Fertilisation and weed control effects on yield and weeds in durum wheat grown under rain-fed conditions in a Mediterranean climate

Summary A field study was undertaken to examine the effect of fertiliser type and weed control system on grain yield, yield components and weed population in durum wheat ( Triticum turgidum. var. durum) grown in a 4-year rotation [bare fallow–barley ( Hordeum vulgare )–vetch ( Vicia sativa )–wheat]. Fertilisation treatments were: no fertilisation, organic fertilisation with 2500 kg ha⁻¹ of compost (sheep manure and cereal straw) and chemical fertilisation with 100–60–60 kg ha⁻¹ of NPK. Weed-control treatments were: no control, herbicide, harrowing with long-flex spring tines and strip sowing with inter-row hoeing. Chemical fertilisation increased grain yield with respect to the other treatments, amongst which no significant differences were noted. Weed-control systems afforded no improvement in yield compared with controls; indeed, yields obtained using inter-row hoeing were lower. The weed population consisted of a large variety of species, of which the most important were Convolvulus arvensis and Polygonum aviculare . Application of weed-control systems reduced weed density. Herbicide was the most effective, reducing weed biomass by 80%, whilst harrowing and hoeing reduced weed biomass by 40% and 52% respectively. Inter-row hoeing does not appear to be a viable alternative to herbicides, when used as the sole weed control method in a non-diverse cropping system in Mediterranean climates. The lack of response to compost suggests a need for further long-term research.     

Incidence of Unilateral Fertilizations after Low Dose Deep Intrauterine Insemination in Spontaneously Ovulating Sows under Field Conditions

A new procedure for non-surgical deep intrauterine insemination (DUI) in unrestrained sows hormonally induced to ovulate, has been reported. In comparison with standard artificial insemination (AI), with this procedure, the sperm numbers inseminated can be reduced 20-fold without reducing the reproductive performance of these hormonally treated sows. The present study evaluated, using two experiments, the reproductive performance applying 20-fold different sperm numbers per AI dose using DUI or standard AI in spontaneously ovulating sows, under field conditions. In experiment 1, AI was applied to crossbred sows at 12, 24 and 36 h after onset of spontaneous oestrus using one of the following two regimes: (i) DUI (treatment) with 0.15 x 10(9) fresh boar spermatozoa in 5 ml of Beltsville thawing solution (BTS) extender (n = 95), and (ii) standard cervical AI (control) with 2.85 x 10(9) fresh spermatozoa in 95 ml of BTS extender (n = 95). The farrowing rates of the two groups of sows were statistically similar (NS). However, a decrease (p < 0.002) in litter size and the total number of pigs born alive was observed in sows inseminated with the DUI procedure. In experiment 2, 42 post-weaned oestrus sows were inseminated following the same design described for experiment 1 during spontaneous oestrus. On day 6 after onset of oestrus, the proximal segment of the uterine horns of the sows were flushed under surgery to retrieve eventual embryos and evaluate the success of fertilization per cornua (e.g. occurrence of effective uni- vs bilateral sperm transport rendering uni- or bilateral, complete or partial fertilization). Retrieved embryos were assessed for cleavage and number of accessory spermatozoa. Although identical overall pregnancy rates were achieved in both insemination groups, the percentage of sows with partial bilateral fertilization and unilateral fertilization was markedly higher (p < 0.05) in the DUI group (35%) compared with the control (standard AI) group (5%), with a consequent lower (p < 0.001) percentage of viable early embryos after DUI. The number of accessory spermatozoa in the zona pellucida of the embryos was highly variable, but higher (p < 0.001) in control animals than in DUI-AI. No accessory spermatozoa were found in oocytes retrieved from sows depicting unilateral fertilization. In conclusion, DUI in spontaneously ovulating sows with 0.15 x 10(9) spermatozoa renders similar farrowing rates but a lower litter size compared with use of standard AI with a 20-fold higher sperm dose. The lower litter size ought to be related to a decreased distribution of spermatozoa after DUI leading to a higher incidence of partial bilateral and unilateral fertilization.     

Clinical and Pathological Findings in Testis, Epididymis, Deferens Duct and Prostate following Vasectomy in a Dog

We report the case of a bilateral and multilocular spermatocele and sperm granuloma in a dog that was vasectomized 5 years before. Clinical examination revealed scrotal dermatitis and benign prostatic hyperplasia. Orchiectomy was performed, and gross and histological examination showed testicular degeneration associated with epididymal sperm granuloma. In relation to this case, the literature about long-term effects of vasectomy in dogs has been reviewed. On the basis of these results, a preventive sonogram and physical assessment in prostate and other reproductive structures before vasectomy is recommended.     

