Sampling Strategies for Mapping ‘Within-field’ Variability in the Dry Matter Yield and Mineral Nutrient Status of Forage Grass Crops in Cool Temperate Climes

In the absence of suitable technology to measure and map the dry matter (DM) yield distributions of forage grass crops within individual fields, a manual procedure of yield mapping has been developed. Samples of herbage are collected just prior to each silage harvest from known grid points within a field, and sward DM yields at each point are predicted from the mineral composition of the herbage, using empirical mathematical models. Yield maps (and maps of sward nutrient status) are then produced by kriging interpolation between the point data. To make the most efficient use of time and resources, however, sampling intensity needs to be kept to the absolute minimum necessary for interpolation purposes. The aim of the present study was to examine the spatial variability in sward DM yield and mineral nutrient status in a large grass silage field under a three-cut system, and devise optimal sampling strategies for mapping the distributions of these parameters at each cut. Herbage samples were collected from the field, prior to each harvest, at 25 m intervals in a regular rectangular grid to provide databases of herbage nutrient contents and DM yields. Different data combinations were abstracted from these databases for comparison purposes, and ordinary kriging used to produce interpolated maps of DM yield and sward N, P, K and S statuses. The results suggested that a sampling density of just seven samples per hectare was adequate for estimating the true population means of sward DM yield and sward N, P, K, and S statuses. For mapping purposes, it was found that the best compromise between interpolation accuracy and sampling efficiency was to collect herbage samples in a 35.4 m×35.4 m equilateral triangular sampling pattern.     

Effects of putrescine injection in broiler breeder eggs

The aim of this study was to evaluate the effects of increasing doses of putrescine injected in ovo on hatchability, intestinal morphology and pre-starter performance of broilers. For this purpose, 720 eggs from broiler breeders were separated into a negative control (no injection) and injection treatments with increasing doses of putrescine (0.05; 0.1; 0.15 and 0.2%), totalling five treatments of 144 eggs each. Eggs were distributed in a completely randomized design inside the setter and the injection of solutions occurred at 17 days of incubation. After hatch, 330 birds were housed in mixed lots following the original treatments, totalling 5 treatments of 6 replicates with 11 birds each. Six birds per treatment were weighed and euthanized by cervical dislocation to collect the liver, intestine and breast 24 hr after injection, at hatch and 24 hr after hatch. At 2 days of age, intestines were collected from 4 animals per treatment to analyse histomorphology. The effects of putrescine levels were evaluated by polynomial regression models, ANOVA and Tukey test at 5% probability. The hatchability decreased linearly in response to increased doses of putrescine. The percentage of residual yolk was lower in animals that received putrescine compared to the control. After injection, the percentage of breast increased linearly, and the percentage of intestine had a quadratic response to increased doses of putrescine. However, 24 hr after hatch, the percentage of intestine linearly decreased, and the percentage of liver linearly increased in response to increased doses of putrescine. Villus height increased quadratically, crypt depth decreased linearly, and goblet cells increased linearly in response to the putrescine dose. FI and BWG were not affected in the pre-starter phase; however, FCR increased in response to increased levels of putrescine. Due to putrescine effects on embryos, it is recommended that the doses injected in ovo not exceed 0.1%.     

Development of a RAPD marker-based classification criterion for quality semen production in Holstein crossbred bulls

In cattle production systems, an intense selection pressure for production traits has resulted in the decline of fertility traits. To optimize an efficient reproduction system, the inclusion of both male and female fertility traits in the selection process is very much essential. RAPD (Random Amplified Polymorphic DNA) was developed as a molecular biology tool and has been extensively used, to study intra- and interspecific genetic diversity. The present study was undertaken to utilize RAPD primers to investigate the association between DNA markers and semen quality traits viz. Sperm concentration, total sperm count ejaculate and initial sperm motility and thereby to identify good/poor semen producers. DNA isolated from the blood samples of healthy bulls was subjected to RAPD-PCR. The multiple regression analysis followed by independent t test was carried out to identify suitable markers. Based on the results, only 12 bands were identified as marker suitable for any of the quality trait. This includes, OPA2 ~ 760, OPA2 ~ 700, OPA6 ~ 1,200, OPA9 ~ 400, OPA9 ~ 380, OPA12 ~ 970, OPA14 ~ 715, OPA14 ~ 605, OPA16 ~ 485, OPA17 ~ 860 and OPA18 ~ 480. Multiple regression analysis selected, OPA2 ~ 760 and OPA2 ~ 1,750 for sperm concentration and OPA2 ~ 760, OPA2 ~ 700, OPA9 ~ 620, OPA4 ~ 670 and OPA18 ~ 1,015 for total sperm count/ejaculate. But the t test revealed a significant association between OPA2 ~ 760 and total sperm count. Further, discriminant function analysis also identified this marker in the first step itself. The results of the present study can be exploited as a low-cost alternative strategy for identification of good /poor semen producers in crossbred bulls at an early age.     

Genetic diversity and population structure of diverse Iranian Nepeta L. taxa

Genetic Resources and Crop Evolution - In the present study, we utilized ISSR molecular markers to investigate infraspecific and infrageneric genetic variations in 34 populations from 25 Nepeta L....     

Conestoga: A new early potato cultivar with very good table and chipping qualities

Conestoga is an early, white-skinned potato with very vigorous early growth. It has very good boiling, baking and chipping qualities. Yield is comparable to that of Superior, with chip colour and specific gravity slightly higher than Norchip’s. Conestoga is moderately resistant to virus leafroll, net necrosis, early blight, and common scab and moderately susceptible to mild and rugose mosaic.     

Elastic constants of wood determined by ultrasound using three geometries of specimens

Knowledge of the twelve elastic constants of wood—three moduli of elasticity (E _L, E _R, and E _T), three shear moduli (G _LR, G _LT, and G _RT), and six Poisson’s ratios (μ _LR, μ _RL, μ _RT, μ _TR, μ _LT, and μ _TL)—is essential in some applications, e.g., in simulations or structural calculation software. The methodology for determining these parameters has been developed by different authors, but typically with different samples, which prevents conclusive comparisons. The aim of the present study was to assess both the methods and associated results of using ultrasound technology on three geometric specimens—multifaceted discs, polyhedrons, and prisms—to characterize samples from three wood species: Eucalyptus saligna, Apuleia leiocarpa, and Goupia glabra. The results from the ultrasound and static compression tests on the prism were obtained from another study by the authors’ group and used for a comparative analysis because the species belonged to the identical sample. In general, the moduli of elasticity and shear moduli were statistically equivalent to those obtained by the static test for the three geometries of the specimens. The results of the Poisson’s ratios depended on the type and geometry of the specimens. The polyhedral geometry showed the best results, whereas the prismatic results were the least suitable. From a methodological perspective, the polyhedron was easier to apply.     

A Real-Time PCR for Detection and Quantification of Mycoplasma ovipneumoniae

A real-time PCR for detection and quantification of M. ovipneumoniae was developed using 9 recently sequenced M. ovipneumoniae genomes and primers targeting a putative adhesin gene p113. The assay proved to be specific and sensitive (with a detection limit of 22 genomic DNA) and could quantify M. ovipneumoniae DNA over a wide linear range, from 2.2 × 10² to 2.2 × 10⁷ genomes.