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81.
Linear models were developed and evaluated for the estimation of daily (24 h) and total lactation milk yield of dairy sheep from single morning (am) or evening (pm) milking records. A total of 22,908 individual test-day milk records of 5110 ewes of the Chios breed, raised in 46 flocks, were used. Depending on the model, different daily milk yield estimates were derived for each ewe, accounting for lactation number, stage of lactation, season of previous lambing and interval between successive milkings. Daily milk yield was also estimated from doubling the single am or pm record. Actual and estimated yields were compared using root mean square errors (RMSEs), mean absolute differences, an accuracy parameter defined as the ratio of the actual yield variance over the sum of the variances of actual yield and absolute difference, and the product moment correlation between estimated and actual yield. Results were validated on independent datasets. Linear models resulted in less biased and more accurate estimates of the daily milk yield than simply doubling the am or pm record. Root mean square errors decreased by 7-37% and the mean absolute difference was reduced by 1-4% of the average daily yield. Higher accuracy and correlation were obtained from linear model application than doubling. Total lactation milk yield was predicted based on actual daily yield and compared to predictions based on estimated daily yield from am or pm records, as well as directly on single milking records. Root mean square errors obtained when daily yield had been estimated with linear models were 26-35% lower compared to doubling the am or pm yield and 0-13% lower compared to estimating the total lactation yield directly from single milking records. Linear model application also resulted in lower mean absolute difference and higher accuracy and correlation than doubling the am or pm record. Recording the yield of a single milking (am or pm) instead of both can benefit milk recording by reducing its cost and increasing farmer participation. In this context, linear models developed in the present study can be used for the accurate estimation of daily (24 h) and total lactation milk yield from single milking records. 相似文献
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GAL‐ and VIP‐Immunoreactive Nerve Structures in the Ileum and Large Intestine of Pigs with Dysentery
W. Sienkiewicz J. Kaleczyc Z. Pidsudko M. Akomy 《Anatomia, histologia, embryologia》2005,34(Z1):47-47
The morphology, neurochemistry and function of intramural nerve structures in the mammalian gastrointestinal tract are relatively well known, but in normal, healthy individuals. The present study was aimed at investigating the chemical coding of nerve structures in the wall of the ileum and large intestine in normal pigs (n = 3) and in pigs undergoing dysentery (n = 6). Dysentery was evoked by artificial infection of the clinically healthy animals per os with Brachyspira hyodysenteriae. All the animals were deeply anaesthetized and transcardially perfused with 4% paraformaldehyde. The cryostat sections of the intestines were processed for double‐labelling immunohistochemistry using antisera against PGP 9.5, GAL and VIP. In the intramural plexuses of the control pigs, the percentage of GAL‐immunoreactive (GAL‐IR) perykarya varied from 11% (descending colon) to 19% (centrifugal turns of the ascending colon) whereas in the dysenteric pigs, it was distinctly higher, reaching from 28% (ileum) up to 48% (cecum). In the control animals, the percentage of VIP‐IR neuronal somata varied from 3% (descending colon) to 19% (ileum). In dysenteric pigs, it was from 6% (descending colon) up to 28% (cecum). In the muscular coat (MC) and mucous membrane (MM) of the normal intestine, very numerous GAL‐ and VIP‐IR nerve fibres were observed. The nerve fibres in the myenteric plexus (MP) were even more numerous than those in the muscular coat while in the outer (OSP) and inner (ISP) submucous plexuses, they were less abundant. In the dysenteric pigs, the nerve fibres found in MC, MP and OSP were less numerous, whereas those observed in ISP and MM were more abundant than those in the control animals. The present results suggest that GAL and VIP are involved in the regulation of inflammatory processes developing in the porcine gastrointestinal tract during dysentery. 相似文献
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不同生态型大白菜抽薹时内源激素含量比较 总被引:5,自引:0,他引:5
大白菜〔Brassicacampestrissubspeciespekinesis(Lour. )Olsson〕先期抽薹一直困扰着春大白菜和高纬度、高海拔地区的大白菜生产。为育成冬性较强不易抽薹的品种,大白菜晚抽薹特性及利用的研究逐渐成为新的热点。不同生态型的大白菜品种,在相同的环境条件下冬性越强越不易抽薹。国外对控制或减轻未熟抽薹的环境条件有较多报道〔1~3〕,本研究主要探讨了低温处理后不同生态型的大白菜品种抽薹时内源生长素类 (IAA、IPA)、赤霉素类(GA3、GA4 )、细胞分裂素类 (ZR、DHZR)和脱落酸(ABA)含量差异,以期为选育具有较强冬性的大白菜品… 相似文献
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Z. Ngoko K.F. Cardwell W.F.O. Marasas M.J. Wingfield R. Ndemah F. Schulthess 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(9):893-902
The aim was to identify biological and physical factors responsible for reducing maize yield in Cameroon. Two surveys were conducted in 137 fields in two agroecological zones in 1995–1997. In the Humid Forest (HF), Bipolaris maydis, Stenocarpella macrospora, Puccinia polysora, Rhizoctonia solani and soil fertility were factors that reduced maize production in 1995 and 1996. In the Western Highlands (WHL), Cercospora zeae-maydis, and the interaction between soil fertility and maize variety were the most important constraints to maize production in 1996. In 1997, C. zeae-maydis, S. macrospora, physiological spot and stem borer damage (Busseola fusca) were negatively related to ear weight. The combination of these biological factors (diseases and insects), and the physical parameter of soil fertility were responsible for reducing maize yield in these selected benchmarks of Cameroon. Maximum potential yield reductions were estimated at 68% due to B. maydis and 46% due to S. macrospora, respectively, in the HF in 1995. In 1996, maximum potential yield reductions in the HF were estimated at 34%, 41% and 30% due to S. macrospora, P. polysora and R. solani, respectively. In the WHL, C. zeae-maydis had the potential to cause a yield reduction of 79% in 1996. In the WHL in 1997, the interaction between C. zeae-maydis and B. fusca, stem diseases and the physiological spot caused potential reductions of 52%, 34% and 39%, respectively. 相似文献