concentration was lower (p < 0.05) in MS rams. The study established the impact of multiple stressors on growth and reproductive performance of Malpura rams. Further, the results revealed that the only semen quality was affected by multiple stressors, but the semen production remained intact between the groups, indicating the extreme adaptive capability of Malpura rams to hot semi-arid tropical environment.     

Screening for polymorphism at the prion protein (PrP) locus (PRNP) in Awassi and Assaf populations in Israel, the Palestinian Authority and Jordan

Screening for polymorphism at the prion protein (PrP) locus (PRNP) was carried out in 33 flocks of Local Awassi (LA) sheep in Israel, the Palestinian Authority (PA) and Jordan. In addition, PRNP genotyping was carried out in two flocks of Improved Awassi (IA) in Israel and the PA and in 11 flocks of Assaf sheep in Israel. Most of the rams present in the flocks at the time of the survey 328, 44 and 298 rams from the LA, IA and Assaf breeds, respectively, were genotyped. The ARQ allele was found to be predominant in all three breeds with average frequencies of 0.74, 0.78 and 0.86 for the LA, IA and Assaf breeds, respectively. Frequencies of the desirable ARR allele in these breeds were 0.10, 0.05 and 0.06, respectively. ARH, AHQ and ARK alleles were identified at low/absent frequencies. Only one Assaf ewe carried the undesirable V allele at codon 136. A few scrapie outbreaks have been documented in the past in the region. To increase ARR allele frequencies in the Awassi and Assaf populations, distribution of homozygous ARR/ARR rams is recommended.