A study on the effect of GnRH administration on the ovarian response and laparoscopic intrauterine insemination of Awassi ewes treated with eCG to induce superovulation

The effect of GnRH administration on superovulatory response of ewes treated with equine chorionic gonadotrophin (eCG) in breeding and nonbreeding seasons and the contribution of laparoscopic insemination to the improvement of fertilization and embryo recovery were investigated. Twenty-four nonpregnant Awassi ewes of 3–4 years of age were randomly allocated into two groups (n = 12). Each ewe was treated with a progesterone impregnated intravaginal sponge for 12 days. The following superovulation treatment was used: ewes of group 1 received 1,200 IU of eCG once as an intramuscular injection 48 h prior to sponge withdrawal; ewes of group 2 also received 1,200 IU of eCG once as an intramuscular injection, 48 h prior to sponge withdrawal and after 24 h of sponge removal. Ewes were injected with 80 μg of GnRH. Ewes of groups 1 and 2 were further subdivided into four equal groups (n = 6). Subgroups A and C (superovulated with eCG and eCG plus GnRH, respectively) were mated naturally at least two times with Awassi rams of proven fertility at 8-h intervals. Subgroups B and D (same as A and C) had intrauterine insemination at 44–46 h after sponge removal, under laparoscopic visualization of uterine horns, depositing 1 ml of diluted semen containing 100 × 10⁶ motile sperm in the distal portion of each uterine horn. Ovarian response was assessed by determining the number of corpora lutea by laparoscopy at day 6 after mating. Embryo recovery was performed by using a semi-laparoscopic flushing procedure in both uterine horns. Results of the present study showed that ewes treated in breeding season with eCG plus GnRH has a higher number (P < 0.05) of corpora lutea than eCG alone as 7.33 ± 0.54 and 4.33 ± 0.39, respectively. There was no significant difference in the number of corpora lutea in nonbreeding season when ewes treated with eCG and eCG plus GnRH. The number of unovulated follicles was significantly higher (P < 0.05) in eCG treated ewes than in ewes treated with eCG plus GnRH, both in the breeding and nonbreeding seasons. The number of recovered embryos from ewes treated with eCG plus GnRH and eCG differ significantly (P < 0.05) as 4.32 ± 0.56 and 1.06 ± 0.26, respectively, in the breeding seasons. No significant difference was observed when these hormones used for superovulation in the nonbreeding season. A higher number of unfertilized ova (P < 0.05) was observed in ewes when naturally inseminated than in ewes inseminated using the intrauterine laparoscopic technique. Higher rate of embryo recovery (P < 0.05) was achieved when ewes were inseminated via intrauterine (4.66 ± 0.66) compared with ewes naturally mated (2.16 ± 0.74). The fertilization rate in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 91.5% and 44.8%, respectively. Fertilization failure in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 8.4% and 55.2%, respectively. It could be concluded that administration of GnRH 24 h after sponge removal increased ovulation rate of Awassi ewes treated with eCG for superovulation in the breeding season. The use of eCG to induce superovulation in Awassi ewes combined with laparoscopic intrauterine insemination increases the fertilization rate.     

A study on superovulation using FSH and eCG in Awassi ewes

The present study was conducted to evaluate superovulatory treatments in Awassi ewes by eCG and FSH. High number of unovulated follicles (P < 0.05) was observed in ewes treated with eCG in non-breeding season. It could be concluded that using FSH to induce superovulation in Awassi ewes is better than eCG.     

