Comparative evaluation of hormonal protocol on the performance of crossbred cattle

A total of 60 animals (38 cows, 22 heifers) were selected and were divided into three groups of 20 animals each (containing both anoestrus and repeat breeder) in which treatment was performed for 60 days. Group I: control (farmer practice), T₁ group: group I?+?hormone (double synch), and T₂ group: group I?+?hormone (Estra double synch). The growth performances were measured in terms of body weight and average daily gain (ADG). Blood collection was done at the start and end of the experiment for assessment of blood biochemical, hematological, and reproductive status of the animals. Results revealed significant improvement in growth and reproductive performances in treatment group as compared to control group. Higher percentage of conception was achieved in group III (60%) followed by group II (55%). The least percentage was in group I (15%), i.e., in control group. So it was found that the effect of treating the reproductive-disordered animals with Estra double synch gave comparatively better result than double synch hormonal application.     

Efficacy of furazolidone in grower diets on subsequent performance of swine--a cooperative study

Nine experiments were conducted at three stations to evaluate the efficacy of furazolidone as a growth promoter in diets for young swine and to determine if an early growth response is maintained after the additive is withdrawn from the diet. A total of 528 pigs (24 replications, 132 pigs/treatment) initially averaging 12 kg body weight were fed a nonmedicated basal diet or a diet with 110 ppm furazolidone for 5 wk, 165 ppm furazolidone for 3 wk or 220 ppm furazolidone for 2 wk. After withdrawal of furazolidone, the basal diet was fed to the end of the test, at which time the pigs averaged 93 kg. During the initial 2-wk period, pigs fed furazolidone gained 15.4% faster (P less than .001) and required 8% less (P less than .001) feed per unit of gain than control pigs fed the nonmedicated diet. At 5 wk, pigs previously fed furazolidone gained 8.4% faster (P less than .001) and 4.5% more efficiently (P less than .001) than controls. By 10 wk, pigs previously fed furazolidone maintained a slight advantage in growth rate over controls (2.6%, P less than .10), but feed/gain responses were similar for the two groups. By the end of the experiment, the early growth response from furazolidone was completely lost. Although there were differences in growth responses among stations, the treatment response patterns were similar for each station, with no evidence of a treatment X station interaction.(ABSTRACT TRUNCATED AT 250 WORDS)     

小麦/玉米/大豆套作的产量、氮营养表现及其种间竞争力的评定

采用多年大田试验研究了小麦-大豆(A1)、小麦-甘薯(A2)、玉米(A3)、小麦/玉米/大豆(A4,麦/玉/豆)和小麦/玉米/甘薯(A5,麦/玉/薯)5种种植模式的生物积累和氮素吸收特性,以探讨麦/玉/豆套作体系的种间竞争力变化规律。试验通过土地当量比(LER)、种间相对竞争力(A)、氮营养竞争比率(NCR)等指标来评定不同套作系统内的作物竞争力。结果表明,麦/玉/豆套作表现出明显的套作优势(LER＞1、A_wc<0、A_cs>0、NCR_wc<0、NCR_cs>1),玉米始终占据套作系统的优势生态位,小麦、大豆处于竞争劣势;与A1、A2、A3及A5相比,麦/玉/豆套作提高了各作物在开花期(或吐丝期)与成熟期的籽粒产量与吸氮量和地上部植株的总生物量与总吸氮量;各作物的生物量与吸氮量在处理间的变化规律为套作＞单作、大豆茬口＞甘薯茬口,以A4处理最高。麦/玉/豆套作的全年总经济产出比麦/玉/薯套作平均高28.02%。     

Effects of additional feed during late gestation on reproductive performance of sows: a cooperative study

