Small Ruminant Research最新文献

This study was designed to evaluate the effect of post-mating GnRH or TAK-683 (kisspeptin analog) treatment on serum progesterone (P₄) concentrations and fertility parameters of ewes during the non-breeding season. One hundred and twenty multiparous, lactating Awassi ewes were used. For estrus synchronization, vaginal sponges containing 60 mg of medroxyprogesterone acetate (MAP) were inserted into the vagina and kept there for nine days. On the day of sponge removal (day 0), 500 IU of eCG and 75 µg of d-cloprostenol were given intramuscularly. Rams were introduced in the flock 24 h after sponge removal and kept with the ewes for 26 days, allowing a second mating period after synchronized estrus. On the fourth day after mating (day 6) the ewes mated by the rams between the 24th and 72nd hours (n = 105) were randomly divided into three groups. Control group (n = 36) received 1 ml of saline solution subcutaneously; GnRH group (n = 34) received 4 μg of buserelin acetate intramuscularly; TAK-683 group (n = 35) received 5 μg of TAK-683 acetate subcutaneously. Blood samples were taken to measure serum P₄ concentrations (ng/ml) at sponge insertion and on the 6th, 9th, 12th, 15th, 19th, 35th, and 50th days after sponge removal. Pregnancy diagnosis was conducted via serum P₄ concentration measurement on the 19th day and transrectal ultrasonography on days 35 and 50. The results showed that GnRH treatment (4.823 ± 0.238; 2.151 ± 0.272) increased (P<0.05) the mean P₄ concentration (ng/ml) in pregnant and non-pregnant ewes during the first mating period compared to Control (3.708 ± 0.207; 1.515 ± 0.164), while TAK-683 treatment (4.457 ± 0.181; 1.967 ± 0.213) was not different between groups. GnRH (58.82 %) and TAK-683 (42.10 %) treatments increased the pregnancy rate in the second mating period in comparison to the Control group (17.39 %) (P<0.05). Cumulative pregnancy and fecundity rates were higher in GnRH (79.41 %; 120.58 %) and TAK-683 (68.57 %; 100.0 %) groups than in the Control group (17.39 %; 58.33 %) (P<0.05). There was no difference in late embryonic loss rate among the groups (P>0.05), whereas early fetal loss rate tended to be lower in the TAK-683 (0 %) and GnRH (0 %) groups than in the Control group (15.38 %) (P=0.07). The total pregnancy loss rate (from day 19 to day 50 post-mating) was lower in GnRH (0 %) and TAK-683 (0 %) groups relative to the Control group (21.42 %) (P<0.05). There were no statistical differences among the groups in terms of the first mating period pregnancy rate, twinning rate, and litter size (P>0.05). As a result, treatment with GnRH and TAK-683 on the fourth day after mating increased fecundity in lactating ewes outside the breeding season by preventing total pregnancy losses (from day 19 to day 50) and increasing second mating pregnancy rates.

The present study aims to elucidate the transcriptomic changes occurring in the cardiac tissue of sheep breeds acclimated to highland versus lowland regions in India. The Changthangi sheep thrives in cold arid highlands of Ladakh in contrast to the Muzzafarnagri sheep which is native to the sub-tropical plains characterized by sweltering heat and high humidity. Four biological replicates of heart tissue from each breed were used to generate the RNA sequencing data. Both breeds exhibited high expression of genes related to crucial cardiac functions such as muscle contraction, hypertrophy and calcium ion homeostasis. Differential gene expression analysis identified distinct expression profiles associated with altitudinal adaptation, with enrichment of apoptotic signals in Changthangi and glycosaminoglycan metabolism in Muzzafarnagri sheep. Gene co-expression network highlighted the significance of apoptosis and EGFR pathway that may orchestrate adaptive responses to low oxygen levels in Changthangi sheep found in high altitude. The nodal genes identified in Muzzafarnagri sheep play essential roles in stress responses and MAPK signaling pathways, pivotal for cellular adaptation and survival under adverse conditions. The key genes identified within our study present compelling candidates for future studies in altitudinal adaptation in ovines. This comprehensive analysis provides valuable insights into the genetic basis of cardiac adaptation to altitude in sheep, shedding light on the molecular pathways involved in physiological adjustments to high-altitude environments.

