Young Lambs Research Articles

The Potential of Three Vetch Species in Enhancing Feed Intake and Body Weight Gain of Growing Male Lambs

An experiment was intended to evaluate the potential of three vetch species in enhancing feed intake and body weight gain of growing male lambs and to investigate the difference among these three vetch species regarding their effect of supplementation on feed utilization and growth performance of growing male lambs. Twenty-four young male Arsi-Bale lambs of similar body weight were assigned to one of the four treatments in a randomized complete block design. The dietary treatments were 350 g of hay each of <i>Vicia sativa,</i> <i>Vicia Villosa,</i> and <i>Vicia narbonensis</i> for T2, T3, and T4, and ad libitum fodder oat hay alone (T1). Weight measurements of the lambs were made every ten days during the ninety-day feeding trial. Compared to T1 and T3, T2's total dry matter intake (1121.4 g/day) was substantially (P<0.05) greater. Lambs fed T2 diets showed significantly higher (P<0.001) crude protein intake (153.3 g/day) and average daily body weight increase (152.0 g/day). In conclusion, supplementation with Vicia sativa (T2) resulted in the highest feed intake and growth performance of lambs across all treatments. As a result, efforts should be undertaken to introduce and expand the production of this forage within the farming system.

Study of Relationships among head, neck and ear measurements in young lambs

The present research work was conducted in order to explore association among various head, neck and ear measurements of local sheep found in Southern Punjab, Pakistan. Data on 97 lambs were recorded including identity of the animal where lambs have ages in the range of 1-6 months. Data on both sexes (males and females) were recorded. The body measurements included Head length, Head width, Ear length, Ear width, Neck length and Neck width. After collecting, data were edited and tested for normality. Data were analyzed to determine the association among them using Pearson’s correlation coefficient. From this study we can explain relationships among various body measurements and predict them from other measurements.

Concept of Rejuvenation in Greek Mythology and Modern Plastic Surgery.

The aim of this study is to capture the enduring fascination with youth and transformation. These themes, epitomized by the myth of Medea, resonate in the context of modern plastic surgery and cosmetic enhancements. Book 7 of Metamorphosis was read and analyzed. Medea is a sorceress and daughter of King Aeëtes. Her magical abilities are highlighted in 2 notable stories: (1) her rejuvenation of Aeson and (2) her attempt to rejuvenate herself. Aeson, the father of Jason, had grown old and frail. Medea, eager to assist Jason's father, employed her magical abilities to restore Aeson's youth. Medea concocted a powerful potion that required a variety of rare ingredients and intricate rituals. This process involved herbs, incantations, and a cauldron for boiling the mixture. To prove her magical prowess to the onlookers, Medea performed a demonstration using an old ram. She dismembered the ram, boiled the pieces in her cauldron with her magical brew, and from the pot emerged a young lamb. Encouraged by this success, she then applied the same magical process to Aeson, rejuvenating him and restoring his vigor. Medea, having endured considerable personal loss and turmoil, resolved to use her magical abilities to restore her youth. She collected the required ingredients, conducted the rituals, and either drank the potion or bathed in it, which rejuvenated her. This act demonstrates her determination to transcend the constraints of mortality. These stories speak to the timeless human quest for youth and immortality while also exploring the themes of power, knowledge, and ethical boundaries.

Immunohistochemistry analyses of the abomasal mucosa show differences in cellular-mediated immune responses to Haemonchus contortus infection in resistant and susceptible young lambs

