PSXIII-23 Influence of reproductive technologies on post weaning calf performance and carcass characteristics

The experiment objective was to evaluate the impact of assisted reproductive technologies on post weaning calf performance. Calves born following various reproductive treatments (synchronized natural service and synchronized AI) in 10 herds over 2 years were fed to reach a target backfat (BF) of 1.27 cm, sent to harvest, and carcass data collected. Calves were classified into calving groups as natural service born early (NS-Early, n = 189), natural service born late (NS-Late, n = 203), or AI sired born early (AI-Early, n = 116). Data were analyzed using the MIXED procedure in SAS with calving group, year and calf gender in the model. Weaning weights were similar between AI-Early and NS-Early; however, earlier born calves (AI-Early and NS-Early) were heavier (P < 0.0001) than NS-Late. AI-Early calves had heavier finished bodyweight (622.2 kg: P = 0.0024) compared to NS-Early (601.4 kg) and heavier HCW compared to both NS-Early and NS-Late (P < 0.01). NS-Early calves reached 1.27 cm BF in fewer days than AI-Early (261 d and 275 d, respectively; P < 0.01) with NS-late requiring the most days on feed to reach the same endpoint (296 d, P < 0.01). No differences in Quality Grade, Yield Grade, REA, marbling, or BF were detected between AI-Early, NS-Early, and NS-Late, or between early- and late-born calves (P > 0.38). Late-born calves required 29 more days on feed (P < 0.001) to reach 1.27 cm BF resulting in greater final bodyweight compared to early-born calves (625.5 kg and 612.8 kg, respectively; P = 0.04); however, hot carcass weights were similar between early- and late-born calves. Reproductive technologies that increase the number of calves born early in the calving season increased weaning weight and post weaning growth performance, but compared to high quality natural service sires, AI did not improve carcass characteristics.

Prediction of Maritime Pine Boards Modulus of Elasticity by Means of Sonic Testing on Green Timber

Timber buildings are experiencing a rapid diffusion due to their good performance and their sustainability; however, some steps of structural timber production process, such as drying, are energy-intensive and environmentally impactful, and many wood species are also affected by low yield. Therefore, it would be important to determine the quality of the green material, that is, in wet condition, before undergoing the most impactful and expensive production steps. This paper describes a research aimed at quantifying the variation of the dynamic modulus of elasticity MoEdyn, which is commonly used for structural timber mechanical grading, from wet to dry condition in Sardinian maritime pine boards to be used for the production of laminated timber, and to examine the relationship between wet and dry MoEdyn. The MoEdyn was determined from measurements of the velocity of sonic waves propagating through the boards. The results show that the dry MoEdyn can be estimated starting from boards sonic testing in the wet condition, so providing a basis for implementing Sardinian maritime pine pre-grading in order to obtain the reduction of manufacturing costs, the abatement of environmental impact, and the increase of structural grade yield.

Effect of Rotation Age and Thinning Regime on Visual and Structural Lumber Grades of Douglas-Fir Logs

Douglas-fir, the most important timber species in the Pacific Northwest, US (PNW), has high stiffness and strength. Growing it in plantations on short rotations since the 1980s has led to concerns about the impact of juvenile/mature wood proportion on wood properties. Lumber recovered from four sites in a thinning trial in the PNW was analyzed for relationships between thinning regime and lumber grade yield. Linear mixed-effects models were developed for understanding how rotation age and thinning affect the lumber grade yield. Log small-end diameter was overall the most important for describing the presence of an appearance grade, generally exhibiting an indirect relationship with the lower quality grades. Stand Quadratic Mean Diameter (QMD) was found to be the next most uniformly important predictor, its influence (positive or negative) depending on the lumber grade. For quantity within a grade, as log small-end diameter increased, the quantity of the highest grade increased, while decreasing the quantity of the lower grades differentially. Other tree and stand attributes were of varying importance among grades, including stand density, tree height, and stand slope, but logically depicted the tradeoffs or rebalancing among the grades as the tree and stand characteristics change. Structural lumber grade presence was described best by acoustic wave flight time, log position (decreasing presence in upper logs), and an increasing presence with rotation age. A smaller set of variables proved useful for describing quantity within a structural grade. Forest managers can use these results in planning to best capture value in harvesting, allowing them to direct raw materials (logs) to appropriate manufacturing facilities given market demand.

Evaluation of flotation process course on the example of sulphide ores

The article concerns investigations over the influence of selected parameters of the flotation process course on the values of technological indices of beneficiation process assessment. Following parameters were under evaluation: the pulp density, pulp aeration (measured through the rotational speed of rotor) as well as dosage of flotation reagents. Four technological indices were registered: concentrate recovery, concentrate grade, yield of the concentrate and the tails grade. There were calculated correlation coefficients between selected parameters of flotation process course and the values of technological indices, along with determination of significance of these coefficient, at accepted probability level 0.95. In the next stage of investigations there were determined mathematical models with the concentrate recovery, concentrate grade, yield of concentrate and tails grade as the functions of pulp density, speed of the rotor and dosage of flotation reagent. On the basis of the investigations carried out, it was appeared that the dosage of flotation reagent was of the most significant influence on the values of technological indices of flotation process assessment. The least significant influence, in turn, was obtained for the pulp density.

Bell Pepper (Capsicum annuum) Tolerance to Imazosulfuron and Thifensulfuron-Methyl

Greenhouse and field studies were conducted to evaluate bell pepper tolerance to the sulfonylurea herbicides imazosulfuron and thifensulfuron-methyl. Imazosulfuron was applied at 56, 112, 224, 336, or 448 g ai ha−1. Thifensulfuron-methyl was applied at 2.6, 5.3, 10.5, 21.0, or 31.6 g ai ha−1. In the greenhouse over 2 yr, bell pepper injury due to imazosulfuron POST ranged from 12 to 27%. Reductions in plant height and numbers of nodes, buds, flowers, and fruits were generally minor or not observed. Injury from thifensulfuron-methyl POST ranged from 40 to 60% in the greenhouse. Similar trends were observed for leaf chlorosis and distortion. Thifensulfuron-methyl tended to decrease numbers of buds, flowers, and fruits in the greenhouse. In the field at three sites, bell pepper injury due to imazosulfuron applied POST-directed (POST-DIR) was less than 10% at all rating times, and height and yield were not affected. Total and marketable yield averaged 40,300 and 35,810 kg ha−1, respectively, across environments and years. Bell pepper injury from thifensulfuron-methyl applied POST-DIR in the field was less than 20% with all rates and less than 10% when rates less than 10.6 g ai ha−1 thifensulfuron-methyl were applied. Bell pepper stand (plants ha−1) or height was not affected by thifensulfuron-methyl. Thifensulfuron-methyl did not affect total bell pepper yield (39,310 kg ha−1 averaged across environments); however, reductions in Fancy grade yield were observed. No. 1 and cull yield grades tended to increase with increasing thifensulfuron-methyl rate, apparently compensating for lost Fancy yield.