Ovarian action of leptin: effects on insulin-like growth factor-I-stimulated function of granulosa and thecal cells

To test the hypothesis that leptin signals metabolic information to the reproductive system in cattle by directly affecting IGF-I-induced ovarian cell function, granulosa and thecal cells from bovine ovarian follicles were cultured for 2 d in serum-free medium with added hormones. Recombinant human leptin at 30 and 300 ng/mL had no effect on basal thecal cell steroidogenesis or thecal cell numbers. However, 300 but not 30 ng/mL of leptin attenuated (p<0.05) luteinizing hormone-induced androstenedione production by 24% in the absence of IGF-I and by 16% in the presence of IGF-I. Leptin had no effect on IGF-I-induced estradiol production in the presence of follicle-stimulating hormone (FSH), but at 100 ng/mL, leptin inhibited (p<0.05) FSH plus IGF-I-induced progesterone production and granulosa cell proliferation by 29 and 31%, respectively. Leptin did not compete for ¹²⁵I-IGF-I binding to granulosa or thecal cells, whereas unlabeled IGF-I did. In conclusion, leptin has weak inhibitory effects on gonadotropin-and/or IGF-I-induced steroidogenesis of thecal and granulosa cells.     

An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production

A quarter of all anthropogenic methane emissions in the United States are from enteric fermentation, primarily from ruminant livestock. This study was undertaken to test the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission in lactating Holstein cows. An experiment was conducted using 48 cows in a randomized block design with a 2-wk covariate period and a 12-wk data collection period. Feed intake, milk production, and fiber digestibility were not affected by the inhibitor. Milk protein and lactose yields were increased by 3NOP. Rumen methane emission was linearly decreased by 3NOP, averaging about 30% lower than the control. Methane emission per unit of feed dry matter intake or per unit of energy-corrected milk were also about 30% less for the 3NOP-treated cows. On average, the body weight gain of 3NOP-treated cows was 80% greater than control cows during the 12-wk experiment. The experiment demonstrated that the methane inhibitor 3NOP, applied at 40 to 80 mg/kg feed dry matter, decreased methane emissions from high-producing dairy cows by 30% and increased body weight gain without negatively affecting feed intake or milk production and composition. The inhibitory effect persisted over 12 wk of treatment, thus offering an effective methane mitigation practice for the livestock industries.The livestock sector is a significant source of greenhouse gas (GHG) emissions in the United States and globally (1, 2). In the United States, enteric fermentation of feed by ruminants is the largest source of anthropogenic methane emissions (0.14 Gt of CO₂ Eq. in 2012; or 25% of the total methane emissions; ref. 3). Globally, according to the most recent Intergovernmental Panel on Climate Change (IPCC) report, GHG emissions from agriculture represent around 10–12% (5.0–5.8 Gt CO₂ Eq/yr) of the total anthropogenic GHG emissions (1). In this report, livestock contribution to the global anthropogenic GHG emissions was estimated at 6.3%, with GHG emissions from enteric fermentation accounting for 2.1 Gt CO₂ Eq/yr and manure management accounting for 0.99 Gt CO₂ Eq/yr (1). The relative contribution of emissions from enteric fermentation to the total agricultural GHG emissions will vary by region depending on the structure of agricultural production and type of livestock production systems. For example, GHG from enteric fermentation were estimated at 57% for New Zealand, a country with a large, pasture-based livestock sector (4). Extensive research in recent years has provided a number of viable enteric methane mitigation practices, such as alternative electron receptors, methane inhibitors, dietary lipids, and increased animal productive efficiency (5). Methane emission in the reticulo-rumen is an evolutionary adaptation that enables the rumen ecosystem to dispose of hydrogen, a fermentation