Haemonchus contortus is known for its high pathogenicity in sheep, and the uncontrolled use of anthelmintics resulted in the emergence of multiple drug-resistant populations. Breeding sheep for gastrointestinal nematode resistance is a sustainable alternative to reduce dependence of anthelmintic drugs, and differences in the degree of resistance between breeds have been reported. Here we compare two sheep breeds (Santa Ines and Ile de France), concerning the differences in innate and adaptive immune response involved in the resistance against H. contortus infection. Immunohistochemical analyses of the abomasum were conducted in naïve Santa Ines (n = 14) and Ile de France (n = 12) lambs randomized into four groups: infected Santa Ines (n = 8), non-infected control Santa Ines (n = 6), infected Ile de France (n = 8), and non-infected control Ile de France (n = 4). The infected lambs were initially infected with H. contortus infective larvae at 14 days of age, and multiple infections were conducted every second day until they reached 66 days of age. There was a significant effect (P < 0.001) of the infection with increase in numbers of CD3+ T; CD79α+ B; GATA3+ Th2/ILC2; POU2F3+ tuft cells; FOXP3+ T reg; and IgE + cells in the fundus of the abomasal mucosa in both Santa Ines and Ile de France lambs. Nevertheless, the infected Santa Ines lambs presented the highest averages for CD79α+ B; GATA3+ Th2/ILC; IgE + cells; and POU2F3+ tuft cells and there was a significant association of the breed and infection status with regards to POU2F3+ tuft cells, with the highest mean in the infected Santa Ines group. The infected Santa Ines group had three lambs with high degree of resistance and five lambs that showed a moderate infection. Our results suggest a mechanism of synergistic coordination between different immune-cell types in promoting resistance of suckling lambs under H. contortus infection.

Unveiling the presence and genotypic diversity of Giardia duodenalis on large-scale sheep farms: insights from the Henan and Ningxia Regions, China

BackgroundThe parasitic protozoan Giardia duodenalis is an important cause of diarrheal disease in humans and animals that can be spread by fecal–oral transmission through water and the environment, posing a challenge to public health and animal husbandry. Little is known about its impact on large-scale sheep farms in China. In this study we investigated G. duodenalis infection of sheep and contamination of the environment in large-scale sheep farms in two regions of China, Henan and Ningxia.MethodsA total of 528 fecal samples, 402 environmental samples and 30 water samples were collected from seven large-scale sheep farms, and 88 fecal samples and 13 environmental samples were collected from 12 backyard farms. The presence of G. duodenalis was detected by targeting the β-giardin (bg) gene, and the assemblage and multilocus genotype of G. duodenalis were investigated by analyzing three genes: bg, glutamate dehydrogenase (gdh) and triphosphate isomerase (tpi).ResultsThe overall G. duodenalis detection rate was 7.8%, 1.4% and 23.3% in fecal, environmental and water samples, respectively. On the large-scale sheep farms tested, the infection rate of sheep in Henan (13.8%) was found to be significantly higher than that of sheep in Ningxia (4.2%) (P < 0.05). However, the difference between the rates of environmental pollution in Henan (1.9%) and Ningxia (1.0%) was not significant (P > 0.05). Investigations of sheep at different physiological stages revealed that late pregnancy ewes showed the lowest infection rate (1.7%) and that young lambs exhibited the highest (18.8%). Genetic analysis identified G. duodenalis belonging to two assemblages, A and E, with assemblage E being dominant. A total of 27 multilocus genotypes were identified for members of assemblage E.ConclusionsThe results suggest that G. duodenalis is prevalent on large-scale sheep farms in Henan and Ningxia, China, and that there is a risk of environmental contamination. This study is the first comprehensive examination of the presence of G. duodenalis on large-scale sheep farms in China. Challenges posed by G. duodenalis to sheep farms need to be addressed proactively to ensure public health safety.Graphical

ЭКОЛОГО-ЭПИЗООТОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА АНОПЛОЦЕФАЛИДОЗОВ МЕЛКОГО РОГАТОГО СКОТА В ФЕРМЕРСКИХ ХОЗЯЙСТВАХ АЛТАЙСКОГО КРАЯ

