Age Of Ewe Research Articles

Pregnancy-associated changes in plasma concentration of the endocrine disruptor di(2-ethylhexyl) phthalate in a sheep model

The plasticizer di(2-ethylhexyl)phthalate (DEHP), used for producing polyvinyl chloride (PVC), acts as an endocrine disruptor with toxic effects on reproductive and developmental processes. Exposure to DEHP in humans is mainly by environment and food. Thus, our aim was to determine plasma levels in livestock animals using the ewe ( Ovis aries) as a model. In a first trial, 150 samples from ewes of different ages (2 to 7 yr) and reproductive status (pregnant and nonpregnant) were analyzed by high-performance liquid chromatography (HPLC). DEHP was detected in 34.7% of the samples, with a mean level of 0.45 ± 0.01 μg/mL (range, 0.05 to 2.81 μg/mL). The percentage of nonpregnant animals with DEHP traces was higher in animals older than 4 yr (n = 66, 37.9%) than in younger animals (n = 69, 17.4%; P < 0.05), although the mean levels in ewes with residues were similar (0.16 ± 0.01 vs. 0.16 ± 0.02 μg/mL). All the pregnant ewes (n = 15) showed presence of DEHP, with higher plasma levels than that in nonpregnant females (1.42 ± 0.18 vs. 0.16 ± 0.01 μg/mL; P < 0.0001). For confirming the effect of pregnancy on mobilization of DEHP from body fat, 101 ewes of the same age were sampled in a second trial at a different farm. The percentage of animals with DEHP traces was higher in pregnant ewes (n = 32, 71.9%; P < 0.005) than in nonpregnant ewes (n = 37, 35.1%) or in ewes that recently gave birth (n = 32, 21.9%), although mean levels were similar (0.42 ± 0.02, 0.33 ± 0.02, and 0.34 ± 0.05 μg/mL, respectively). In conclusion, current results indicate a high incidence of ewes reared in the field showing accumulation of phthalates; percentage of animals with presence of DEHP increases with age, due to an extended period of exposure, but mainly during pregnancy, due to the mobilization of body reserves.

Factors influencing variation of fatty acid content in ovine milk

Between January 2006 and December 2007, a total of 4,579 test-day observations for contents of milk fatty acids (FA) were obtained from 2,218 lactations of 1,109 ewes belonging to 14 Churra dairy flocks. The 36 analyzed FA were quantified as grams per 100g of total FA and were grouped as 18 dependent variables: 10 FA, 6 groups of FA, and 2 FA indexes. Flock, day of testing within flock (TD), ewe age, stage of lactation, and season effects contributed significantly to variations in FA. The 2 most important variation factors were flock (3 to 30% of total variance) and TD (35 to 70% of total variance). The percentage of variance explained by the TD effect for conjugated linoleic acid (CLA, C18:2 cis-9, trans-11) and linolenic acid (C18:3 cis-9, cis-12, cis-15) was particularly high: 60.7 and 68.2%, respectively. The season effect was also a very important variation factor, closely linked to feeding. The most significant seasonal variations were observed in polyunsaturated FA, with the highest values occurring in spring and summer and the lowest in winter. More specifically, CLA and linolenic acid contents were 44 and 30% higher in spring-summer than in winter. As the age of the ewe increased, the monounsaturated and polyunsaturated FA decreased and the short- and medium-chain saturated FA increased. The CLA and the CLA/C18:1 trans-11 Δ9-desaturase index increased significantly throughout lactation. The correlation coefficient between rumenic acid (CLA) and vaccenic acid was high (0.47) because of the precursor-product relationship via the Δ9-desaturase enzyme. The correlation coefficients were high between C10:0 and C12:0 (0.79), C12:0 and C14:0 (0.73), and C14:0 and C16:0 (0.29), probably because of their similar metabolic origin. Positive correlations were also obtained among the C18 FA family. All the studied factors of FA variation would be considered as fixed effects in the statistical models used for estimation of genetic and phenotypic parameters from test-day records of commercial flocks.