Fattening performance of purebred and crossbred lambs from fat-tailed Kurdi ewes mated to four Iranian native ram breeds

A crossbreeding experiment was carried out to determine the sire breed effects on fattening performance of fat-tailed lambs. Rams from four Iranian fat-tailed sheep breeds, namely Kurdi (K), Afshari (A), Chaal (C) and Sanjabi (S) were mated to Kurdi ewes producing 454 progeny of four genotype groups (KK, AK, CK and SK). A total of 80 lambs comprising ten female and ten male lambs from each genotype group were used in a fattening experiment during a period of 88 days. Genotype of the lamb had significant effect on average dry matter intake (ADMI) (P < 0.05). SK lambs had the lowest ADMI. Average daily gain (ADG) and food conversion ratio (FCR) were not influenced by genotype of the lamb. Sex of the lamb had significant effect on both ADG and FCR (P < 0.01). Slaughter weight (SLW), hot carcass weight (HCW), cold carcass weight (CCW) and daily carcass gain (DCG) were not affected by lamb's genotype. However, genotype had significant effect on dressing percentage, carcass loss percentage (P < 0.01), carcass length (CL), leg circumference (LC), carcass compactness (CC) (P < 0.01) and carcass density (CD) (P < 0.05). Carcass width (CW) and leg length (LL) were not affected by lamb's genotype. Sex of the lamb had significant effects on CL, CW, LC, CC, CD (P < 0.01) and LL (P < 0.05). The results indicated the existence of sire breed difference for daily dry matter intake and carcass conformation in the fat-tailed sheep.     

Vitamin and trace element supplementation in grazing dairy ewe during the dry season: effect on milk yield,composition, and clotting aptitude

A study was carried out to evaluate the influence of vitamin and trace mineral supplementation on milk production and composition in grazing dairy ewes during the dry season. Ewes (n = 50) were assigned at weaning to blocks and treatments. Ewes were daily conducted (8 h/day) on a pasture based on Italian ryegrass (Lolium multiflorum). At fold, ewes received a basal diet composed by ad libitum oat hay and a definite amount of a pelleted concentrate. Dietary treatments included: (1) the control concentrate containing background of vitamin and trace mineral only, and (2) the experimental concentrate containing the premix supplement (10 g/kg of dry matter). Vitamin and trace mineral supplementation did not affect ewes’ body weight. Milk, fat- and protein-corrected milk, fat percentage, and clotting properties were improved in ewes fed supplemented concentrate. There was a week × treatment interaction (P < 0.05) for yield of milk and corrected milk that was greatest at peak production in ewes fed the premix. Our findings indicate that in grazing dairy ewe, the dietary vitamin and trace mineral supplementation during dry season led to an increase of milk production and quality, with positive improvement in milk clotting aptitude.     

Lamb survival analysis from birth to weaning in Iranian Kermani sheep

Survival records from 1,763 Kermani lambs born between 1996 and 2004 from 294 ewes and 81 rams were used to determine genetic and non-genetic factors affecting lamb survival. Traits included were lamb survival across five periods from birth to 7, 14, 56, 70, and 90 days of age. Traits were analyzed under Weibull proportional hazard sire models. Several binary analyses were also conducted using animal models. Statistical models included the fixed class effects of sex of lamb, month and year of birth, a covariate effect of birth weight, and random genetic effects of both sire (in survival analyses) and animal (in binary analyses). The average survival to 90 days of age was 94.8%. Hazard rates ranged from 1.00 (birth to 90 days of age) to 1.73 (birth to 7 days of age) between the two sexes indicating that male lambs were at higher risk of mortality than females (P < 0.01). This study also revealed a curvilinear relationship between lamb survival and lamb birth weight, suggesting that viability and birth weight could be considered simultaneously in the selection programs to obtain optimal birth weight in Kermani lambs. Estimates of heritabilities from survival analyses were medium and ranged from 0.23 to 0.29. In addition, heritability estimates obtained from binary analyses were low and varied from 0.04 to 0.09. The results of this study suggest that progress in survival traits could be possible through managerial strategies and genetic selection.     