product and an important energy substrate for the methanogenic archaea (6), which may otherwise accumulate and inhibit carbohydrate fermentation and fiber degradation (7, 8). Some compounds may be effective in decreasing methane emission, but they may also decrease feed intake, fiber degradability, and animal productivity (5), or the rumen archaea may adapt to them (9). Therefore, it is important to evaluate methane mitigation strategies in long-term experiments, which for livestock experimentation requires treatment periods considerably longer than the 21–28 d, common for crossover designs. In addition, due to a variety of constraints and confounding factors of batch or continuous culture in vitro systems (5, 10), mitigation compounds, including methane inhibitors, have to be tested in vivo using animals with similar productivity to those on commercial farms. An example of the limitations of in vitro systems is a series of experiments with garlic oil. In continuous rumen culture, garlic oil was very effective in inhibiting rumen methane emission (11), but it failed to produce an effect in sheep (12). The nutrient requirements of high-producing dairy cows are much greater than those of nonlactating or low-producing cows (13) and hence any reduction in feed intake caused by a methane mitigation compound or practice would likely result in decreased productivity, which may not be evident in low-producing cows.Methane inhibitors are chemical compounds with inhibitory effects on rumen archaea. Compounds such as bromochloromethane, 2-bromoethane sulfonate, chloroform, and cyclodextrin have been tested, some successfully, in various ruminant species (5). Inhibition of methanogenesis by these compounds in vivo can be up to 60% with the effect of bromochloromethane shown to persist in long-term experiments (5, 14). However, the viability of these compounds as mitigation agents has been questioned due to concerns for animal health, food safety, or environmental impact. Bromochloromethane, for example, is an ozone-depleting agent and is banned in many countries.Among the efficacious methane inhibitors identified is 3-nitrooxypropanol (3NOP; ref. 15). This compound was part of a developmental program designing specific small molecule inhibitors for methyl coenzyme-M (CoM) reductase, the enzyme that catalyzes the last step of methanogenesis, the reduction of methyl CoM and coenzyme-B (CoB) into methane and a CoM–CoB complex (16). A continuous in vitro culture study (11) was followed by in vivo experiments in sheep (17), beef (18), and dairy cattle (19, 20), which demonstrated that 3NOP is an effective methane inhibitor. However, these experiments were conducted using nonlactating animals (17), or were short-term (<35 d; refs. 19 and 20). The rumen microorganisms have the ability to adapt to foreign agents or changes in the feeding regimen and, therefore, short-term responses are not representative of the effect of a given mitigation compound or practice in real farm conditions. McIntosh et al. (21), for example, showed that the MIC50 of essential oils doubled or tripled for a number of important rumen bacteria (Butyrivibrio fibrisolvens, Prevotella bryantii, Ruminococcus albus, Ruminobacter amylophilus), if they were adapted to the treatment for a period of 10 d. Thus, it is critically important for the success of GHG mitigation efforts to substantiate the mitigation potential of a given compound in long-term animal experiments before considering it for adoption by the livestock industries.     

Schmallenberg virus in domestic cattle, belgium, 2012

To determine prevalence of antibodies against Schmallenberg virus in adult cows and proportion of infection transmitted to fetuses, we tested serum samples from 519 cow/calf pairs in Belgium in spring 2012. Of cattle within 250 km of location where the virus emerged, ≈91% tested positive for IgG targeting nucleoprotein. Risk for fetal infection was ≈28%.     

Susceptibility of N''Dama and Boran cattle to tsetse-transmitted primary and rechallenge infections with a homologous serodeme of Trypanosoma congolense

