Synchronization of oestrus with prostaglandins

Luteolytic doses of the Tham salt of PGF₂ or one of its synthetic analogues cause premature regression of, the corpus luteum between the 5th and the 16th day of the oestrous cycle, inducing, 2 to 4 days after the injection, endcrine changes similar to a normal lultolysis and oestrus. After insemination at the time of this oestrus or at predefined times 72 to 96 hours after the injection, fertility is similar to that in controls. The paractical use of prostaglandins for the synchronization of oestrus in a herd of randomly cyclic animals takes account of the fact that only animals between the 5th and the 16th day respond to an injection. Various techniques are proposed, notably a double injection with an interval of 10–12 days.

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Kurzfassung Luteolytische Dosen eines Tham'schen Salzes von PGF₂, oder einer dessen synthetischen Analogen bringen vorzeitige Regressionen des corporis lutei zwischen dem 5ten und dem 16ten Tage hervor. Als Folge dieser Regressionen entwickeln sich innerhalb 2 bis 4 Tage nach der Einspritzung endokrine Veränderungen, die der normalen Luteolyse und Brunst ähnlich sind. Nach einer Besamung zur Zeit dieser Brunst oder zu vorherbestimmten Zeiten und zwar 72 und 92 Stunden nach der Einspritzung wird die gleiche Frunchtbarkeit wie in unbehandelten Kontrollen beobachtet. Nur ein Teil einer zyklischen Herde reagiert auf Prostaglandin, und es werden daher verschiedene Methoden der Viehwirtschaftsführung zur Überwindung dieses Problems erörtert, wie auch den Gebrauch einer Doppeleinspritzung von Prostaglandin mit einem 10 bis 12 tägigen Abstand zwischen den Behandlungen.

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Resume Les doses lutéolytiques de sel Tham de PGF₂ ou d'un de ses analogues synthetiques causent une reégression prématurée du corps jaunne entre le 5ème et le 16ème jour du cycle provoquant, 2 à 4 jours après l'injections, des changements endocriniens semblales à une lutéolyse normale et à un oestrus. Après l'insémination au moment de cet oestrus ou à des temps prédéfinis de 72 à 96 heures après l'injection, la fertilité est semblable à celle des animaux témoins non traités. L'utilisation pratique des prostaß-landinesd pour la synchronisation des chaleurs dans un troupoeau de femelles cyclées tient compte du fait que seules les femelles entre le 5ème et 16ème jour du cycle répondent à une injection. Différentes techniques sont proposées, notamment la double injection à 10–12 jours d'intervalle.

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Riassunto Le dosi luteolitiche del sale Them PGF₂ o di uno dei suoi analoghi sintetioi causano una regressione prematura del corpo giallo tra il 5^o ed il 16^o giorno del ciclo provooando, dopo un periodo che va dai 2 ai 4 giorni dall'iniezione, dei cambiamenti endocrini simili ad una luteolisi normale o ad un estro. Dopo l'inseminazine, nel momento di questo estro oppure in tempi predeterminati, in un periodo compreso tra 72 e 96 ore dopo l'iniezione, la fertilità è simile a quella jdegli animali di controllo non trattati. L'utilizzazione poratioa della prostaglandine per la sincronizzazione dei oalori in una mandria di femmine cicliche dimostra che le femmine rispondono all'iniezione soltanto tra il 5^o ed 16^o giorno del ciclo. Si propongono diverse techniche, in poarticolasre la doppia iniezione ad un intervallo di 10–12 giorni.

     

Simulation study of the competitive ability of erect, semi-erect and prostrate cowpea (Vigna unguiculata) genotypes

Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterised, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the competition of cowpea genotypes and sunflower than companion field experiments for the competition of cowpea and purslane. The validated simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habit on final biomass production of cowpea and sunflower. The model suggested that erect growth habit was more competitive than semi‐erect and prostrate growth habit, when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass. Our simulation approach is suggested as a method for crop breeders to gauge the likely success of selection for competitive crops before undertaking expensive long‐term breeding experiments.     

