Review on Effects of Fescue Grass Ergot Alkaloids in the Horse and Preliminary Study on Effect of Fescue Grass Ergot Alkaloid in the Stallion

Feed with ergot alkaloids ingested by horses has a deleterious clinical and economic impact on the industry. The clinical manifestation of the effects in mares is early embryonic mortality, abortions, prolonged gestation, dystocia, thickened (edematous) or retained placental membranes, agalactia, and increased rates of newborn mortality. For the stallion, very little is known, although ergot alkaloids decrease the ejaculate volume. However, a large number of breeding stallions graze endophyte infected (E+) pastures. This is especially true in the southeastern United States, and clinically we do not perceive that any stallions have any defined problems that could be attributed to ergot alkaloids. However, the number of spermatozoa produced by any stallion might mask the effects. The effects on fertility may be more subtle and only evident with sperm cell manipulation such as chilling or freezing. A preliminary study was performed on six breeding stallions fed feed containing infected fescue seed. We were not able to determine any significant (P < .05) detrimental effects on sperm motility, number morphology, and sperm morphology when compared with controls.     

Effect of milking frequency in early lactation on energy metabolism, milk production and reproductive performance of dairy cows

The objective of this study was to evaluate the effect of imposing different milking frequencies for the first 4 weeks of lactation on energy balance, blood metabolic profiles and reproductive performance. The milking frequencies imposed were once daily for the first 4 weeks of lactation and twice daily subsequently (X1), twice daily for the entire lactation (X2) and three times daily for the first 4 weeks of lactation and twice daily subsequently (X3). Two weeks prior to the first expected calving date, sixty-three multiparous, Holstein-Friesian cows, were allocated to treatments based on expected calving date, parity (lactation number = 2 and lactation number > 2), BCS and BW. Mean DMI was lower (P < 0.05) on X1 than X2 (15.7 and 17.1 kg/day) over the first 4 weeks of lactation, but DMI on X3 was not different to either. Milk yield was lower (P < 0.05) on X1 than on X2 and X3 (24.1, 31.9 and 31.4 kg/day) from weeks 1 to 4 and at week 10 of lactation (30.9, 33.9 and 33.7 kg/day) but was not different at week 20. Yield of milk constituents followed the same pattern as milk yield. Milking frequency had no significant effect on milk fat or protein concentration but milk lactose concentration was higher (P < 0.05) on X1 than on X2. Cows on X1 experienced less (P < 0.05) negative energy balance than those on X2 and X3 from weeks 1 to 4, with no difference between X2 and X3. Cows on X1 lost less BW (P < 0.05) from weeks 1 to 4 and lost less BCS up to day 73 of lactation than cows on X2 and X3. Plasma NEFA and BHB concentrations tended to be lower and plasma glucose tended to be higher on X1 than on X2 and X3 from weeks 1 to 4, while plasma insulin was higher on X1 than on X2 and X3 for the first 2 weeks of lactation. There was no difference between treatments in any reproductive performance variable measured. These results indicate that reduced milking frequency decreases milk yield and improves energy balance and metabolic status in early lactation.     

Effect of environmental factors on fertility of Holstein–Friesian cattle in Japan

We investigated the environmental factors in Japan, including meteorological conditions, on the fertility of a European cattle breed, Holstein–Friesian, by examining conception rates in different regions. First artificial insemination and associated conception details were recorded for 69,952 Holstein female cattle. In general, meteorological conditions vary considerably according to latitude in Japanese islands. Conception rates were higher in the Northern (above 37°N) than the Southern (below 37°N) region (61.3% vs. 53.3%). All the factors analyzed in the statistical model, including insemination year, region, month, AI technician, service sire and interaction between region and month, had significant effects on the conception rate. In the Southern region, conception rates were lower in the summer months (average temperature, 27.8 °C, and maximum temperature, 32.3 °C). However, this seasonal decline was not observed in the Northern region (average temperature, 23.7 °C, and maximum temperature, 28.4 °C). Regression analysis of conception rate in relation to temperature showed highly significant negative regression coefficients (− 0.66 to − 0.63% per °C; p < 0.001) in the Southern region, but non-significant coefficients in the Northern region. Humidity had a minimal effect on conception rate in both regions. Our data collectively suggest that 37°N latitude is a threshold that affects Holstein–Friesian conception rates in Japan.     