Effect of feeding calcium salts on performance of nursing Awassi ewes

Twenty nursing Awassi ewes (BW = 50 ± 2.35 kg, age = 4.5 ± 1.2 years) with their lambs were used to evaluate the effects of feeding calcium salts in lactation diets on performance and pre-weaning growth of their lambs. Treatments were 0% calcium salts (CON) or 5% calcium salts (FAT). At the end of the study, a digestibility experiment was performed. Milk yield was greater (P < 0.05) for ewes fed the FAT diet than the CON diet. Milk composition was similar (P > 0.05) between diets. However, milk energy value (kcal/day) tended to be greater (P = 0.07) for the FAT diet than the CON diet. Concentrations of milk C18:1c9 and C20:0 were greater (P < 0.05) in ewes fed the FAT diet than the CON diet. However, concentration of trans-10, cis-12 CLA was lower (P = 0.05) in the FAT diet than in the CON diet. No differences in feed intake and body weight change were detected between diets. Digestibility of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, and acid detergent fiber were similar (P > 0.05) for diets. For lambs, weaning weight was not affected by treatments. However, average daily gain and total gain were greater (P = 0.053) for the FAT diet than the CON diet. Results suggest that supplementing lactating ewes with calcium salts at the beginning of lactation phase improves daily milk yield of ewes and pre-weaning growth of their lambs with no major negative impact on feed intake and digestibility.     

The effect of shearing in a hot environment on some welfare indicators in Awassi lambs

The aim of this study was to analyze the effects of shearing on the individual behaviors and rectal temperature profile during the day at hot environment in Awassi lambs. Twenty Awassi male lambs were randomly allocated into shorn (n = 10) and unshorn (n = 10) groups (28.8 ± 0.7 and 29.9 ± 0.7 kg, respectively) and were kept indoor during the experiment. The physiological and behavioral response variables measured were rectal temperature, standing, lying, feeding, ruminating, drinking, locomotor activity, and elimination. The effect of day, time of day, and all interactions on rectal temperature were found significant (P < 0.001). The effect of shearing on the rectal temperatures of lambs was tend to be significant (P = 0.06). Overall, unshorn lambs showed more frequencies of locomotor activity (P < 0.05) and there was a tendency of less standing behavior (P = 0.08) when compared to the lambs in shorn group. The difference of the other behaviors was not significant (P > 0.05). Within the observation hours, there was a tendency of difference for behavioral frequencies between groups especially early in the day and late at night (P = 0.07). But during the day, the difference of behavior type between groups was highly significant at 1300 and 1600 hours (P < 0.01 and P < 0.001, respectively). The findings of the current study showed that the behavior of shorn lambs changed with the changing of environmental heat and showed more behavioral differences at 1300 hours but they tend to cope with heat stress better than unshorn lambs in a hot environment when their rectal temperatures were compared.     

The effects of time and dose of pregnant mare serum gonadotropin (PMSG) on reproductive efficiency in hair sheep ewes

The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG) on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days. After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100, 200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at −48 h, −24 h, and at sponge removal. PMSG was not administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly, and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected (P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency of hair sheep ewes.     

Growth performances of Washera sheep under smallholder management systems in Yilmanadensa and Quarit districts,Ethiopia

A study was conducted to evaluate growth performances of Washera sheep under smallholder production systems in the Yilmanadensa and Quarit districts of the Amhara National Regional State, Ethiopia. Data were collected and analysed on the growth of 690 lambs owned by 110 households from October 2004 to September 2007. Weight (kilograms) of Washera lambs at birth, 1, 3, 6, 9 and 12 months of age was 2.69 ± 0.02, 7.10 ± 0.16, 12.42 ± 0.11, 16.12 ± 0.91, 20.05 ± 0.55 and 23.47 ± 0.68, respectively. Birth weight was significantly (P < 0.05) affected by district, year of birth, parity of the dam, birth type and sex of lamb and by the interaction effect of parity by birth type and parity by sex of lamb. Weaning weight was also affected by year of birth, type of birth and sex of lamb. Yearling weight was affected by only year of birth and sex of birth. The average daily weight gain (ADG; grams) from birth to 30 days, birth to 90 days, 90 to 180 days and birth to 1 year of age was 143.37 ± 13.46, 107.09 ± 2.67, 39.78 ± 9.73 and 60.13 ± 1.89, respectively. Growth rates from birth to 30 and 90 days of age were significantly (P < 0.05) affected by birth year, birth type and sex. ADG from birth to 1 year of age was affected by lamb sex and district. The indigenous Washera sheep had faster growth rate than those sheep breeds of Ethiopia extensively studied thus far. Integrated efforts combining improved nutrition, health and participatory community-based breeding would help the smallholder farmers to utilise and conserve this immense sheep genetic resource of Ethiopia.     

