Combined Risk Factors and Digestive Disorders in Mid-Lactation Holstein Cows: A Case Study

Digestive disorders can be a significant cause of disease on dairies and are frustrating because of their unpredictability. Diets that may support excellent health in most cases may nonetheless result in significant gastrointestinal disease, even leading to deadly conditions such as hemorrhagic bowel syndrome. To our knowledge, there is limited research on these conditions, as many risk factors fail to reproduce disease when experimentally administered to cows, leading many to conclude that these disorders are generally multifactorial in nature and difficult to replicate. In this case study, we document the outbreak and resolution of digestive disorders among 15 control cows enrolled in a larger production study. Over 14 weeks, cows were individually fed, with milk yield and composition, blood variables, and health observations recorded. The diet included drought-stressed corn silage that introduced difficulties including low energy density, high dry matter content (making it unstable at feedout), and mycotoxin contamination. By weeks 4–5 on the study, sporadic diarrhea began to appear and milk fat content had dropped from 3.7% to 3.4%, on average. Coincident with the onset of environmental heat stress, three cows developed severe digestive disorders, resulting in a displaced abomasum in one cow. At that point, the diet was changed to replace some corn silage with wheat straw, a direct-fed microbial was added to the diet, and organic acid treatment of the silage face was initiated. Within a month after these changes were implemented, essentially all signs of digestive problems resolved, including milk fat content, fecal consistency, and blood plasma concentrations of haptoglobin and D-lactate. This case study points to multiple factors that likely combined to lead to microbial and gastrointestinal disruptions resulting in clinical disease in a subset of cows

Performance of lactating dairy cattle housed in two-row freestall barns equipped with three different cooling systems

One hundred fifty-nine Holstein cows (66 primiparous and 93 multiparous) were assigned to each of three different cooling systems installed in two-row freestall barns on a northeast Kansas dairy. One barn was equipped with a row of five 48-inch fans mounted every 40 ft over the freestalls and a row of 10 36-inch fans mounted every 20 ft over the cow feed line. Another barn was equipped with five 48-inch fans mounted over the freestalls. Both of these barns were also equipped with identical sprinkler systems mounted over the feed line. The third barn was equipped with a row of five 48-inch fans mounted over the freestalls. In addition to the sprinklers over the feed line, additional sprinklers were mounted on the back alley of the third barn. Data were collected for an 85- day period to evaluate the three systems under heat stress during the summer of 1999. Cows cooled with these three systems produced similar amounts of milk and consumed nearly equal amounts of feed. Summer heat stress generally reduces milk production 20%, if cooling systems are not installed. Based on this estimated loss, these systems returned over $10,000/pen/year above ownership and operational cost. These results indicated that effective cooling in a two-row freestall barn includes a sprinkler system on the feed line and properly sized and spaced fans over the freestalls

Effects of Dietary Supplementation of Scutellaria baicalensis Extract During Early Lactation on Milk Production of Dairy Cattle

Multiparous Holstein cows (n = 122) were used in a randomized block design to determine the effect of short-term and long-term postpartum administration of Scutellaria baicalensis extract (SBE) on 305-day milk yield, 120-day milk component yield, and early lactation milk markers of inflammation and metabolic function. Treatments were (1) control, (2) short-term (5-day) administration of the SBE (SBE5), and (3) longterm (60-day) administration of the SBE (SBE60). Treatments were included in a treatment pellet that was identical to the control pellet in ingredient source and composition except for the extract, and both pellets were provided via an automated milking system. Milk samples were collected on day 1, 3, and once during days 5–12 of lactation, followed by weekly sampling for the remainder of the 120 days collection period. Milk samples collected in the first 2 weeks were used for biomarker analysis (haptoglobin and β-hyroxybutyrate [BHBA]), and all samples were used for composition analysis. Cows were scored for body condition every 2 weeks prepartum and postpartum. Milk production, programmed pellet allocation, and actual provision of both pelleted feeds were recorded daily. There was no difference in daily treatment pellet feeding between SBE5 and SBE60 for the first 5 days of lactation. Total pellet intake was greater for SBE60 than SBE5 and control cows during the treatment period (weeks 1–9), but not during the carryover period (weeks 10–36). No treatment effects were observed for body condition, milk haptoglobin, or milk BHBA. Whole-lactation milk yield was increased for SBE60 compared to control, but SBE5 did not differ from control. Milk lactose and fat yields were significantly greater and milk protein yield tended to be greater for SBE60 than control. Treatment SBE60 decreased somatic cell count (SCC) compared to control during weeks 3–5 and 8, whereas SBE5 did not affect SCC. Mastitis incidence was lesser for both SBE5 and SBE60 compared to control. Time to pregnancy did not differ, but retention in the herd tended to be greater for SBE60 than control. In conclusion, despite no detected treatment effects on BCS or milk biomarkers of inflammation and metabolic status, supplementation of postpartum dairy cows with Scutellaria baicalensis extract for 60 days was effective at decreasing mastitis incidence and increasing milk yield

Effects of Pre-Cutting Round Alfalfa Hay Bales on Forage Quality and Processing Time