Genetic analysis of ewe stayability and its association with lamb growth and adult production

Records from 2,525 adult Targhee ewes and 10,099 lambs were used to estimate genetic parameters in an animal model for ewe stayability (STAY), productive life (PL), adult BW (AW) and BCS, fleece characteristics, and number of lambs born (NLB) and for lamb BW at birth and approximately 45 d, 120 d (120W; weaning), 12 mo, and 18 mo of age. Stayabilities were analyzed as overall stayability (STAYn|2), which indicated presence or absence of a ewe at n yr of age, given that she was present at 2 yr of age, or marginal stayability (STAYn|n-1) recording the presence of a ewe at n yr of age, given that she was present in the previous year. Productive life was measured as the age of ewe in years at her last lambing. Lamb BW were corrected for age at weighing; BW taken at or before weaning were adjusted for effects of type of birth and rearing, age of dam, and sex using National Sheep Improvement Program methods. The NLB was likewise adjusted for effects of ewe age before analysis. Birth year was included as a fixed effect for all traits. Year of record and, for AW and CS, the number of lambs born or born and reared were also included in models for adult traits. Models for all traits included random additive genetic and residual effects. Random maternal genetic and dam permanent environmental effects were also included in the model for lamb (pre)weaning BW, and random permanent environmental effects of the ewe were included in models for adult traits. The heritability estimate for PL was 0.05 (P < 0.10). Additive variance in STAY was only present after 5 yr of age (P < 0.05), with estimated heritabilities ranging from 0.04 to 0.10. Phenotypic correlations between STAY and other traits were near zero, ranging from -0.07 to 0.14. Estimates of genetic correlations of STAY5|4 and STAY6|2 with maternal genetic effects on 120W were positive (both 0.46; P < 0.05), suggesting that STAY and maternal effects on 120W both reflect genetic variation in ewe fitness characteristics. Genetic correlations between STAY5|4 and 120W, AW, and NLB were not different from zero (0.06, 0.13, and -0.06, respectively; P > 0.10). However, genetic correlations between STAY6|2 and 120W, AW, and NLB were all negative, with values of -0.17, -0.32 (P < 0.05), and -0.03, respectively, indicating a possible small antagonism between STAY and genetic effects on body size.

Phenotypic and genetic associations between lamb growth traits and adult ewe body weights in western range sheep

Data from the Montana State University Targhee flock were used to estimate genetic and environmental relationships between lamb BW and adult ewe BW, condition score, and prolificacy. The flock was managed under commercial western range conditions typical of the area. Data included records from 12,154 lambs born to 2,930 dams and 200 rams between 1960 and 2005. Lamb traits included BW at birth and approximately 45 d, 120 d (weaning), 12 mo, and 18 mo of age and fleece characteristics at 12 mo of age. Adult traits included ewe litter size; BW and BCS at weaning, in late gestation, and in early lactation; and adult fleece measurements. Multiplicative factors were used to adjust (pre)weaning lamb BW for effects of age of dam, type of birth and rearing, and lamb sex and to adjust adult litter sizes for effects of ewe age. An animal model was used to estimate genetic relationships. Models for lamb traits included fixed effects of year of birth and, for postweaning data, lamb sex and random additive genetic effects and, for (pre)weaning BW, additive genetic maternal and permanent environmental maternal effects. Models for adult traits included fixed effects of year of birth, year of record, and, when appropriate, numbers of lambs born or born and reared and random additive genetic and animal permanent environmental effects. Heritability estimates for lamb birth weight, 45-d BW, weaning weight, yearling weight, 18-mo BW, fleece weight, staple length, and spinning count were 0.19, 0.07, 0.12, 0.32, 0.38, 0.32, 0.31, and 0.25, respectively. Maternal heritabilities for lamb birth, 45-d, and weaning weights were 0.15, 0.09, and 0.08, respectively. Heritability estimates for adult traits were 0.12 for litter size, averaged 0.43 for BW and 0.13 for body condition, and were 0.44, 0.37, and 0.25 for adult fleece weight, staple length, and spinning count, respectively. Correlations between genetic effects on adult BW and direct and maternal genetic effects on lamb BW ranged from 0.21 to 0.96 (P < 0.05) and 0.29 to 0.53 (P < 0.05), respectively, with residual correlations ranging from 0.05 to 0.95. Correlations of lamb traits with adult body condition and number of lambs born were generally not different from zero; genetic and residual correlations ranged from -0.52 to 0.69 and -0.39 to 0.31, respectively.