A note on the reproductive performance of Damara,Dorper and Merino sheep under optimum management and nutrition for Merino ewes in the eastern wheatbelt of Western Australia

The reproductive performance of 48 Damara, 42 Dorper and 46 Merino ewes was evaluated under an optimum nutritional regime for Merino ewes that included one annual joining in a mixed (cropping and sheep) farming system in the eastern wheatbelt of Western Australia (W.A.) over a 3-year period. In 2005, when the Damara, Dorper and Merino ewes were aged between 8 and 9 months at joining and weighed 41.2, 42.4 and 33.3 kg with average body condition scores of 2.3, 2.4 and 1.8, respectively, their weaning rates were 71% (Damara), 81% (Dorper) and 13% (Merino). The Merino ewes had significantly lighter body weights and were lower conditioned (p < 0.001) resulting in significantly lower weaning rates (p < 0.001). In 2006, the Damara, Dorper and Merino ewes weighed 61.9, 69.5 and 61.6 kg at joining, with body condition scores of 2.8, 3.3 and 2.8, respectively, resulting in weaning rates of 52% (Damara), 122% (Dorper) and 117% (Merino). While the Damara and Merino weights and body condition scores were not different (p > 0.05), the Damara weaning rates were significantly lower compared with the Dorper and Merino groups (p < 0.001). The Dorpers were heavier and greater conditioned (p < 0.001); however, the weaning rates between the Dorper and Merino were not different (p > 0.05). In 2007, the Damara, Dorper and Merino ewes weighed 71.6, 77.1 and 70.2 kg at joining with body condition scores of 2.8, 2.8 and 2.5, respectively. Again, the Dorper ewes were heavier (p < 0.001) than the Damaras and Merinos, which were not different (p > 0.05). The Damara and Dorper had the same body condition while the Merino ewes were less and different (p < 0.05). However, there were differences in weaning rates between the three breeds (p < 0.001), of 64% (Damara), 105% (Dorper) and 134% (Merino). Over the 3-year period, under a nutritional management system optimal for Merino sheep and with one annual joining, with increasing age the Merino ewes weaned more lambs. However, while the Damara and Dorper ewes conceived and weaned relatively high lamb numbers when they were joined as lambs, their reproductive performance decreased over time. This nutritional regime resulted in increased levels of fatness of the Damara and Dorper ewes with no increase in reproduction rates under an annual joining system. A significant factor for the lower conception and weaning rates in the Damara ewes was the enlarged fat tail due to the increased fat levels, which made it difficult for the rams to impregnate the ewes.     

The effect of estrus synchronization treatments on somatic cell count of transitional-anestrus Awassi ewes’ milk

Fifty-three transitional-anestrus Awassi ewes, randomly assigned to three groups: fluorogestone acetate (FGA, n = 18), FGA-Prostaglandin (FGA-PGF, n = 18) and control (n = 17), were used to examine the effect of estrus synchronization protocols and steroid hormones concentrations on milk somatic cell count (SCC). Intravaginal FGA sponge was inserted for 13 days and 600 IU equine chorionic gonadotropin was administered for ewes of FGA and FGA-PGF groups at the time of sponge removal (day 0). In addition, 10 mg was administered to ewes of FGA-PGF group on day 0. Blood and milk samples were collected from all ewes on days -13, -6, 0, 1, 2, 7 and 14. Estradiol had significant positive correlation with the SCC during the periods of sponge insertion (P = 0.015, r = 0.235) and within two days (P = 0.063 r = 0.23) after sponge removal with no correlation with SCC of both udder halves during the luteal phase. Progesterone concentrations, on the other hand, had a significant positive correlation (P < 0.001; r = 0.420) with the SCC of both udder halves during the luteal phase of the experiment, but not during the periods of sponge insertion and expected estrus. SCC returned under the influence of endogenous progesterone on days 7 and 14 to pre-synchronization values. In conclusion, sheep milk SCC is affected significantly with induction of estrus and steroid hormones concentrations. However, peak SCC recorded during estrus was far below the upper limit of the current standard for normal milk. With the current standards for SCC of 1,000,000/ml as legal limit for abnormal milk control programs in sheep, estrus synchronization programs and the estrus status should not be considered when bulk-tank milk SCC is being investigated, but should be considered during the process of setting new standards.     

