Dairy cows with prolonged calving seek additional isolation

In modern calving facilities, dairy cows either calve in a group pen or are moved to a separate individual pen when calving is imminent. In practice, cows are often moved too close to calving, which poses a health risk to cow and calf. Thus, a need exists for new calving facility designs and management practices that better align with the motivations of the cow. This study examined dairy cow preferences for individual calving pens by offering 3 different levels of isolation (tall and narrow, low and wide, and tall and wide) by analyzing the association between precalving behavior, choice of degree of isolation, and the progress of calving. The hypotheses were that cows would prefer the highest level of isolation when giving birth, and that calving in a high level of isolation would be associated with less restlessness and a shorter calving duration. Contrary to these hypotheses, no specific preference between degrees of isolation or difference in calving behavior in the different calving pens was found. However, cows experiencing a longer calving duration chose to calve in the most secluded calving pen (tall and wide). These results cannot determine cause and effect, but may suggest that interactions between motivation for isolation seeking and calving behavior exist.     

Effect of pasture versus indoor feeding systems on quality characteristics,nutritional composition,and sensory and volatile properties of full-fat Cheddar cheese

The purpose of this study was to investigate the effects of pasture-based versus indoor total mixed ration (TMR) feeding systems on the chemical composition, quality characteristics, and sensory properties of full-fat Cheddar cheeses. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n = 18) for an entire lactation. Group 1 was housed indoors and fed a TMR diet of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass only pasture (GRS); and group 3 was maintained outdoors on perennial ryegrass/white clover pasture (CLV). Full-fat Cheddar cheeses were manufactured in triplicate at pilot scale from each feeding system in September 2015 and were examined over a 270-d ripening period at 8°C. Pasture-derived feeding systems were shown to produce Cheddar cheeses yellower in color than that of TMR, which was positively correlated with increased cheese β-carotene content. Feeding system had a significant effect on the fatty acid composition of the cheeses. The nutritional composition of Cheddar cheese was improved through pasture-based feeding systems, with significantly lower thrombogenicity index scores and a greater than 2-fold increase in the concentration of vaccenic acid and the bioactive conjugated linoleic acid C18:2 cis-9,trans-11, whereas TMR-derived cheeses had significantly higher palmitic acid content. Fatty acid profiling of cheeses coupled with multivariate analysis showed clear separation of Cheddar cheeses derived from pasture-based diets (GRS or CLV) from that of a TMR system. Such alterations in the fatty acid profile resulted in pasture-derived cheeses having reduced hardness scores at room temperature. Feeding system and ripening time had a significant effect on the volatile profile of the Cheddar cheeses. Pasture-derived Cheddar cheeses had significantly higher concentrations of the hydrocarbon toluene, whereas TMR-derived cheese had significantly higher concentration of 2,3-butanediol. Ripening period resulted in significant alterations to cheese volatile profiles, with increases in acid-, alcohol-, aldehyde-, ester-, and terpene-based volatile compounds. This study has demonstrated the benefits of pasture-derived feeding systems for production of Cheddar cheeses with enhanced nutritional and rheological quality compared with a TMR feeding system.     

Diurnal variations of progesterone,testosterone, and androsta-1,4-diene-3,17-dione in the rumen and in vitro progesterone transformation by mixed rumen microorganisms of lactating dairy cows

Five Holstein lactating dairy cows fed 5 total mixed rations (TMR) with different forage combinations were used in a 5 × 5 Latin square design to investigate diurnal variations of progesterone (P4), testosterone, and androsta-1,4-diene-3,17-dione (ADD) concentrations in the rumen. Meanwhile, different P4 inclusion levels [0 (control), 2, 20, 40, 80, and 100 ng/mL in culture fluids] were incubated in vitro for 6, 12, 24, 36, 48, and 72 h together with rumen mixed microorganisms grown on a maize-rich feed mixture (maize meal:Chinese ryegrass hay = :1) with an aim to determine microbial P4 transformation into testosterone and ADD. Ruminal P4, testosterone, and ADD concentrations of lactating dairy cows were greater in the TMR with forage combination of corn silage plus alfalfa hay or Chinese wild ryegrass hay than the TMR with the corn stover-based forage combination. The diurnal fluctuation pattern showed that P4, testosterone, and ADD concentrations in the rumen were greater at nighttime than daytime and peaked 6 h after feeding in the morning or afternoon. The in vitro batch cultures showed that the P4 elimination rate was highest at the P4 addition of 20 ng/mL and declined with the further increased addition of P4. The treatments after dosing P4 exhibited a shorter time than the control group until half of the initial P4 inclusion was eliminated (i.e., half time), and the lowest half time (1.46 h) occurred at the P4 addition of 20 ng/mL. In summary, the ruminal steroids concentration was affected by forage type and quality, and the rumen microorganisms exhibited great ability to transform P4 into testosterone and ADD, depending on incubation time and initial P4 addition level, suggesting that the host might affect the metabolism of its rumen microorganisms via the endogenous steroids.     