EVALUATION OF TEST-DAY MILK YIELD FOR AWASSI EWES

Data were collected from 83 Awassi ewes raised on to two flocks during the lambing season (2003-2004). The first flock belongs to private farmers, at Al-Nahrawan region, 5 Kms to the west of Mosul city, whereas the second flock belongs to the General Directorate of Applied Agriculture Researches (Animal Husbandry Station of Mosul). 750 and 614 records of test – day of milk yield and fat percentage, respectively, were used in this study. Data were subjected to statistical analysis using by General Linear Model (GLM) to study the effect of fixed factors on milk yield and fat percentage, to find the correlation coefficients between variables studied and prediction equations of total milk yield . The overall mean of TDMY (Test Day Milk Yield) and fat percentage were 569.824 g, %4.461 respectively. The effects of flock, age of ewe, stage of lactation were significant (p < 0.01) on TDMY. However, the effect of sex of lamb was not significant . All the non-genetic factors studied had significant effect (p < 0.01) on fat percentage. Repeatability estimates for TDMY and fat percentage were 0.481, 0.273 respectively.

The fertility of ram sperm held for 24 h at 5 °C prior to cryopreservation

Diluted ram sperm can be held for 24 h at 5 °C prior to cryopreservation without impacting cryosurvival rates, however, the effects this storage has on subsequent fertility are unknown. These studies were conducted to evaluate the fertility of semen held for 24 h (to mimic shipping semen to a cryopreservation center), prior to freezing. Semen from Suffolk rams ( n = 3 in experiment 1 and n = 6 in experiment 2) with initial motility of greater than 70%, were diluted to 200 × 10 6 sperm/mL, in one step, with a Tris–egg yolk–glycerol diluent. In experiment 1, diluted samples were cooled to 5 °C over 2 h, and then divided. Sperm in one fraction were loaded into 0.5 mL straws, frozen (T0) and stored in liquid nitrogen until thawing. Sperm in the second fraction were held at 5 °C for 24 h (T24) before being frozen. In experiment 2 ejaculates were collected and divided into two fractions. Sperm in one fraction were treated with cholesterol-loaded cyclodextrin (CLC) and sperm in the other served as control. Both fractions were diluted, cooled, and cryopreserved as described in experiment 1. Stage of the estrous cycle was synchronized in ewes ( n = 196) using controlled internal drug releasing devices (CIDR) for 12 d and at CIDR removal each ewe was administered PMSG (500 IU in experiment 1 and 350 IU in experiment 2) immediately before insemination. Ewes were stratified by age and randomly assigned to one of the semen treatments; experiment 1: Fresh (F), T0, or T24; experiment 2: F, T24, or CLC, and inseminated laparoscopically 56 h after CIDR removal. Differences in fertility were detected between experiments, but not for treatments within experiments. Differences in fertility were also observed due to ewe age, with the 3-year-old ewes having the greatest fertility (50.7%) and 6-year-old ewes having the least fertility (9.6%; P < 0.05). Differences in the prolificacy rates due to semen treatment were also observed but differences due to ewe age were not detected. Therefore, sperm can be held at 5 °C for 24 h prior to cryopreservation without altering sperm fertility.

