Abortion and Lamb Mortality between Pregnancy Scanning and Lamb Marking for Maiden Ewes in Southern Australia

The contribution of abortions to the overall mortality of lambs born to maiden (primiparous) ewes in Australia remains unclear. This cohort study aimed to quantify abortion and lamb mortality for ewe lambs and maiden Merino two-tooth ewes. Lamb mortality from pregnancy scanning to marking were determined for 19 ewe lamb and 11 Merino two-tooth ewe flocks across southern Australia. Average lamb mortality from scanning to marking was 35.8% (range 14.3–71.1%) for the ewe lambs and 29.4% (range 19.7–52.7%) for the two-tooth ewes. Mid-pregnancy abortion was detected in 5.7% of ewes (range 0–50%) in the ewe lamb flocks and 0.9% of ewes (range 0–4.4%) in the two-tooth ewe flocks. Mid-pregnancy abortion affecting ≥2% of ewes was observed in 6/19 ewe lamb flocks and 2/11 two-tooth ewe flocks. Lamb mortality from birth to marking represented the greatest contributor to foetal and lamb mortality after scanning, but mid-pregnancy abortion was an important contributor to lamb mortality in some ewe lamb flocks. Variability between the flocks indicates scope to improve the overall reproductive performance for maiden ewes by reducing foetal and lamb losses. Addressing mid-pregnancy abortion may improve the reproductive performance in some flocks.

Growth and behaviour of post-weaned Mérinos d'Arles ewe lambs, as measured by a Walk-over-Weighing system under Mediterranean grazing conditions.

Liveweight (LW) is a key and conventional indicator for monitoring and assessing overall animal performance and welfare, representing the progress along different physiological stages, while providing close indication of individual physical and health status. Measuring LW in practice is still, however, quite rare and infrequent under commercial sheep farming conditions, mainly because sessions are time-consuming, stressful either for the operator and the animals. A Walk-over-Weighing (WoW) system, already evaluated with other breeds under different conditions, was tested in this experiment lasting 14 weeks (i.e. 3 for acclimation and adaptation and 11 for data collection). We validated its use for routine and frequent monitoring the growth rate in post-weaned Merinos d'Arles ewe lambs, reared under Mediterranean grazing conditions. Similarly to previous work, the necessity for an initial adaptation period of the animals as well as for an essential data cleaning procedure of the raw database automatically collected by the WoW, were corroborated. Adaptation of naive ewe lambs enabled the required voluntary passages across the weigh platform and a high volume of individual and daily data after 2-3 weeks. Close monitoring of individual growth was then possible after performing sound data cleanings. A strong concordance of WoW LW data with the gold standard (a standard static scale) LW reference data was demonstrated. At the individual level, even with the lowest number of LW values collected with WoW, it was possible to monitor variations in LW at daily intervals. The establishment of an early warning system to help farmer decision making could therefore be possible. Our results show interesting perspectives for more precise and frequent monitoring of LW in grazing sheep without human intervention, compared to what is currently carried out on commercial farms.

Effect of Breeding Heavier Romney Ewe Lambs at Seven Months of Age on Lamb Production and Efficiency over Their First Three Breeding Seasons

This experiment examined the effect of breeding heavier ewe lambs on lamb production and their efficiency over their first three breeding seasons. Two groups of ewe lambs were bred at seven months of age at an average pre-breeding live weight of either 47.9 ± 0.36 kg (heavy; n = 135) or 44.9 ± 0.49 kg (control; n = 135). Ewe live weight, number of lambs born and weaned, and lamb live weight were recorded until 39 months of age, and efficiency was calculated for each ewe. Although the number and lamb weaning weight did not differ between treatments over three years, when data were pooled, heavier ewe lambs at breeding weaned a greater number of lambs over the three-year period. The total lamb weaning weight over the three-year period increased by 2% for each additional kilogram at ewe lamb breeding. Breeding heavier ewe lambs had no effect on efficiency. These results suggest that although breeding heavier ewe lambs had a positive effect on lamb production over the three-year period, it had no effect on efficiency. Before final recommendations can be made, lifetime performance and longevity to five years of age of heavier ewe lambs at breeding are required.

