Shorn Ewes Research Articles

Intra- and Inter-sample Variation in Wool Cortisol Concentrations of Australian Merino Lambs Between Twice or Single Shorn Ewes

Stress in Merino sheep can cause a reduction in the quantity and quality of fine wool production. Furthermore, it has been found that environmental stress during pregnancy can negatively affect the wool follicles of the developing fetus. This study was part of a larger field investigation on the effects maternal shearing frequency on sheep reproductive and productivity outcomes. For this study, we investigated the intra- and inter- sample variation in wool cortisol levels of weaner lambs. We conducted two experiments, the first was to determine the intra- and inter- sample variation in wool samples taken from the topknot of weaned lambs, and the other aim was to determine any difference between maternal shearing treatment (single or twice shearing) on absolute wool cortisol levels of weaned lambs. In the first experiment, topknot wool was collected from 10 lambs, and each sample was further divided into four subsamples, leading to a total of 40 wool subsamples. For the second experiment, we collected the topknot from the 23 lambs produced by the shearing frequency treatment ewes (once or twice shorn). The samples were then extracted and analyzed using a commercially available cortisol enzyme-immunoassay in order to determine the concentration of cortisol in each of the samples. Statistical analysis for the first experiment showed that there was no significant difference between the subsamples of each topknot wool sample taken from each lamb (p = 0.39), but there was a statistical difference between samples (p < 0.001), which was to be expected. In the second experiment, there was a significant difference between the lambs born to the one shearing and two shearing treatments (p = 0.033), with the lambs of the twice sheared ewes having higher average wool cortisol levels [2.304 ± 0.497 ng/g (SE); n = 14] than the ones born to once shorn ewes [1.188 ± 0.114 ng/g (SE), n = 8]. This study confirms that the topknot wool sampling can be a reliable method adapted by researchers for wool hormonal studies in lambs. Second, ewes shorn mid-pregnancy gave birth to lambs with higher cortisol concentrations than ewes that remained unshorn during pregnancy. This result warrants further investigation in a controlled study to determine if maternal access to nutrition (feed and water) may impact on the HPA-axis of lambs.

Interplay Between Stress and Reproduction: Novel Epigenetic Markers in Response to Shearing Patterns in Australian Merino Sheep (Ovis aries).

In this study, we determined the effect(s) of early shearing on Australian Merino ewes (Ovis aries) and their lambs. To test this research question, we used a suite of field and laboratory methods including GPS collars, wool cortisol, and epigenetic change between ewes and lambs identified using Illumina NovaSeq RRBS. Once shorn ewes (n = 24) were kept on their full fleece throughout the entire gestation period, whereas twice (early) shorn ewes (n = 24) had their wool shorn pre-joining. Top-knot wool sample was taken from ewes during pre-joining, day 50 (mid-gestation), and day 90 (late gestation) for laboratory analysis. Ewes were pregnancy scanned at mid-gestation to determine whether they were early or late parturition (this confirmation is provided by the pregnancy scanner based on fetus size). Top-knot wool sample was also taken from the lambs at weaning for hormone and wool quality testing. Ear tissue was taken from ewes at day 50 (mid-gestation) and from lambs at lamb marking for DNA analysis. Results showed that twice or early shorn ewes grazed 10% higher and maintained stronger body condition than once shorn ewes. Wool cortisol levels were also significantly lower in the early shorn ewes between mid- and late gestation. Lambs bred from twice shorn ewes had on average better visual wool quality parameters in terms of micron, spin finesses, and curvature. For the DNA methylation results, when comparing a group of once sheared with twice sheared ewes, we have discovered one locus (Chr20:50404014) that was significantly differentially methylated [False Discovery Rate (FDR) = 0.005]. This locus is upstream of a protein-coding gene (ENSOARG00000002778.1), which shows similarities to the forkhead box C1 (FOXC1) mRNA using BLAST searches. To further our understanding of the potential interaction between pregnancy status and shearing frequency of the ewes, we performed further differential methylation analysis using a combination of shearing treatment and pregnancy scanning status. The comparisons (1) late pregnancy vs. early pregnancy for ewes with one shearing treatment and (2) late pregnancy vs. early pregnancy for sheep with two shearing treatments were carried out to identify associations between loci and pregnancy duration for sheep with either one or two shearing events. We discovered that 36 gene loci were significantly modulated either between different shearing treatments or late vs. early pregnancy status of ewes. This result suggests that maternal pregnancy and nutritional status during gestation influence DNA methylation. We further investigated DNA methylation in lambs and identified 16 annotated gene loci that showed epigenetic modulation as a result of being born from an early or late stage pregnancy. From the genomics data, we pointed out that ewes go through epigenetic modifications during gestation, and there is a degree of intra-individual variation in the reproductive performance of ewes, which could be due to combination of intrinsic (genetic and physiological) and extrinsic (management and climatic) factors. Collectively, this research provides novel dataset combining physiological, molecular epigenetics, and digital tracking indices that advances our understanding of how Merino ewes respond to shearing frequency, and this information could guide further research on Merino sheep breeding and welfare.