Non-genetic factors affecting reproductive traits in Lohi sheep

The data on breeding and performance records (3830) of 1134 Lohi ewes kept at an Institutional Livestock Experiment Station, Okara in Punjab province during the period from 1972 through 2001 were used to study the influence of some non-genetic factors such as year and season of birth/lambing, age and weight at first service sex of lamb born, birth type, age of dam on various reproductive traits. The age of ewes at first service averaged 615.6±8.2 days and was not significantly affected by the year and season of birth of the ewes. The ewes born during spring season had comparatively low (613.6±7.9 days) age at first service than autumn born (617.5±9.8 days). The type of birth did not significantly influence age at first service. The least squares mean for the weight at first service was 42.10±0.24 kg and was significantly (P<0.01) influenced by the ewe's year and season of birth. The spring-born ewes were heavier (42.3±0.3 kg) at first service than autumn-born ewes (41.9±0.3 kg). The weight at first service was also significantly affected by the age at first service. The type of birth did not significantly influence weight at first service. The number of services per conception averaged 1.29±0.03 and varied significantly (P<0.01) between seasons. The number of services per conception was higher (1.37±0.02) in ewes bred during autumn than those bred in spring (1.16±0.06). The effects of years and weight at service on the number of services per conception were non-significant. The number of services per conception significantly increased with advancing age. Mean gestation period was 152.31±0.08 days and it was significantly affected by the years and seasons of lambing and the age of the ewe at lambing. However, gestation length was not significantly affected due to birth type and sex of the lamb born.

Evaluation of the influence of melatonin implants during the gestation period in sheep from a selenium-deficient region

To evaluate the possible effect of melatonin implants on blood glutathione peroxidase (GSHPx) activity and in the prevention of selenium (Se)-responsive disorders in sheep from an Se-deficient region. Randomized controlled clinical trial. 100 Merino ewes. Ewes of the same age, parity, body weight, body condition, and reproductive and health history were randomly allotted to 1 of 2 groups (control and implanted) of 50 sheep each. Treatment consisted of implants of melatonin (18 g) administered SC in the pinna of the right ear 6 weeks prior to introduction of rams. The control group did not receive implants. Hematologic and serum biochemical analyses were performed at various points before and after treatment, in addition to determinations of erythrocyte mean corpuscular fragility (MCF) and blood GSHPx activity. The incidence of Se-responsive disorders in lambs was recorded in both groups. Hematologic and serum biochemical analyses yielded values within respective reference ranges for both groups. Significant differences between groups were evident in MCF at early mating (lower in the implanted group vs the control group) and in blood GSHPx activity at early mating, gestation, and early lambing (higher in the implanted group vs the control group). There were significantly fewer lambs with nutritional myodystrophy in the implanted versus the control group. Use of melatonin implants in sheep may improve reproductive performance and yield an earlier start of breeding season. The stimulating effect of melatonin on GSHPx activity may protect against oxidative damage during the first stage of gestation.

Lambing season and fertility of fat-tailed ewes under an extensive production system are associated with liveweight and body condition around mating

The objective of this study was to investigate to what extent fertility and lambing season of fat-tailed ewes raised under an extensive production system are related to liveweight, body condition and changes around mating. Ewe liveweight and body condition score (BSC) were recorded in June, July and August over a period of 3 years (1999–2001) in 11 flocks (eight flocks of Kurdi breed and three flocks of Kurdi × Sanjabi crossbred). Both Kurdi and Sanjabi are native fat-tailed breeds in western Iran. In total, 3278 lambing records relating to 1592 ewes and data on mating date, liveweight and BCS of 1930 ewes (3975 records) were used for statistical analyses. The statistical model for bodyweight and body condition data included fixed effects of breed group, flock nested within breed group, year, the future lambing status following summer breeding (barren, autumn lambing and winter lambing), ewe age and all two-way interactions. Breed group had a significant effect on ewe liveweight (P &lt; 0.01). However, there was no significant difference between BCS of the two breed groups around mating. Ewe liveweights measured in June, July and August had significant effects on fertility and lambing season (P &lt; 0.01). Ewes that produced lambs were generally heavier at mating than barren ewes (P &lt; 0.01). Autumn-lambing ewes were heavier than winter-lambing ewes in June and July (P &lt; 0.01). Effects of changes in liveweight on fertility and lambing season were significant (P &lt; 0.01). The effects of BCS in June, July and August (P &lt; 0.01) and changes in BCS during the mating period (P &lt; 0.05) on fertility and lambing season were also significant. The mean BCS (in June and July) of autumn-lambing ewes was greater than that of the winter-lambing and barren ewes (P &lt; 0.05). The proportion of autumn-lambing ewes significantly increased as BCS in July increased, whereas the proportion of barren ewes decreased (P &lt; 0.01). Fertility was associated with age so that as the age of the ewes increased from 2 to 7 years, the proportion of barren ewes significantly decreased from 29 to 5% (P &lt; 0.01). There was a relatively high proportion of very thin ewes of 2 and 3 years of age. These findings imply that low body condition is a particular problem in younger ewes suggesting the importance of giving special nutritional treatment to younger ewes to reduce the proportion of barren ewes.