The objective of this study was to assess the probiotic and technological properties of lactic acid bacteria (LAB) isolated from artisanal sheep milk cheeses for potential use in dairy products made from goat milk. Strains studied were Lacticaseibacillus paracasei LC6, Lactiplantibacillus plantarum LP48, Lactococcus lactis subsp. hordniae LH69 and Leuconostoc mesenteroides LM99. The criteria studied were fermentative capacity, carbohydrate fermentation profile, β-galactosidase (lactase) activity, auto-aggregation capacity, hydrophobicity, antimicrobial activity, resistance to simulated gastric secretion, bile resistance, and resistance to different pH and salts concentrations, as well as growth and viability in goat milk. In general, the strains studied showed characteristics compatible with potential probiotic effects. However, according to criteria studied, L. plantarum LP498 best met the conditions; it was compatible with probiotic potential under all the conditions considered and showed noteworthy differences compared to the other micro-organisms studied, particularly in its capacity for self-aggregation and pH resistance. Therefore, L. plantarum LP48 could be adequate for the manufacture of artisanal goat milk products.

This study evaluated the effect of different orange essential oil (OEO) inclusion rates on live weight gain, eating behavior, carcass characteristics, morphology of the ruminal epithelium, and fatty acid profile in the meat of feedlot lambs. Forty uncastrated Dorper × Santa Inês ram lambs with an initial average body weight of 21.8 ± 4.7 kg and average age of 86 ± 15 days were allocated to one of five dietary treatments in a randomized complete block design. Dietary treatments consisted of a 90:10 concentrate-to-forage ratio total mixed ration supplemented as follows: 1. non-additive supplementation (Control), and 2. additive supplementation with 100, 500, and 1000 mg OEO/kg diet DM (OEO100, OEO500, and OEO1000) or with 25 mg sodium monensin/kg diet DM (MON). The feeding lasted 84 d. Supplementation with OEO increased linearly dry matter intake (DMI), growth rate and feed efficiency (FE). Because of the linear increases in growth rate and the efficiency of energy utilization of the diet, lambs receiving OEO exhibited a greater (increasing linear effect) hot carcass weight (HCW), Longissimus muscle area (LMA), subcutaneous fat thickness (SFT), and body wall thickness (BWT) than lambs fed with Control. Lambs fed MON had lower DMI, growth rate and FE than Control and OEO. Compared to Control and OEO supplemented, lambs that received MON showed lower HCW, LMA, SFT, and BWT. Lambs fed with MON had lower oocyst counts than lambs fed with all other treatments. Lambs fed with MON spent more time eating and ruminating, with higher chewing rates than lambs fed all other diets. Rumen morphometry was unaffected by dietary treatment. The OEO supplementation increased the sum of monounsaturated fatty acids, improved the human health promotion index (HP index), and reduced the thrombogenicity index in the meat relative to lambs fed the MON treatment. Under the conditions in which the experiment was conducted, the inclusion of up to 1000 g/kg diet DM in high-energy finishing diets promotes DMI and improved growth performance and FE. Improvements in the carcass (HCW, LMA, and BTF) with OEO supplementation were mainly due to improvements in growth rate rather than effects on gain composition. Based on growth performance and carcass characteristics, OEO was a superior feed additive to sodium monensin. The OEO supplementation has a discreet effect on the fatty acid profile of the meat, but it is sufficient to improve the HP index. These findings highlight its potential as an effective additive for enhancing lamb productivity.

The growth rate of sheep determines their productivity; the faster the growth rate, the higher the productivity. Sheep growth is usually measured by body weight, which is an important indicator of overall growth, and body size, which reflects body shape and structure. Therefore, in sheep production, the selection and improvement of growth traits is one of the important means to improve production efficiency. In this study, 857 males of Hu sheep were selected to record growth traits, including body weight, height, length, and chest, and cannon circumference at 80, 100, 120, 140, 160 and 180 days of age, as well as live weight before slaughter and carcass weight. Correlation analyses conducted between these growth traits at different stages were significantly correlated with both live weight before slaughter and carcass weight. And the strongest correlation was observed for body weight, while body height showed the weakest correlation. The myosin heavy chain 3 (MYH3) gene in the MYH gene family was selected as the target gene, and a synonymous mutation (MYH3 g.33834192A>G) in the exon 12 region of MYH3 was identified by polymerase chain reaction (PCR) and Sanger sequencing. Further association analysis using competitive allele-specific PCR (KASPar) technique showed that the MYH3 g.33834192A>G locus was significantly (P < 0.05) associated with growth traits (including body weight from 80 to 160 days of age, body height at 80 and 100 days of age, body length at 100 and 140 days of age, chest circumference at 80, 100, 160, and 180 days of age, cannon circumference at 80–140 days of age and carcass weight). Among them, the dominant genotype was GG. Meanwhile, the tissue expression results indicated that the highest level of MYH3 gene expression was found in muscle tissues. Therefore, this locus can be used as a candidate molecular genetic marker for improving growth traits in Hu sheep.