Acute Stress Response of Sheep to Shearing Procedures: Dynamic Change of Cortisol Concentration and Protein Electrophoretic Pattern.

Simple SummaryFarm animals are daily subjected to a wide range of abiotic stressors. Shearing, one practice of routine management procedures, is applied periodically to harvest sheep’s wool. During shearing, short-term acute stress is likely to occur. This study aimed to evaluate the change in hematological parameters, serum cortisol concentration and serum protein electrophoretic pattern in Comisana sheep following shearing procedures. The findings obtained in the current study suggest a linkage between the endocrine and immune systems and an acute phase response during the shearing procedure.The current study aimed to investigate the influence of acute stress by shearing procedures on hematological parameters, serum cortisol concentration and serum protein electrophoretic pattern in Comisana sheep. A total of 20 not pregnant and not lactating adult ewes, aged 3–4 years old and with a mean bodyweight of 55.50 ± 3.50 kg, were enrolled in the study. From each animal, blood samples were collected before shearing (TPRE) and 5 (TPOST5) and 60 (TPOST60) minutes after the end of the shearing procedure in order to assess the values of hematological parameters, serum cortisol, total proteins and protein fractions, including albumin, α-, β1-, β2- and γ-globulins. According to statistical analysis results, albumin values were lower at TPOST60 than TPOST5 (p < 0.01), whereas α- and β2-globulins and the A/G ratio were higher at TPOST60 with respect to TPRE (p < 0.01) and TPOST5 (p < 0.01). A higher serum concentration of cortisol was found at TPOST5 and TPOST60 than TPRE (p < 0.01), and at TPOST60 than TPOST5 (p < 0.01). The serum cortisol values were negatively correlated with the serum values of albumin, β1-globulins and A/G ratio at TPOST60, and positively correlated with α- and β2-globulins at TPOST5 and TPOST60. The decrease in the albumin concentration and the increase in the α- and β2-globulins observed in ewes after shearing with respect to the baseline values suggests an acute phase response in shorn ewes. Additionally, the correlation found between the serum cortisol concentration and the serum protein fractions confirmed the immunomodulatory effect of this hormone, emphasizing the linkage between the endocrine and immune systems during an acute stress condition.

Effect of early shearing during gestation on the performance of the progenie

Research has shown the interesting contributions of shearing during mid or late gestation on the performance of lambs from birth to weaning. However, there is no information on the effects of shearing in the first third of pregnancy, on the well-being and productivity of the offspring in adult life. The aim of this study was to investigate whether shearing during the first third of gestation, in a critical time window for the development of the placenta and the fetus, can influence the live weight at parturition, weaning and the survival of the lambs. Additionally, it was studied whether shearing in the first third of gestation is capable of programming metabolic and physiological modifications in the fetus that affect the growth, health and reproductive performance in the adult life of the offspring. Shearing in the first third of gestation significantly increased birth weight of single lambs (P = 0.004) and twins (P = 0.05). The higher weaning weight (P &lt; 0.0001) was related to the higher daily live weight gain (P ˂ 0.0001) in birth-weaning period. The extension of the gestation period (P &lt; 0.0001) explained only 56% and 87% (single and twins) of the increase in total live weight at lambing. Twin lambs from prepartum shorn ewes attempted (P = 0.004) and succeeded in suckling earlier (P = 0.0004) than control lambs. The greater vigor at lambing, together with the greater weight at weaning, may explain the higher (P = 0.04) survival rate. Early prepartum shearing did not affect live weight of ewe lambs from weaning to 18 months old. However, the gastrointestinal parasite egg counts per gram of fecal matter (P = 0.07), as well as the Famacha index (P = 0.02) were significantly lower than in controls. Prepartum shearing affected live weight of male lambs (P = 0.02), although there were no differences in the response to the parasitic challenge. Prepartum shearing did not affect any of the reproductive variables studied in ewes and male lambs. The results of this thesis show that shearing in the first third of gestation is a technique capable of affecting the productive performance of the offspring in the short and long term.