Phenotypic and genotypic analysis of a barebreech trait in Merino sheep as a potential replacement for surgical mulesing

The potential for adopting a genetic solution to protect sheep from blowfly strike on the breech was investigated in a flock of sheep that contained several animals expressing a trait characterised by low wool coverage over the breech and through a wide channel from the anus to the udder or scrotum. A scoring system (1, bare to 5, woolly) was developed and used to determine the heritability of the trait and its phenotypic and genetic correlations with other traits of importance in a sheep enterprise. In comparison to animals with woolly breeches, the skin in the breech of animals with a low bareness score was characterised by a low density of follicles producing short, medullated fibres, with histological evidence of immune rejection and follicular atrophy. The bareness score of progeny was influenced by the score of their respective sires suggesting a strong genetic component. The heritability of bareness score was moderate to high (h2 = 0.45 ± 0.02, 0.53 ± 0.01 and 0.38 ± 0.02 at lamb, hogget and adult ages, respectively). The lactation status and age of ewes influenced their bareness score, resulting in a low repeatability (0.42) of the trait between ages in females. Genetic correlations between bareness score and most other economically important traits were low. The weight of belly wool and the weight of skirtings was genetically related to bareness score (rg = +0.52 and +0.48 respectively), indicating that animals with barer breeches tend genetically towards lighter belly wool weights and lower weight of skirtings at wool classing. Selection and breeding for bareness score should achieve relatively rapid progress towards fixing the trait in a flock and without adverse effects on other important traits. Caution should be exercised in extrapolating these results to other bloodlines and environments where genetic mechanisms or environmental influences may be different.

Flock dynamics of desert Barki sheep in relation to age structure

Reproduction data of 8689 ewe records spread over 40 years (from 1960 to 2000) representing 2952 breeding Barki ewes were used in this study. The flock belonged to the Desert Research Center in Egypt. Flock dynamics of nine age groups (2-10 yrs) were assessed. Two parameters were used to evaluate flock dynamics, net reproduction rate (R(o)) (number of ewe- lambs reaching joining age and produced by each ewe during its lifetime in the flock) and intrinsic rate of increase (r(m)) (flock growth when no resource is limiting). Age of ewe had a highly significant (P < 0.01) effect on number of ewes lambing per ewe joined (E(PJ)), number of lambs born per ewe joined (L(BJ)), number of lambs weaned per ewe joined (L(WJ)) and number of ewe lambs reaching joining age per ewe joined (L(EJ.J)). All estimates tended to increase with dams age up to four years and decreased thereafter. The results of R(o) and r(m) showed that the studied flock must consist of 5 age groups to maintain its size and replace itself. It may be recommended to cull the breeding ewe at the age of 6 years to accelerate genetic improvement.