The purpose of the study is to identify in the Altay Region the most pathogenic helminths among small livestock that threaten the health of farm animals, and their harmfulness and extent of spread. Using the coprooscopic method, fecal samples from sheep of 3 groups were examined: up to one year, from 1 to 2 years and over 2 years. Using the method of complete helminthological autopsies, 18 heads of sheep were opened on farms, of which 11 were aged from 1 to 2 years and 7 heads were older than 2 years. We studied the timing of infection in lambs by monthly examination of the same animals, starting from two months of age until they reach two years of age. All lambs were from the same farm; no anticestodal measures were carried out, so the natural course of the invasion was not disturbed. The survey began at the end of May 2020 with a group of lambs that reached two months of age in the amount of 26 heads. The number of oribatid mites was studied by collecting oribatid mites using a special technique. From the class of cestodes among sheep, 5 species are most often recorded with an average level of extensive infestation from 0.5 to 44.4 %. Anoplocephalid eggs were first discovered in lambs of the current year of birth in July. Moniesia were found throughout the year in young animals from one to two years of age. In March, April, and May they were recorded in single animals in this group of sheep. The seasonal dynamics of the number of oribatid ticks is directly dependent on natural and climatic conditions: significantly fewer ticks were recorded in the steppe zone than in the forest-steppe and floodplain zones. The results of the study show that monieziosis in young lambs kept on pasture is detected coprologically in the conditions of the Altai Region no earlier than July. Two peaks of activity of the intermediate hosts of moniesia, oribatid mites, have been recorded: spring and autumn.

The Relationship of Mitochondrial-derived Peptide (MOTS-c) and Brain Mitochondrial Carrier Protein 1 (BMCP1) Response in Sheep with Some Physiological Parameters

Background: Mitochondria are organelles called power plants of the cell, which are found in eukaryotic cells and are responsible for the production of energy needed by the cells through aerobic respiration. Mitochondrial dysfunction causes endocrinological, cardiovascular, metabolic and neurodegenerative diseases. The aim of this study was to examine the effects of body condition score (BCS), lactation, pregnancy, age and gender on Mitochondrial-Derived Peptide (MOTS-c) and Brain Mitochondrial Transporter Protein 1 (BMCP1) levels in Akkaraman sheep. Methods: Sheep are classified into 3 categories according to BCS (BCS less than 2, BCS=3-3.5, BCS≥4). In creating groups in terms of BCS, it was determined by the palpation method applied to the waist area. The sheep included in the study were divided into 4 groups: early lactation, early pregnancy, late pregnancy (dry period) and age (female and male sheep).1st group, ewes in the first period of pregnancy (on the 100th day of the first pregnancy) (n = 30), 2nd group, ewes in the early lactation period (n = 30), 3rd group, ewes in the dry period (the last two months of pregnancy) (n = 30) and in the 4th group, less than 2 (young) (n=30), 2-8 (adult) (n=30), 8 greater than (old) (n=30), male and female sheep (n=30) of different ages. =180) total of 270 animals. Blood samples were taken from the jugular vein of the sheep before the morning feeding. MOTSc and BMCP1 levels were determined in blood serum samples by ELISA method. Result: In the study, serum MOTS-c and BMCP1 levels in sheep during lactation and pregnancy were determined to be lowest in the VKS less than 2 group and highest in the VKS≥4 groups. Likewise, in age and gender groups, the highest level was detected in young lambs and yearlings in the VKS less than 2 group, while the highest level was detected in old sheep and rams in the VKS≥4 group. As a result, it was determined that different age, gender, pregnancy and lactation periods affected serum MOTS-c and BMCP1 levels depending on the change in BCS (P less than 0.05). It was concluded that MOTS-c and BMCP1 may be useful parameters in the evaluation of mitochondrial function, energy metabolism and metabolic profile.

Characterization of intestinal mononuclear phagocyte subsets in young ruminants at homeostasis and during Cryptosporidium parvum infection.