Mid- and late-pregnancy ewe shearing affects lamb neonatal reactivity and vigour

Poor lamb survival is an important production and welfare issue, and the lamb must express complex behaviours to successfully transition to life ex-utero. Even under best management practices, sheep husbandry events, such as shearing, yarding and transport can be stressful for animals, and when they take place during pregnancy these stressors could possibly impact the neonate as well as the dam. This study examined the effects of some of the common stressors produced by shearing during pregnancy on neonatal lamb behaviour. Pregnant ewes were either subjected to shearing/cold stress or were handled (sham treatment), during mid- or late-pregnancy (four groups, n = 15 per group). Shorn ewes were wetted using sprinklers on three occasions the week following shearing to exacerbate the effect of cold. Neonatal lamb behaviour was assessed using a separation test and observance of lamb vigour related measures: Latency-to-Bleat; Latency-to-Stand; and Return-to-Ewe times, before and after a cold challenge at 4 °C of 1 h duration. Overall, lambs born to ewes shorn during pregnancy displayed higher Latency-to-Bleat than control lambs (P = 0.04). Mid-pregnancy shearing resulted in shorter Latency-to-Bleat than mid-pregnancy control treatment (P = 0.03). When shearing treatment was applied during late-pregnancy, lamb Return-to-Ewe time was higher than for lambs from ewes treated during mid-pregnancy which was in turn shorter than for control lambs (P = 0.006 & P = 0.04). Regardless of treatment groups, single lambs exhibited higher Latency-to-stand than twin lambs (P = 0.02). Lambs reacted faster and had shorter latencies to display behaviour after a cold challenge than before (P = 0.004). It seems that prenatal stress due to shearing of ewes during pregnancy adversely impacted neonatal behaviours but improved the behavioural responses of lambs after a cold stress challenge. Overall, shearing of ewes during pregnancy affected neonatal lamb behaviour and responses to cold challenge; however, the effects varied depending on litter size and timing of shearing. Differences between treatment groups and particularly between different timing of the stress treatment suggest there may be different mechanisms impacting on neonatal behaviour. Exposure to physiological stressors during pregnancy may improve resilience to these specific stressors. Further work is required to understand the underlying mechanisms leading to the observed changes in lamb behaviour.

Effect of early shearing during gestation on the productive and reproductive behavior of female sheep offspring in their first 18 months of age

The research has shown the interesting contributions of shearing in mid-gestation on the performance of lambs from birth to weaning. Other studies have reported that shearing at early pregnancy influences the development of the placenta and lamb live weight at birth. However, there was a lack of information on the effect of early-prepartum shearing on the behavior of the offspring from weaning onward. This study evaluated the effect of shearing ewes at 50 days of gestation on the growth, reproductive behavior and response to a gastrointestinal parasite challenge in the female offspring from weaning to 18 months old. Fifty-seven Polwarth female lambs were used, 22 being singles and 35 twins born to ewes either shorn at 50 days of pregnancy (PS, n = 23) or shorn at 62 days postpartum (U, control, n = 34) resulting in four subgroups: single lambs born to PS ewes (n = 8), born to U ewes (n = 14), twin lambs born to PS ewes (n = 15) or born to U ewes (n = 20). All progeny were managed together under improved pasture with a minimum forage allowance of 6% live weight on dry basis. Body weight, body condition score and fecal eggs count were recorded every 14 days from weaning to 18 months of age. Concentrations of progesterone were measured weekly (from 4 to 10 months of age and from 14 to 18 months of age) to establish the onset of puberty. Ovulation rate at an induced and a natural heat (545 ± 1.0 and 562 ± 1.0 day old) was recorded. Prepartum shearing did not affect the age at puberty or the ovulation rate of female offspring, but those born as singles were more precocious ( P = 0.03) and heavier ( P = 0.02) at puberty than twin born lambs. Both the average value of parasite egg count ( P = 0.0 7) and the Famacha index ( P = 0.02) for the entire study period were lower in lambs born to prepartum shorn ewes than those born to postpartum shorn ewes. In conclusion, shearing at 50 days of gestation did not affect the growth or the reproductive behavior of female offspring. However, female lambs born from ewe shorn during gestation showed a better response to the parasitic challenge, and further research is required to confirm this.

Effect of shearing on some physiological and hormonal parameters in Akkaraman sheep.