Round hay balers with knives that cut the hay as it enters the baling chamber reduce the particle size upon baling, and eliminate the need for a tub grinder. The objective of this study was to evaluate the effects of a round hay baler with knives on forage quality of alfalfa hay at baling and after storage, and the effects of the processing method on nutrient composition and particle size distribution. Alfalfa hay was baled (560 M Megawide HC2, John Deere, Moline, IL) with knives every 4 inches (CUT; theo­retical length of cut) or without knives (NORM). At baling and after 6 months of uncovered storage, bales were weighed, measured, and 10 core samples were obtained for nutrient analysis. Cores were separated into outer 6 inches and inner 6- to 18-inch segments to determine the depth of spoilage. After storage, particle size was reduced to approximately 4 inches using a mixer wagon for CUT (CUT-MIX) or a tub grinder for NORM (NORM-GRIND). Compared with NORM, CUT increased bale weight and density. Core depth interacted with storage timepoint whereby acid detergent fiber (ADF) concentration increased more for outer than inner cores from baling to the end of storage, with similar effects for lignin and 240-hour undigest­ible NDF. Compared with NORM, CUT increased concentrations of aNDF organic matter, ADF, and lignin, and decreased relative forage quality (RFQ). The CUT-MIX treatment increased time to reduce particle size, but decreased processing shrink by 6.1% compared with NORM-GRIND. Additionally, when compared with NORM-GRIND, CUT-MIX increased fiber content and decreased fiber digestibility, which may have been due to sampling error from longer particle size. In summary, CUT produced larger, more dense bales and increased fiber content slightly, and CUT-MIX decreased processing shrink but increased fiber content with additional longer particles after processing, which could be advantageous for physically effective fiber in ruminant diets. Further work should continue to evaluate leaf loss during baling, and options for processing and incorporating pre-cut hay into diets

Atomic picture of ligand migration in toluene 4-monooxygenase

Computational modeling combined with mutational and activity assays was used to underline the substrate migration pathways in toluene 4-monooxygenase, a member of the important family of bacterial multicomponent monooxygenases (BMMs). In all structurally defined BMM hydroxylases, several hydrophobic cavities in the α-subunit map a preserved path from the protein surface to the diiron active site. Our results confirm the presence of two pathways by which different aromatic molecules can enter/escape the active site. While the substrate is observed to enter from both channels, the more hydrophilic product is withdrawn mainly from the shorter channel ending at residues D285 and E214. The long channel ends in the vicinity of S395, whose variants have been seen to affect activity and specificity. These mutational effects are clearly reproduced and rationalized by the in silico studies. Furthermore, the combined computational and experimental results highlight the importance of residue F269, which is located at the intersection of the two channels.This work has been funded by the EU projects INDOX (KBBE20137613549) and ERC 2009Adg25027PELE (to V.G) and the Spanish Ministry of Education and Science project CTQ201348287 (to V.G).Peer ReviewedPostprint (author's final draft

Impact of dried seaweed meal on heat-stressed lactating dairy cattle

Twenty-four lactating Holstein cows were used to determine the production response to the inclusion of brown seaweed in the basal diet during summer heat stress. Cows were blocked by lactation number, days in milk, and energy-corrected milk and then allotted to either a control or control + brown seaweed diet. Cattle on the brown seaweed diet were fed 4 ounces per cow per day for 7 days , and then 2 ounces per cow per day for 14 days, before the start of the experiment. All cattle were housed in a tie-stall barn, fed individually, and milked twice daily. Cows fed brown seaweed produced more (P<0.01) milk (77.6 vs 73.8 lb) and milk protein than controls did. But the addition of brown seaweed did not reduce respiration rates, rectal temperature, or rear-udder skin temperature. This indicated a similar heat-stress response for treated and control cows. Other studies have shown a reduction in respiration rates and body temperature when stressed cattle were fed brown seaweed. Further investigation is necessary to determine the factors that resulted in the observed milk and milk-protein responses in this study

Using vaginal temperature to evaluate heat stress in dairy cattle

Dairy Research, 2005 is known as Dairy Day, 2005A rise in body temperature is a signal that heat stress has exceeded the heat-exchange capacity of the dairy cow. Previous studies have shown a strong positive correlation between vaginal temperature and respiration rate, demonstrating a stress response to an increased body temperature. Vaginal temperature was collected by using temperature probes attached to an external data logger. Although these devices were very sensitive to changes in body temperature of cows housed in tie-stalls, the external data logger presented a significant application challenge for freeranging animals housed in freestalls. A data logger was acquired that would be completely indwelling in the vagina. The U12 stainless steel model (Onset Computer Corporation, Pocasset, MA) was 0.5 × 4 inches and weighed about 2.6 oz. It was retained in the vagina with foam and a blank CIDR insert. These devices were used continuously to measure and record body temperature in freeranging cattle for 5 to 7 days. Vaginal temperature was recorded at 1-minute intervals and then averaged into 5-minute blocks. Data were then graphed over a 24-hour period. Vaginal temperature increased with activity and amount of heat stress. Effective heatabatement systems were shown to reduce vaginal temperature. On commercial farms, data were used to identify where heat abatement should be improved. Heat stress issues with milking parlor holding pens were easily identified. Producers and industry personnel could use data loggers to evaluate heat stress and the effectiveness of heat-abatement systems on free-ranging dairy cattle. Devices also could be used to validate the effectiveness of modifications to heat-abatement systems identified by the initial evaluation