Resorcylic acid lactone as an anabolic agent in cattle

This paper discusses the use of resorcylic acid lactone as an anabolic agent in cattle. When given to finishing steers it increases daily gain by 10–18% and final carcass weight by 6–10 kg. When given to finishing steers in conjunction with trenbolone acetate, there is an additive response in terms of growth rate and carcass weight. The final carcass weights were 310±2.1, 319±2.0, 316±2.0 and 328±2.0 for unimplanted steers, or steers implanted with resorcylic acid lactone or trenbolone acetate or a combination of both compounds respectively. Responses in finishing steers in spring at pasture were similar to responses obtained in winter. In male calves, average liveweights at the end of a 134-day experimental period were 123, 142 and 140 kg (SE ± 5.4 kg) respectively for control calves or calves given resorcylic acid lactone or a combination of resorcylic acid lactone and trenbolone acetate. After a further 134 days grazing together these calves weighed 271, 294 and 297 kg (SE ± 7.9 kg) respectively, indicating that the extra gain was retained once the implants ceased to be effective. No significant effect on daily gain or carcass weight of heifers was obtained in our trials with resorcylic acid lactone. Results from feed efficiency trial indicated resorcylic acid lactone significantly increased feed efficiency. Therefore, resorcylic acid is an effective growth promoter in male castrate cattle.     

Conservation Program Participation and Adaptive Rangeland Decision-Making

This paper analyzes rancher participation in conservation programs in the context of a social-ecological framework for adaptive rangeland decision-making. We argue that conservation programs are best understood as one of many strategies of adaptively managing rangelands in ways that sustain livelihoods and ecosystem services. The framework hypothesizes four categories of variables affecting conservation program participation: operation/operator characteristics, time horizon, social network connections, and social values. Based on a mail survey of California ranchers, multinomial logit models are used to estimate the impact of these variables on different levels of rancher involvement in conservation programs. The findings suggest that ranchers with larger amounts of land, an orientation towards the future, and who are opinion leaders with access to conservation information, are more likely to participate in conservation programs.     

Fungi isolated from bovine udders,and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources.

METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi.

RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats.

CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi.

CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance.     

Assessment of Different Functional Parameters of Frozen–Thawed Buffalo Spermatozoa by Using Cytofluorimetric Determinations

Flow cytometry is a useful tool that provides an accurate, objective and rapid evaluation of semen quality. The use of this technique could significantly improve the quality of buffalo semen samples used in artificial insemination. This study was carried out to evaluate, by flow cytometry, frozen–thawed buffalo spermatozoa quality parameters such as sperm viability by SYBR‐14/propidium iodide staining; mitochondrial function by JC‐1 potentiometric probe; sperm chromatin stability (SCSA) by acridine orange; and acrosome reaction (AR) by FITC‐PNA staining. Semen samples from five Italian Mediterranean buffalo bulls were used. Sperm viability was not different between bulls and ranged from 33.4% to 43.6%. A consistent rate (55.1 ± 10.8%) of sperm cells showed high mitochondrial membrane potential (Δψ^high), with no significant differences between subjects. Sperm chromatin structure assay differed significantly between the five buffalo bulls; moreover, data showed high stability within each buffalo. DNA fragmentation indexes (DFI), such as %‐DFI, ‐DFI, SD‐DFI, were 11.2 ± 8.6, 153.3 ± 24.6 and 81.6 ± 21.2, respectively. Regarding AR, the percentage of acrosome‐reacted live (ARL) and acrosome‐reacted dead (ARD) spermatozoa was 0.3 ± 0.2 and 15.3 ± 5.5, respectively. This functional parameter differed significantly between buffalo bulls and showed high stability. Following to Ca²⁺ ionophore A23187 for 3 h, AR significantly differed between subjects and was characterized by an increase in both ARL (10.8%) and ARD population (22.0%). This study indicates that flow cytometry could be a useful tool for a quick multiparametric evaluation of sperm quality in buffalo. In particular, SCSA and AR resulted in sperm functional parameters sensitive enough for the diagnosis of frozen‐thawed semen fertilizing potential.     

Effect of short‐term exposure of cumulus–oocyte complex to 3‐morpholinosydnonimine on in vitro embryo development and gene expression in cattle