ObjectiveShearing is one of the practices that is applied periodically to fiber producing animals, which can also alter resistance of animals to high temperatures in especially summer months. This study aimed to investigate effects of shearing on some physiological and hormonal parameters in Akkaraman sheep during summer season.MethodsThis study was carried out on 39 non-pregnant Akkaraman ewes (aged 1.5 years at the beginning of experiment). The 39 ewes were chosen randomly from the flock belonging to the Erciyes University and they were assigned to two groups as follows: i) group A (n = 20) designed as the control group, they were shorn and group B (n = 19) designed as the experimental group, they were unshorn. Prior to the shearing (−1 day) and on days 1, 7, 15, 30, 45, 60, 75, and 90 following the shearing, blood samples were taken from the vena jugularis of each sheep. Cortisol, β-endorphin, growth hormone (GH), thyroxine (T4), triiodothyronine (T3), and heat shock protein 70 (HSP-70) concentrations were determined using the enzyme immunoassay method. Body weight (BW), rectal temperature (RT), pulse rate (PR), and respiratory rate (RR) of each sheep were recorded at the same time. The data obtained were analyzed using two-way repeated measures analysis of variance.ResultsStatistical analysis showed a significant effect of shearing×period interaction (p< 0.01) and a significant effect of period (p<0.01) on BW, HSP-70, cortisol, T4 and RT, PR, GH, β-endorphin, T3, respectively. Also these analysis showed no significant effect of shearing× period interaction or period on RR.ConclusionThe results showed that the thermoregulation abilities of sheep were affected by shearing treatment and the shorn ewes were less affected by heat stress. In conclusion, based on the data of this study, shearing can be considered as a necessary management practice that requires protection for sheep from the effect of heat stress.

Behavioural and physiological changes in pregnant ewes after winter shearing

Our aim was to characterize the behavioural and physiological changes provoked by winter shearing of late pregnant ewes. Twelve ewes were shorn at 120 days of gestation, and the remaining 12 ewes remained unshorn as controls. The frequency in which animals were standing, lying down, and grazing, and the distance to the closest member of the group were recorded from Day -3 to Day -1 (shearing = Day 0), from Day 1 to Day 5, and on Days 13 and 20-21. The blood total protein, albumin and globulin concentrations were also determined in blood samples collected immediately before shearing, and on Days 10, 15 and 22. Shearing pregnant ewes triggered behavioural changes, such as decreased time allocation to resting and greater allocation to standing and grazing than controls possibly reflecting an increased consumption. The time allocated to grazing increased after shearing and remained higher than controls until the end of the study. During the first two days after shearing ewes were more dispersed probably due to difficulties in recognizing flock-mates. Total protein concentration was slightly greater in shorn ewes.

Time of shearing the ewe not only affects lamb live weight and survival at birth and weaning, but also ewe wool production and quality

ABSTRACTDuring a four-year period, mature ewes were either shorn in mid-pregnancy or post-partum to study impacts on lamb live weight and survival. Furthermore, placental measurements were collected post-partum from a subset of single-bearing ewes and yearly fleece weights and wool samples were collected from a subset of single- and twin-bearing ewes. Lambs born to ewes shorn in mid-pregnancy were heavier (p < .05) and displayed greater (p < .05) survival than those born from post-partum shorn ewes regardless of litter size. Shearing treatment had no effect (p > .05) on the weight of the placenta, and diameter or the weight of the cotyledons. However, the number of cotyledons was greater (p < .05) in mid-pregnancy than post-partum shorn ewes. Ewes shorn in mid-pregnancy produced lighter (p < .05) fleeces with greater (p < .05) yields. The fleece displayed shorter (p < .05) staple length, stronger staple strength (p < .05), and was less (p < .05) bright with poorer (p < .05) colour than those shorn in post-partum.

Infrared thermal imaging as a method to evaluate heat loss in newborn lambs

Thermal imaging technology has been identified as a potential method for non-invasive study of thermogenesis in the neonatal lamb. In comparison to measurement of the core body temperature, infrared thermography may observe thermal loss and thermogenesis linked to subcutaneous brown fat depots. This study aimed to identify a suitable method to measure heat loss in the neonatal lamb under a cold challenge. During late pregnancy (day 125), ewes were subjected to either shearing (n=15) or mock handling (sham-shorn for 2min mimicking the shearing movements) (n=15). Previous studies have shown an increase in brown adipose tissue deposition in lambs born to ewes shorn during pregnancy and we hypothesized that the shearing treatment would impact thermoregulatory capacities in newborn lambs. Lambs born to control ewes (n=14; CONTROL) and shorn ewes (n=13; SHORN) were subjected to a cold challenge of 1h duration at 4h after birth. During the cold challenge, thermography images were taken every 10min, from above, at a fixed distance from the dorsal midline. On each image, four fixed-size areas were identified (shoulder, mid loin, hips and rump) and the average and maximum temperatures of each recorded. In all lambs, body surface temperature decreased over time. Overall the SHORN lambs appeared to maintain body surface temperature better than CONTROL lambs, while CONTROL lambs appeared to have higher core temperature. At 30min post cold challenge SHORN lambs tended to have higher body surface temperatures than lambs (P=0.0474). Both average and maximum temperatures were highest at the hips. Average temperature was lowest at the shoulder (P<0.05), while maximum temperatures were lowest at both shoulder and rump (P<0.005). These results indicate that lambs born to shorn ewes maintained their radiated body surface temperature better than CONTROL lambs. In conjunction with core temperature changes under cold challenge, this insight will allow us to understand whether increased body surface temperature contributes to increased overall heat loss or whether increased body surface temperature is indeed a mechanism contributing to maintenance of core body temperature under cold challenge conditions. This study has confirmed the utility of infrared thermography images to capture and identify different levels of thermoregulatory capacity in newborn lambs.

