Feeding fodder beet (Beta vulgaris L.) with either barley straw or pasture silage to non-lactating dairy cows

AIMS: To determine the suitability of diets containing either approximately 85% fodder beet (Beta vulgaris L.) with barley straw or 65% fodder beet with pasture silage when fed to non-lactating dairy cows, by measuring intakes, digestibility, rumen function including microbial growth, and N excretion.

METHODS: Holstein-Friesian cows fitted with permanent rumen fistulae were fed either 65% fodder beet with pasture silage (Silage; n=8) or 85% fodder beet with barley (Hordeum vulgare L.) straw (Straw; n=8) in an indoor facility over a 9-day period, for measurement of intakes, digestibility, rumen function and urine production. The cows were adapted to the diets over 2 weeks before the indoor measurements. Feed was available for about 6 hours/day, as practiced commercially for wintering non-lactating cows.

RESULTS: Five cows fed the Straw diet had to be removed from the trial because of acute acidosis; four on Day 1 of the measurement period and one on Day 7. One cow allocated to the Silage diet refused to eat fodder beet bulbs and was also removed from the trial. Two cows fed the Silage diet were also treated for acidosis. DM intakes were lower with the Straw than Silage diets (6.4 (SE 0.4) vs. 8.3 (SE 0.5) kg/day) and organic matter (OM) digestibility was lower with the Straw than Silage diets (77 (SE 1) vs. 83 (SE 1) g/100g). The N content of the two diets was 1.14 and 1.75?g/100?g DM and there was a net loss of N by cows fed the Straw diet (?22.7 (SE 7) g/day). Rumen microbial N production was much lower in cows fed the Straw than the Silage diet (6.6 (SE 1.3) vs. 15.8 (SE 0.7) g microbial N/kg digestible OM intake). Concentrations of ammonia in rumen liquid collected on Days 5–6 were below detection limits (<0.1?mmol/L) in 36/48 (75%) samples collected from cows fed the Straw diet and in 27/48 (56%) cows fed the Silage diet. Mean urinary N excretion was lower in cows fed the Straw than the Silage diet (52.0 (SE 5.8) vs. 87.7 (SE 5.9) g/day).

CONCLUSION AND CLINICAL RELEVENCE: An over-wintering diet for dry cows comprising about 65% fodder beet with 35% pasture silage provided adequate nutrition, although there was some risk of acidosis. In contrast, the diet containing about 85% fodder beet with barley straw resulted in lower DM intakes, poor rumen function, negative N balance so that both nutrition and welfare were compromised.     

Growth,nutrient utilization,and body composition of dairy calves fed milk replacers containing different amounts of protein

Male Holstein calves < 1 wk of age were allowed a 2-wk adaptation period after purchase, and then were blocked by BW and assigned randomly within block to either a baseline slaughter group or one of four experimental groups (n = 8 to 9 per group). Treatments were isocaloric milk replacers (12.5% solids) fed at 12% of BW that contained 16.1, 18.5, 22.9, or 25.8% CP (DM basis) from whey protein sources. After a 6-wk feeding period, all calves were slaughtered and the weights and chemical composition of the viscera-free carcasses (VFC; including head, hide, feet, and tail) were determined. Gain of BW (0.38, 0.45, 0.56, and 0.62 kg/d) and gain:feed ratio (0.51, 0.59, 0.71, and 0.78) increased linearly (P < 0.001) as dietary CP increased; rate of change in body length, wither height, and heart girth also increased linearly (P < or = 0.05). Balance measurements conducted during wk 3 and 4 of the experimental period showed that both absorbed N (16.9, 20.0, 25.8, and 30.6 g/d) and retained N (7.6, 9.0, 13.2, and 15.6 g/d) increased linearly (P < 0.001) as dietary CP increased. Retained N as a percentage of absorbed N increased linearly (P < 0.01) as dietary CP increased (44.3, 44.7, 50.7, and 50.9%), whereas biological value was unaffected (71.1, 68.7, 69.5, and 67.3%; P = 0.26). Digestible energy and ME represented 94.5 and 89.7% of intake energy, respectively, and were not affected by dietary CP content. Plasma urea N concentration increased linearly (2.9, 3.3, 4.6, and 6.0 mg/dL) as dietary CP increased. Contents of water (68.2, 69.1, 70.2, and 70.5%; P < 0.001) and protein (19.6, 20.0, 20.0, and 20.2%; P < 0.10) in VFC increased linearly, whereas contents of fat (7.2, 6.2, 5.5, and 5.2%; P < 0.001) and ash (5.1, 5.2, 4.8, and 4.7%; P < 0.02) decreased linearly as dietary CP increased. Trends in visceral tissue composition were similar to those for VFC. The content of water in VFC tissue gain increased, whereas contents of fat and energy decreased, as dietary CP increased. Final VFC energy and gain of energy in VFC were not affected by dietary CP. At similar initial ME intakes, increasing dietary CP (i.e., increasing protein: energy) linearly increased ADG, gain:feed, N retention, and deposition of lean tissue in VFC, demonstrating that diet composition can markedly affect components of body growth in preruminant dairy calves.     