Ovarian activation delays in peripubertal ewe lambs infected with Haemonchus contortus can be avoided by supplementing protein in their diets

Background The ewe lamb nutritional and physiological state interfere with the ovarian environment and fertility. The lack or excess of circulating nutrients reaching the ovary can change its gene expression. A protein deficiency in the blood caused by an Haemonchus contortus abomasal infection is detrimental to the organism’s development during puberty. The peripubertal period is a time of intensive growth that requires a high level of nutrients. An essential feature controlling pubertal arousal and female reproductive potential is ovarian follicle growth activation. Protein supplementation improves the sheep’s immune response to helminthic infections. We aimed to determine if supplementing protein in infected ewe lambs’ diet would impact the ovarian environment leading to earlier ovarian follicle activation than in infected not supplemented animals. Methods We fed 18 Santa Ines ewe lambs (Ovis aries) - bred by the same ram - with either 12% protein (Control groups) or 19% protein (Supplemented groups) in their diets. After 35 days of the diet, they were each artificially infected or not with 10,000 Haemonchus contortus L3 larvae. Following 77 days of the diet and 42 days of infection, we surgically collected their left ovaries and examined their genes expression through RNA sequencing. Results We found that protein supplementation in infected animals led to an up-regulation of genes (FDR p-values < 0.05) and biological processes (p-value cut-off = 0.01) linked to meiotic activation in pre-ovulatory follicles and primordial follicle activation, among others. The supplemented not infected animals also up-regulated genes and processes linked to meiosis and others, such as circadian behaviour. The not supplemented animals had these same processes down-regulated while up-regulated processes related to tissue morphogenesis, inflammation and immune response. Conclusion Diet’s protein supplementation of peripubertal infected animals allowed them to express genes related to a more mature ovarian follicle stage than their half-sisters that were not supplemented. These results could be modelling potential effects of the interaction between environmental factors, nutrition and infection on reproductive health. When ovarian activation is achieved in a timely fashion, the ewe may generate more lambs during its reproductive life, increasing sheep breeders’ productivity.

Comparative assessment of economically valuable traits of semi-coarse hair and coarse-hair sheep in Republic of Tuva

In Republic of Tuva sheep breeding is a leading branch of animal husbandry. According to the Ministry of Agriculture and Food, the number of sheep is 980 thousand heads at the 1st of January 2021. Among them the percentage of Tuva-Saraja coarse-hair hybrids is more than 60%. The purpose of the work is to study economically valuable traits of Tuva-Saraja sheep of a new type in comparison with Tuva coarse-hair short-fat tailed sheep. For comparative assessment of live weight, dirty wool clip and length of wool according to the method of random sample, out of the herd there were selected 30 heads of ram lambs yearlings and 30 heads of ewe lambs yearlings of Tuva-Saraja semi-coarse-hair sheep of new type and Tuva coarse-hair short-fat tailed sheep. The results of research have shown, that rams and ewes yearlings of Tuva-Saraja semi-coarse-hair breed of new type significantly differ in size and wool productivity. They predominate over the lambs of the same age of Tuva coarse-hair short-fat tailed in live weight by 3.2-3.4 kg (9,7-10.2 %) statistically more, than Tuva coarse-hair short-fat tailed of the same age. The longest wool was recorded in rams yearlings of new type, with underwool of 7.8 cm that exceeded the length of underwool of Tuva ram lambs yearlings by 1.3 cm or 20.0 %, the top hair was 14.4 cm and exceeded the same index in analogues by 3,4 cm or 30.9 %. Tuva coarse-hair ewe lambs yearlings gave way to the semi-coarse-hair ewes of new type in the length of underwool and top hair. Thus, the rams and ewes yearlings semi-coarse-hair ewes of new type considerably differ in live weight, dirty wool clip and length of wool in comparison with Tuva coarse-hair short-fat tailed of the same age.