Eight trypanotolerant N'Dama cattle controlled an infection of Trypanosoma congolense ILNat 3.1 transmitted by Glossina morsitans centralis, more efficiently than a group of similarly infected trypanosusceptible Boran cattle. All eight N'Damas maintained their PCV above 15% throughout the primary infection whereas the PCV of six of the eight Borans dropped below 15%; these latter animals were treated with diminazene aceturate to prevent possible death. Lymphocyte, neutrophil and platelet counts also decreased in the Boran during the primary infection. In contrast, a lymphocytosis was observed in the N'Dama; and although the neutrophil and platelet counts decreased, the drop was less severe than in the Boran. Two years after the primary infection and immediately prior to a homologous rechallenge infection, all eight N'Damas had neutralizing anti-metacyclic trypanosome variant-specific antibodies present in their sera compared to five of the eight Borans. Following the homologous rechallenge infection the eight N'Damas became parasitaemic but there were no alterations in their erythrocyte or leukocyte counts. The Borans became highly parasitaemic and developed severe, chronic anaemia and leukopaenia. Thus, the trypanotolerant N'Damas controlled a primary infection of T. congolense more efficiently than trypanosusceptible Boran cattle and eliminated a homologous rechallenge infection without the pathology associated with the disease.     

畜牧活动对蜱虫密度分布的影响

了解浙江省义乌市家养动物寄生蜱情况。

于2021年对义乌市家养动物寄生蜱进行监测、鉴定及分析。

共监测452只家养动物,寄生蜱阳性306只,阳性率67.70%,捕获蜱2 603只,蜱指数5.76,隶属于生蜱1科4属10种,长角血蜱为优势蜱种（占59.16%）,其次为镰形扇头蜱（26.32%）、微小扇头蜱（6.45%）。各种家养动物寄生蜱阳性率、蜱指数、蜱虫种类数依次为：山羊（74.37%、7.45、7种）、黄牛（62.50%、4.14、6种）、犬（54.62%、2.59、8种）。单只家养动物寄生≥2种蜱种的动物主要是山羊（25.99%）、掺和多重寄生蜱种以长角血蜱（91.26%）最多。山羊优势蜱种为长角血蜱（65.15%）及镰形扇头蜱（29.42%）;黄牛优势蜱虫为微小扇头蜱（67.67%）及镰形扇头蜱（20.69%）,犬优势蜱种为长角血蜱（57.14%）及豪猪血蜱（21.10%）。山羊、黄牛、犬3种家养动物蜱指数随季节变化其变化趋势也有所不同,山羊与犬蜱指数同长角血蜱消长呈一致,均为3月份为主高峰,9、10月份为次高峰;黄牛蜱指数与微小扇头蜱消长一致,有4月份、8—9月份2个高峰。幼蜱、若蜱、成蜱均有捕获,以若蜱为多,存在单只动物重叠寄生同种不同虫态蜱虫现象,山羊占比较高,其中以长角血蜱多见。

义乌市家养动物寄生蜱较为普遍,蜱种类较多,以长角血蜱为优势蜱虫,危害较大,应引起重视。

     

Emerging Tickborne Bacteria in Cattle from Colombia

Ehrlichia minasensis is a new pathogenic bacterial species that infects cattle, and Borrelia theileri causes bovine borreliosis. We detected E. minasensis and B. theileri DNA in cattle from southwestern Colombia by using PCR. E. minasensis and B. theileri should be considered potential etiologies of febrile syndrome in cattle from Colombia.     

Bovine Polyomavirus-1 (Epsilonpolyomavirus bovis): An Emerging Fetal Pathogen of Cattle That Causes Renal Lesions Resembling Polyomavirus-Associated Nephropathy of Humans

