Parturition In Ewes Research Articles

Duration of parturition in ewes and its consequences on behavioural traits in mother-lamb bond: Doctoral thesis abstract

Lamb mortality within the first 72 hours of life greatly affects sheep breeding, especially in extensive rearing, resulting in important economic losses and involving animal welfare. Prolonged fetal expulsion phase can influence maternal behaviour, and the extended period of hypoxia during birth can also affect the behaviour of the neonate. Limited information exists regarding the necessary duration of the fetal expulsion phase for these changes in maternal behaviour to occur or for the resulting hypoxia from prolonged delivery to either be reversed or cause sequelae that affect lamb viability. Behavioural disturbances of both the mother and the neonate prevent establishing a proper mother-lamb bond. This thesis aims to investigate the required time for the duration of the fetal expulsion phase to have consequences on both maternal and offspring behaviour. For early detection of foetal hypoxia, the effectiveness of a non-invasive and easy-to-use tool, a pulse oximeter, was evaluated and compared with venous blood gas analysis. The prolonged duration of parturition affected the behaviour of both dams and lambs, disrupting the mother-lamb bond and leading to a higher percentage of abandonment. A linear correlation between the duration of delivery and poor maternal behaviour was observed in primiparous ewes, but not in multiparous ones. The pulse oximeter successfully detected lambs with low oxygenation at birth, which would allow to establish therapeutic or management measures to improve survival. Reducing the duration of the foetal expulsion phase through programmed parturition assistance improved maternal behaviour and lamb vigour in primiparous ewes, enabling the establishment of an appropriate mother-lamb bond and potentially enhancing neonatal survival.

Birth, colostrum, and vigour traits of lambs born from Corriedale ewes grazing native pastures supplemented during the peripartum period

To evaluate the effect of a short-term energy-protein supplementation during the peripartum on birth, colostrum, and vigour traits of lambs, 214 multiparous Corriedale pregnant ewes grazing native pastures were used. Ewes, according to body conditions score and body weight, were assigned to a 2 × 2 factorial design: type of birth (single or twin), and supplementation (yes or no). Single (n = 67) and twin bearing (n = 39) non-supplemented, and single (n = 67) and twin bearing supplemented ewes (n = 41) were observed during lambing in two similar sub-paddocks. There was no detected interaction between supplementation and type of birth for any of the experimental variables (P > 0.05), except in the time the lambs took to stand after birth. Length of gestation and type of parturition (normal vs. dystocia) were not affected by supplementation or type of birth (P > 0.05). The duration of parturition (phase II) was longer in supplemented than non-supplemented and in single than in twin bearing ewes (P < 0.05). Colostrum production was greater, heavier, and less viscous in supplemented than non-supplemented ewes, and in single than twin bearing ewes (P < 0.05). Colostrum nutritional values were greater in supplemented than non-supplemented ewes; there was more total lactose in single than twin bearing ewes (P < 0.05). Birth weight of lambs was not affected by supplementation (P > 0.05), but it was higher in single than twin lambs (P < 0.05). There were more lambs with blood glucose concentration greater than 20 mg/dl at birth from supplemented than non-supplemented, and from single than twin bearing ewes (P < 0.05). There was no effect of supplementation in the time taken by lambs to stand and suck their mothers (P > 0.05), however in non-supplemented ewes, single lambs stood and sucked faster than twin lambs (P < 0.05). No differences in lamb mortality to 72 h were observed due to supplementation or type of birth (P > 0.05) but lesions of dystocia/stillbirth/birth injury as cause of death was less frequent in supplemented than non-supplemented ewes (P < 0.05), without differences by type of birth (P > 0.05). In conclusion, a short-term energy-protein supplementation in ewes during peripartum period influenced positively the volume, viscosity and composition of colostrum and blood glucose of lambs at birth, reducing lesions of dystocia/stillbirth/birth injury as cause of death of lambs, but did not affect the length of gestation, duration, or type of parturition in ewes, birth weight, lamb vigour, or lamb mortality to 72 h.