Ovine progressive pneumonia provirus levels associate with breed and Ovar-DRB1

Previous studies initiated defining the role of host genetics in influencing the outcome of exposure to ovine progressive pneumonia virus. However, specific genes influencing host control of virus replication and disease progression have not been identified. This study, using 383 ewes of the Columbia, Polypay, and Rambouillet breeds, tested the hypothesis that host control of OPPV as measured by provirus levels in the peripheral blood associates with certain breeds and MHC class II Ovis aries (Ovar)-DRB1 expressed alleles. Rambouillet ewes were less likely to have measurable provirus levels as compared to Columbia ewes at ages 5 and 6 (P value < 0.02), and they exhibited lower provirus levels when compared to both Columbia and Polypay ewes of the same ages (P value < 0.05). The presence of DRB1*0403- or DRB1*07012-expressed alleles were significantly associated (P value = 0.019 and 0.0002, respectively) with lower OPP provirus levels but only were only found in 11% of the ewe flock. Analysis of each segregating amino acid in the beta1 domain of DR beta-chain revealed that amino acids Y31, T32, N37, T51, Q60, or N74 significantly associated (P value range = 0.0003-0.018) with lower OPP provirus levels, whereas amino acids H32, A38, or I67 associated (P value range = 0.013-0.043) with higher OPP provirus levels. These results suggest that Ovar-DRB1 contributes as one host genetic factor that controls OPP provirus levels, but does not fully account for the breed-specific OPP proviral differences.

The estimation of variance components for prolificacy and growth traits of Sakız sheep

The aim of the current study was to investigate the fix effects which are considered to influence ewe prolificacy, growth traits and to estimate genetic parameters for fertility, litter size at birth (LSB) and litter size at weaning (LSW), survival rate (SR), birth weight (BW), weaning weight (WW), yearling weight (YLW), average daily gain from birth to weaning (ADG) of Sakız sheep. Data and pedigree information of Sakız sheep used in this study were collected at the Marmara Animal Livestock Research Institute from 2001 to 2008. Estimates of genetic parameters were obtained by the use of DFREML package programs. The material ewe was classified according to birth year (8), age of ewe at lambing (6). The lamb material was classified year, age of dam, birth type and sex. The effects of years and ages of ewe were not significant for fertility ( P > 0.05), litter size at birth (LSB), but the year effect was significant for LSW ( P < 0.05). The effects age of ewes, sex and birth types of lambs were significant ( P < 0.05, P < 0.01 and P < 0.001) of birth weight (BW), weaning weight (WW), yearling live weight (YLW) and average daily gain (ADG) of Sakız sheep. Estimates of heritability were 0.035 for LSB, 0.189 for LSW, 0.163 for survival rate, 0.188 for BW, 0.174 for WW, 0.148 for YLW and 0.251 for ADG, respectively.

Determinants and life-history consequences of social dominance in bighorn ewes

Studies of social rank in female ungulates consistently suggest that dominance increases with age, perhaps because dyadic relationships are established early in life, when the older female is always larger than the younger one. This relationship then remains unchanged, even if for fully grown adults size and age are not correlated, suggesting that typically female ungulates normally gain little from being dominant. In contrast, social interactions among 64 marked known-age bighorn sheep ewes (Ovis canadensis) over 3 summers at Ram Mountain, Alberta, Canada, suggest that the effect of age on social rank weakened substantially for ewes older than 6 years. Mass was strongly related to rank for ewes age 7 years and older, whereas horn size had no effect on dominance. Once they reach asymptotic mass, bighorn ewes appear to challenge older but lighter females to whom they were formerly subordinate. Although these results suggest that bighorn ewes may benefit from high social rank, we found no effect of rank on reproductive success, lamb sex ratio or lamb birth date.

