商品肉鸭配套杂交组合的筛选

试验采用来源不同的四品系北京鸭组成ＢＣ、ＡＢ、ＡＣ、ＡＤ、ＢＤ５个杂交组合，在相同舍饲条件下，对生长性状和肉用性能进行了测定。结果表明，５个杂交组合中，以ＢＣ、ＡＢ效果最好，可用于商品生产。     

不同品系北京鸭肉用性能及肌肉品质特性的研究

本文对Z型北京鸭3个品系的胴体性能及肌肉品质进行了比较。结果表明:北京鸭3个品系间活重、胸肌重和胸肌率存在极显著差异(P<0.01),表现为Z4系>杂交系>Z1系。而3个品系的腿肌率、腹脂重、腹脂率、皮脂厚和肌间脂肪宽无显著差异。剪切力以Z1系北京鸭为最高;失水率以北京鸭杂交系为最低;肌肉pH值以杂交系北京鸭最高。杂交系北京鸭天门冬氨酸、苏氨酸、丝氨酸、谷氨酸、丙氨酸、胱氨酸、蛋氨酸、异亮氨酸、亮氨酸、苯丙氨酸、赖氨酸、组氨酸、精氨酸、以及总氨基酸含量显著高于北京鸭Z1、Z4系(P<0.05),而且肌苷酸和各种氨基酸含量以及总氨基酸含量均为杂交系北京鸭最高。综合本试验可得出:北京鸭杂交系肉品质优于父系和母系,在品种选育过程中发挥出了杂交优势,且Z1系×Z4系这种杂交组合有利于北京鸭肉质的改良。     

仙湖3号鸭品系配合力的研究

１９９６年４月至１９９８年１１月期间,用仙湖３号鸭Ａ系和Ｂ系进行了３次杂交试验,并在旱地饲养条件下进行了生长性能等项目的观察和测定,结果表明：Ａ系比Ｂ系的生长速度快、体重大、饲料报酬高,杂交组合ＡＢ在生长速度及饲料报酬方面总体上优于ＢＡ,表现出一定的杂交优势,是进行商品生产较理想的杂交组合。     

长岛,高邮鸭及其杂交子代血浆生化指标与部分生产性状的关系

长岛、高邮鸭及其杂交子代血浆生化指标与部分生产性状的关系吴立军（江苏省扬州市畜牧兽医站２２５００１）为了探索长岛鸭血浆生化指标，了解长岛鸭代谢情况，作者对长岛鸭、高邮鸭和长岛鸭与高邮鸭杂交后代进行了血浆生化指标测定。试验材料１、鸭群组成：３个不同组合...     

番鸭及其杂交鸭胴体中常量营养成分的比较

本试验以番鸭以及与家鸭的杂交后代（半番鸭）为试验素材，测定鸭的部分屠宰性状和肝脏，肌肉中水分，粗蛋白，粗脂肪的含量。结果：番樱杂交鸭活量，屠体重，全净膛重和肝脏重均高于其亲本番鸭及其它组合的杂交鸭，其腹脂率低于番鸭和番金杂交鸭，番樱杂交鸭肌肉水中分和粗脂肪含量高于番鸭和其它杂交组合，表明利用樱桃谷肉鸭作母本生产的半番鸡，其屠宰性能和肉质均较好。     

蛋鸭公鸭肥育性能研究

前言绍鸭是我国著名的蛋鸭品种,具有性成熟早,产蛋率高,饲料报酬好等优良特性。但也存在着蛋重偏轻,公鸭体型小,生长缓慢等缺点。为探明绍鸭杂交对公鸭肥育性能影响效果,特进行本试验。     

高邮鸭及其杂交组合产蛋性能和蛋品质的比较分析

为探索高邮鸭产蛋性能的有效组合,试验对高邮鸭及其与金定鸭、绍鸭大蛋系、绍鸭高产系正反交的后代进行产蛋性能和蛋品质的比较,通过对7个组合结果的分析研究,结果表明:不同杂交组合之间的产蛋性能和蛋品质存在一定差异.综合各指标,高邮鸭♂×金定鸭♀为较理想的杂交组合.     

白嗉黑鸭杂交利用效果的研究

为了对白嗉黑鸭的生产性能进行改良,研究以白嗉黑鸭白壳系和北京鸭为素材,进行正反杂交试验,并设纯系为对照组,对公母鸭的孵化效果、F,代生长性能、羽毛颜色和杂种优势率进行比较.结果显示:后代公、母鸭的10周龄体重在正反交组合间均差异不显著(P＞0.05);试验B组(白嗉黑鸭白壳系♂×北京鸭♀)的孵化效果最佳,种蛋受精率和受...     