Superovulatory response and embryo quality in Katahdin ewes treated with FSH or FSH plus eCG during non-breeding season

The aim of this study was to evaluate the effect of a co-treatment of follicle-stimulating hormone (FSH) plus equine chorionic gonadotrophin (eCG) on serum insulin and insulin-like growth factor 1 (IGF-1) concentrations, superovulatory response, ovulatory rate, and number and production of embryos in Katahdin breed ewes during the non-breeding season. Twenty Katahdin ewes were synchronized with progestagens (CIDR) and assigned to two superovulation treatments (n = 10): (1): ewes treated with 200 mg ewe⁻¹ of FSH from day 5 to 8 after CIDR insertion at decreasing doses every 12 h (FSH group) and (2) ewes treated as FSH group plus 300 IU of eCG on day 5 after CIDR insertion (FSH + eCG group). Estrous behavior was monitored and direct mating was performed. On days − 7 (CIDR insertion), 0 (CIDR withdrawal), and 7 (embryo recovery), blood samples were collected to determine serum hormone concentrations. Co-treatment with eCG (FSH group) did not affect (P > 0.05) serum hormone levels. Superovulation response, ovulation rate, recovery rate, fertilization, and number of embryos were also similar (P > 0.05) between treatments. Compared with FSH group, FSH + eCG ewes had lower (P < 0.05) number of transferable embryos and higher (P < 0.05) number of oocyte and a tendency to increase the number of degenerated embryos (P = 0.07). Overall results suggest that the administration of eCG is not beneficial either to improve the ovulatory response or the amount of transferable embryos in Katahdin ewes superovulated with a protocol using progesterone and FSH at decreasing doses.

     

Effect of concentrate supplementation on performance,ovarian response,and some biochemical profile of Malpura ewes

Effect of feed flushing on ovulation rate was investigated during the autumn seasons on 24 adult Malpura ewes (BW 34.8 ± 0.58 kg and age 4–7 years) equally divided into two groups. Ewes in G1 (group 1) were grazed 8–10 h daily on Cenchrus ciliaris pasture interspersed with seasonal shrub. In addition to grazing, concentrate was provided at 1.5% of BW to the animals in G2 (group 2) for a period of 35 days. Estrus was synchronized by a double injection schedule of PGF_2α at 0 and 10 days of the experiment and detected by parading aproned rams at 6 h intervals. Blood samples were collected at weekly interval during the estrous cycle. A rumen fermentation study was conducted on day 23 of the experiment at 0 and 4 h post-concentrate feeding. Ovarian responses in terms of number of corpora lutea and large follicles was examined on all the ewes by laparoscopy after 3 to 6 days of each estrus and were found to be similar in both the groups. Hemoglobin and packed cell volume, total protein, albumin, and globulin were similar among the groups. Concentration of plasma glucose (12 and 22 days) was higher (P < 0.05) in G2 vis-à-vis control. Plasma urea was higher (P < 0.01) in the control than G2. Rumen liquor pH, concentration of total N, TCA–ppt N, NH₃–N, and TVFA were significantly higher (P < 0.01) in G2 than the control. Thus, it can be concluded that concentrate supplementation in ewes prior to mating (flushing) did not enhance ovulation response during the autumn season.     