Cryptosporidiosis is a poorly controlled zoonosis caused by an intestinal parasite, Cryptosporidium parvum, with a high prevalence in livestock (cattle, sheep, and goats). Young animals are particularly susceptible to this infection due to the immaturity of their intestinal immune system. In a neonatal mouse model, we previously demonstrated the importance of the innate immunity and particularly of type 1 conventional dendritic cells (cDC1) among mononuclear phagocytes (MPs) in controlling the acute phase of C. parvum infection. These immune populations are well described in mice and humans, but their fine characterization in the intestine of young ruminants remained to be further explored. Immune cells of the small intestinal Peyer's patches and of the distal jejunum were isolated from naive lambs and calves at different ages. This was followed by their fine characterization by flow cytometry and transcriptomic analyses (q-RT-PCR and single cell RNAseq (lamb cells)). Newborn animals were infected with C. parvum, clinical signs and parasite burden were quantified, and isolated MP cells were characterized by flow cytometry in comparison with age matched control animals. Here, we identified one population of macrophages and three subsets of cDC (cDC1, cDC2, and a minor cDC subset with migratory properties) in the intestine of lamb and calf by phenotypic and targeted gene expression analyses. Unsupervised single-cell transcriptomic analysis confirmed the identification of these four intestinal MP subpopulations in lamb, while highlighting a deeper diversity of cell subsets among monocytic and dendritic cells. We demonstrated a weak proportion of cDC1 in the intestine of highly susceptible newborn lambs together with an increase of these cells within the first days of life and in response to the infection. Considering cDC1 importance for efficient parasite control in the mouse model, one may speculate that the cDC1/cDC2 ratio plays also a key role for the efficient control of C. parvum in young ruminants. In this study, we established the first fine characterization of intestinal MP subsets in young lambs and calves providing new insights for comparative immunology of the intestinal MP system across species and for future investigations on host-Cryptosporidium interactions in target species.

The Effects of Housing on Growth, Immune Function and Antioxidant Status of Young Female Lambs in Cold Conditions

Cold conditions in northern China during winter may reduce sheep growth and affect their health, especially if they are young, unless housing is provided. We allocated 45 two-month-old female lambs to be housed in an enclosed building, a polytunnel, or kept outdoors, for 28 days. The daily weight gain and scalp and ear skin temperature of outdoor lambs were less than those of lambs that were housed in either a house or polytunnel; however, rectal temperature was unaffected by treatment. There was a progressive change in blood composition over time, and by the end of the experiment, outdoor lambs had reduced total antioxidant capacity (T-AOC), catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) and increased malondialdehyde compared to those in the house or polytunnel. In relation to immune responses in the lambs’ serum, in the polytunnel, immunoglobulin A (IgA), tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4) were higher and immunoglobulin G (IgG) lower compared with the concentrations in lambs that were outdoors. Over the course of the experiment, genes expressing heat shock proteins and antioxidant enzymes increased in lambs in the outdoor treatment, whereas they decreased in lambs in the indoor treatments. It is concluded that although there were no treatment effects on core body temperature, the trends for progressive changes in blood composition and gene expression indicate that the outdoor lambs were not physiologically stable; hence, they should not be kept outdoors in these environmental conditions for long periods.

Refugia, climatic conditions and farm management factors as drivers of adaptation in Nematodirus battus populations

Parasites are known for their ability to rapidly adapt to changing conditions. For parasitic helminths, changes in climate, along with farming and management practices associated with the intensification of livestock farming, provide novel challenges which can impact on their epidemiology and control. The sustainability of livestock production partially relies on effective control of helminth infection. Therefore, understanding changes in parasite behaviour, and what drives these, is of great importance. Nematodirus battus is an economically important helminth in the UK and temperate regions. Its infective larvae typically overwinter in eggs on pasture and hatch synchronously in spring, causing acute disease in lambs. Attempts to control disease typically rely on whole-flock benzimidazole (BZ) treatments. In recent years, the emergence of BZ-resistance, alongside the hatching of eggs without the classical over-winter ‘chill stimulus’, have made N. battus more difficult to control. In three previous studies, after collecting a large number of N. battus populations alongside farm management data from commercial farms, we explored the prevalence of genetic mutations associated with BZ-resistance (n = 253 farms), the ability of eggs to hatch with and without a chill stimulus (n = 90 farms) and how farm management practices varied throughout the UK (n = 187 farms). In the present study, we identify factors which may be acting as drivers, or barriers, to either the development of resistance or the variable hatching behaviour of N. battus eggs. Generalised linear mixed effect models were applied to regress experimental hatching and genotyping data on farm management and additional environmental data. Both variable hatching and resistance development appeared associated with the maintenance of parasite refugia as well as grazing management, particularly reseeding of pasture routinely grazed by young lambs each spring and the practice of set-stocked grazing. Effective quarantine measures were identified as the main protective factor for the development of BZ-resistance whereas set stocked grazing and population bottlenecks, resulting from reseeding heavily contaminated pastures, were risk factors. Spring maximum temperature and other climatic factors were associated with ‘typical’ hatching of eggs following a chill stimulus whilst several management factors were linked with hatching without prior chilling. For example, practices which reduce parasite numbers on pasture (e.g. re-seeding) or restrict availability of hosts (e.g. resting fields), were found to increase the odds of non-chill hatching. Retention of the timing of lambing and infection level of the host within the fitted model indicated that requirement for a chill stimulus prior to hatching may be plastic, perhaps subject to change throughout the grazing season, in response to immune development or parasite density-dependence within the host. Further investigation of the influence of the factors retained within the fitted models, particularly the theme of parasite refugia which was highlighted in relation to both the presence of BZ-resistance alleles and alternative hatching, is required to establish robust, sustainable parasite control and farm management strategies.