Maternal and fetal ultrasonographic characteristics, vulvar temperature, and vaginal mucous impedance as variables associated with the onset of parturition in term and induced pre-term ewes

The aim of this study was to assess and compare ultrasonographic characteristics of maternal and fetal structures, vulvar temperatures, and vaginal mucous impedance in pregnant ewes in the term parturition group (TPG, n = 15) and induced pre-term parturition group (IPPG; n = 15). All the measurements were taken every 12 h throughout the last gestational week. Maternal and fetal structures and the fetal heart rate (HR) were assessed using ultrasonography. The vulvar temperature and vaginal mucous impedance were determined using a non-contact infrared thermometer, and an electronic estrous detector, respectively. The vulvar temperature was less in the TPG and greater in the IPPG; the end-diastolic velocities (EDVs) of the arteries of the placentome and uterus gradually increased before parturition in the IPPG (P = 0.02, P = 0.02 and P = 0.009, respectively). The placentome shear wave velocity (SWV) was greater in the ewes of the IPPG than TPG 48, 36, and 0 h before parturition (P = 0.001). The following variables were associated with the onset of parturition within the next 12 h in the ewes of the IPPG: resistance index (< 0.54) and EDV (> 0.34 cm/s) of the uterine artery; and vulvar temperature (> 37.3 °C). A fetal kidney SWV of < 1.31 m/s was associated with the onset of parturition in the next 12 h in all the ewes. Results indicate vulvar temperature and certain maternal and fetal factors detected using ultrasonograpy may aid in determining fetal maturity and/or the time of parturition in ewes.

Evaluation of an alternative treatment protocol by aglepristone to induce parturition in ewes with an experimental model of early pregnancy toxemia

A new protocol with aglepristone to induce parturition in ewes with pregnancy toxemia has been reported in the present manuscript. Four experimental groups were defined: Group AG5 (n = 10), Group DEX (n = 10), Group NC (n = 5) and Group PT (n = 5) in which ewes were injected twice with 10 mg/kg of aglepristone and 5 ml dexamethasone in first two groups, respectively; whereas negative control and pregnancy toxemia groups received no treatment for parturition induction. Different clinical parameters associated with parturition in ewes and their newborns were investigated. Blood hematology and biochemical measurements were carried out both in ewes and lambs. Blood pH values of lambs were recorded during the study. The injection time-lambing time, injection time-vaginal discharge intervals, placental expulsion periods, placental weight and vaginal delivery interval between lambs, hematological and biochemical results were not statistically different among the groups (p > 0,05). Increased NEFA and β-HBA concentrations accompanied the disease and all ewes in AG, DEX and PT Groups developed clinical pregnancy toxemia (NEFA; P = 0,009) and β-HBA; (P = 0,039). The differences in rectal body temperature of lambs were not significant (p > 0,05), whereas birth weight was found statistically significant among groups (p < 0,05). Blood pH, biochemical and hematologic measurements of lambs had also significant differences depending on different time points. Parturition pathology by means of incomplete cervical dilatation was severely observed in DEX Group.The results of this study show that aglepristone application in pregnancy toxemia to induce parturition could precisely control lambing time without any side effects in either mothers or lambs. Apart from these, it could be speculated that dexamethasone seems to induce parturition causing crucial pathologies, which results in important and risky changes in newborns’ life. Incomplete cervical dilatation and continued ineffective uterine contractions could be a major factor of newborn losses because of placental separation and cessation of blood supply.

Comparison of targeted selective and whole flock treatment of periparturient ewes for controlling Haemonchus sp. on sheep farms in Ontario, Canada

Haemonchosis is commonly associated with late gestation and parturition in ewes during the spring in Ontario, Canada. Due to widespread anthelmintic resistance, targeted selective treatment (TST) of ewes with closantel, an anthelmintic not previously available in Canada, at lambing was investigated as a potential strategy to manage haemonchosis in both ewes and lambs, while also maintaining parasite refugia (i.e., a population of parasites not exposed to anthelmintic). In a longitudinal pilot study in 2013 and 2014, six client-owned farms were randomly assigned as either whole treatment (WT) farms (n=3), where all the ewes were treated with oral closantel (10mg/kg) at lambing, or TST farms (n=3), where ewes were treated with oral closantel (10mg/kg) at lambing only if they met at least one of four criteria: a) the last grazing season was their first grazing season; b) body condition score ≤2; c) FAMACHA© score ≥4; and/or d) three or more nursing lambs. Pasture samples to assess larval burdens and fecal samples from a minimum of 20 ewes and 20 lambs on every farm were collected monthly during the grazing season (May-October). Additional anthelmintic treatments given by producers (either fenbendazole or ivermectin) and deaths attributable to parasitism were also recorded. Pre-treatment arithmetic mean Haemonchus sp. fecal egg counts (FECs) on each farm at the beginning of the study in May 2013, ranged from 506 to 2738 eggs per gram of feces. The number of animals treated on TST farms was reduced by as much as 47% compared to WT farms, and there was no significant difference between TST and WT farms in the proportion of additional treatments given by producers throughout the grazing season or the percentage of parasitism deaths reported. In the first year of the study, Haemonchus sp. larval burdens on pasture were generally higher on TST than WT farms at the beginning of the grazing season, but were not significantly different at the end of the grazing season. In the second year, there were no significant differences in Haemonchus sp. larval burdens on pasture between TST and WT farms throughout the grazing season. This study suggests that, under Ontario conditions, when TST indicators are able to accurately identify animals with high Haemonchus sp. FECs, TST of ewes at lambing can be employed to control Haemonchus sp. FEC in the flock, thereby maintaining refugia and delaying the onset of anthelmintic resistance.