Effect of doe milking and supplementation using <Emphasis Type="Italic">Dichrostachys cinerea</Emphasis> pods on kid and doe performance in grazing goats during the dry season

Effects of supplementation and milking of Matebele does four weeks pre-partum to weaning, on milk yield, kid birth weight and growth rate were studied. Forty does were divided into four treatments: supplemented and milked (SM), supplemented and not milked (SNM), not supplemented and milked (NSM); and not supplemented and not milked (NSNM). Supplemented goats were given 200 g/doe/day of Dichrostachys cinerea pods containing 19% CP. The study was carried out in September during time of feed unavailability and animals were grazed on rangelands for seven hours before being given the supplement. Fifty-six kids were born from all the experimental animals and 24 were singles whereas 32 were twins. Milk yield was higher (P < 0.05) in supplemented than non-supplemented does. Although supplementation had no effect on kid birth weights, growth rates were higher (P < 0.05) in the SNM group (103 ± 10.1 g/day) than in the SM group (74 ± 10.8 g/day). Among the non-supplemented groups, kids from milked does had higher (P < 0.05) daily gains (85 ± 10.9 g/day) than those from non-milked does (67 ± 10.7 g/day). Weaning weights were higher (P < 0.05) in SNM does (12.8 ± 1.30 g/day) than in the SM does (10.2 ± 1.17 g/day). Among kids from the non-supplemented does, those from milked does had superior (P < 0.05) weaning weights (11.2 ± 1.23 g/day) than those from non - milked does (9.2 ± 1.27 g/day). Mortalities were also lowest in kids born from SNM does. It is concluded that pre-partum to weaning supplementation generally increases milk production which then increases kids growth rates and weaning weights, as well as reduce kid mortalities.     

Adaptability and growth of Malpura ewes subjected to thermal and nutritional stress

A study was conducted to assess the effect of combined stresses (thermal and nutritional) on physiological adaptability and growth performance of Malpura ewes. Twenty-eight adult Malpura ewes (average BW 33.56 kg) were used in the present study. The ewes were divided into four groups, viz., GI (n = 7; control), GII (n = 7; thermal stress), GIII (n = 7; nutritional stress), and GIV (n = 7; combined stress). The animals were stall-fed with a diet consisting of 60% roughage and 40% concentrate. GI and GII ewes were provided with ad libitum feeding, while GIII and GIV ewes were provided with restricted feed (30% intake of GI ewes) to induce nutritional stress. GII and GIV ewes were kept in climatic chamber at 40°C and 55% RH for 6 h/day between 1000 and 1600 hours to induce thermal stress. The study was conducted for a period of two estrus cycles. The parameters studied were feed intake, water intake, physiological responses (viz., respiration rate, pulse rate, and rectal temperature), body weight, and body condition scoring (BCS) of ewes. Both thermal and combined stress significantly (P < 0.05) affected the feed intake, water intake, respiration rate, and rectal temperature. The feeding schedule followed in the experiment significantly (P < 0.05) altered the body weight and BCS between the groups. The results reveal that when compared with thermal stress, nutritional stress had less significant effect on the parameters studied. However, when both these stresses were coupled, it had a significant influence on all the parameters studied in these ewes. It can be concluded from this study that when two stressors occur simultaneously, the total cost may have severe impact on biological function.     