仙湖3号鸭产蛋量与性成熟体重的回归分析

本文利用二次曲线方程，对数曲线方程和Ｌｏｇｉｓｔｉｃ方程分别对仙湖３号鸭Ｂ系１１个月的产蛋量与性成熟体重之间的回归关系进行综合，结果表明，３个方程均能较好地拟合两者间的关系。相关指数Ｒ＾２都在０．９以上，且以二次曲线方程ｙ＝－１６６．２９３＋１１２．０７３ｘ＝１６．７９７ｘ＾２的似合最佳。根据此方程可估计仙湖３号鸭Ｂ系１１个月的产蛋量，这对种鸭的早期选择及提高种鸭生产效果具有一定的指导意义。     

袁隆平超级稻田推行“稻鸭共生”模式

超级杂交水稻田里，“金定鸭”、“四川麻鸭”自由自在地嬉戏着。这是发生在深圳龙岗的国家杂交水稻碧岭科研基地、袁隆平超级稻田里的情景。“稻鸭共生”模式原是日本生态农业示范推广项目，此次首次进入袁隆平超级稻田试用，目前效果良好，实现了稻、鸭的共生共长。     

新美系猪选育群及其杂交组合的杂交效果分析

试验共设6个组,包括杜、长、大三个纯种组和长×大、大×长、杜×长大三个杂交组,每组选取健康的、体重约25 kg的试验猪12头,公母各半,经过预饲调整后每组选取10头开始正式试验。饲养至组平均体重达100 kg左右时,每组选取4头（2♂2♀）进行屠宰测定和肉质分析,并计算了三个杂交组猪的各主要经济指标的杂优率（H）。结果表明,目前选育群各品种猪的日增重830 g以上,料肉比2.53以下,瘦肉率67%以上,肉质优良。三个纯种组中生长速度以杜洛克为最快,平均日增重达912 g;料肉比以大白猪的最低,为2.35;长白猪的屠宰率、胴体斜长、眼肌面积、瘦肉率最高,背膘厚最薄;6个组中杜×长大商品猪生长最快,平均日增重达977 g,料肉比为2.34,并有较理想的杂优率,而相对于长×大和大×长组合而言,许多重要经济性状,如背膘厚、眼肌面积、后腿比例、脂率、贮存损失等,大×长的杂优率均优于长×大,表明大×长组合也是非常有效的杂交组合,可为筛选新的杂优组合提供参考依据。     

益生性活性卵白制剂对早期断奶仔猪生产性能和肠道pH的影响

试验选取28日龄断奶的三元[杜×（大×长）]杂交仔猪36头,平均初始体重为5.22±0.89 kg,随机分为活性卵白试验组和对照组,每个处理组3个重复,每个重复6头。对照组饲喂基础日粮,活性卵白试验组在相同的基础日粮基础上口服饲喂活性卵白制剂,剂量为10 ml/d·只,连续服用10 d（断奶前5 d至断奶后5 d）,研究添加服用益生性活性卵白制剂对断奶仔猪生产性能、腹泻率和肠道各段pH的影响。结果表明,活性卵白物质可显著提高断奶仔猪的日增重、日采食量,显著改善仔猪生长性能,具有更好的提高断奶仔猪生长速率的趋势及较好的阶段增重优势。在预防仔猪消化道疾病方面活性卵白制剂具有良好效果,可提高断奶仔猪的存活率,腹泻率下降幅度较大,对缓解腹泻的作用明显优于对照组。因此,早期断奶仔猪口服活性卵白制剂有助于提高其生产性能,降低腹泻率,具有降低仔猪肠道内容物pH的趋势。     

Direct and maternal genetic effects due to the introduction of Bos taurus alleles into Brahman cattle in Florida: I. Reproduction and calf survival

Pregnancy rate, calf survival rate to weaning and calf age at weaning of several types of crossbred cows (2/3 or more Brahman) were compared to those of straightbred Brahman and Angus cows over a 12-yr period at Subtropical Agricultural Research Station near Brooksville, FL. The purpose of this study was to determine the relative importance of additive vs nonadditive genetic effects on reproductive and calf survival traits in a population of cattle whose foundation was selected on the basis of superior reproductive performance under harsh environmental conditions. Best linear unbiased estimates (BLUE) of direct additive effect (measured as the deviation of Brahman additive breed effect from Angus) for pregnancy rate and calf age, measured as traits of the dam, were 6 +/- 3% and -7.2 +/- 2.1 d, respectively. Thus, Bos taurus germ plasm did not increase pregnancy rate but resulted in an earlier calving date. The BLUE of nonadditive (intralocus) direct genetic effects measured as deviations from intralocus group genetic effects in the parental breeds on pregnancy rate and calf age at weaning were 25 +/- 4% and -6.4 +/- 2.5 d. Nonadditive effects on pregnancy rate were the primary cause of the superior reproductive rates observed in Brahman crossbred cows. Calf survival was considered to be a trait of the calf, and BLUE of direct additive, direct nonadditive, maternal additive and maternal nonadditive genetic effects was obtained. Only maternal nonadditive genetic effects were found to have a significant effect on survival rate (9 +/- 4%).     