Decrease in body surface temperature before parturition in ewes.

This study investigated the correlation between the body surface temperature (BST) and core body temperature of ewes and changes in BST during the prepartum stage in pregnant ewes. Four non-pregnant adult ewes were used in the first experiment. The BST of the upper neck, vaginal temperature (VT), and ambient temperature (AT) were measured every 10 min for seven days and analyzed for correlations. The mean (± SD) BST and VT of ewes during the study period were 35.4 ± 1.7°C and 39.1 ± 0.4°C, respectively, with a correlation of r = 0.62, P < 0.001. This finding suggested that the BST was associated with core body temperature in ewes. In the subsequent experiment, seven pregnant ewes in their third trimester were used to evaluate changes in BST measured at the upper neck 72 h before parturition. The mean BST at –24–0 h (0 h = time of parturition) was significantly lower than that at –72– –48 h and –48– –24 h (P < 0.05). The BST tended to decrease toward parturition; all BST measurements at –16– –3 h were significantly lower than those at –72 h (P < 0.05). A clear circadian rhythm in the BST was observed at two days and the day before parturition and an unclear circadian rhythm was observed on the day of parturition. Therefore, these findings indicate that the BST also decreases before parturition, as do vaginal and rectal temperatures.

Identification of effective treatment criteria for use in targeted selective treatment programs to control haemonchosis in periparturient ewes in Ontario, Canada

Haemonchosis is often associated with late gestation and parturition in ewes in Canada. Due to widespread concerns about development of anthelmintic resistance (AR), targeted selective treatment (TST), where individual animals are treated with an anthelmintic rather than the entire flock, is a possible strategy to control clinical signs in recently lambed ewes while still maintaining parasite refugia. Performing fecal egg counts (FEC) on individual animals is often cost-prohibitive, so indicators that identify ewes with high FEC are essential for TST programs. The study objectives were to: a) evaluate the ability of four TST indicators to identify periparturient ewes with high Haemonchus sp. FEC and b) determine appropriate treatment thresholds for statistically-significant indicators. A field study was conducted during the 2013 and 2014 lambing seasons (February-May) on three client-owned farms in Ontario with documented AR and problems with haemonchosis in ewes. Ewes were examined within three days of lambing and selected for treatment with oral closantel (10mg/kg body weight), a novel anthelmintic to Canada, if they met at least one of four criteria: a) the last grazing season was their first grazing season; b) body condition score ≤2; c) Faffa Malan Chart (FAMACHA©) score ≥3; and/or d) three or more nursing lambs. Fecal samples were collected per rectum on the treatment day from each of 20 randomly selected treated and untreated ewes on each farm. Haemonchus sp. percentages on each farm, as determined by coproculture, ranged from 53% to 92% of total fecal trichostrongyle-type egg counts. Mean Haemonchus sp. FECs were significantly higher in treated ewes (n=136) than in untreated ewes (n=103) on the day of treatment in both years (p=0.001), suggesting the indicators were suitable for identifying animals with high Haemonchus sp. FEC. A linear mixed model was fit with logarithmic-transformed Haemonchus sp. FEC as the outcome variable, the four indicators and year as fixed effects, and farm as a random effect. FAMACHA© score was the sole indicator to remain significantly associated with FEC (p=0.002). A receiver-operator curve determined that test sensitivity was maximized (92.4%) with FAMACHA© score ≥3 as the sole indicator. FAMACHA© score should therefore be included in TST programs to identify ewes requiring treatment at lambing due to Haemonchus sp.