A cooperative research study involving 1,080 litters was conducted at eight stations to determine the effects of additional feed during the last 23 d of gestation on reproductive performance of sows and on preweaning performance of their pigs. Primiparous and multiparous sows were fed fortified corn- or sorghum-soybean meal diets (14% crude protein). Control sows received 1.82 kg/d from March through November and 2.27 kg/d from December through February. Treated sows were fed an additional 1.36 kg of feed/d from d 90 of gestation to farrowing. Sows were allowed to consume the same diet ad libitum during a 21-d lactation. Additional feed in late gestation resulted in greater (P less than .001) sow weight gain from d 90 to d 110 of gestation (16.8 vs 9.0 kg) and greater (P less than .001) parturition-lactation weight loss (21.3 vs 16.4 kg). Total weight gain from breeding to 21 d of lactation favored sows that received extra feed (27.5 vs 22.7 kg; P less than .001). Sows receiving extra feed had more live pigs at farrowing (10.05 vs 9.71, P = .06) and at 21 d postpartum (8.35 vs 8.06, P = .09), and the pigs were heavier at birth (1.48 vs 1.44 kg, P = .003) and at 21 d (5.37 vs 5.20 kg, P = .006). Lactation feed intake and number of days from weaning to estrus were not affected by treatment. The results indicate that additional feed in late gestation improves reproductive performance in sows. In this study, the cost of an additional 31 kg of feed/sow was more than offset by the value of the additional sow weight gain (approximately 5 kg), the additional .3 of a pig/litter at weaning and the additional 2.6 kg of total litter weaning weight.     

Effects of supplemental biotin during gestation and lactation on reproductive performance of sows: a cooperative study

A cooperative experiment to evaluate biotin addition to sow diets was conducted at three research stations using 303 litters. Primiparous and multiparous sows (overall average parity 2.8) were fed a 14% CP corn-soybean meal diet (140 micrograms/kg biotin), with or without supplemental biotin (330 micrograms added biotin per kg feed), throughout gestation and lactation. As many sows as possible were fed their respective diets through three successive parities. During gestation, sows were given from 1.82 to 2.27 kg of feed per day, depending on environmental conditions; during lactation sows had ad libitum access to feed. Supplemental biotin had no effect (P greater than .35) on sow weights at breeding, at d 109 of gestation, at farrowing or at weaning. No differences were found in litter size at birth (P greater than .18), but at d 21 of lactation, sows fed the diet containing supplemental biotin had larger litters than sows fed the unsupplemented diet (9.4 vs 8.7 pigs, respectively; P = .01). Pig weights at birth and d 21 of lactation were not affected (P greater than .20) by dietary treatment. Biotin supplementation did not affect (P greater than .28) the length of the interval from weaning to estrus. No evidence was found that feet cracks or bruises were reduced by biotin supplementation. The results indicate that biotin supplementation of a corn-soybean meal diet during gestation and lactation increased the number of pigs at d 21 of lactation, but it did not decrease the incidence of foot lesions.     

小蚕共育技术要点

小蚕共育是根据小蚕的生理特点和生活习性,将一定数量的小蚕进行集中饲养和管理,以保证小蚕发育整齐、体质强健,为大蚕饲育打好基础的一种科学饲育模式。它不仅能使养蚕高产、稳产、质优、高效,而且还能节省桑叶、节省劳力、节省投资。     

农民专业合作社注册登记概述

依法注册登记是农民专业合作社开展生产经营活动并获得法律保护的重要依据.农民专业合作社作为独立的市场经营主体,要获得法人地位,必须依法设立登记.只有经过登记,获得法人地位,才能同其他的市场主体一样,参与市场竞争,开展交易和生产经营活动.     

Effects of dietary salt level during gestation and lactation on reproductive performance of sows: a cooperative study

Two experiments involving 1,020 litters were conducted at eight research stations to determine the effects of dietary NaCl (salt) concentration during gestation and lactation on reproductive performance of sows. Primiparous and multiparous sows were fed fortified corn- or grain sorghum-soybean meal diets at 1.82 kg/d during gestation. During the winter months (December, January, February) the feeding level was increased to 2.27 kg/d. Sows had ad libitum access to diets during lactation. Dietary concentrations of added salt were .50 and .25% in Exp. 1 and .25 and .125% in Exp. 2. When more feed was fed during gestation, the salt concentrations were reduced to .40, .20, .20 and .10%, respectively, in order to maintain a constant daily intake of Na and Cl during gestation. Gestation weight gain and lactation (21-d) weight loss of the sows were not affected by dietary salt level in either experiment. In Exp. 1, lowering the salt concentration did not influence the number of pigs farrowed, but it resulted in a .05 kg/pig reduction (P less than .01) in average birth weight. Average 21-d pig weights also tended (P less than .19) to be lower in the low-salt group. There was a decrease in litter size from the first to the second farrowing for sows fed low salt, but not for sows fed the higher salt concentration. In Exp. 2, reducing the salt content from .25 to .125% did not alter reproductive performance. The overall ratio of males to females at birth in the population of greater than 10(4) pigs was 52.3:47.7. Lower salt intakes tended to reduce the percentage of males born in both experiments, although the differences were not significant (P greater than .3). The results indicate that reducing the salt concentration in sows diets from .50 to .25 or .125% reduces birth weight in newborn pigs. When continued for more than one reproductive cycle, feeding less than .5% salt appears to reduce litter size at birth and weaning.     

