Factors contributing to the blackspot bruise potential of Idaho potato fields

Blackspot bruise is a major problem in the fresh market and frozen french fry industry. The blackspot bruise potential of Russet Burbank and Ranger Russet in Idaho potato fields was determined by surveying commercial fields during 1993 and 1994. Management factors were monitored to determine what practices were contributing to blackspot susceptibility in addition to mechanical damage. The survey included 17 Russet Burbank and 3 Ranger Russet fields in 1993, and 28 Russet Burbank and 8 Ranger Russet fields in 1994. The 1993 season was unusually cool and wet whereas 1994 was warmer than normal, resulting in a wide range of environmental conditions for the 2 year study. Blackspot bruise potential was determined at different stages of tuber physiological maturity by collecting samples several weeks prior to normal harvest, immediately before harvest, and after storing sub-samples for several months. The blackspot bruise potential was measured by both impact and abrasive peel tests. Field maturity was the factor most consistently related to blackspot potential both years. In 1994 a multiple regression of 3 independent variables — field maturity index, specific gravity, and percent available soil water at tuber sampling, compared with the blackspot potential as the dependent variable gave a correlation coefficient of r = 0.73 (p = 0.001). Due to the cool, wet growing season in 1993, there was not enough variability in specific gravity and available soil water among the fields sampled for these factors to correlate with the blackspot potential. The available fertility data, although not complete for all fields, indicated no direct relationship between N, P, or K fertilization and blackspot potential. Preharvest samples in late August had lower blackspot potential than harvest samples in mid September, and storage samples in February had the highest susceptibility. There was a consistent increase in blackspot severity when tubers were equilibrated at 4 C compared with 10 C prior to bruising.     

Interaction of swine nursery and grow-finish space allocations on performance

Two experiments were conducted to evaluate the possible interaction of nursery space allocations and grow-finish space allocations in swine. In Exp. 1, crowding was achieved by varying the number of pigs per pen. During the nursery phase, decreasing the space allocation (0.16 m2/pig vs 0.25 m2/pig; 8 and 12 pens per treatment, respectively) by increasing the number of pigs per pen (18 vs 12) resulted in a decrease in daily feed intake (0.609 vs 0.683 kg/d; P < 0.001) and daily gain (0.364 vs 0.408 kg/d; P < 0.001). Pigs were mixed within nursery treatment groups and reassigned to grow-finish pens (6 pens per treatment) at the end of the 35-d nursery period providing either 0.56 m2/pig (14 pigs/pen) or 0.78 m2/pig (10 pigs/pen). Crowding during the grow-finish phase decreased daily feed intake (P < 0.003) and daily gain (P < 0.001). In Exp. 2, space allocations of 0.16 m2/pig vs 0.23 m2/pig during the nursery phase (24 pens per treatment) resulted in a decrease in daily feed intake (0.612 vs 0.654 kg/d; P < 0.005) and daily gain (0.403 vs 0.430 kg/d; P < 0.001). Pigs remained in the same (social) groups when moved to the grow-finish phase. Unlike Exp. 1, there was no effect of crowding during the grow-finish phase (0.60 m2/pig vs 0. 74 m2/pig) on daily feed intake or daily gain. The difference in results between experiments suggests that the response to crowding during the grow-finish phase may depend in part on whether pigs are mixed and sorted following movement from the nursery.     

母猪饲养新概念

母猪饲喂体系应用的表面方式和循环周期已经给养猪生产者留下诸多疑惑。如今真正需要思考的是现代母猪的基因型及如何将其与母猪营养研究最新的成果结合起来。如今瘦肉型母猪及小母猪食欲往往较低,从营养学的角度来看这种情况容易出现很多的问题。科学技术的发展同样已对母猪的饲养产生了一定的影响,例如母猪电子给料器,这意味着我们可以按照事先拟定的"饲喂方案"对每头母猪分别进行饲喂。     

Influence of market stress and protein level on feeder pig hematologic and blood chemical values

One hundred twenty crossbred feeder pigs were used in 2 trials to determine the effects of food and water deprivation at the auction market and the effects of protein levels of receiving diet on blood chemical values. Food- and water-deprived animals had significantly higher packed-cell volume, colloid osmotic pressure, and cortisol values than did nondeprived animals. Total osmolality and plasma triiodothyronine values were significantly lower in deprived animals. Measurable effects of food and water deprivation were no longer apparent by 14 days after arrival at the research facility. Plasma colloid osmotic pressure had a positive linear relationship with increasing dietary protein level and was statistically different among levels of protein fed. Gilts had higher plasma triiodothyronine values than did barrows. Differential WBC ratios were not different between groups. Measurable differences for treatments (food and water deprivation vs food and water access; and level of protein in the receiving diet) were no longer apparent 84 days after pigs had arrived at the finishing unit.     

EQUINE PARANASAL SINUSOGRAPHY

Contrast paranasal sinusography was a simple procedure that enhanced evaluation of the paranasal sinuses in the standing horse. Two techniques of positive-contrast paranasal sinusography were developed using cadavers and sedated horses. For both techniques, 37% organically bound iodine was used. For the first technique, the conchofrontal sinus was injected with 30 ml of contrast medium followed by an additional 100 ml and 70 ml. For the second technique, the rostral maxillary sinus was injected with 20 ml followed by an additional 50 ml. Each technique enhanced visualization of different paranasal sinuses, and each was necessary for complete positive-contrast radiographic evaluation of the paranasal sinuses. The techniques of positive-contrast radiographic evaluation of the paranasal sinuses are described.     