Effects of gender and genotype on the response of growing pigs to exogenous administration of porcine growth hormone

Sixty crossbred pigs (Large White x Landrace) were used in a 2 x 2 x 2 factorial experiment to investigate the effects of gender (intact males vs females) and strain (A vs B) on the response to exogenous porcine growth hormone (pGH) administration (0 [excipient-treated] vs .1 mg pGH.kg live weight-1.d-1). All pigs had ad libitum access to their diet; pGH was administered daily from 60 to 90 kg live weight. All aspects of growth performance and body composition were affected to different degrees by gender and pGH. Strain A pigs had a higher capacity for protein accretion, superior growth performance and contained less fat in the eviscerated carcass and empty body compared with Strain B pigs. Within each strain, intact males ate more feed, had a higher rate of protein deposition and exhibited faster and leaner growth than females. Exogenous pGH administration increased average protein deposition and growth rate by 84 and 34%, respectively, and reduced average feed intake, fat deposition rate, feed:gain and carcass fat content by 14, 59, 37 and 33%, respectively. The magnitude of the changes in growth performance, tissue accretion rates and body composition elicited by pGH were independent of strain. However, within each strain the improvement in feed:gain and reduction in carcass fat measurements elicited by pGH were proportionately larger for females than for intact males.     

Comparison of performance of F1 Romanov crossbred ewes with wool and hair breeds during spring lambing under intensive and extensive production systems

The objective was to evaluate wool (Dorset and Rambouillet) and hair (Dorper, Katahdin, and White Dorper) breeds for their ability to complement Romanov germplasm in two distinct production systems by estimating direct sire and grandsire effects on lamb growth, survival, and ewe productivity traits. Rams of the five breeds (n = 75) were mated to Romanov ewes (n = 459) over a 3-yr period to produce five types of crossbred lambs (n = 2,739). Sire breed (P > 0.06) did not impact body weight or survival traits of the first-generation crossbred (F1) lambs. The productivity of retained crossbred ewes (n = 830) mated to Suffolk and Texel terminal sires was evaluated at 1, 2, and 3 yr of age in each production system. In the intensive production system, labor and harvested feed were provided for sheep that lambed in March in barns, and ewes were limited to rearing two lambs with additional lambs reared artificially. Ewes in the extensive production system lambed in May on pasture and were responsible for rearing all lambs born with no labor or supplemental feed provided before weaning. A total of 1,962 litters and 4,171 lambs from 2,229 exposures to two terminal sire breeds (Suffolk and Texel) were produced in the experiment. Crossbred ewes in the intensive production system were mated in October, resulting in larger litter sizes than crossbred ewes mated in December for the extensive production system. However, single- and twin-born lamb mortality was similar between the two systems that differed greatly in labor, feed, and facilities. Lambs produced in the intensive system received concentrate feed from an early age and were heavier at 24 wk of age than lambs produced in the extensive system. These outcomes resulted in greater 24-wk litter weight in the intensive than in the extensive system (P < 0.0001). Unexpectedly, the relative performance of crossbred types did not differ importantly between production systems. White Dorper × Romanov crossbred ewes had numerical advantages in productivity in each system; however, differences between ewe types were not significant. In the extensive system, without labor and shelter at lambing or supplemental feed until weaning, 3-yr-old crossbred ewes of all types averaged 1.78 lambs marketed per ewe lambing, and 40% of the ewes that gave birth to triplets weaned their entire litters. These results document that prolific sheep and extensive systems can be successfully combined if appropriate crossbred types are used.     

Comparison of feed intake, digestibility and fattening performance of Brahman grade cattle (Bos indicus) and crossbred water buffalo (Bubalus bubalis)