Effects of hexarelin and isolation stress on the Met-enkephalin system in young lambs

Koziec K., S canes C.G., Z ubel-Łojek J., Gajewska A. 2023. Effects of hexarelin and isolation stress on the Met-enkephalin system in young lambs. Folia Biologica (Kraków) 71: 195-206.Stress stands out as the primary instigator of numerous diseases – ranging from cardiovascular and gastro- intestinal to diabetes and nervous disturbances – in most developed nations. Endogenous opioid peptides (EOP), particularly Met-enkephalin, play a crucial role in mitigating the up-regulation of the hypothalamo- pituitary-adrenal axis during stress responses, consequently reducing the risk of serious diseases. Hexarelin, a synthetic analog of Met-enkephalin, has been predominantly investigated for its impact on growth hormone (GH) release in both human subjects and rodent models. This study was undertaken to evaluate the influence of isolation stress and/or hexarelin administration on various Met-enkephalin-related parameters in a novel animal model – 3-month-old lambs. Four distinct groups were established: a control group, a group intravenously injected with hexarelin, a group subjected to 60 min of isolation stress from the herd, and a group treated with both hexarelin and stress. Blood and hypothalamus samples were collected to analyze cortisol and Met-enkephalin profiles, proenkephalin (PENK) gene expression, Met-enkephalin concentration, in vitro Met-enkephalin secretion, and opioid receptor binding. The findings revealed a significant impact of stress on all assessed parameters. Hexarelin alone led to a decrease in cortisol levels and Met-enkephalin synthesis, release, and receptor binding in the hypothalamus. When administered prior to stress, hexarelin potentiated the responses of opioid parameters to isolation. These results, for the first time, demonstrate that hexarelin interacts with Met-enkephalin, modulating the stress response at both central and peripheral levels in growing lambs. It is suggested that hexarelin plays a crucial role during stress responses; however, further research on its effects should be conducted concurrently with the examination of opioid profiles.

Postnatal development of salivary phosphate, sodium and potassium secretion in calves.

The transition of young lambs and calves from a non-ruminating to a ruminating animal include substantial, developmental changes to alter saliva production. Due to the simultaneous development of the forestomach system, the salivary glands must transfer more and more substances such as bicarbonate and phosphate (Pi), but also sodium (Na), into saliva in order to create and to maintain optimal environmental conditions for microbial metabolism. The objective of the present study was to characterize the effects of different dietary energy levels on the ability of the salivary glands to concentrate minerals in young ruminants in more detail during the first 7 weeks of life. Blood and saliva samples were collected from twelve female calves of the German Holstein breed fed different levels of milk replacer. Plasma and saliva samples were collected over 7 weeks postpartum and Na, Pi and potassium (K) concentrations were measured. Salivary Na and Pi concentrations (p < 0.001) increased as a function of time and were not affected by varying energy intake, while K concentration (p < 0.001) decreased over the developmental period and was also not affected by energy intake. This suggests that the ability to specifically concentrate minerals such as Na and Pi in saliva follows a genetic program in the salivary glands rather than being influenced by dietary factors such as energy intake in young ruminants.