Fertility of dairy cows in Northern Ireland

A comprehensive database was established on the milk production and reproductive performance of dairy cows in 19 selected herds in Northern Ireland, varying in size, management system and genetic merit. Data were obtained for 2471 cows, 1775 of which calved in a second year, and 693 were culled from the herd for specific reasons. The estimated mean rate of heat detection (assessed by the interheat interval during the main breeding season) in all the herds was 71 per cent, with a range from 53 to 92 per cent The average conception rate to first insemination was 37.1 per cent (range 21 to 66 per cent). The average calving interval for the retained cows was 407.2 days (range 359 to 448 days). Twenty-eight per cent of the cows that calved were culled, with infertility being the largest single reason (26.8 per cent of the cows culled). There were major differences in reproductive performance between the herds, but heat detection rate, conception rate and calving interval did not appear to be affeded by a herd's genetic merit. The herds with shorter calving intervals were characterised by better heat detection efficiency (83 v 61 per cent, P<0.01), a shorter interval from calving to first insemination (74 v 97 days; P<0.05), a higher conception rate to first insemination (45 v 34 per cent, P>0.10) and a lower removal rate (23 v 37 per cent, P<0.01). Furthermore, the cows in these herds had lower body condition scores (BCS) in the dry period (3.0 v 3.3; P<0.05) but lost less body condition in early lactation (0.3 v 0.6 BCS units, P<0.05). These results show that dairy herd fertility in Northern Ireland is generally low and similar to that previously reported for England and the USA, but that in some herds changes in herd management practices improved the cows' fertility.     

Regional brain monoamine concentrations and their alterations in bovine hypomagnesaemic tetany experimentally induced by a magnesium-deficient diet

Monoamines are important brain neurotransmitters. An investigation was carried out to determine if hypomagnesaemic tetany was associated with alterations in regional brain monoamine concentrations in bovines. The results, established in cows with normal magnesium status, demonstrated that regional differences existed in the distribution and concentration of brain monoamines in the adult bovine, which were similar to those in other species. In magnesium-deficient cows, severe hypomagnesaemia and lowered cerebrospinal fluid (CSF) magnesium concentrations were associated with significant alterations in monoamine concentrations in some brain regions. Alterations in 3,4-dihydroxyphenylalanine (DOPA) and dihydroxyphenylacetic acid (DOPAC) concentrations in the corpus striatum, and dopamine (DA) in the cerebral cortex and cerebellum were recorded. These regions play an important role in both voluntary and involuntary motor function, and therefore these alterations may play a role in the aetiology of hypomagnesaemic tetany. However, there was no significant change in DA concentrations in the corpus striatum (the main dopaminergic region in the brain) associated with hypomagnesaemia. In addition, a significantly lower norepinephrine (NE) concentration in the corpus striatum of hypomagnesaemic animals was also recorded. Norephinephrine is generally excitatory and therefore lowered NE concentrations would be expected to result in depression rather than stimulation of motor function.     

The Prediction of Parturition Date in Canine Pregnancy

In bitches, the length of gestation is highly variable when measured from the day of mating, thus prediction of parturition may be greatly inaccurate when determined from this point. The ability to precisely predict the duration of pregnancy is of practical importance for managing parturition or planning caesarean section and this review analyses the methods that can be used to accurately forecast the day of parturition. At the time of breeding, determination of the luteinizing hormone surge and the initial rise in progesterone provide reliable information on gestational length of the bitch, but when pregnancy is ascertained, ultrasonography is the most useful tool to predict the delivery day. In fact, by ultrasonographic measurements of the extra-foetal and foetal structures an accurate prediction can be made both in early and late pregnancy.     

Uterine rupture as a postpartum complication in two mares

Uterine rupture was diagnosed in 2 postpartum mares with hemorrhagic vaginal discharge. Both mares had abdominal pain, as evidenced by pawing, kicking at the abdomen, or attempting to roll. Peritoneal fluid analysis was useful in establishing a diagnosis. One mare had many RBC in the peritoneal fluid and was anemic; this mare was managed medically with oxytocin, antibiotics, and blood transfusion. The mare was able to raise her foal to weaning age. The second mare had many RBC, degenerate neutrophils, and intracellular and extracellular bacteria in peritoneal fluid. Surgical repair of the uterus was performed, and the mare was treated for peritonitis. The mare later became pregnant.     

林木遗传工程及木质素的生物合成调节(英文)

林木遗传工程有利于保存林木遗传资源，改善全球气候，减轻自然林的过度采伐和满足人类日益增长的林木产品需求。控制林木真菌、病毒病、虫害和杂草的遗传工程方法正被广泛地研究和应用。尽管转基因林木的历史不长，种类不多，但它有广泛的应用前景。目前，抗除草剂基因、抗虫基因以及和木材质量相关的基因已被分离并应用于林木遗传工程。植物分子生物学和基因组学中的新技术使得高效林木遗传改良成为可能并将促进这些技术的商业化应用。木质素的应用已有一百年的历史，但木质素生物合成的全过程并不完全清楚。有关松树自然突变体和转基因林木的最新研究结果表明，木质素的生物合成是一个可以调节的过程。这些发现对完善木质素的生物合成途径、加深对木质素前体生物合成途径的理解和通过遗传工程改善木材质量有促进作用。本文综述了林木遗传工程在这些领域中取得的一些进展。     

工能基因组学:T-DNA介导的基因诱捕和植物基因鉴定(英文)

拟南芥菜、水稻、蕃茄、土豆、玉米、小麦和大豆的全基因组测序为植物细胞和发育生 物学研究提供了许多有用的信息。基因组学的中心任务是利用这些信息去探索蛋白质的功能 和鉴定与发育有关的重要基因。尽管依赖于毁坏基因和产生可识别的突变表型的经典遗传学 方法仍然是极为成功的基因鉴定方法，借助于报告基因结构，随机插入植物基因组的T-DNA 介导的基因诱捕正发展成为植物细胞和发育生物学研究的极强有力的技术。本文描述了基因 诱捕、启动子诱捕和增强子诱捕在植物生物学中的应用，并且希望这些基因鉴定方法有助于 植物分子生物学家和生物技术工作者的研究。