Short term repeatability of body fat thickness measurement and body condition scoring in sheep as assessed by a relatively small number of assessors

This study evaluated the intra-observer repeatability of the rump fat thickness (RFT) measurements by ultrasound and body condition scoring (BCS) in sheep, and the reproducibility of RFT and BCS determined i) by six investigators, ii) at different sites (left and right, lumbar and sternal) and iii) in unshorn and shorn sheep. Six investigators with different experience in estimating body condition score in sheep determined BCS and RFT repeatedly at the different sites in 65 ewes before and after shearing. Intra-observer repeatability was greater for repeated measurement of RFT left (r=0.83 and r=0.84, in unshorn and shorn sheep) than RFT right (r=0.64 and r=0.77, resp.). A lower repeatability for measuring the sternal fat thickness (SFT) in unshorn sheep (r=0.31) indicates that this method is not feasible to score ewes. The correlation between fat thicknesses determined at different sites (RFT left, RFT right, SFT) and in unshorn and shorn sheep revealed a generally higher reproducibility of RFT measurements left and right (r=0.63–0.76) compared with the reproducibility of RFT and SFT (r=0.37–0.79). Repeatability and reproducibility varied between investigators and in unshorn and shorn sheep. The repeatability for measuring BCS lumbar in unshorn and shorn sheep was greater (κ=0.73 and κ=0.67, resp.) than for determining BCS sternal (κ=0.01 and κ=0.44, resp.) and varied between investigators and in unshorn and shorn ewes. Reproducibility of lumbar and sternal BSC determined by the six investigators was poor to fair in unshorn and poor to moderate in shorn ewes. In summary, measuring RFT or BCS at a sternal site cannot be recommended. Furthermore, taking measurement on shorn seep improved reproducibility. Based on these results, the assessment of RFT or BCS in sheep has the greatest repeatability in the lumbar region. It has to be noted that this study analyzed the repeatability but not the accuracy of the described methods.

Reduced Cortisol and Metabolic Responses of Thin Ewes to an Acute Cold Challenge in Mid-Pregnancy: Implications for Animal Physiology and Welfare

BackgroundLow food availability leading to reductions in Body Condition Score (BCS; 0 indicates emaciation and 5 obesity) in sheep often coincides with low temperatures associated with the onset of winter in New Zealand. The ability to adapt to reductions in environmental temperature may be impaired in animals with low BCS, in particular during pregnancy when metabolic demand is higher. Here we assess whether BCS affects a pregnant animal's ability to cope with cold challenges.MethodsEighteen pregnant ewes with a BCS of 2.7±0.1 were fed to attain low (LBC: BCS2.3±0.1), medium (MBC: BCS3.2±0.2) or high BCS (HBC: BCS3.6±0.2). Shorn ewes were exposed to a 6-h acute cold challenge in a climate-controlled room (wet and windy conditions, 4.4±0.1°C) in mid-pregnancy. Blood samples were collected during the BCS change phase, acute cold challenge and recovery phase.ResultsDuring the BCS change phase, plasma glucose and leptin concentrations declined while free fatty acids (FFA) increased in LBC compared to MBC (P<0.01, P<0.01 and P<0.05, respectively) and HBC ewes (P<0.05, P<0.01 and P<0.01, respectively). During the cold challenge, plasma cortisol concentrations were lower in LBC than MBC (P<0.05) and HBC ewes (P<0.05), and FFA and insulin concentrations were lower in LBC than HBC ewes (P<0.05 and P<0.001, respectively). Leptin concentrations declined in MBC and HBC ewes while remaining unchanged in LBC ewes (P<0.01). Glucose concentrations and internal body temperature (Tcore) increased in all treatments, although peak Tcore tended to be higher in HBC ewes (P<0.1). During the recovery phase, T4 concentrations were lower in LBC ewes (P<0.05).ConclusionEven though all ewes were able to increase Tcore and mobilize glucose, low BCS animals had considerably reduced cortisol and metabolic responses to a cold challenge in mid-pregnancy, suggesting that their ability to adapt to cold challenges through some of the expected pathways was reduced.