A modified reduced nocturnal temperature regimen for early-weaned pigs

A four-trial experiment utilizing 3- to 4-wk-old newly weaned pigs was conducted to evaluate the effect of a modified reduced nocturnal (MRNT) nursery temperature regimen on weaned pig and subsequent grower-finisher performance. Nursery treatments were 1) a control temperature (CT) regimen of 30 degrees C constant air temperature lowered 2 degrees C/wk and 2) a regimen beginning 1 wk after weaning in which the temperature from 1900 to 0700 was lowered 6 degrees C from CT. Weaned pigs gained faster (P less than .01) in the MRNT treatment than in the CT treatment, with gains in Trials 1, 2, 3 and 4 being .39 vs .37, .28 vs .27, .38 vs .37 and .39 vs .36 kg/d, respectively. This improvement in gain was due to an increase (P less than .005) in feed intake for the same periods (.60 vs .58; .48 vs .42; .59 vs .58; .63 vs .58 kg/d). There was no difference in feed conversion (P greater than .1). There was no effect (P greater than .1) of MRNT vs CT on subsequent performance to slaughter weight for average daily gain (.69 vs .69 kg/d), average daily feed (2.22 vs 2.23 kg/d) or gain/feed (.31 vs .31). These results support the conclusions that weaned pigs eat more feed and gain faster with a reduced nocturnal temperature scheme and that there are no carry-over effects during the growing-finishing phase.     

Pathology of experimentally induced polybrominated biphenyl toxicosis in pregnant heifers.

Toxicosis was induced in pregnant Holstein-Friesian heifers by giving polybrominated biphenyls a in gelatin capsules at the rate of 25 g/day. Initially, this dosage was approximately 67 mg/kg of body weight. Clinical signs were anorexia, excessive lacrimation and salivation, diarrhea, emaciation, dehydration, depression, and abortion. Fever was not evident during the experiment. Values for serum glutamic-oxalacetic transaminase, lactic dehydrogenase, blood urea nitrogen, and bilirubin were increased. Changes in packed cell volume, hemoglobin content, total erythrocyte and leukocyte counts, and differential leukocyte counts were minimal and reflected dehydration and secondary infection. The principal urine changes were decreased specific gravity and moderate proteinuria. Gross necropsy findings included dehydration; subcutaneous emphysema and hemorrhage; atrophy of the thymus; fetal death with concomitant necrosis of cotyledons; kidneys that were enlarged, pale tan to gray; thickened wall of the gallbladder; inspissated bile; edema of abomasal folds; mucoid enteritis; linear hemorrhage and edema of the rectal mucosa; and secondary pneumonia. Microscopic changes were most marked in the kidneys, gallbladder, and eyelid. In the kidney, the principal changes were extreme dilatation of collecting ducts and convoluted tubules, with epithelial degenerative changes of cloudy swelling, hydropic degeneration, and separation from the basement membrane. Common changes in the gallbladder were moderate to marked hyperplasia and cystic dilatation of the mucous glands in the lamina propria. The changes in the eyelids were characterized by hyperkeratosis, with accumulations of keratin in hair follicles of the epidermis and squamous metaplasia with keratin cysts in the tarsal glands. Clinical signs and lesions of toxicosis did not develop in heifers given the polybrominated biphenyls at the rate of 0.25 mg and 250 mg/day for 60 days. Initially these rates were approximately 0.00065 mg/kg and 0.65 mg/kg of body weight, respectively.     

Effect of feeding Sarsaponin in cattle and swine diets

In four trials, steer calves were received in the feedlot, processed and fed diets supplemented with soybean meal (SBM), 1% urea (UR) or 1% urea plus sarsaponin (S) over a 28-d period. In trials 1 and 2, the feeding period was extended to approximately 62 d, in which steers were fed a common (SBM) diet the last 34 d. In trials 3 and 4, a SBM plus S diet treatment was included. During the first 28 d (four trial summary) daily gains of steers fed urea plus S (.74 kg) were intermediate to and significantly different from gains of steers fed SBM (.84 kg) or UR (.66 kg) diets. However, at the end of the 62-d feeding period (two trial summary) daily gains, feed intakes and feed efficiency did not differ (P greater than .05) among treatments. No significant improvements in performance were found in steers fed SBM diets supplemented with S. In swine trials, pigs were fed diets containing no additive, 63 mg S X kg-1, 55 mg chlortetracycline (C) X kg-1 or S plus C in a grower-finisher (GF) and grower (G) trial. In the GF trial, overall efficiency of feed conversion was improved (P less than .05) by feeding S or S plus C. In the G trial, daily gains and intakes were greatest for pigs fed S plus C and differed (P less than .1) from those of pigs fed S or C in the diet. Compared with feeding S or C alone, gain and intake of growing pigs were stimulated to a greater extent when S was fed in combination with C. Feeding S with or without C improved efficiency of feed conversion in finishing pigs.     

Potential impact of harvesting for the long-term conservation of arboreal marsupials

We used a simulation approach to study the trade-off between forest harvesting and the conservation of arboreal marsupials in managed eucalypt forests of south-eastern New South Wales (Australia). The EDEN gap model is used to predict tree biomass harvested and the resulting shifts in habitat quality (HQ) for arboreal marsupials under different harvesting scenarios. These harvesting scenarios generate a gradient of biomass harvested by varying rotation length and tree retention in different topographic positions. The results suggest that the shape of the curve of reduction of HQ along the harvesting gradient is very sensitive to topographic position and hence to the proportion of topographic units in the landscape. Consequently arboreal marsupial management in logged forests will be region-dependent as each region will have its own pattern of landscape complexity.