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In an attempt to improve the reproductive performance of gilts mated at puberty, 70 Yorkshire x Landrace gilts were allocated at 120 d of age and 60 kg body weight to one of two treatments. Restricted gilts were fed 2.0 kg d-1 of a diet formulated to provide 18% crude protein and 14.5 MJ DE kg-1 from selection until mated at their first estrus (n = 35). Flushed gilts were fed 2.0 kg d-1 of the same diet from 120 to 150 d of age, but then had their feed intake increased to 3.5 kg d-1 until mated at their first estrus (n = 35). An additional group of gilts (control fed; n = 33) were fed 3.0 kg d-1 from selection until they were bred at their third estrus in order to investigate the influence of feed restriction on the onset of puberty. During gestation all gilts were fed 1.8 to 2.2 kg d-1 of a 16.8% crude protein diet having 13.7 MJ DE kg-1. Control fed gilts were younger (p less than 0.05) at puberty (150 d) than restricted (165 d) or flushed gilts (165 d). There was no difference in subsequent litter size between the restricted and flushed gilts (7.7 and 8.0, respectively). It is concluded that the institution of a flushing nutritional regime in the prepubertal period will not enhance piglet production from gilts mated at puberty.  相似文献   
2.
There are few reports of coagulation times in marsupial species. Blood samples collected from 14 Bennett's wallabies (Macropus rufogriseus) under anaesthesia during routine health assessments were analysed for prothrombin time (PT) and activated partial thromboplastin time (aPTT) using a point‐of‐care analyser (POC) (Abaxis VSPro®). The wallabies had an aPTT mean of 78.09 s and median of 78.1 s. The PT for all wallabies was greater than 35 s, exceeding the longest time measured on the POC. Although PT was significantly longer, aPTT was similar to the manufacturer's domestic canine reference range.  相似文献   
3.
大杜鹃(Cuculus canorus)通常寄生小型雀形目鸟类。由于杜鹃雏鸟的排他性拱卵或拱雏,导致宿主繁殖失败,因此宿主进化出如卵识别能力的反寄生策略。反过来,杜鹃也同时进化出如模拟宿主卵的寄生策略。于是两者之间的相互作用可形成类似军备竞赛的协同进化关系。在匈牙利,大苇莺(Acrocephalus arundinaceus)是大杜鹃的主要宿主,寄生率可高达约 40-65%。以往被认为是大苇莺一个亚种的东方大苇莺(A. orientalis)在日本的种群也被大杜鹃寄生(25-40%)。通过采用光纤光谱仪量化大杜鹃及其宿主的卵色特征,我们比较了东、西半球大杜鹃对两种苇莺的寄生模拟程度。鸟类视觉模型显示,对于可见光颜色,杜鹃与宿主之间卵色的模拟程度在匈牙利高于日本,但匈牙利杜鹃和宿主均较大的卵色变异程度可导致卵色模拟困难。杜鹃与苇莺卵色的量度差异在日本较低,这被证明是宿主拒卵行为的一个重要影响因素。苇莺对大杜鹃卵的拒绝率在日本(35%)和匈牙利(37%)相似。与匈牙利不同,在日本,宿主对杜鹃寄生的应对策略如拒卵行为,先于杜鹃的反适应对策。我们认为,两种近缘物种大苇莺对杜鹃寄生的不同反寄生行为,代表了协同进化军备竞赛的不同演化阶段。  相似文献   
4.
始建于16世纪初的拙政园是中国园林的杰出代表,建园之初,文徵明曾多次作有拙政园图。从文氏《王氏拙政园记》和《拙政园卅一图》探析明代拙政园的原貌,可以了解到明代江南文人园林设计的理想品质和"虽由人作,宛如天开"的深邃意境。对当代园林景观建设也有一定的借鉴意义。  相似文献   
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This study was undertaken to determine some blood and other physiological parameters with potential for use as prognostic indicators of viability of newborn goat kids. Of the 143 kids born during the on-farm study, 97 were crosses of Galla x Small East African (SEA) and 46 were pure SEA. The SEA x Galla kids were 46 single males, with a mean body weight at birth of 2.77 +/- 0.22 kg, 43 females with a mean body weight at birth of 2.36 +/- 0.76 kg and 5 and 3 sets of female and male twins (mean body weight at birth of 1.8 +/- 0.19 kg and 2.05 +/- 0.07 kg for the female and male kids, respectively). The SEA kids comprised 36 single male and female kids (mean body weight at birth of 2.48 +/- 0.04 kg and 10 sets of twins (both male and female) (mean body weight at birth of 1.50 +/- 0.04 kg ). Pre-suckling sera obtained on-station from kids born of does vaccinated against Escherichia coli (n = 8) and unvaccinated does (n = 7) had a total protein content of <40.0 g/l and no detectable levels of IgG and A or E. coli antibodies. Sera obtained 12 hours post partum) from kids that survived in both groups contained about 19-22 g of Ig g/l, 50-80 g total protein/l, blood glucose of >5 mmol/l and had an E. coli antibody titre of between 1/160 and 1/640. On the other hand, kids that died within 48 hours of birth (parturient deaths) and had been classified in categories 3 and 4 righting reaction had low (<40 g/l) total protein, low white blood cell count (4,000/ml) and low blood glucose concentration (<4.9 mmol/l). It is concluded that kids with delayed righting reaction (>45 minutes), low rectal temperature (<36 degrees C), low birth weights (<1.5 kg for singles and <1.0 kg for twins), low white blood cells (<4,000/ml), low (<2 mmol/l) blood glucose levels, low total protein (<40.0 g/l), low (<1:160) E. coli antibody titre and IgG (< or =3,350 mg/l) in sera obtained 12 hours after birth have a poor prognosis for survival.  相似文献   
6.
Veterinary Research Communications - Livestock plays a significant role in the socio-economic development of developing countries by providing livelihood and nutritional security, transport,...  相似文献   
7.
A study on the semen obtained from breeding goats suffering from mild to severe chronic besnoitiosis revealed marked changes in semen volume, colour, density, concentration, mass and individual motility and percentage live. There were also many neutrophils and spermatozoa with primary and secondary defects, including missing tails and deformed heads and tails. The observed changes were considered to be severe enough to account for the infertility observed in the flock. Sections of testes obtained for histopathology were characterised by massive blockage of the pampiniform plexus, degeneration of the germinal epithelium, tubular necrosis with an inflammatory infiltrate and, in some cases, accumulation of haemosiderin-like material in the tunica vaginalis.  相似文献   
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