Effect of Inter‐Breed Embryo Transfer on Lamb Growing Performance and Survival

The roles of recipient and embryo genotype in determining the growth performance and survivability of offspring based on specific behavioural differences were investigated using inter‐breed embryo transfer. This study was carried out using three recipient genotypes (Awassi, Redkaraman and Tuj) and two embryo genotypes (Charollais and Romanov) to obtain the six possible combinations of ewe and lamb genotypes. Data were collected from 71 recipient ewes (10 Redkaraman with Charollais and 15 Redkaraman with Romanov embryos; 10 Tuj with Charollais and 12 Tuj with Romanov embryos, and 12 Awassi with Charollais lambs and 12 Awassi with Romanov embryos); all ewes received two frozen‐thawed embryos. Awassi ewes had a significantly longer duration of the licking/grooming event (25.5 min, p < 0.05) than Tuj ewes. Charollais lambs were significantly (p < 0.05) more likely to require birth assistance compared to Romanov lambs. Romanov lambs were significantly more (p < 0.01) active than Charollais lambs in the first 2 h after birth; ewe breed had no effect on lamb behaviour. There was no recipient breed effect on either birth or weaning weights of lambs. Charollais lambs were recorded with higher birth (5.5 ± 0.3 kg vs 3.9 ± 0.2 kg; p < 0.001) and weaning (29.4 ± 1.2 kg vs 22.4 ± 1.9 kg; p < 0.001) weights compared to Romanov lambs. At weaning Romanov lambs had significantly higher (95% vs 75%; p < 0.05) survival rates, however, this was not significantly affected by recipient breed. It was concluded that recipient breed was not an important factor in survival and weaning performance of embryo transferred lambs from a prolific breed (Romanov) while these traits recorded for lambs from meat type (Charollais) embryos were influenced by dam breed.     

Characterization of Oestrous Induction Response,Oestrous Duration,Fecundity and Fertility in Awassi Ewes During the Non‐breeding Season Utilizing both CIDR and Intravaginal Sponge Treatments

The aim of this study was to investigate characterization of oestrous response, onset of induced oestrus, oestrous duration, fecundity and fertility in Awassi ewes treatment with intravaginal sponges and Controlled Intravaginal Drug Release (CIDR) devices in combination with pregnant mare serum gonadotropin (PMSG) under local environmental conditions during the non‐breeding season. A total of 62 ewes were divided into three groups. Group CIDR (n = 20) was treated with CIDR devices for 12 days and 400 IU PMSG was injected upon removal of the CIDR. For ewes in Group Sponge (SP) (n = 24), 30 mg fluorogestone acetate was administered to the sheep for 12 days and 400 IU PMSG was injected upon withdrawal of the sponge. Group Control (CON) (n = 18) served as a control group and received no treatment. Adult, intact and sexually experienced Awassi rams were introduced to all groups at the time when the intravaginal devices were removed. There were no significant differences in terms of oestrous response (CIDR: 90%, SP: 87.5%), time to onset of oestrus and duration of induced oestrus between the CIDR and SP groups. The oestrous response of treatment groups was significantly greater (p < 0.05) than in the control ewes. There were no significant differences in pregnancy (CIDR: 70%, SP: 70.8%), lambing (CIDR: 85%, SP: 79.2%) and fecundity rates between ewes treated with CIDR and those treated with sponges. However, pregnancy and lambing rates were significantly (p < 0.05) higher in ewes treated with CIDR or sponges when compared with those in the control group. It was concluded that it is possible to induce fertile oestrus, successful pregnancy and lambing with the treatment of either CIDR or intravaginal sponge in combination with PMSG in Awassi ewes during the non‐breeding season.     

Changes of vitamins A, E, and C and lipid peroxidation status of breeding and pregnant sheep during dry seasons on medium-to-low quality forages