Effects of shearing, ambient cooling and feeding with byproducts as partial roughage replacement on milk yield and composition in Assaf sheep under heat-load conditions

Information is lacking in the literature on the effects of ambient cooling in combination with shearing and replacement of roughage with highly digestible byproducts on milk production in Assaf ewes. Two experiments were conducted in two sequential summer seasons. Experiment 1 measured the effects of sheep shearing and of shearing+ambient cooling during late pregnancy and lactation on lamb weight and milking performance of mature Assaf ewes. Experiment 2 measured the effects of altered dietary regime and its combination with shearing+cooling on milking performance of Assaf mature and first-lambing ewes. Experiment 1 demonstrated that ambient cooling under heat-load conditions decreases the temperature humidity index (THI) in the sheep barn by 3.8 units, and reduces lactating ewes’ respiratory rate and rectal temperature relative to non-cooled ewes. Cooling of shorn ewes during late pregnancy increased lamb weight at birth relative to the non-sheared non-cooled (control) group. Effect of cooling shorn ewes was reflected in an 8.4% increase in intake, followed by a 7.4 and 9.7% increase in yields of milk and energy-corrected milk (ECM), respectively, as compared with the non-cooled ewes. The positive effect of shearing+cooling continued after termination of cooling at 80d in milk. In Experiment 2, feeding the experimental diet to mature ewes increased intake, and yields of milk and ECM, and the dietary effect was complementary to the cooling effect. In first-lambing ewes, the diet increased milk and ECM production under the non-cooling, but not the cooling regime.

Impact of shearing on body weight and serum total proteins in ewes

The aim of the present study was to evaluate the influence of shearing ewes during summer season on the evolution of body weight and serum total proteins. Forty Valle del Belice (Sicily, Italy) ewes, clinically healthy and well-fed, were divided into two groups of 20 subjects each. Twenty ewes were let unshorn as a control group (Group A) and 20 ewes were shorn (Group B). All animals were weighed using a mechanical balance in the morning before shearing and the measurements were repeated for each subject of Groups A and B after shearing (1 day) and after 7, 15, 30, 45, 60, 75 and 90 days from the shearing. In experimental days climatic conditions were recorded and temperature humidity index was calculated. Blood samples were collected by means of a jugular venipuncture and were centrifuged; and the obtained sera were separated to assess serum concentration of total proteins. Two-way repeated measures analysis of variance (ANOVA), followed by the Bonferroni’s test, was used to determine significant differences between two groups for body weight and total proteins. ANOVA did not show a significant effect of shearing and of time on body weight but showed a statistical significant effect of shearing and of time on total proteins. These confirm that shearing induces adaptive responses in the organism. Both shorn and unshorn ewes are subject to heat stress, but it is evident there is a different sensitivity to heat stress in shorn ewes in comparison with unshorn ewes.

A Text with Teeth: Augustine’s Exegesis of Song of Songs 4:2 as Paradigm of His Hermeneutics

In the second book of his treatise on scriptural interpretation, On Christian Doctrine, Augustine introduces the theme of the obscurity of some biblical texts with a quotation from the notoriously difficult Song of Songs: ‘‘Your teeth are like a flock of shorn ewes coming up from the washing, which all give birth to twins, and there is not one among them that is barren’’ (4:2). Unsurprisingly, he finds references to baptism and the double commandment of love of God and neighbour. What strikes a modern reader is Augustine’s unembarrassed use of violent imagery to describe how the saints cut off errors and then chew the newly converted until they are soft for digestion by the Church. In later texts, Augustine will advert to the violence of biblical imagery to emphasize the necessity of transformation into the likeness of God and to reinforce the eschatological hope of the Church. This paper will examine the role of difficulty and obscurity in Augustine’s understanding of the process by which Scripture forms and orients its readers to prepare them for the vision of heaven.

The effect of different types of stressors during mid- and late pregnancy on lamb weight and body size at birth