Control of Strongyles in First-Season Grazing Ewe Lambs by Integrating Deworming and Thrice-Weekly Administration of Parasiticidal Fungal Spores

Parasiticidal fungi have been used in several in vivo experiments in livestock farms worldwide, constituting an effective tool for the biocontrol of gastrointestinal parasites in grazing animals. In the first year of study, two groups of eight first-season pasturing ewe lambs infected by strongyles were dewormed with albendazole, and then, the test group received an oral dose of 106 chlamydospores of Mucor circinelloides and 106 Duddingtonia flagrans individually and thrice a week from mid-September to May (FS1), while the control group remained without fungi (CT1). In the second year, two new groups of first-season grazing ewe lambs were treated with ivermectin and subjected to the same experimental design (FS2 and CT2, respectively). The anthelmintic efficacy was 96.6% (CT1), 95.6% (FS1), 96.1% (CT2), and 95.1% (FS2). The counts of strongyle egg output increased in the control groups (CT1 and CT2) throughout the study and reached numbers higher than 600 eggs per gram of feces (EPG), while in FS1 and FS2, they were <250 EPG. The values of red blood cell parameters registered for CT1 and CT2 were lower than those of the reference standards, while a significant increment was recorded in FS1 and FS2, and values within the physiological range were attained. It is concluded that integrating efficient anthelminthic deworming with rotational pasturing and the regular intake of chlamydospores of M. circinelloides and D. flagrans provides a helpful strategy for maintaining low levels of strongyle egg output in first-season grazing ewe lambs and improves their health status.

What Are Sheep Doing? Tri-Axial Accelerometer Sensor Data Identify the Diel Activity Pattern of Ewe Lambs on Pasture

Monitoring activity patterns of animals offers the opportunity to assess individual health and welfare in support of precision livestock farming. The purpose of this study was to use a triaxial accelerometer sensor to determine the diel activity of sheep on pasture. Six Perendale ewe lambs, each fitted with a neck collar mounting a triaxial accelerometer, were filmed during targeted periods of sheep activities: grazing, lying, walking, and standing. The corresponding acceleration data were fitted using a Random Forest algorithm to classify activity (=classifier). This classifier was then applied to accelerometer data from an additional 10 ewe lambs to determine their activity budgets. Each of these was fitted with a neck collar mounting an accelerometer as well as two additional accelerometers placed on a head halter and a body harness over the shoulders of the animal. These were monitored continuously for three days. A classification accuracy of 89.6% was achieved for the grazing, walking and resting activities (i.e., a new class combining lying and standing activity). Triaxial accelerometer data showed that sheep spent 64% (95% CI 55% to 74%) of daylight time grazing, with grazing at night reduced to 14% (95% CI 8% to 20%). Similar activity budgets were achieved from the halter mounted sensors, but not those on a body harness. These results are consistent with previous studies directly observing daily activity of pasture-based sheep and can be applied in a variety of contexts to investigate animal health and welfare metrics e.g., to better understand the impact that young sheep can suffer when carrying even modest burdens of parasitic nematodes.

Repeatability of gaseous measurements across consecutive days in sheep using Portable accumulation chambers