Twenty growing crossbred cattle and crossbred water buffalo (carabao) with an average age of 22 (18–24 months) months were equally distributed into two treatment groups according to species. The animals were fed with the same ration made up of corn silage (50%) + wet brewer's spent grain (30%) + concentrate mixture (20%), and their fattening performance was monitored. The digestibilities of the different nutrients were likewise determined. The economics of raising the animals under intensive production system was calculated. Species differences did not influence total dry matter intake of the animals, when expressed as percentage of the bodyweight and per metabolic body size. There were no significant differences in digestion coefficients of the different nutrients, except for crude protein in crossbred water buffalo and crossbred cattle, although the digestibility of dry matter, organic matter and nitrogen free extract tended to be high in the former than in the latter. Likewise, average daily gain (ADG) was similar, although crossbred water buffalo had numerically higher ADG (828.6 vs 785.5 g) than crossbred cattle during the 6 months feeding. During the first 3 months of feeding (1–90 days), the ADG of crossbred water buffalo was 1066.1 g compared to 940.1 g for crossbred cattle. From 91 to 180 days, the crossbred cattle had slightly higher ADG (630.1 vs 591.1 g) but also the difference was not significant. The return above feed cost was comparable for crossbred cattle and crossbred water buffalo during the first 90 days of feeding. However, extending the feeding period from 91 to 180 days , income over feed cost was higher (P < 0.05) for crossbred cattle by PhP 5.3/kg gain than crossbred water buffalo. Results showed that crossbred water buffalo could attain similar growth rate with that of crossbred cattle under intensive system, when fed with high quality feed materials.     

蛋鸡杂种胚胎生活力及其杂交遗传力的研究

在利用京白快羽母鸡对１７０只罗曼Ｄ系公鸡的快慢羽基因位点进行测交试验的过程中，收集了杂种后代孵化期胚胎生活力的数据用于本研究，结果表明：（１）孵化后期（１３－２１天）平均每天的胚胎死亡率约为前中期的两倍，孵化前期（１－６天）的死亡率略高于中期，孵化中期（７－１２天）的死亡率最低；（２）罗曼Ｄ系纯合慢羽公鸡杂交后代的生活力与杂合公鸡后代相比没有显著的差异，据此可以假设：快慢羽基因与胚胎生活力性状间无相关关系；（３）用ＨｅｎｄｅｒｓｏｎⅢ估计的胚胎生活力性状的杂种遗传力在０．００６到０．０５４之间，ＲＥＭＬ方法的估计值在０．００１到０．０４７之间。用ＨｅｎｄｅｎｏｎⅢ估计的遗传力一般均高于ＲＥＭＬ方法的估计值。     

Polymorphisms in the bovine leptin promoter associated with serum leptin concentration, growth, feed intake, feeding behavior, and measures of carcass merit

Leptin is the hormone product of the obese gene synthesized and secreted predominantly by white adipocytes. It functions as a lipostatic signal regulating BW, food intake, energy expenditure, reproduction, and certain immune system functions. Although previous studies have identified polymorphisms in the coding regions of the leptin gene in cattle that show considerable associations with feed intake, milk quality and quantity, and carcass fatness, no such associations have been reported for the leptin promoter. The current study reports associations between SNP in the 5' untranslated promoter region of the bovine leptin gene with serum leptin concentration, growth, BW, feed intake, feeding behavior, and carcass merit in hybrid cattle (n = 150). The study showed that animals with the TT genotype of a less frequent cytosine/thymine (C/ T) substitution (UASMS2; frequency of thymine allele equals 0.21) detected at position 528 in the bovine leptin promoter (GenBank Accession No. AB070368) show 48 and 39% increases in serum leptin concentration (P < 0.001), 39 and 31% increases in backfat thickness (P < 0.001), and 13 and 9% increase in marbling score (P = 0.01), compared with CC or CT genotypes, respectively. Animals with the TT genotype also show significantly higher feed intake (P < 0.001), growth rate, metabolic BW (P < 0.05), and live weight at slaughter (P < 0.10). Animals with the GG genotype of a more frequent cytosine/guanine (C/G) substitution (UASMS3; frequency of G allele equals 0.59) at position 1759 in the bovine leptin promoter (GenBank Accession No. AB070368) also show higher feed intake (P = 0.001), growth rate (P < 0.10), and BW (P < 0.01). The thymine allele of UASMS2 and the guanine allele of UASMS3 were separately associated with higher feeding duration (P < 0.05). The two SNP show significant linkage disequilibrium and could also be relevant in predicting other characteristics, such as milk yield and quality in cattle. These results, however, represent the initial associations of the polymorphisms with these traits, and further efforts are required to validate these findings in other populations.     

发酵豆粕“肽多乐”对断奶仔猪生产性能的影响

试验选用40日龄杜×大×长三元杂交仔猪240头,按窝别、性别、体重相近的原则分为3组,即试验Ⅰ、Ⅱ、Ⅲ组,每组4个重复,试验Ⅰ组为对照组,试验Ⅱ组添加6%的大豆浓缩蛋白(SPC),试验Ⅲ组添加8%的肽多乐,试验共进行30d。结果表明:肽多乐提高了断奶仔猪的日增重和日采食量(P<0.05);试验猪的腹泻率和死淘率显著降低(P<0.05);经济效益得到明显提高。