Bovine polyomavirus-1 (BoPyV-1, Epsilonpolyomavirus bovis) is widespread in cattle and has been detected in commercialized beef at supermarkets in the USA and Germany. BoPyV-1 has been questioned as a probable zoonotic agent with documented increase in seropositivity in people exposed to cattle. However, to date, BoPyV-1 has not been causally associated with pathology or disease in any animal species, including humans. Here we describe and illustrate pathological findings in an aborted bovine fetus naturally infected with BoPyV-1, providing evidence of its pathogenicity and probable abortigenic potential. Our results indicate that: (i) BoPyV-1 can cause severe kidney lesions in cattle, including tubulointerstitial nephritis with cytopathic changes and necrosis in tubular epithelial cells, tubular and interstitial inflammation, and interstitial fibroplasia; (ii) lesions are at least partly attributable to active viral replication in renal tubular epithelial cells, which have abundant intranuclear viral inclusions; (iii) BoPyV-1 large T (LT) antigen, resulting from early viral gene expression, can be detected in infected renal tubular epithelial cells using a monoclonal antibody raised against Simian Virus-40 polyomavirus LT antigen; and (iv) there is productive BoPyV-1 replication and virion assembly in the nuclei of renal tubular epithelial cells, as demonstrated by the ultrastructural observation of abundant arrays of viral particles with typical polyomavirus morphology. Altogether, these lesions resemble the “cytopathic-inflammatory pathology pattern” proposed in the pathogenesis of Human polyomavirus-1-associated nephropathy in immunocompromised people and kidney allograft recipients. Additionally, we sequenced the complete genome of the BoPyV-1 infecting the fetus, which represents the first whole genome of a BoPyV-1 from the Southern Hemisphere. Lastly, the BoPyV-1 strain infecting this fetus was isolated, causing a cytopathic effect in Madin–Darby bovine kidney cells. We conclude that BoPyV-1 is pathogenic to the bovine fetus under natural circumstances. Further insights into the epidemiology, biology, clinical relevance, and zoonotic potential of BoPyV-1 are needed.     

Detection of Crimean-Congo Hemorrhagic Fever Virus Antibodies in Cattle in Plateau State,Nigeria

Crimean-Congo hemorrhagic fever (CCHF) is a vector-borne viral hemorrhagic disease with global clinical significance. Certain species of ticks are vectors of CCHF, which can be transmitted from animals to humans and humans to humans by direct exposure to blood or other body fluids. The zoonotic transmission at the human–animal interface from viremic animal hosts to humans is a public health concern with a paucity of data in Nigeria. Samples from 184 pastoral cattle from three local government areas (LGAs) of Plateau state, Nigeria, were screened for CCHF virus using a commercial enzyme-linked immunosorbent assay (ID Screen^® CCHF Double Antigen for Multi-Species). Overall seropositivity of 30.4% (n = 56) (95% CI: 23.88%, 37.63%) was recorded from the study areas in Plateau State, while 48/126 (38.1%, 95% CI: 29.59%, 47.17%) sampled cows tested positive for CCHFV antibodies. Seropositivity was significantly higher (p < 0.001) among older cattle greater than two years, 54.69% (95% CI: 2.88%, 11.24%) compared to cattle younger than two years, 17.5% (95% CI: 11.17%, 25.50%). The location of farms played a significant role in the seropositivity of CCHF with the least risk observed in Wase LGA. CCHF is an important zoonotic disease in different parts of the globe with a high risk of transmission to pastoralists, livestock keepers/slaughterhouse workers, and veterinarians who handle animals. There is a need for a collaborative one-health approach with various stakeholders to unravel the dynamics of CCHFV epidemiology in Nigeria.     

Chromosomal evolution in bovids: a comparison of cattle,sheep and goat G- and R-banded chromosomes and cytogenetic divergences among cattle,goat and river buffalo sex chromosomes

A G- and R-banding comparison of cattle (Bos taurus, 2n=60), goat (Capra hircus, 2n=60) and sheep (Ovis aries, 2n=54) chromosomes at the 450 band level was made. The study revealed a large number of banding homologies among the autosomes of the three species and resolved some ambiguities in arranging some of their small disputed acrocentrics by direct and indirect comparisons with some bovid marker chromosomes. A loss of the subcentromeric G-positive band in sheep chromosome 2q was observed when the G-banding patterns of sheep 2q and homologous cattle and goat chromosome 2 were compared. The chromosomal divergences among cattle, goat and river buffalo (Bubalus bubalis, 2n=50) sex chromosomes are shown to have occurred by pericentric and paracentric inversions with a loss (or acquisition) of constitutive heterochromatin.