Parturition induction in ewes by a progesterone receptor blocker, aglepristone, and subsequent neonatal survival: Preliminary results

The clinical effects of aglepristone treatment to induce parturition in ewes and their newborns were reported. Three experimental groups were defined: group AG5 (n = 5), group AG10 (n = 5), and group CG (n = 5) in which ewes were injected twice with 5, 10 mg/kg of aglepristone, and saline solution of ewes, respectively. Different parameters associated with parturition in ewes and their newborns were investigated. Serum progesterone, oxytocin, and free and conjugated total estrogens were measured after treatments until parturition. No statistical difference was found from first aglepristone administration to onset of lambing between AG5 and AG10 (23.90 ± 6.20, 40.00 ± 6.71 hours). Parturition induction in two groups shortened the gestational length significantly compared with the control group (P = 0.003). Dystocia was observed in two ewes in group AG10. The placental weight showed statistically significant difference only between the AG10 and CG (P = 0.039), but no difference was observed in the placental expulsion period between the groups. Decrease in food consumption 24 to 36 hours after parturition in all ewes and skin necrosis in an ewe in group AG5 were observed. Progesterone concentration was significantly lower in AG5 than that in ewes in group AG10 and CG (P < 0.05). No difference was observed in concentrations of free total estrogens and oxytocin between groups. The body temperature of lambs was significantly different between AG10 and CG groups both right after (P = 0.011) and 12 hours after parturition (P = 0.014). The lambs in CG had the highest mean birth weight (4.29 ± 0.28 kg), which was significantly different from the induced groups. No significant difference of blood pH and blood gases values between groups was identified both at birth and 12 hours after parturition for lambs. Significant differences could clearly be observed in total protein and blood urea nitrogen and total protein findings 12 hours after parturition (P < 0.05), whereas no difference was found in blood glucose, albumin, inorganic phosphor, triglyceride, or total cholesterol parameters. The results of this study show that the administration of aglepristone to induce parturition can precisely control lambing time without any side effects in either mothers or lambs.

Effect of Vitamin E and PMSG in Some Hematological and Biochemical Parameters before and after Parturition in Ewes

Effect of Vitamin E and PMSG in Some Hematological and Biochemical Parameters before and after Parturition in Ewes

Two treatment protocols for induction of preterm parturition in ewes—Evaluation of the effects on lung maturation and lamb survival

Lambs born prematurely are often unable to breathe due to pulmonary immaturity and a lack of surfactant production. Attempts to deliver live, moderately preterm lambs from critically ill ewes in late pregnancy are therefore often unsuccessful. The objective of this study was to evaluate the potential benefits of repeated administration of dexamethasone (DEXA) to final-stage pregnant ewes on subsequent perinatal lamb survival and respiratory and metabolic disorders associated with neonatal asphyxia. Two different treatment protocols with dexamethasone were used to induce parturition on days 137 and 138 of pregnancy (full term 149 days).In group LTP (long-term protocol, n=12) low doses of dexamethasone were administered repeatedly starting with 2mg once daily on days 130–133, followed by a single dose of 4mg on day 134. For the final induction of parturition 16mg of the drug were administered on day 135 and this dose was then repeated every 12h until lambing. In group STP (short-term protocol) 15 ewes received 16mg DEXA on day 135, followed by the same dose every 12h until lambing. The vitality and laboratory parameters of the lambs born to these dams were compared to lambs delivered by caesarean section (group CS) on day 147 or 148 of gestation whose dams (n=23) had received a single injection of 10mg dexamethasone 12h prior to surgery, and to lambs born naturally to 19 ewes at full term (group FT) after an average of 149 days of gestation.Lambs from groups LTP and STP were born between day 137 and 139 of gestation, showing characteristics of immaturity. Of 18 lambs in group LTP, 16 survived without critical care (88.9%; 95% confidence interval (CI)=67.2–96.9%). Group STP comprised 24 lambs, 18 of which survived without critical care (75%; 95% CI=55.1–88.0%). Out of 39 lambs in group CS, 37 survived (94.9%; 95% confidence interval (CI)=83.1–98.6%), and 27 of the 28 lambs in group FT, respectively (96.4%; 95% CI=82.3–99.4%). There was no statistically significant difference in the survival rates between the four groups. In all four groups there was a significant increase of pH, BE and HCO3− values within the first 24h post natum, and a significant decrease in pCO2(v) values.Compared to previous studies which indicated high mortality rates in moderately preterm lambs the results indicate that repeated exogenous administration of DEXA has a positive effect on the survival rates of lambs born after induced parturition at around 92% of the full pregnancy term.