含分布式电源的配电网继电保护方案研究综述

分布式电源接入配电网之后,对原有的配网保护产生了很大的影响,本文从影响重合闸、潮流方向、短路电流、孤岛运行等四个方面进行了总结分析,综述了国内外主要的一些含分布式电源的配网继电保护措施以及各自的一些优缺点,对于进一步的方案改进有一定的意义。     

An improved protocol for electrotransformation of Corynebacterium pseudotuberculosis

We developed an improved protocol for the electrotransformation of Corynebacterium pseudotuberculosis, testing variations of parameters in the procedures that are routinely used for the preparation of electrocompetent cells of this species, including (i) culture conditions, (ii) cell growth phase, (iii) electroporation solutions and (iv) quantity of plasmid DNA. We obtained the greatest efficiency of transformation when the cells were grown until the stationary phase and then washed with 10% glycerol electroporation solution. The transformation efficiency was inversely proportional to the quantity of plasmid DNA. The transformation efficiency reached 10(5) colony-forming units (cfu)/mug plasmid DNA. This protocol would be useful for genetic studies of C. pseudotuberculosis.     

Genetic analysis of residual feed intakes and other performance test traits of Japanese Black cattle from revised protocol

The performance test protocol for Japanese Black cattle was revised in April 2002. This resulted in restriction of access to concentrate (based on body weight) and modification of the concentrate's ingredients. Genetic parameters of growth and feed utilization traits of the performance test were estimated using 1304 records using the revised protocol. Residual feed intakes (RFIs) as alternative indicators for feed utilization efficiency were included. (Co)variance components were estimated by EM-REML. Heritabilities for growth traits were between 0.26 and 0.47. Heritabilities for feed intakes and conversions ranged from 0.25 to 0.37 and from 0.03 to 0.29, respectively. Genetic variances and heritabilities were lower for the revised protocol. Highly positive genetic correlations of daily gain (DG) with feed intakes indicated selection on DG is expected to increase feed intake. Selection on feed conversion may lead to higher DG. The heritability estimates for RFIs ranged from 0.10 to 0.33 and were generally higher than corresponding estimates for feed conversion ratios. RFI of TDN showed positive genetic correlations with all feed intakes. The reduction of feed intakes could be expected through selection on the RFI without changing body size. RFIs were considered to be alternative indicators to improve feed utilization efficiency under the new performance test.     

A novel cognitive palatability assessment protocol for dogs

Assessment of canine palatability is important for both the pet food and pharmaceutical industries; however, the current palatability assessment protocols are limited in their utility. The most common technique, the two-pan test, does not control for the satiating effects of food and may not be useful for long-term palatability analysis because nutritional or caloric characteristics of the diets may interfere with the results. Furthermore, the large quantities of foods consumed may be detrimental to the health of animals that do not self-limit their food intake. The purpose of this study was to determine whether a cognitive protocol could be used to determine food palatability in dogs. Five beagle dogs were trained on a three-choice object-discrimination learning task. After establishing object preferences, the preferred object was associated with no reward, a second object was associated with the dog's normal laboratory diet (Purina Agribrands Canine Lab Chow No. 5006; Agribrands Purina Canada, Inc., Woodstock, ON, Canada), and the third object was associated with a commercial (Hill's P/D; Hill's Pet Nutrition Inc., Topeka, KS) diet. In the discrimination-training phase, dogs were trained until they learned to avoid the no-reward object. They were subsequently given an additional 20 test sessions, which were used to determine food preference. In the reversal phase, which involved reversal learning, the object-food associations were modified, such that the object that was previously associated with Hill's P/D diet was now associated with the normal laboratory diet and vice versa. Once the dogs learned to avoid the no-reward object, they were tested for an additional 20 sessions. All subjects learned to avoid the no-reward object during the initial learning, and the number of choices to the object associated with the Hill's P/D diet was greater than the number of choices to the objects associated with the dry laboratory diet (P < 0.05) and no reward (P < 0.05), indicating a strong preference for the Hill's P/D diet. The object preferences were reversed in only three of five dogs when the food-choice associations were reversed, although the two phases did not differ significantly from one another. The protocol in the present study provides a robust measure of food palatability and circumvents many of the limitations associated with other palatability assessment techniques. The present protocol should be useful as a replacement or adjunct to other tests of palatability, but requires further validation by comparing the assessment of more similar and novel foods directly with other palatability tests.     