Dairy cow handling facilities and the perception of Beef Quality Assurance on Colorado dairies

A survey was conducted on Colorado dairies to assess attitudes and practices regarding Dairy Beef Quality Assurance (DBQA). The objectives were to (1) assess the need for a new handling facility that would allow all injections to be administered via DBQA standards; (2) establish if Colorado dairy producers are concerned with DBQA; and (3) assess differences in responses between dairy owners and herdsmen. Of the 95 dairies contacted, 20 (21%) agreed to participate, with a median herd size of 1,178. When asked to rank the following 7 traits—efficiency, animal safety, human safety, ease of animal handling, ease of operation, inject per Beef Quality Assurance (BQA) procedures, and cost—in order of priority when designing a new handling facility, human and animal safety were ranked highest in priority (first or second) by the majority of participants, with ease of animal handling and efficiency ranked next. Interestingly, the administration of injections per BQA standards was ranked sixth or seventh by most participants. Respondents estimated the average annual income from the sale of cull cows to be 4.6% of all dairy income, with 50% receiving at least one carcass discount or condemnation in the past 12 mo. Although almost all of the participating dairy farmers stated that the preferred injection site for medications was the neck region, a significant number admitted to using alternate injection sites. In contrast, no difference was found between responses regarding the preferred and actual location for intravenous injections. Although most participating producers are aware of BQA injection guidelines, they perceive efficiency as more important, which could result in injections being administered in locations not promoted by BQA. Dairy owners and herdsmen disagreed in whether or not workers had been injured in the animal handling area in the last 12 mo. Handling facilities that allow for an efficient and safe way to administer drugs according to BQA guidelines and educational opportunities that highlight the effect of improved DBQA on profitability could prove useful. Dairy producers play a key role in ensuring that dairy beef is safe and high quality, and just as they are committed to producing safe and nutritious milk for their customers, they should be committed to producing the best quality beef.     

高效复合肥料硝酸铵钙的生产及市场概况

介绍了硝酸铵钙的物化性能;概述了硝铵熔融液与石灰石混合法生产硝酸铵钙的工艺技术;分析了硝酸铵钙在农作物种植上的施用效果和产品市场前景。     

奶牛采食量检测仪的设计与技术研究

为了及时、准确地测量出奶牛的采食量，本文根据奶牛在采食、反刍和吞咽时的行为表现，本文提出了通过传感器实时检测奶牛颞窝部位的运动规律来反映牛只采食量大小的原理，并根据此原理研制了一种基于单片机控制和检测的奶牛采食量自动检测仪。该检测仪能够准确地测量并计算出奶牛的吞咽次数，然后根据奶牛吞咽时食团质量的大小计算出奶牛的采食量，并且可将一定时期内的采食量进行回归分析制定出相应的营养方案。本检测仪实现了快速、方便和精确的采食量测定目的。     

猪粪原料沼气工程系统中的原核微生物群落结构

采集了中国不同地区的13个猪粪原料沼气工程系统的沼液,利用16S rRNA基因扩增子高通量测序技术研究了原核微生物群落组成及多样性。结果表明,Firmicutes是猪粪原料沼气工程系统中的主导微生物,其次为Bacteroidetes、Proteobacteria和Chloroflexi。在相似的温度条件下,铵态氮与磷酸盐的比例是影响猪粪原料沼气工程系统原核微生物群落结构及多样性的主要因素。较高的铵磷比会富集Firmicutes门的菌群,尤其是Clostridium sensu stricto属;而较低的铵磷比则有利于Bacteroidetes和Proteobacteria。不同营养类型产甲烷菌对高浓度铵态氮耐受程度不同（氢营养型产甲烷菌 >Methanosarcina >Methanosaeta）,影响着产甲烷菌群落组成。产甲烷菌和互营菌的群落组成是影响沼气发酵产气效率的重要生物因素,高比例的氢型产甲烷菌和丙酸互营菌更有利于提高产甲烷效率。     

酸改性猪粪生物炭的制备及其对直接红23染料的吸附性能

以直接红23染料(DR23)溶液模拟印染废水,对比分析了酸改性前后猪粪生物炭对DR23的吸附特性与机理。通过静态吸附实验考察了DR23溶液的pH、初始浓度、吸附时间、吸附温度、吸附剂添加量等条件对吸附效果的影响,并确定了该吸附过程的吸附动力学和吸附等温线。研究发现,相比于未改性生物炭(PMB),酸改性后生物炭(PMB_acid)结构变得疏松多孔,表面官能团丰富,表现出更优的脱色性能,对DR23的吸附去除率最高可达96.10%,最大饱和吸附量为111.51mg/g,且在经过3次循环再生后,PMB_acid对DR23的去除率仍可达到88.31%;此外,pH对PMB_acid的脱色吸附性能影响较小。PMB_acid对DR23的吸附是一个受反应速率和扩散控制的复杂过程,符合于伪二级动力学模型和Langmuir等温吸附模型;PMB_acid对DR23的吸附机理取决于吸附剂的物理化学性质,其孔结构及各官能团通过不同的机制参与了生物炭对DR23的吸附过程。     

畜禽粪便中四环类抗生素的残留和环境行为

我国畜禽养殖业很发达,畜禽粪便中残留的四环素类抗生素的污染对生态环境构成了巨大的潜在威胁。针对这种状况,本文总结了我国四环素类抗生素在畜禽粪便中的残留状况及其进入环境的途径,并概述了其在环境中的迁移和降解状况。