Comparison of respiratory and metabolic disorders in lambs following different treatment protocols to induce preterm parturition in ewes

Comparison of respiratory and metabolic disorders in lambs following different treatment protocols to induce preterm parturition in ewes

Variation in colostral immunoglobulin G concentration in fat tailed sheep and evaluation of methods for estimation of colostral immunoglobulin content

In ruminants, colostrum is a vital source of immunoglobulins that provide passive immunity for their offspring during the neonatal period. It is suggested that colostral immunoglobulin G (IgG) concentration varies between and within breeds and could also be affected by maternal factors. The aim of this study was to investigate possible effects of litter type and ewe parturition number on colostral IgG concentration in two Iranian fat-tailed breeds of sheep (Shaul and Lori Bakhtyari) as well as usefulness of different methods for estimation of IgG concentrations in colostrum. The colostral IgG concentrations were measured in 38 Shaul and 59 Lori Bakhtyari ewes by single radial immunodiffusion, zinc sulphate turbidity and Biuret methods. Measurement of IgG by single radial immunodiffusion revealed that Lori Bakhtyari ewes had significantly (P &lt;0.05) lower colostral IgG levels (48.82 ± 2.10 mg/ml) than Shaul ewes (62.86 ± 2.48). With regard to the effect of litter type and parturition number, a significant (P &lt;0.05) difference in IgG concentration of colostrum was only observed between the first (65.17 ± 5.74 mg/ml) and third parturition (41.10 ± 4.60 mg/ml) of Lori Bakhtyari ewes. The colostral IgG concentration was not associated with ewe serum IgG concentration (P &gt;0.05). The mortality rate was higher in lambs born to ewes with lower IgG in their colostrum. Single radial immunodiffusion did not correlate either with zinc sulphate turbidity method (r = -0.253,P &gt;0.05) or with Biuret method (r = -0.005,P &gt;0.05). We can conclude that concentration of colostral IgG could be influenced by breed but not by litter type and parturition number.

Forage preservation (grazing vs. hay) fed to ewes affects the fatty acid profile of milk and CPT1B gene expression in the sheep mammary gland

BackgroundAlterations in lipid metabolism occur when animals are exposed to different feeding systems. In the last few decades, the characterisation of genes involved in fat metabolism and technological advances have enabled the study of the effect of diet on the milk fatty acid (FA) profile in the mammary gland and aided in the elucidation of the mechanisms of the response to diet. The aim of this study was to evaluate the effect of different forage diets (grazing vs. hay) near the time of ewe parturition on the relationship between the fatty acid profile and gene expression in the mammary gland of the Churra Tensina sheep breed.ResultsIn this study, the forage type affected the C18:2 cis-9 trans-11 (CLA) and long-chain saturated fatty acid (LCFA) content, with higher percentages during grazing than during hay feeding. This may suggest that these FAs act as regulatory factors for the transcriptional control of the carnitine palmitoyltransferase 1B (CPT1B) gene, which was more highly expressed in the grazing group (GRE). The most highly expressed gene in the mammary gland at the fifth week of lactation is CAAT/ enhancer- binding protein beta (CEBPB), possibly due to its role in milk fat synthesis in the mammary gland. More stable housekeeping genes in the ovine mammary gland that would be appropriate for use in gene expression studies were ribosomal protein L19 (RPL19) and glyceraldehyde- 3- phosphate dehydrogenase (GAPDH).ConclusionsSmall changes in diet, such as the forage preservation (grazing vs. hay), can affect the milk fatty acid profile and the expression of the CPT1B gene, which is associated with the oxidation of fatty acids. When compared to hay fed indoors, grazing fresh low mountain pastures stimulates the milk content of CLA and LCFA via mammary uptake. In this sense, LCFA in milk may be acting as a regulatory factor for transcriptional control of the CPT1B gene, which was more highly expressed in the grazing group.