This study assessed the changes of plasma vitamin A, E, and C and the lipid peroxidation status of sheep during breeding and pregnancy under drought conditions. The study was conducted on 105 cross-bred fat tailed ewes, 3–5 years old with body condition scores (BCS) of 2.5 to 3.5. The ewes were grazing on medium-to-low quality forages during summer and low quality forages within the succeeding months and had ad libitum access to a mixture of alfalfa hay (40%) and wheat straw (60%) in the afternoons. From 3 weeks before breeding till 1 month after the introduction of rams, 300 g of barley grain/head/day was offered to the ewes and then the supplemental grain was reduced to 100 g/head/day. For better synchronization of estrus cycles in ewes, they were isolated from the rams for at least 2 months and then kept in close proximity of the rams for 1 week before the introduction of the rams to the ewe flock. Then, whole blood samples were collected on days 1, 7, 21, and 120 after ram introduction. Vitamins A, E, and C were measured in plasma. Malondialdehyde (MDA) was measured in the hemolysate as a biomarker of lipid peroxidation. Plasma progesterone (P4) was measured in the samples of day 120 for assessing pregnancy status of the ewes. Vitamins A and C showed continuous and significant declines (P < 0.05) through days 1 to 120. Vitamin E declined only during the first 21 days of the study and remained almost constant till day 120. MDA concentration increased significantly at day 21. An elevated concentration of MDA was also detected at day 120. The difference between days 21 and 120 was not significant (P > 0.05). A positive correlation between vitamins E and C was detected at day 120 (r = 0.349, P < 0.01). Age and BCS did not affect the patterns of changes. Assuming that the ewes with P4 concentrations ≥2.5 ng/ml were pregnant, 95 out of 105 ewes (90.5%) were pregnant at day 120 of the study. Under the conditions of the present study with medium-to-low quality pastures as the main sources of feed, ewes of various ages and body conditions may suffer from oxidative stress during breeding and pregnancy.     

Sexual behaviour of yearling Awassi,Charollais × Awassi and Romanov × Awassi rams exposed to oestrousAwassi ewes

This study was conducted to evaluate the sexual performance of 10-month-old, ram lambs of different breed groups. Eight ram lambs each of Awassi (A), F₁ Charollais × Awassi (CA) and F₁ Romanov × Awassi (RA) breed types were subjected to sexual performance tests by being individually exposed to two oestrous Awassi ewe lambs for four 20-min periods. Bouts of leg kicking and anogenital sniffing were similar among breed groups. Mounting frequency was greater (p < 0.05) in RA than in A and CA ram lambs. Tail-raising was greater (p < 0.05) and mating rate tended to be greater (p < 0.10) in A than in RA and CA ram lambs. The number of mounts per tail-raising (efficiency) was influenced by breed group and test day (p < 0.05). Awassi ram lambs maintained the best efficiency throughout the experiment. Efficiency in RA and CA ram lambs improved with each test day. Results of the present study indicate that RA ram lambs have greater mounting frequency than A and CA, while Awassi are more capable of mating with fat-tailed females than the CA and RA ram lambs.     

Follicular Dynamics,Interval to Ovulation and Fertility After AI in Short‐Term Progesterone and PGF2α Oestrous Synchronization Protocol in Sheep

The study was aimed to assess the influence that short‐term progesterone treatments have on follicular dynamics, oestrus and ovulation in sheep. The treatment was tested thereafter in a field trial to assess its fertility after AI with fresh semen. In a first experiment, 12 ewes without CL were grouped to receive a new (n = 6) or used CIDR (n = 6) for 7 days and blood samples were obtained to follow plasma progesterone profiles. In a second experiment, 39 cycling ewes were synchronized by a 7‐day P4+PGF2α protocol using a new (n = 20) or a 7‐day used CIDR (n = 19). Half of both groups received 400 IU eCG and half remained untreated as controls. Ultrasound ovarian examination and oestrous detection were used to compare follicular dynamics, oestrus and ovulation in both groups. In a third experiment, 288 ewes in 3 farms were synchronized by the short‐term P4+PGF2α+eCG protocol and ewes were AI with fresh semen 24 h after oestrous detection. Lambing performance was used to test the fertility of the treatment. In Experiment 1, ewes with new inserts presented higher P4 concentration than ewes with used inserts throughout the sampling period (p < 0.05) and exhibited a P4 peak at days 1‐2 of the treatment that was not observed in ewes with used inserts. In Experiment 2, ewes treated with new and used inserts show similar ovarian and behavioral traits (p > 0.10). However, ewes treated with eCG show shorter interval to oestrus (p = 0.004) and tend to have larger mature CL (p = 0.06). In Experiment 3, oestrous presentation and lambing performance after AI with fresh semen was considered normal compared to published results. Results suggest that the oestrous synchronization protocol based on P4+PGF2α allows little control of follicular dynamics without compromising fertility after AI with fresh semen provided that eCG is added at the end of the treatment.