Effects of Breed on Follicular Dynamics and Oestradiol Secretion during the Follicular Phase in Sheep

Current study evaluates effects from breed and management background on follicular dynamics and endocrine output during the follicular phase of sheep oestrous cycle. Follicular phases were synchronized with three cloprostenol doses, 10 days apart, in three groups of 10 females of different non-prolific Spanish breeds (Manchega, Rubia del Molar and Negra de Colmenar). Development of all follicles reaching antral diameters >or=2 mm was assessed by daily transrectal ultrasonographies, whereas follicular function was evaluated by measurement of plasma oestradiol concentrations. All the ovulatory follicles were present at induced luteolysis in Manchega sheep, while a 93.7% were detected in Rubia del Molar and Negra de Colmenar ewes. The mean size of these ovulatory follicles was similar between breeds at 0 h, but their growth rates were higher in Manchega ewes, reaching a larger size at oestrous detection than in Negra de Colmenar and Rubia del Molar sheep (p < 0.05). Conversely, the oestradiol levels increased with time in Rubia del Molar and Negra de Colmenar (p < 0.05); whilst remained stable in Manchega females. However, the patterns of follicular turnover were similar between breeds. These results indicate that, though differences in follicular size and size distribution, patterns of follicular turnover in sheep are affected neither by the breed nor by the background of management and selection.     

Biogeochemical cycles of nutrients in tropical Eucalyptus plantations: Main features shown by intensive monitoring in Congo and Brazil

The sustainability of fast-growing tropical Eucalyptus plantations is of concern in a context of rising fertilizer costs, since large amounts of nutrients are removed with biomass every 6–7 years from highly weathered soils. A better understanding of the dynamics of tree requirements is required to match fertilization regimes to the availability of each nutrient in the soil. The nutrition of Eucalyptus plantations has been intensively investigated and many studies have focused on specific fluxes in the biogeochemical cycles of nutrients. However, studies dealing with complete cycles are scarce for the Tropics. The objective of this paper was to compare these cycles for Eucalyptus plantations in Congo and Brazil, with contrasting climates, soil properties, and management practices.The main features were similar in the two situations. Most nutrient fluxes were driven by crown establishment the two first years after planting and total biomass production thereafter. These forests were characterized by huge nutrient requirements: 155, 10, 52, 55 and 23 kg ha^?1 of N, P, K, Ca and Mg the first year after planting at the Brazilian study site, respectively. High growth rates the first months after planting were essential to take advantage of the large amounts of nutrients released into the soil solutions by organic matter mineralization after harvesting. This study highlighted the predominant role of biological and biochemical cycles over the geochemical cycle of nutrients in tropical Eucalyptus plantations and indicated the prime importance of carefully managing organic matter in these soils. Limited nutrient losses through deep drainage after clear-cutting in the sandy soils of the two study sites showed the remarkable efficiency of Eucalyptus trees in keeping limited nutrient pools within the ecosystem, even after major disturbances. Nutrient input–output budgets suggested that Eucalyptus plantations take advantage of soil fertility inherited from previous land uses and that long-term sustainability will require an increase in the inputs of certain nutrients.     

Identification of Apoptotic Bodies in Equine Semen

Apoptosis in the testis is required to ensure an efficient spermatogenesis. However, sometimes, defective germ cells that are marked for elimination during this process escape elimination in the testes, giving rise to ejaculates with increased percentages of abnormal and apoptotic spermatozoa and a high percentage of apoptotic bodies. Apoptosis markers in the ejaculate have been associated with low fertility, either in animals or humans. Therefore, the goal of this study was to investigate whether fresh equine semen contains apoptotic bodies [initially named Merocyanine 540 (M540) bodies] and to study the relationship between the quantity of these bodies and cell concentration, the volume of ejaculate, viability and motility. Moreover, we also studied whether the presence apoptotic bodies in fresh semen was related to the resistance of the stallion spermatozoa to being incubated at 37°C or being frozen and thawed. Fresh equine semen was stained with fluorescent dyes such as M540 and Annexin‐V. Active Caspase 3 was studied in fresh semen through Western blotting and immunofluorescence with a specific antibody. Sperm kinematics was assessed in fresh, incubated and thawed samples using computer‐assisted semen analysis, and viability was evaluated with the LIVE/DEAD Sperm Viability Kit. Overall, our results demonstrate for the first time the presence of apoptotic bodies in equine semen. The quantity of apoptotic bodies was highly variable among stallions and was positively correlated with Caspase 3 activity in fresh samples and negatively correlated with the viability and motility of stallion spermatozoa after the cryopreservation process.     

Colloid Centrifugation Selects Normal Spermatozoa from Polymorphic Bull Ejaculates: A Case Study

Semen from a Western Finncattle bull exhibiting a highly polymorphic spermiogram was processed by colloid centrifugation using Androcoll‐B, a species‐specific silane‐coated silica colloid. In the first experiment, Single Layer Centrifugation (SLC) was used to identify which density colloids were needed to separate different cell populations. Colloids of the two chosen densities were then used in a density gradient resulting in two sperm subpopulations, one containing nearly all normally sized spermatozoa and the other enriched for the macrocephalic spermatozoa. Microcephalic spermatozoa did not appear in either of the selected subpopulations. Using a combination of SLC and DGC with this species‐specific colloid, it was possible to separate the spermatozoa into different subpopulations, that is, a subpopulation containing nearly all normally sized spermatozoa, and another one enriched for the macrocephalic spermatozoa. Thus, colloid centrifugation could be used to select sufficient normal spermatozoa from a highly polymorphic ejaculate for AI, if desired.