Influence of the type of forage supplied to ewes in pre- and post-partum periods on the meat fatty acids of suckling lambs

The aim of this study was to evaluate the use of forage diets (grazing vs. hay) around the time of ewe parturition, on the fatty acids profile of suckling lamb meat (10–12kg body weight). Forty-eight multiparous single-bearing ewes were used. The experimental treatments were conducted during the last 5weeks of pregnancy and the 5weeks of lactation in a 2×2 factorial design. Ewes were fed ad libitum on pastures or hay in the autumn. Results showed that milk from grazing ewes during the pre-partum period had a higher content of PUFA and CLA (P<0.05) and VA, CLA in their suckling lambs' meat (P<0.05). The effect in post-partum feeding was greater, revealing higher CLA, PUFA/SFA, PUFA n-3 and PUFA n-6/n-3 in milk and meat (P<0.05). The CLA, VA and PUFA n-6/n-3 ratios are those that are most affected by grazing. Pre-partum grazing, regardless of post-partum feeding, improves FA composition, increasing CLA content in both milk and meat.

Does forage type (grazing vs. hay) fed to ewes before and after lambing affect suckling lambs performance, meat quality and consumer purchase intention?

The aim of the study was evaluate the use of forage diets (grazing pasture vs. hay) around ewe parturition on the performance and meat quality of suckling lambs (10–12kg body-weight). Forty-eight multiparous single bearing ewes from the Churra Tensina breed were used. The experimental treatments were conducted during the last 5 weeks of pregnancy (pre-partum period) and the 5 weeks of lactation (post-partum period) in a 2×2 factorial design. Ewes were fed ad libitum on mountain pastures or pasture hay. Hay was made in late spring from the same pasture paddocks to those grazed in autumn. Results showed that ewes body-weight (BW) and body condition score (BCS) were not affected by forage type feed around ewe parturition. The week post-partum had a more determinant effect on milk production and composition than forage type pre- and post-partum. The energy-corrected milk yield peaked on first week of lactation (1.39l/day, P<0.05), and decreased significantly from week 3 post-partum onwards (1.29l/day vs. 1.02l/day, P<0.05). Forage type supplied to ewes during the pre-partum period did not affect any of the studied variables on lambs. During post-partum period forage type had effect on lamb ADG, which was higher in grazing system than in hay feed (259g/day vs. 220g/day). Consequently, age at slaughter was greater in lambs raised by ewes receiving hay post-partum compared to grazing ewes (36 days vs. 32 days, P<0.05). Caudal fat colour was affected only by post-partum forage type, showing grazing group greater redness, yellowness and absolute value of the integral of the translated spectrum (SUM) than that forage type (P<0.05). Carcasses from lambs raised by post-partum grazing ewes led to a muscle with lower lightness and yellowness and greater redness than hay forage type (P<0.05). Lambs whose dams grazed presented a higher visual appraisal score at cutting time, however these differences disappeared as time advanced. Grazing forage had a positive effect on consumer purchasing decision (P<0.10). In conclusion, forage type in pre-partum period did not affect the studied parameters whereas ewes grazing on mountain pastures after autumn-lambing improved lamb performance without any detrimental effect on carcass and instrumental meat quality.

Polwarth and Texel ewe parturition duration and its association with lamb birth asphyxia12

The objective of the present study was to test the hypothesis that parturition duration is related to birth asphyxia in lambs and that asphyxia affects newborn lamb viability and vigor. Two sire and dam genotypes (Texel: TX; Polwarth: PW) and their crosses were represented in the study. Eighty lambs (25 PW sire × PW dam, 13 TX × TX, 25 TX × PW, and 17 PW × TX) born to 69 grazing ewes were used. At birth, the log₁₀ length of the second stage of parturition, birth weight, placental weight, and several body measurements were recorded on all lambs, and jugular blood samples were analyzed with the i-Stat Portable Clinical Analyzer (Abbott, Montevideo, Uruguay). A modified Apgar viability score at birth and lamb behavior during their first hour of life were recorded. Brain weight, muscle:bone ratio, and bone density were recorded in 20 male lambs (5 from each breed group) that were euthanized and dissected 24 h after birth. Data were analyzed by linear regression, least squares ANOVA, and ordinal and binary logistic regressions. Mean blood gas and acid-base variables were 7.21 ± 0.09 for pH, 18.4 ± 9.8 mmHg for partial pressure of oxygen, 53 ± 12.5 mmHg for partial pressure of carbon dioxide, and -4 ± 5.1 mmol/L for extracellular fluid base excess. Parturition duration increased with birth weight (P < 0.001) and was shorter in TX ewes (P < 0.001), female lambs (P < 0.05), twins (P < 0.09), and twin females (sex × litter size interaction, P < 0.02). Twenty-six (32.9%) lambs were born asphyxiated (pO₂ < 10 mmHg or pH <7.1). Parturition duration increased the risk of asphyxia (P < 0.001), decreased the viability score (P < 0.001), and increased the latency to suckle the udder (P < 0.05). Twin-born lambs presented at birth a 16-fold greater risk of asphyxia (P < 0.01) and reduced placental efficiency (P < 0.05). Texel-sired lambs appeared immature at birth, with less bone density (P < 0.05), smaller brain (P < 0.05), shorter forelimbs (P < 0.05), greater anterior (P < 0.001) and posterior (P < 0.05) neck circumference, and greater muscle:bone ratio (P < 0.05). Immaturity may explain greater TX biotype survival. Together these results demonstrate that a relationship exists between parturition duration, neonatal viability and behavior, and acid-base balance values in single- and twin-born lambs, suggesting that birth asphyxia is an important risk factor in perinatal lamb mortality.