Short‐term exposure of gametes to different types of stress might induce stress tolerance in mammalian embryos. The aim of this study was to evaluate the effect of short‐term exposure of bovine mature cumulus–oocyte complex (COC) to 3‐morpholinosydnonimine (SIN‐1) on subsequent in vitro embryo development, embryo quality and relative gene expression. Matured COCs were incubated with SIN‐1 (0, 0.1, 1, 10 and 100 μM SIN‐1) for 1 hr before in vitro fertilization and zygotes were cultured until Day 7. The cleavage rate at 72 hr did not show any differences among groups. However, the blastocyst rate on Day 7 decreased with all treatments evaluated, with the embryos generated with 10 μM SIN‐1 showing the lowest embryo production rate. Embryo quality analysis did not show any differences in total cell number (TCN) or inner cell mass (ICM) among groups. Relative gene expression analysis showed a downregulation of eNOS expression and an upregulation of nNOS expression in all treatments evaluated compared to the control group. Also, a downregulation was observed in some treatments: SOD2 at 0.1 μM; SOD1 at 0.1 and 100 μM; PRDX5 at 0.1, 10 and 100 μM; and NANOG at 10 and 100 μM; and an upregulation of CDX2 expression was observed at 100 μM. The other genes (OCT4, HIF1A, HSPA1A, BCL2A and iNOS) did not show any differences in the relative gene expression. These results suggest that the short‐term exposure of mature bovine COCs to SIN‐1 does not induce stress tolerance and has no beneficial effect on bovine in vitro embryo production.     

Butterfly dispersal in farmland: a replicated landscape genetics study on the meadow brown butterfly (<Emphasis Type="Italic">Maniola jurtina</Emphasis>)

Context

Anthropogenic activities readily result in the fragmentation of habitats such that species persistence increasingly depends on their ability to disperse. However, landscape features that enhance or limit individual dispersal are often poorly understood. Landscape genetics has recently provided innovative solutions to evaluate landscape resistance to dispersal.

Objectives

We studied the dispersal of the common meadow brown butterfly, Maniola jurtina, in agricultural landscapes, using a replicated study design and rigorous statistical analyses. Based on existing behavioral and life history research, we hypothesized that the meadow brown would preferentially disperse through its preferred grassy habitats (meadows and road verges) and avoid dispersing through woodlands and the agricultural matrix.

Methods

Samples were collected in 18 study landscapes of 5 × 5 km in three contrasting agricultural French regions. Using circuit theory, least cost path and transect-based methods, we analyzed the effect of the landscape on gene flow separately for each sex.

Results

Analysis of 1681 samples with 6 microsatellites loci revealed that landscape features weakly influence meadow brown butterfly gene flow. Gene flow in both sexes appeared to be weakly limited by forests and arable lands, whereas grasslands and grassy linear elements (road verges) were more likely to enhance gene flow.

Conclusion

Our results are consistent with the hypothesis of greater dispersal through landscape elements that are most similar to suitable habitat. Our spatially replicated landscape genetics study allowed us to detect subtle landscape effects on butterfly gene flow, and these findings were reinforced by consistent results across analytical methods.

     

CAN SONOGRAPHIC FINDINGS PREDICT THE RESULTS OF LIVER ASPIRATES IN DOGS WITH SUSPECTED LIVER DISEASE?

While abdominal ultrasound and ultrasound-guided fine-needle aspiration cytology are often combined to help determine the type of liver disease in dogs, little is known about the relationship that may exist between the results of these tests. We hypothesized that specific sonographic findings, or combinations of findings, may predict results of liver ultrasound-guided fine-needle aspiration cytology. Hepatic and extrahepatic sonographic findings were recorded prospectively using a standardized form in 70 dogs with clinically suspected liver disease and in which liver ultrasound-guided fine-needle aspiration cytology was performed. The predictive value of sonographic findings in regard to the category of cytology results was assessed with stepwise logistic regression analysis. Sonographic detection of a hepatic mass (≥3 cm; risk ratio [RR] 3.83, 95% Wald confidence intervals [95% CI] 2.42–3.93, P =0.0036), ascites (RR 3.82, 95% CI 1.94–4.28, P =0.0044), abnormal hepatic lymph node(s) (RR 3.01, 95% CI 1.22–4.88, P =0.0262), and abnormal spleen (RR 3.26, 95% CI 1.20–3.85, P =0.0274) were the most predictive of liver neoplasia on cytology. Conversely, sonographic detection of hepatic nodules (<3 cm; RR 1.97, 95% CI 0.95–2.96, P =0.0666) was most predictive of vacuolar hepatopathy on cytology. In dogs with suspected liver disease, several sonographic findings, alone or combined, are thus predictive of liver ultrasound-guided fine-needle aspiration cytology results. In the light of the fact that ultrasound-guided fine-needle aspiration cytology of the liver has limitations, these predictabilities could influence the selection of diagnostic tests to reach a reliable diagnosis.