Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. IV. Characterization of metacarpal, metatarsal, femur, humerus and turbinate bones of sows during three parities

The effect of early nutrition on subsequent bone development was studied using gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council-recommended daily Ca and P from weaning to 100 kg. During the three-parity reproductive study, sows were fed a 14% protein diet. Metacarpals and metatarsals were taken from sows culled due to lameness or failure to breed and from sows after completing three parities. Femur and humerus articular cartilage and turbinates were described at necropsy. Metacarpals and metatarsals were heavier and tended to have thicker walls when sows were previously fed ad libitum or fed 150% Ca and P. Energy intake produced the greater response. Metacarpal breaking strength was greatest for sows previously fed ad libitum. Metatarsals were not affected by energy intake. Stiffness, Young's modulus of elasticity (YME) and flexural modulus for metacarpals and metatarsals were not affected by energy intake. Previously fed Ca and P intakes did not affect any of the mechanical bone characteristics. Metacarpals were heavier, had a greater breaking strength, were more elastic and exhibited slightly less resistance to bending than the metatarsals. The ether extract, ash, Ca and P content and the Ca:P ratio of metacarpals and metatarsals were not affected by previously fed energy or Ca and P intakes. The ether extract content tended to decrease and the ash, Ca and P content tended to increase with age. Articular cartilage and turbinate scores were not influenced by previously fed energy or Ca and P intakes. The YME and flexural modulus were the only bone characteristics that were even poorly correlated (average r = .25) with soundness scores, suggesting that high values result in poorer soundness scores. Energy and Ca and P intakes during growth and development had only minimal effects on bone characteristics and no apparent effect on structural soundness and longevity of sows kept for three parities.     

A possible influence of pedicel dimensions on fruit size and yield in strawberry

During the investigation of factors affecting fruit size in strawberry, the physical characteristics of the fruiting structure were examined as a possible cause of size limitation in fruit. The greatest total weight of fruit which can be sustained at any one time on an inflorescence appeared to be related to the dimensions of the main peduncle. At this limit the fruit yield may be no more than half the potential fruit yield of the inflorescence, indicating that unless ripe berries are removed development of immature berries may be restricted or stopped.This implies that under conventional management high yields will require frequent picking to achieve full potential. Once-over cropping, as in mechanical harvesting, may entail accepting yields one half or less of those now being obtained by conventional hand picking.It is suggested that if evaporative losses from ripe berries can be reduced, as by cloching, tunnelling, windbreaks, or plant breeding for less permeable cell walls, increased yields might be expected.     

Characteristics of canopy interception and its simulation with a revised Gash model for a larch plantation in the Liupan Mountains,China

Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.(larch) plantation in the Liupan Mountains of northwestern China during the growing season(May–October) of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss(79%) mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model's ability in simulating the interception of individual rainfall events were suggested.     

Cloning and tissue expression of the equine transferrin receptor

Background: Characterization of anemia in horses presents a challenge, as they do not release reticulocytes into peripheral blood. Transferrin receptor (TfR) expression is highest on erythroid cells in people and rats, and measurement of a soluble serum form (sTfR) is used to quantify erythropoiesis in these species. We hypothesized that equine TfR (eTfR) expression is similar in quantity and distribution to that in these other species and thus has potential for characterization of the regenerative response in anemic horses. Objective: This study was conducted to clone and sequence the eTfR gene and measure expression levels using quantitative real‐time PCR and immunohistochemical (IHC) staining. Methods: Total RNA from equine bone marrow was used to produce cDNA. The eTfR gene was amplified using pooled gene‐specific primers, and PCR products were sequenced. Rapid amplification of cDNA ends was used to obtain the first 22 nucleotides of the coding sequence. Quantitative PCR was performed using eTfR gene‐specific primers, and IHC staining was used to localize TfR protein expression. Results: The deduced amino acid (aa) sequence (767 aa) of the eTfR was 75–83% identical with sequences of the receptor in several other mammals. As in people and rats, eTfR mRNA expression was highest in the bone marrow, and distribution in other tissues was also similar. Conclusion: The eTfR gene is similar to that of other mammals in structure and expression levels. We hypothesize that it is also similar in function and that, following development of an immunoassay, determining sTfR concentrations will be useful for identifying the regenerative response in anemic horses.     

Foliar Application of Urea and Triazone Nitrogen to Cotton

Upland cotton (Gossypium hirsutum) requires adequate nitrogen (N) for optimum yields. Foliar applications of urea to supplement soil applied N have been tried for many years across the Cotton Belt, but responses have been highly variable. No published information is available regarding response by irrigated cotton to foliar applied N in subtropical South Texas. This study investigated the response of cotton to foliar applied urea and triazone N over a three-year period near Weslaco, Texas. In all years, foliar applied urea tended to increase seed cotton yield when soil applied N was limiting. In the absence of soil applied N, the increase due to foliar urea was significant in two of the three years (28.7 and 15.7% increases). Foliar applied triazone N was ineffective at increasing seed cotton yields.     

Indicators of Cotton Nitrogen Status

ABSTRACT

Nitrogen (N) deficiency limits cotton yields, while too much N causes excessive vegetative growth hurting yields, wastes expensive inputs, and causes environmental pollution. Diagnostic indicators are needed to assess cotton N status so that yields can be optimized as efficiently as possible. This study evaluated selected tools for predicting cotton responses to N fertilizer application. Petiole nitrate (NO₃)-N (PNN) concentration was found to correlate with cotton N status and a good indicator of potential for response to N application. Critical PNN concentrations for irrigated cotton in subtropical South Texas at first bloom, and 10, 20 and 30 d later were determined to be 15.0, 9.0, 4.5, and 2.0 g kg^{? 1}, respectively. These critical PNN levels are higher than in more humid areas of the traditional southern US Cotton Belt, probably due to the effects of the subtropical climate. Cotton plants in this area tend to be less vegetative, possibly due to shorter growing season day lengths, and therefore need to be “pushed” slightly harder with greater N fertilization. Leaf total N concentrations were found to be less responsive to changes in applied N than were PNN levels. Although leaf N tended to be more stable over time, there was no consistent pattern between years. Leaf N values of 35 g kg^{? 1} or less appear to represent a deficiency at any time, and optimum levels may be slightly higher. Nodes above white flower showed very small responses to N fertilization and the differences occurred late in the bloom period. Chlorophyll meter readings showed a good relationship with N fertilizer application within a given sampling date, but much greater variability occurred between dates and due to other factors. The most effective indicator of cotton N status was found to be PNN, and to a lesser extent leaf N, but none of other parameters could be recommended for purposes of making inferences as to N status of cotton.