Mid-pregnancy shearing has consistently been shown to increase lamb birth weight, which can lead to an increase in lamb survival rates. However, shearing ewes during the winter months and under outdoor pastoral farming conditions can expose the recently shorn ewe to a greater risk of hypothermia. The aim of this study was to determine if exposure of ewes to repeated stressors, in mid- and late pregnancy, would result in an increase in lamb birth weight. This information may assist in the elucidation of the mechanism for the birth weight response to mid-pregnancy shearing, which in turn could assist in the design of management options to increase lamb birth weight without placing the ewe at risk. One hundred and forty-four twin-bearing Romney ewes were allocated to one of six mid-pregnancy treatments: control, isolation on 2 or 10 occasions, sham-shearing on 10 occasions, intramuscular cortisol injection on 10 occasions or shearing. Isolation, sham-shearing and cortisol treatments were conducted twice a week beginning, on average, day 74 of pregnancy and shearing occurred on day 76. During pregnancy, ewe treatment had no effect on ewe live weight. However, average ewe body condition scores were higher in the shorn group than in the sham-shorn or cortisol groups (P < 0.05). Intramuscular injections of cortisol had a greater effect on ewe plasma cortisol concentrations than all other treatments (P < 0.05). Shearing produced a greater plasma cortisol response than isolation × 10 and sham-shearing (P < 0.05). Ewe plasma cortisol responses decreased during the 5 weeks of isolation and sham-shearing but cortisol injections produced a greater response during the fifth treatment than the first or ninth treatments (P < 0.05). Lambs born to shorn ewes were heavier and had a longer crown rump, forelimb and hind limb lengths than all other lambs (P < 0.05). In addition, lambs born to ewes in the cortisol treatment were lighter than lambs born to control, isolation × 2, isolation × 10 and shorn ewes (P < 0.05). The plasma cortisol concentrations observed for ewes injected with cortisol were far greater than those observed in all other groups, which is likely to explain the low birth weights of lambs born to ewes in that group. These results indicate that the mechanism by which mid-pregnancy shearing increases lamb birth weight is unlikely to be repeated stressors.

Effects of shearing at housing, grass silage feed value and extended grazing herbage allowance on ewe and subsequent lamb performance

The study involved 120 crossbred ewes (sixty 1.5 years old animals and sixty 2.5 years old animals; initial liveweight 67.6 kg, condition score 3.7), that were mated in October. They were assigned to six treatments (two shearing treatments (shorn and unshorn) × two silage feed values (low and medium) and two extended grazed herbage allowances (1.0 and 1.8 kg dry matter (DM)/day)) designed to evaluate the effects of shearing at housing, grass silage feed value and extended-grazed herbage allowance on their performance and the performance of their progeny. Swards, which had silage harvested on 6 September, received fertiliser N (34 kg/ha) for extended (deferred) grazing between 19 December and lambing in mid-March. The herbage was allocated at DM allowances of 1.0 or 1.8 kg/ewe daily until 1 February. For the final 6 weeks of pregnancy, daily herbage DM allowances were 1.5, 1.6, 2.0, 2.0 and 2.0 kg for weeks 6, 5, 4, 3 and 2 to parturition, respectively. Two grass silages (low and medium feed value) were offered from housing on 19 December to lambing in mid-March. At housing, half the ewes were shorn whilst the remainder remained unshorn. Each ewe received 23.4 kg concentrate prior to lambing. For the extended-grazed herbage and the low and medium feed-value silages, DM concentrations were 132, 225 and 265 g/kg, and metabolisable energy (ME) concentrations were 10.0, 10.0 and 10.7 MJ/kg DM, respectively. Treatment did not alter (P > 0.05) litter size or number reared. Grass silage feed value did not significantly alter silage DM intake, or ewe and subsequent lamb performance. Increasing herbage allowance in mid-pregnancy decreased herbage utilisation (P < 0.05) and increased herbage intake (P < 0.05). Shearing increased silage intake (P < 0.05), lamb birth weight (P < 0.01) and tended to increase lamb weaning weight (P = 0.07). Relative to the housed shorn ewes, extended grazing did not alter (P > 0.05) ewe or subsequent lamb performance. It is concluded that shearing ewes at housing increased lamb birth weight due to increased silage intake probably associated with cold stress immediately post shearing and reduced heat stress in late pregnancy. Based on differences in lamb weight at weaning 0.8 kg of grass silage DM intake had the same feed value as a daily extended herbage DM allowance of 1.8 kg per ewe throughout the study. Neither silage feed value nor herbage allowance in mid-pregnancy affected lamb birth weight or subsequent growth rate.

The effect of mid-pregnancy shearing and litter size on lamb birth weight and postnatal plasma cortisol response