Variation in feed resource availability within production systems can cause genotype by environment interactions that change the ranking of the best animals to select between environments. Mediterranean environments have high variation in pasture growth between years that could cause genetic by environment interactions for sheep production traits. Therefore, we estimated heritabilities for live weight, fleece weight, fibre diameter and number of lambs weaned in six years from 2000 to 2005 and correlations between years comparing multivariate analysis and random regression analysis. We compared 3 methods: 1 multivariate analysis estimating (co)variances for traits in each year, 2 Random regression estimated (co)variances for intercept and slope for traits as repeated measurements fitted against average pasture growth in each year and 3. Random regression fitted against corrected average performance of animals in each year. Random regression was estimated with an order of polynomial of one for additive genetic variance and zero for permanent environmental effects. This combination of polynomials was the best fit based on Bayesian information criterion. We estimated heritabilities for each year and correlations between years using records from 3299 pedigreed Merino ewes managed at Katanning in Western Australia. There were 4651 records for adult live weight, 6750 for adult clean fleece weight, 6965 for adult fibre diameter, and 7774 for number of lambs weaned across all 6 years. Number of lambs weaned had more genotype by environment interactions than other traits, with fibre diameter and fleece weight having genotype by environment interactions between only a few years. Based on Bayesian information criterion values, multivariate analysis fit the data better for live weight, fleece weight and fibre diameter. Additionally, random regression estimated higher genetic correlations between years than multivariate analysis suggesting there was not enough flexibility in the random regression analysis, which used only first order polynomials, to fit differences between years. Pasture growth across years did not explain differences in performance for traits across years. Therefore, for number of lambs weaned, random regression using corrected average performance was a better fit than average pasture growth. For other traits, more years or a better indicator of variation in performance within and between years are required to use random regression for genotype by environment interactions.

Oxalic acid, a crucial secondary metabolite prevalent in most plants, often constitutes an unavoidable component of the diet for grazing animals, particularly in saline-alkaline grasslands. This research focused on examining the effects of elevated oxalic acid consumption on various aspects of sheep health and metabolism, including growth performance, nutrient digestibility, blood biochemical indices, rumen fermentation, and microbial populations. Employing a single-factor experimental model, 24 six-month-old German Merino sheep (with an average body weight of 32.08 ± 3.43 kg) were systematically segregated into three distinct groups. Each group contained eight replicates, with each replicate comprising a single sheep. The diet of the experimental groups was enhanced with oxalic acid concentrations of 1 % (T1) and 2 % (T2), whereas the control group received no oxalic acid addition. Under ad libitum feeding, the duration of the experimental phase spanned a total of 60 days. Outcomes demonstrated that a 2 % oxalic acid augmentation notably diminished the sheep's daily weight gain (ADG) (P<0.05), elevated the feed conversion ratio (FCR) (P<0.05), and reduced the ruminal pH levels (P<0.05), compared to both control group and 1 % oxalic acid group. This pH reduction markedly curtailed the synthesis of essential ruminal constituents such as acetic acid, propionic acid, and butyric acid (P<0.05). Furthermore, there was a notable decline in serum alkaline phosphatase (ALP) levels, alongside rises in both blood urea nitrogen (BUN) and serum creatinine (CREA)(P<0.05), coupled with a significant reduction in serum calcium concentrations (P<0.05) in 2 % oxalic acid group, compared to both control group and 1 % oxalic acid group. Moreover, the 2 % oxalic acid addition adversely impacted the digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF), as well as the concentration of NH₃-N in the rumen fluid (P<0.05), compared to both control group and 1 % oxalic acid group. Pertaining to rumen microorganisms, there was a significant escalation in the relative abundance of Proteobacteria at the phylum level, contrasted by a substantial reduction in the presence of Fibrobacteres (P<0.05). At the genus level, an increased concentration of oxalic acid in the diet correlated with a pronounced decline in the relative abundance of Prevotella_1, and a substantial decrease was observed in the relative abundance of Ruminococcaceae_UCG-014 (P<0.05). In summary, while sheep can acclimate to an inclusion of 1 % oxalic acid in their diet, an augmentation of 2 % oxalic acid appears detrimental, impinging upon growth performance, fiber and crude protein (CP) digestibility, blood calcium levels, rumen pH, volatile acid content, and the microbial ecosystem within the sheep’s rumen.