不同品种兔眼越橘花粉超微结构与营养成分的观察分析

为探索越橘花粉稔性与超微结构及营养成分的关系,以灿烂、园蓝、粉蓝、杰兔和顶峰5个兔眼越橘品种的花粉为试材,运用透射电镜观察花粉结构及测定了花粉营养成分。结果表明,越橘花粉结构中,内膜系统清晰可见,发育程度因品种而异。花前的花粉细胞核仁较大,蛋白质合成旺盛。通过花粉超微结构与营养成分间关系的分析比较表明,花粉壁的厚度、花粉细胞的蛋白质含量与花粉的萌发率没有相关性。花粉细胞的全糖和脯氨酸含量与花粉发芽率有正相关趋势。内质网发育程度与蛋白质含量呈正相关趋势。     

不同季节和种鸡日龄对种蛋孵化率的影响

夏季和冬季出雏的二批罗曼种鸡饲养和孵化测定结果表明，不同季节对种蛋的受精率和孵化率有一定的影响；而不同的种鸡日龄对种蛋的受精率和孵化率也有较大的影响；季节和种鸡日龄的双重影响对受精率和孵化率的影响更明显。     

榨菜胞质雄性不育及其农艺性状的研究

榨菜（ＢｒａｓｓｉｃａｊｕｎｃｅａＣｏｓｓ．ｔｕｍｉｄａＴｓｅｎｅｔＬｅｅ）胞质雄性不育系的雄蕊形态有两种类型：１）雄蕊无花药结构；２）雄蕊花药瘦小而干瘪。不育系雄性器官败育时期有两种类型：１）孢子体败育型；２）配子体败育型，属小孢子发育受阻。不育系雄蕊内源激素ＩＡＡ和ＺＴ含量随花器发育而极缓慢地增长，在花盛开时，每枚雄蕊分别为８．０ｎｇ和２２．４ｎｇ，近保持系的１／４和１／６，出现明显的ＩＡＡ和ＺＴ含量亏损现象。雄性不育率和不育度均为１００％，不育性世代稳定。不育系９０％的植株雌蕊育性正常，人工授粉后平均单果结籽１４．６粒，比保持系多１．２粒。其余１０％的植株其雌蕊部分不育。在保持系为父本进行自然授粉条件下，不育系单株种子产量７．２ｇ，较正常株高１６．６％。不育系经济性状优良，基本达到保持系和栽培品种水平。     

Efficacy of oral nicotinic acid and choline in the treatment and prevention of fatty liver in dairy cow

Nicotinic acid (N.C.)and choline were given orally to the periparturient cows to treat and prevent fatty liver.Blood parameters of glucose,β-hydroxybutyrate,albumin,total protein,magnesium,aspartate aminotransferase(AST) and non-esterified fatty acid(NEFA) were measured.There were no significant differences between the reated and untreated groups in the plasma concentrations of albumin,total,protein and magnsium.Significant decrease in plasma concentrations of β-hydroxybutyrate,NEFA and AST were observed in the treated cows following administration of N.C.and choline.All the fatty liver cows(100%) treated with N.C.and choline recovered within 5 weeks after calving compared with 71.4%(5/7) of untreated cows recovered.The incident ate of fatty liver postpartum in the cows with N.C.and choline given 2 weeks before calving was 30%(3/10),and the affected cows had a range of mild to moderate fatty liver whilst the incident rate was 50%(5/10)in the untreated cows.which had a range of mild to of severe fatty liver,Meanwhile,the treated cows had a significant higher prodection of milk and shorter intervals from calving to uterine involution,to the first postpartum ovulation and to conception.     

两系稻在江西不同地区的生育特性及其育性转换初探

本研究通过不同地区的分期播种试验,观察了W6154S、5460S的生育特性和育性转换特性,指出了两个核雄性不育系的播种至始穗历期随纬度和海拔升高而增加,随栽培季节温度的升高而缩短。温度是诱导两个核雄性不育系育性转换的主导因素。同时提出了其制种与繁殖的适宜季节。     

牧压和肥力对亚热带山地牧草净生产的影响

在亚热带山地湿润环境条件下,研究牧压和土壤肥力对人工草地净生产的影响.三年试验结果表明,绵羊在轮牧下,产草量和磷肥对全年及各月牧草净生产具有显著影响.禁牧时,夏季地上生物量积累到一定程度后,只有很少量的净生产.放牧时,产草量在1000 kg DM/hm2左右时,净生产最大,当产草量低于300 kg DM/hm2以下时,净生产量则降低.每年施一次P2O5 36～60 kg/hm2,可以显著增加牧草净生产,尤以春末夏初时施肥更为显著.最低产草量出现在不施肥处理.