Effects of pre-mating nutrition on mRNA levels of developmentally relevant genes in sheep oocytes and granulosa cells

The present study was designed to investigate the relationship between pre-mating nutrition and the relative amounts of a panel of developmentally relevant genes in ovine oocytes and granulosa cells. Cast age ewes were fed a ration providing 0.5x (0.5 M) or 1.5x (1.5 M) live weight maintenance requirements for 2 weeks before slaughter. The ewes were synchronized and superovulated with FSH and pregnant mares serum gonadotropin. At slaughter, oocytes and granulosa cells were aspirated from follicles >2 mm in diameter and the relative abundance of 8 and 17 transcripts in oocytes and granulosa cells respectively were analyzed by semi-quantitative RT-PCR. In the oocytes, no differences between groups were observed for five transcripts (GDF9, BMP15, c-kit, glucose transporter 1 (SLC2A1), and hexokinase 1), but a lower amount of glucose transporter 3 (SLC2A3), sodium/glucose cotransporter 1 (SLC5A1), and Na(+)/K(+) ATPase mRNAs was detected in the 0.5 M group. Increased expression of PTGS2, HAS2, and the leptin receptor long form was observed in granulosa cells from the 0.5 M group. No differences between groups were observed for the other transcripts (early growth response factor-1, estrogen receptor-alpha, LH and FSH receptors, gremlin 1, pentraxin 3, KIT ligand, glucose transporters 1, 3, and 8, IGF1, IGF1 receptor, leptin receptor, and tumor necrosis factor-stimulated gene 6). Expression of leptin and sodium/glucose cotransporter 1 was not detected in both groups. The present data indicate that pre-mating nutrition is associated with alteration in the mRNA content in oocytes and surrounding follicle cells in ewes, which may account for the reduced reproductive performance typical of ewes that are fed a restricted ration for a short period of time before mating.

An Abattoir Study on Hepatic Tumors of Sheep

The aim of the present study was to assess the incidence and age distribution of hepatic tumors of sheep as well as study of their histopathologic characteristics. For this purpose, 3000 slaughtered sheep, consisting of 284 rams with approximate age of 7 to 20 months and 2716 ewes with approximate age of 3 to 7 years, were inspected during a routine postmortem examination. This study was conducted at Tabriz abattoir in the East Azerbaijan province of Iran, in a course of 8 months from March to November 2006. In this survey, two livers were encountered tumoral. Representative sections of the tumors were stained with hematoxylin and eosin. Gross and microscopic features of these tumors supported diagnosis of hepatocellular carcinoma and cholangiocellular carcinoma for a seven-years-old crossbreed ewe and a five-years-old native breed ewe respectively. In this survey, 0.074% of slaughtered ewes had hepatic neoplasia. That is, the prevalence of hepatocellular carcinoma and cholangiocellular carcinoma in aged ewes was equally 0.037% in this study.

Effect of willow supplementation upon plasma amino acid concentration in ewes grazing drought pastures of low nutritive value

Effects of supplementing willow stem cuttings to ewes grazing drought pastures upon plasma amino acid (AA) concentrations was studied on Massey University's Riverside Farm, near Masteron, on the East Coast of New Zealand. Ewes of similar age and weight ( i.e., 59.0 ± 2.22 kg) were assigned to two groups of 7 each, either with (supplemented) or without (control) supplementation of willow, and experimental grazing was carried for 10 weeks from early February until mid April of 2005. Live weight (LW) was recorded fortnightly and body condition score (BCS) was monthly. Blood samples for quantification of plasma amino acids were collected at week 5 and 10. Both groups had a similar pre-grazing pasture mass ( i.e., 2000 kg of dry matter/ha) and dead matter content (0.80) with the diet selected by the ewes containing a metabolisable energy (ME) of 8.3 MJ/kg DM, which is typical of drought conditions. The willow was readily eaten, with intake averaging 0.26 kg DM/ewe/d. Willow was of higher ME content than short drought pasture ( i.e., 10.1 versus 8.4 MJ/kg DM) and contained condensed tannins at 40.8 ± 1.97 g/kg DM. Both groups of ewes lost live weight at about 50 g/d. Plasma concentration of 3-methyl histidine (88 versus 127 μmol/L) at week 5 and non-essential amino acids (1082 versus 1417 μmol/L) at week 5 and (1155 versus 1324 μmol/L) at week 10, were substantially lower ( P<0.05) in willow supplemented versus control ewes, indicating that willow supplementation reduced catabolism of body proteins in ewes under drought feeding conditions.