This experiment was conducted to evaluate the effect of milk thistle (Silybum marianum) seed powder supplementation in the diet on weight gain, feed conversion efficiency, and physiological parameters in fattening lambs. In this experiment, thirty crossbred Shawl × Romanov male lambs were divided into three groups based on a completely randomized design. The experimental treatments included a control group receiving a diet without milk thistle seed powder (MSP), a group receiving a diet containing 1 % MSP, and a group receiving a diet containing 2 % MSP. Animals fed the diet containing 2 % MSP exhibited higher nutrient intake, average daily gain, and final body weight compared to the other treatment groups (P < 0.05). Lambs receiving the 2 % MSP diet had the most favorable feed conversion ratio (P < 0.05). The apparent digestibility of dry matter, organic matter, and crude protein was highest in lambs fed the diet containing MSP compared to the control group (P < 0.05). Ruminal NH₃-N concentration and populations of total protozoa and Entodinium genus were lowest in lambs fed the MSP-containing diets (P < 0.05). The molar concentrations of acetate and valerate in the rumen fluid of lambs receiving the diet containing 2 % MSP were lower compared to the control group, while propionate concentration was higher (P < 0.05). Feeding the diet containing 2 % MSP reduced serum cholesterol, triglycerides, LDL, and liver enzyme activities compared to the control group (P < 0.05). Based on these results, supplementing lamb diets with 2 % MSP increased growth performance measures, nutrient digestibility coefficients, and reduced blood cholesterol and LDL concentrations.

In ruminants, the signal (interferon-tau, IFNT) for the maternal recognition of pregnancy has effects on maternal extrauterine organs, and progesterone plays a key role during pregnancy. However, it is unclear that early pregnancy has effects on the expression of interferon-stimulated genes (ISGs), progesterone receptors (PGRs), and progesterone-induced blocking factor (PIBF) in ovine small intestine. In this study, small intestines were obtained at day 16 of the estrous cycle, days 13, 16, and 25 of pregnancy, and RT-qPCR assay, Western blot, and immunohistochemistry were used to analyze the effects of early pregnancy on the expression of ISGs, PGR, and PIBF in the small intestine. The results indicated that expression levels of ISG15-conjugated protein, signal transducer and activator of transcription 1 (STAT1), myxovirus resistance protein 1, and interferon-gamma-inducible protein 10 (IP-10) at day 13 of pregnancy were the lowest. However, expression levels of PGR isoforms (60 kDa and 40 kDa), PIBF, STAT1 and 2′,5′-oligoadenylate synthetase 1 upregulated, but the expression value of IP-10 downregulated at day 25 of pregnancy compared with day 16 of the estrous cycle. In conclusion, early pregnancy modulated the expression of ISGs, PGR, and PIBF in ovine duodenum, which was implicated in immunoregulation and nutrient absorption of the small intestine in ewes.

The objective of the research was to quantify the levels of heat stress, physiological variables and losses of sensible and latent heat in sheep native to the Brazilian semi-arid region, kept in a climatic chamber at thermoneutral temperatures and heat stress. The experimental design was completely randomized with five temperatures and 24 sheep, with an average age of 5.0±1.0 months and an average weight of 15.0±2.3 kg. According to the heat stress index (HSI) at temperatures from 20.0 to 28.0 °C the environment was classified as comfortable, at a temperature of 32.0 °C, the environment was classified as mild to moderate discomfort, and at a temperature of 36.0 °C, it was classified as alert. With the increase in temperature, the animals significantly (P<0.05) increased rectal and superficial temperatures and respiratory rate and, in TNT, sensitive heat exchanges corresponded to an average of 55.9 % and in HST to 12.9 % of the total, and at a temperature of 32.0 °C, sensible heat exchanges corresponded to 17.9 % and latent heat exchanges corresponded to 82.1 % and, at a temperature of 36.0 °C, 95.8 % of heat exchanges were due to latent means, of which 85.1 % were cutaneous. Sheep kept in stressful thermal conditions increase their physiological variables and eliminate the majority of excess metabolic heat through latent means (skin and respiratory tract).