Increasing the productive potential of large and small cattle breed resources in the South of Russia based on modern breeding methods

The results of the genetic characteristics research of large and small cattle populations grown in the Southern Russia are stated. Breed-specific DNA patterns have been identified in three of the most common cattle breeds of meat productivity in arid conditions. The milk productivity of Holstein cows of different breeding lines has been studied. It was found that increasing the frequency of animals of Vis Back Ideal and Reflection Sovering lines in the parent pairs could be able to increase the level of milk productivity of offspring and improve the quality indicators of dairy raw materials. The adaptive abilities and milk productivity of imported foreign Holstein cows depending on their origin were estimated. In comparison with Australian and Danish Holstein cows, American and German analogues have a higher level of milk productivity. However Australian and Danish animals have a more flexible adaptive capacity. As a result of the comparative study of the economic and biological characteristics of two generations of Aberdeen-Angus cattle (parental foreign generation, and the first generation - obtained under breeding conditions in Southern Russia), tendencies to increase productive values are revealed. The features of the meat productivity formation in Kalmyk steers different exterior and constitutional types are investigated. It was found that the Kalmyk steers of the tall body type have a higher meat productivity compared with their analogues of medium and compact body types. However, the beef of compact steers has a higher fat percentage, more attractive taste characteristics, culinary and technological indices. The features of polymorphism of CAST, GH, GDF9, CLPG, FABP4 and MC4R genes in populations of sheep of different breeds grown in the Republic of Kalmykia, Volgograd and Rostov regions, Kabardino-Balkaria Republic were also studied. As a promising method of early diagnosis of presence economically useful traits in sheep during ontogenesis, the effectiveness of DNA analysis in young lambs and the further selection of animals with desirable genotypes according to these genes were justified.

CONTROL OF COCCIDIOSIS OF FARM BREEDING SHEEP

"Infection with coccidia is one of the most common and damaging sheep diseases, particularly young lambs and economically important diseases of sheep. Coccidiosis is caused by parasitic protozoa in the genus Eimeria. Coccidial infection is virtually universal in sheep and large numbers of oocysts may be found in the faeces of clinically normal animals. Usually it is presented at animals at 4-10 weeks.Lamb and kids infection had moderate morbidity and low mortality rate. Environmental contamination and resulting clinical disease is generally influenced by local weather conditions and the grazing management practices of the flock. In our paper, we present measures to control coccidiosis in sheep kept in frame breeding conditions."

Are alpacas especially protective of lambs? An insight into alpaca guardian behaviour towards sheep using an arena preference test

Alpacas are increasingly used as a guardian species in Australian sheep flocks in an effort to improve lamb survival rates. Yet little is documented about the role and mechanisms of alpaca guarding behaviours within this environment. The first phase of this study, evaluated the temperament of 44 alpacas by assessing their behaviour when individuals were separated from herd mates. Tests included agitation while in an isolation enclosure, flight speed and behaviour in observation arena tests. The second phase of the study evaluated alpaca responses to different auditory, olfactory and visual cues representative of young lambs, adult sheep (ewes) and other novel stimuli. Alpacas (n = 24) which had not previously been exposed to sheep were individually presented with stimuli in a test arena. Behavioural responses were recorded over 2 min and analysed to compare differences between stimuli type (lamb/ewe/other) and stimuli cue form (live animal/auditory only/olfactory only/visual only). In phase one of this study alpacas exhibited little agitation while retained in an isolation enclosure with 67% of animals demonstrating a low agitation score. Females appeared to have a more ‘reactive’ temperament than males, exhibiting significantly faster flight speeds (P < 0.01) and more frequent pacing behaviour (P < 0.01) in the observational pen. In the arena test both male (n = 12) and female (n = 12) alpacas consistently exhibited greater attraction towards the lamb stimuli type (for all cue forms) compared to the ewe and other atypical stimuli (P < 0.05 for all comparisons). Alpacas showed the greatest attraction towards the live lamb compared to visual (P < 0.01), auditory (P < 0.01) and olfactory lamb cues (P < 0.001). Both male and female alpacas demonstrated similar response times and there were no significant differences between alpaca sex in the total time spent reacting to the lamb and ewe stimuli. This study demonstrates that alpacas exhibit a greater attraction towards or interest in young vulnerable animals such as lambs and supports the available anecdotal evidence that the use of alpacas as livestock guardians may be useful in improving lamb survival rates.