Performances en croisement et facteurs de variation des ovins Beni Guil au Maroc. I. Caractères de reproduction de la brebis et de viabilité et de croissance pré-sevrage des agneaux

Les performances de reproduction des brebis, de viabilité et de croissance des agneaux ont été analysées pour les années 1994 à 1998 sur 484 brebis et 461 agneaux issus de l’accouplement de la race Béni Guil en race pure et en croisement avec les béliers de race D’man, Ile-de- France et Lacaune, à la station expérimentale El Koudia de l’Inra. Les résultats ont montré que la race du bélier a eu un effet très significatif sur la fertilité, le poids de la portée et les performances pondérales de la naissance au sevrage, mais elle n’a eu aucune influence significative sur la taille de la portée et la viabilité des agneaux à la naissance et au sevrage. La race Beni Guil a réalisé des performances moindres, excepté pour les caractères de fertilité et de viabilité des agneaux. Les croisements de la brebis Beni Guil avec les béliers Ile-de-France et Lacaune ont donné les meilleurs poids, gains de poids et productivité pondérale. L’âge de la brebis et l’année de naissance n’ont pas eu d’effet significatif sur les caractères de reproduction, à l’exception du poids de la portée à 90 jours. A tout âge, les agneaux nés simples et de sexe mâle ont réalisé une croissance supérieure à celle des femelles. L’année de naissance a eu un effet important sur les performances pondérales des agneaux. Il a été conclu que le croisement avec les béliers Ile-de-France et Lacaune améliore la productivité pondérale par brebis au Maroc.

Biomechanical comparison of the pullout properties of external skeletal fixation pins in the tibiae of intact and ovariectomised ewes

The pin-bone interface is the least stable component of the external skeletal fixator. Concerns exist regarding the ability to obtain adequate implant purchase in poor quality bone. Consequently, reduced bone quality has been viewed as a contra-indication for the use of external skeletal fixators. The aim of this study was to investigate the holding power of two different fixator pin designs in bone from entire and ovariectomised sheep. Thirty-two aged ewes were divided into two groups. Group 1 were controls, and Group 2 were ovariectomised (OVX). The ewes were sacrificed 12 months post-ovariectomy and five pairs of tibiae were harvested from each group. The holding power of cortical and cancellous fixator pins was assessed at five standardised locations on each tibia. An increase in mean cortical thickness was noted in the OVX group. The holding power of cancellous fixator pins was superior to that of cortical pins, irrespective of whether or not ovariectomy had been performed. Cancellous pins had an increased holding power in post ovariectomy bone compared to control bone. Cortical pin performance was not affected by ovariectomy. There was a lack of correlation between the incidence of insertional fractures of the far cortex and implant holding power. The results raise questions over the effectiveness of ovariectomy in establishing osteopaenic bone suitable for assessing implant performance, hence further investigations are warranted.

Study on Influence of Environmental Effect on Birth Weight, Weaning Weight and Daily Growth of Baluchi Sheep

This study investigates different environmental effects on birth and weaning weight and daily growth of Baluchi lambs. For this purpose, we analyzed 10680 records that collection within a period of 21 years (1983-2003) in Abbasabad Sheep Breeding Station, located in northeast of Mashhad, Iran. Three different statistical models with considering effects of flock, litter size, sex, ewe age in parturition, lamb age in weaning weight and their interaction were used for parameters measurement. Except for effect of flock on weaning weight and daily growth, other effects were significant (p<0.01). For statistical analyses SAS software was used and coefficients of determination (R ) and coefficients of variance (CV) were estimated 2 0.47 and 12.88 for birth weight, 0.54 and 16.43 for weaning weight, 0.44 and 19.62 for daily growth, respectively. Male lambs in comparison with female lambs and single-born lambs in comparison with multiple-born lambs had higher birth weight and daily growth, however, effect of litter size on birth and weaning weights was higher in young ewes.