Effect of feed and(or) water deprivation prior to weaning on reproductive performance of sows: a cooperative study

A total of 292 sows, at three experimental stations (Auburn, Texas A&M, Texas Tech), was used to determine the effects of depriving sows of feed and(or) water before weaning on reproductive performance. The four treatments were arranged as a 2 X 2 factorial to evaluate two periods of feed deprivation (0 and 48 h) and two periods of water deprivation (0 and 24 h) before weaning. Sows were allowed to consume feed ad libitum during lactation, and were fed 1.8 kg/d during the weaning to breeding interval. Only sows nursing six or more pigs at weaning were used. Pigs were weaned at approximately 42 d at Auburn and 28 d at Texas A&M and Texas Tech. Treatment responses were similar at each station with no evidence of a station X treatment interaction for any of the traits (P greater than .10). During the 48-h treatment period, sows receiving feed and water ad libitum lost 1 kg compared with weight losses of 16 kg for sows deprived of feed for 48 h, 13 kg for sows deprived of water for 24 h, and 17 kg for sows deprived of feed for 48 h and water for 24 h. Weight losses for sows deprived of water only, may have partially resulted from reduced feed intake during the 24-h treatment period; however, feed intake during this period was not measured. At breeding, sows deprived of feed and(or) water maintained their greater weight losses, suggesting that some tissue loss occurred during the 48- or 24-h treatment periods.(ABSTRACT TRUNCATED AT 250 WORDS)     

Putative urinary pheromone of bulls involved with breeding performance of primiparous beef cows in a progestin-based estrous synchronization protocol

The objective of this study was to determine if factors associated with the biostimulatory effect of bulls alter breeding performance of primiparous, suckled beef cows using a progestin-based estrous synchronization protocol. We tested the hypotheses that the estrous synchronization response and AI pregnancy rates differ among cows exposed to bulls, continuously exposed to bull urine, and exposed to fence-line contact with bulls or cows not exposed to bulls or bull urine. Data were collected from 3 experiments performed over consecutive years. Cows were assigned to the following treatments: bull exposure (BE; n = 26) or no bull exposure (NB; n = 25) in Exp. 1, bull urine exposure (BUE; n = 19) or steer urine exposure (SUE; n = 19) in Exp. 2, and fence-line contact with bulls (BFL; n = 26) or no bull exposure (NB; n = 26) in Exp. 3. Synchronization protocols in each experiment included the use of a controlled internal drug release device (d -10), PGF(2alpha) (d -3), and GnRH and fixed-time AI (TAI; d 0). Cows that were observed in estrus by 60 h after PGF(2alpha) were inseminated 12 h later. Cows not observed in estrus by 60 h after PGF(2alpha) were TAI at 72 h and given GnRH (100 mug). Pregnancy was determined by ultrasonography 35 d after TAI. In Exp. 1, 2, and 3, cows were exposed directly to bulls, bull urine, or bull fence-line contact for 35, 64, and 42 d, respectively. Data were analyzed between treatments within each experiment. The proportion of estrous cycling cows did not differ between treatments at the beginning of each experiment; however, more (P < 0.05) BE and BFL cows were estrous cycling at the beginning of the estrous synchronization protocol than NB cows in Exp. 1 and 3. The proportion of cows that showed estrus and interval to estrus after PGF(2alpha) did not differ between treatments in Exp. 1 and 3. However, in Exp. 2, more BUE cows tended (P = 0.09) to have shorter intervals to estrus and to exhibit estrus after PGF(2alpha) than SUE cows. Overall, AI pregnancy rates were greater (P < 0.05) for BE and BUE cows than for NB and SUE cows in Exp. 1 and 2, respectively. There was no difference in AI pregnancy rates between BFL and NB cows in Exp. 3. The presence of bulls and exposure to bull urine appeared to improve breeding performance of primiparous beef cows using a progestin-based estrous synchronization protocol, whereas fence-line bull exposure was insufficient to cause this biostimulatory effect. We propose that a novel urinary pheromone of bulls may be responsible for the enhancement of fertility in the primiparous, postpartum cow.