Herbage intake and performance of grazing lambs in tropical erect grass pastures maintained at different heights

One of the main constraints for sheep production in tropical and subtropical areas is the lack of knowledge of how to manage erect tropical grasses for lambs. The objective of this study was to assess the effect of pasture height and structure of an erect tropical grass, Aruana Guinea grass (Megathyrsus maximus cv. IZ-5) on the intake and performance of young weaned lambs. The experiment was repeated in two consecutive years. Thirty young weaned lambs were equally assigned, each year, to three pasture heights: (1) Tall 75 cm; (2) Medium 50 cm and (3) Short 25 cm. Herbage mass (HM), pasture height, plant morphological composition, pasture nutritional quality, lambs’ average daily gain, gain per hectare and herbage intake were measured. The Short treatment had higher (p < 0.05) leaf:stem ratio (L:S; 2.6 ± 0.27) and average daily gain (ADG; 92 ± 10 g day−1) than the Tall treatment (0.9 ± 0.11 and 40 ± 13 g, respectively). The Medium treatment showed intermediate ADG (69 ± 11 g) and L:S ratio (1.4 ± 0.09). The height of the pasture affects the rate at which the number of stems increases relative to the number of leaves. There was a significant interaction between treatment and period (summer and early autumn) for herbage intake. Intake decreased markedly on the Tall treatment from the first to the second period. This study showed that for a better performance of weaned young lambs during summer–autumn, it is important to maintain tropical swards at a short height (25 cm). However, if the grass height exceeds this condition, the use of cattle or a mower are good options to maintain the sward height.

Melatonin Administration to Pregnant Ewes for Coccidiosis Control in Their Offspring.

In livestock research, there has been a growing interest in the impact of melatonin on both health and disease conditions. The hypothesis of the present study was that melatonin treatment prenatally could support the immune competence and growth of experimentally infected lambs. This is the first study that aimed to investigate the impact of melatonin administration throughout pregnancy on immunity and oocyst excretion of pre-partum ewes and their offspring after experimental infection with Eimeria species. Thirty pregnant ewes were allocated into five equal groups, ΚΜ, ΚC, CM, CC, and NC, and gave birth to 47 lambs. Ewes of the KM and KC groups were orally challenged with a cocktail of Eimeria-sporulated oocysts (mainly consisting of Eimeria ovinoidalis), on day 120 of pregnancy, as well as all the lambs at the age of 5-9 days apart from those born from the NC group (environmental control). Fecal samples were collected from all ewes before infection and at parturition and from all lambs 14 times (S0-S13), before infection and during the following 8 weeks, for counting oocysts per gram of feces (OPG). Immunoglobulin (IgG) and cytokine (IL-1β, IL-6, IL-10, IFN-γ) levels were determined in ewes' plasma collected before infection and at parturition, in lambs' plasma at 24 and 72 h after their birth, and in colostrum samples at parturition and 72 h later. Body weight of lambs was recorded five times from birth until the age of 60 days. Accordingly, the leucogram was evaluated in blood samples collected six times within the same period. On average, IgG concentration was higher (p < 0.05) in the blood of KM-ewes compared to KC and CC groups and in colostrum of KM-ewes compared to other groups (p < 0.001). KM-lambs had greater IgG titer and IFN-γ level than the other groups (p < 0.05). The IL-10/ IFN-γ ratio in KM-ewes was lower than the CC group (p = 0.06). Overall, the growth rate of lambs did not differ among groups (p > 0.05). Total oocysts' excretion in KM- and CM-lambs was reduced by 94.9% (p = 0.05) and 92.6% (p = 0.025), respectively, compared to KC-lambs, following the 3-week period after challenge, when E. ovinoidalis predominated in all groups. The dominant type of leucocytes was monocytes in all experimentally infected lambs, but not in NC-lambs, while overall lymphocytes were lower in KC-lambs than in NC-lambs (p < 0.05). Considering that almost all young indoor-reared lambs are exposed to coccidia species during their early life, melatonin treatment prenatally could suggest an alternative management tool in alleviating infection pressure.