Passive immune transfer in fat-tailed sheep: Evaluation with different methods

Passive immune transfer is the only way to provide protection in neonate ruminants. As it is suggested to be affected by both maternal and neonatal factors in different breeds, we tried to investigate possible effects of sex, litter type, ewe parturition number and birth weight on it and also on the immunoglobulin concentration during the first month of life in a fat-tailed sheep. Total immunoglobulin and IgG concentrations of 39 Shaul lambs were measured at days 3, 15 and 30 by quantitative zinc sulfate turbidity and serum radial immunodiffusion tests, respectively. To determine different serum protein concentration, cellulose acetate electrophoresis was applied. Sex, litter type, ewe parturition number and birth weight had no significant effects on passive transfer. Moreover, these factors had no impact on IgG catabolism and serum protein concentrations during the first month of life. Passive immune transfer in Shaul breed does not seem to be affected by sex, litter type, ewe parturition number and birth weight.

Plasma and Amniotic Fluid Nitric Oxide Level and Adenosine Deaminase Activity in Sheep

Atakisi, O., Atakisi, E., Pancarci, S.M. and Ozcan, A. 2009. Plasma and amniotic fluid nitric oxide level and adenosine deaminase activity in sheep. J. Appl. Anim. Res., 35: 197–199. The objective of this study was to determine nitric oxide (NO) levels and adenosine deaminase (ADA) activities in plasma of pregnant (10) and non-pregnant (10) ewes and amniotic fluid at parturition in ewes. Plasma ADA activity was highest in pregnant ewes (P<0.001), whereas, NO level was highest in amniotic fluid. This is the first study to report ADA activities and NO levels in amniotic fluid of healthy pregnant ewes at parturition. The future studies are warranted to clarify the role of ADA activities and NO levels in amniotic fluid in relation to pregnancy and parturition.

Perinatal visceral events and brain mechanisms involved in the development of mother–young bonding in sheep

In sheep the onset of maternal responsiveness and the development of the mutual mother–young bond are under the combined influence of hormonal and visceral somatosensory stimulations. These stimuli are provided in the mother by parturition (via steroids and vaginocervical stimulation) and in the neonate by the first suckling episodes (via cholecystokinin and oro-gastro-intestinal stimulation). In addition, each partner relies on specific chemosensory stimulation for reciprocal attraction: amniotic fluids for the mother, colostrum for the young. In the ewe parturition activates several brain structures to respond specifically to sensory cues emanating from the young. The main olfactory bulbs undergo profound neurophysiological changes when exposed to offspring odors at parturition. Additional activations in the hypothalamus – preoptic area – and the amygdala – medial and cortical nuclei – also contribute to maternal responsiveness and memorization of lamb odors. In the neonate, post-ingestive stimulations activate the brain stem via vagal afferents. Like in the ewe, several regions of the hypothalamus and the amygdala respond to colostrum ingestion suggesting common ground for the integrative neural processes involved in early learning and bonding. This leads to rapid visual and auditory recognition in both partners although olfaction remains important in the ewe to display selective nursing. It is concluded that the biological basis for the development of maternal and filial bonding in sheep presents striking similarities.

Induction of parturition in ewes

Induction of parturition in ewes