The study was conducted to determine the effect of mid-pregnancy shearing on lamb birth weight, body dimensions and postnatal plasma cortisol response to a stressor. Fetal exposure to excess maternal glucocorticoids at specific stages of pregnancy may influence postnatal function of the hypothalamic-pituitary-adrenal (HPA) axis. This in turn may have implications on the growth, development and survival of lambs. Romney ewes of various ages, bearing singletons ( n = 47) or twins ( n = 48) were shorn or not (control) on day 80 of pregnancy. Ewes were managed as a single flock throughout pregnancy under general commercial farming conditions. Within 12 h of birth the lamb's live weight and body dimensions were recorded. On day 39 of lactation the plasma cortisol levels of the ram lambs in response to handling or castration was assessed. A random sample of ram lambs born to the control (6 singleton and 9 twins) or shorn (7 singleton and 11 twins) ewes were allocated to either a handling or castration treatment. Singleton and twin lambs born to shorn ewes were 7% heavier at birth than their counterparts. Lambs born to ewes shorn in mid-pregnancy recorded longer ( P < 0.05) crown rump (53.1 cm versus 51.7 cm) and forelimb (30.8 cm versus 30.0 cm) measurements than the counterparts born to control ewes, respectively. However, when the lamb's live weight was considered in the model these differences were not significant. Mid-pregnancy shearing had no effect on the cortisol response of singleton or twin-born ram lambs to handling or castration. The postnatal plasma cortisol response of twin lambs was higher ( P < 0.05) than that of singletons (30.8 mmol l −1 min versus 14.4 mmol l −1 min), regardless of the treatment. Mid-pregnancy shearing resulted in increased lamb live weights and body dimensions in both singleton and twin lambs at birth—while plasma cortisol response of lambs to handling or castration was unaffected. These data suggest that mid-pregnancy shearing had little effect on HPA axis development in singleton or twin offspring and the increase in lamb birth weight caused by mid-pregnancy shearing did not result in altered postnatal HPA function.

The effect of mid- and late-pregnancy shearing of hoggets on lamb birthweight, weaning weight, survival rate, and wool follicle and fibre characteristics

Pregnancy shearing of mature ewes has been shown to influence lamb birthweight and sometimes lamb survival to weaning and wool follicle characteristics. However, the effects of shearing hoggets in mid- or late-pregnancy under New Zealand’s pastoral conditions have not been examined. This study was designed to determine the effects of mid- and late-pregnancy shearing on lambs born to Romney hoggets. Single-bearing hoggets were either shorn at average day 79 of pregnancy (n = 74), at average day 119 (n = 80), or left unshorn (n = 76) while their twin-bearing counterparts were either shorn at average day 79 of pregnancy (n = 18) or left unshorn (n = 12). Mid-pregnancy shearing was found to increase the birthweights of singles (by 0.32 kg, P &lt; 0.05) in comparison with unshorn ewes; however, this relationship was not observed in twins. Neither mid- nor late-pregnancy shearing affected lamb survival to weaning. Singles born to late-pregnancy shorn ewes had whiter wool (P &lt; 0.05) in comparison with lambs born to unshorn dams. Dam treatment had no other effects on follicle or wool characteristics. The results of this study indicate that mid-pregnancy shearing of hoggets can be used as a technique to increase birthweight in single lambs but not twin-born lambs. Pregnancy shearing had no effect on lamb survival rates to weaning, whereas shearing in late-pregnancy had minor effects on wool colour that would be unlikely to affect wool value in Romneys. Shearing in mid-pregnancy had no effect on either progeny follicle or wool characteristics.

The effect of maternal shearing and thyroid hormone treatments in mid pregnancy on the birth weight, follicle, and wool characteristics of lambs

Mid pregnancy shearing of ewes has been associated with a short‐ to medium‐term increase in maternal thyroid hormone concentrations. To determine the role of this elevation in the observed changes in lamb birth weight and fibre characteristics, ewes in mid pregnancy were either: shorn at day 70 of pregnancy with thyroid glands left intact (Shorn), unshorn with intact thyroid glands (Unshorn), thyroidectomised but left unshorn with a short‐term elevation in thyroxine (T4) concentrations in mid pregnancy (Tx+T4), or unshorn with intact thyroid gland and prolonged elevation in T4 concentrations (+T4). The Tx+T4 regime successfully increased maternal thyroid hormone for a short period post‐treatment, while the +T4 regime increased maternal thyroid hormone levels for a prolonged period during mid to late pregnancy. Lambs born to Shorn ewes were significantly (P < 0.05) heavier than those born to Tx+T4 and +T4 ewes and tended to be heavier than those born to Unshorn ewes (P = 0.10). Birth weights of lambs born to Tx+T4 and +T4 ewes did not differ from those born to Unshorn ewes. Ewe treatment had no effect on lamb wool follicle characteristics or fibre diameter, coefficient of variation of mean fibre diameter, yield, or loose wool bulk; but treatment tended to affect colour (P = 0.05) and staple length (P = 0.09). These results suggest that an elevation in maternal thyroid hormones is not the sole endocrine mechanism responsible for either the birth weight effect or changes in fibre characteristics observed in lambs born to mid pregnancy shorn ewes. However, it is still possible that an elevation of T4 and T3 concentrations in conjunction with other factors are required to achieve the observed effects.