Portable accumulation chambers (PAC) enable gaseous emissions from small ruminants to be measured over a 50 min period, to date however, the repeatability of consecutive days of measurement in the PAC has not been investigated. The objectives of this study were to investigate: 1) the repeatability of consecutive days of gaseous measurements in the PAC, 2) the number of days required to achieve precise gaseous measurements, and 3) to develop a prediction equation for gaseous emissions in sheep. A total of 48 ewe lambs (c. 10 to 11 mo of age) were randomly divided into four measurement groups each day, for 17 consecutive days. Gaseous measurements were conducted between 0800 h and 1200 h daily. Animals were removed from perennial ryegrass silage for at least 1 h before measurements in the PAC and animals were assigned randomly to each of the 12 chambers. Methane (CH4; ppm) concentration, oxygen (O2; percentage) and carbon dioxide (CO2; percentage) were measured at 3 time points (0, 25, and 50 min after entry of the first animal into the first chamber). To quantify the effect of animal and day variation on gaseous emissions, between-animal, between-day and error variances were calculated for each gaseous measurement using a linear mixed model. The number of days required to gain a certain precision (defined as the 95% confidence interval (CI) range) for each gaseous measurement was also calculated. For all 3 gases the between-day variance (39% to 40%) accounted for a larger proportion of total variance compared to between-animal variance, while the repeatability of 17 consecutive days of measurement was 0.36, 0.31 and 0.23 for CH4, CO2 and O2, respectively. Correlations between consecutive days of measurement were strong for all 3 gases; the strongest correlation between d 1 and the remaining days for CH4, CO2 and O2 was 0.71 (d 1 and d 6), 0.77 (d 1 and d 2) and 0.83 (d 1 and d 5), respectively. A high level of precision was achieved when gaseous measurements from PAC were taken over 3 consecutive days. The prediction equation over-estimated gaseous production for all 3 gases: the correlations between actual and predicted gaseous output ranged from 0.67 to 0.71, with the r 2 ranging from 0.45 to 0.71. Results from this study will aid the refinement of the protocol for the measurement of gaseous emissions in sheep using the PAC.

PSXII-26 Effects of levels of brackish water and NaCl on water and feed intake by different breeds of goat and hair sheep yearlings

Angora, Boer, and Spanish doelings and Dorper, Katahdin, and St. Croix ewe lambs (6 per type; initial age=296±2.1 d) consumed water varying in mineral levels of a natural brackish source (BR) and NaCl (SL) to determine effects on water and feed intake. There were 6 simultaneous 6×6 Latin squares with 3-wk periods. Water treatments (WT) were fresh (FR), BR alone (100-BR), similar total dissolved salt (TDS) level as 100-BR via NaCl addition to FR (100-SL), BR with concentrations of all minerals increased by 50% (150-BW), the same TDS level as 150-BR by NaCl addition to FR (150-SL), and the 150 TDS level by addition of a 1:1 mixture of BR minerals and NaCl to 100-BR (150-BR/SL). Concentrations (mg/kg) in BR were 4,928 TDS, 85.9 bicarbonate, 225 calcium, 1,175 chloride, 60.5 magnesium, 4.59 potassium, 1,387 sodium, 1,962 sulfate, and 8.3 boron, and TDS in other WT was 453, 5,684, 7,508, 8,222, and 7,319 for FR, 100-SL, 150-BR, 150-SL, and 150-BR/SL, respectively. Wheat hay (10% crude protein, 66.8% neutral detergent fiber, and 8.5% acid detergent lignin) was consumed ad libitum. There were no AT×WT interactions in water or feed intake. Water intake was affected by animal type (AT) and WT (P = 0.019 and 0.038, respectively), with values of 5.21, 4.06, 3.88, 4.65, 5.69, and 4.97% body weight (BW) for Angora, Boer, Spanish, Dorper, Katahdin, and St. Croix (SEM=0.388) and 4.66, 4.50, 4.61, 4.42, 5.30, and 4.96% BW for FR, 100-BR, 100-SL, 150-BR, 150-SL, and 150-BR/SL, respectively (SEM=0.249). Dry matter intake did not differ among WT (P = 0.573) but was affected by AT (P = 0.002), with values of 2.04, 2,54, 2.58, 2.72, 2.99, and 3.06% BW for FR, 100-BR, 100-SL, 150-BR, 150-SL, and 150-BR/SL, respectively (SEM=0.161). In conclusion, based on feed intake all AT seemed resilient to these WT with TDS less than 10,000 mg/kg.