The impact of environmental temperature on ewe reproduction, adaptive responses during insemination, and productive characteristics of the lambs obtained from them

The reproductive function of ewes and the development of their offspring are largely influenced by their clinical condition and the temperature of the environment. The maximum temperature values have significantly increased over the last two decades, making climate change a pressing issue for sheep breeding worldwide, including Ukraine. The consequences of exposure to high temperatures of the outside air, above all, in the mating season, can be marked by a significant increase in the heat load on the body of the brood stock, a decrease in clinical indicators and reproductive capacity. On the other hand, the current understanding of how these components interact is insufficient, which conditions the relevance of this work. In order to determine the effective terms of insemination of sheep in the mating season of 2021, taking into account the terms of insemination and the characteristics of the outside air temperature, three technological groups of ewes were formed, which were in the same flock and were artificially inseminated with freshly obtained sperm from the same breeders in August–September: from August 15 to August 27; from August 28 to September 9 and from September 10 to September 21. It was discovered that ewes inseminated between August 28th and September 9th were less adaptable to environmental conditions, experiencing increased daily fluctuations of body temperature, pulse and breathing rates, stillborn lambs, cases of abortion, and decreased preservation of young animals, including ewe lambs, which are highly valuable in breeding – by 15.8% and 10.9% concerning the initial and final phases of the insemination period. However, the young lambs born from ewes inseminated between August 15th and August 27th had the highest survival rate until weaning due to better survival of ewe lambs compared to those inseminated during later phases of the mating season against the background of a lower percentage of output of rams until the moment of weaning against ewes that were inseminated from August 28 to September 9. It has been shown that the growth rate of lambs during early postnatal development varies depending on the timing of their mothers' insemination. Ewes inseminated between August 15th and 27th produced lambs with the highest weight at 90 days, reaching 26.81 and 24.18 kg, respectively; 20.1% and 26.8% more than rams, and 19.1% and 18.8% more than female lambs whose mothers were inseminated in the middle and at the end of the breeding season. A similar picture is characteristic of the average daily growth values. It was determined that the formation of clinical indicators, and above all, the body temperature of young animals born from mothers fertilized at the beginning and in the middle of the mating season, was the most intense. The results of this study made it possible to understand the adaptive mechanisms of the response of sheep to changes in environmental temperature, which will be useful in future investigations to determine its effect on the thermopotential and clinical condition of lambs during the first day after birth, which is the most critical.

Tickborne disease responsible for deaths of young lambs.

Tickborne disease responsible for deaths of young lambs.

Exploring the transcriptomic changes underlying recombinant vaccine efficacy against Teladorsagia circumcincta in 3-month-old lambs

Teladorsagia circumcincta is an abomasal parasitic nematode that can cause serious issues in small ruminant production, which are aggravated by drug resistance. Vaccines have been suggested as a feasible, long-lasting alternative for control since adaptation to the host’s immune mechanisms by helminths develops at a much slower pace than anthelmintic resistance. Recently, a T. circumcincta recombinant subunit vaccine yielded over a 60% reduction in egg excretion and worm burden and induced strong humoral and cellular anti-helminth responses in vaccinated 3-month-old Canaria Hair Breed (CHB) lambs, but Canaria Sheep (CS) of a similar age were not protected by the vaccine. Here, we compared the transcriptomic profiles in the abomasal lymph nodes of such 3-month-old CHB and CS vaccinates 40 days after infection with T. circumcincta to understand differences in responsiveness at the molecular level. In the CS, differentially expressed genes (DEG) identified were related to general immunity processes such as antigen presentation or antimicrobial proteins and down-regulation of inflammation and immune response through regulatory T cell-associated genes. However, upregulated genes in CHB vaccinates were associated with type-2 oriented immune responses, i.e., immunoglobulin production, activation of eosinophils, as well as tissue structure and wound repair-related genes and protein metabolism pathways such as DNA and RNA processing. These results highlight potentially more optimal timing and orientation of immune responses in CHB sheep compared to CS associated with vaccine-induced protection. The data obtained in this study thus deepens our understanding of variations in responsiveness to vaccination in young lamb and provides insights for vaccine refinement strategies.