When heifers calve very young, there is a greater risk of stillbirth and lower first-lactation milk production. When heifers are old at calving, their fertility may be negatively affected and it raises their culling risk. Plus, there is the cost of feeding them to that age before you get any return. So what is the sweet age for first calving to maximize average lifetime production? To answer that question, researchers at USDA analyzed production, reproduction, and lifetime data along with genetic (relationship) data from 13.9 million Holstein, 1.2 million Jersey, and 90,400 Brown Swiss cows. (Isn’t the national dairy database great? That’s just cows who first calved from 1997 through 2015!) Genomic data from about 205,000 of those animals were also used.
One of the first interesting results of this study was documentation of the significant trend toward younger ages at first calving (see Table 1). It’s been most pronounced for Jerseys.
Table 1. Percentages falling into each age-at-first-calving (AFC) category in 1997 and 2012. (Data condensed from Hutchison et al. 2017.)
Age at first calving may serve as an indirect indicator of general productivity and survivability, as lower ages at first calving correlate with higher lifetime production and fertility. That is, heifers capable of getting pregnant at younger ages may just be more robust animals in general. In order to capitalize on those individuals, one shouldn’t start breeding too late. The data support a target age of 21-22 months for Holsteins and Brown Swiss to deliver their first calves and 20-21 months for Jerseys. However, breeding at ages younger than 11-13 months is not recommended because younger heifers are more likely to have stillborn calves. The authors of the study suggest that AFC be incorporated in bull selection indexes, which would enable population-level selection for an AFC that increases profitability.
In a Canadian study published in the July 2017 issue of Journal of Dairy Science, researchers compared a quaternary ammonium compound-based (QAC) footbath to a more conventional copper sulfate (CuSO4) footbath. Five farms used a standard 5% footbath concentration of CuSO4. Another five farms used a 1% footbath concentration of QAC (per the manufacturer’s recommendation). An additional five farms that did not alter their standard hoofcare routine were also included. These dairies averaged 143 cows and a prevalence of active digital dermatitis (DD) lesions (hairy warts) of 15%. The protocols for the CuSO4 and QAC interventions had cows walking through freshly prepared footbaths once a day after milking Monday–Friday for 12 consecutive weeks.
In the CuSO4 group, the prevalence of chronic DD lesions decreased over the 12 weeks of the study. For the QAC group, chronic DD lesion prevalence decreased at the same rate for weeks 0–6, but then leveled off between 6 and 12 weeks. The QAC treatment also did not decrease the proportion of cows with active DD lesions. The researchers concluded that QAC was inferior to CuSO4 for footbath control of hairy warts. This is unfortunate, as a viable alternative to CuSO4 would be useful to reduce the amount of copper that ends up in pastures and crop fields (via manure handling and application systems).
For those with bunker silos, there’s a new study that suggests using an oxygen barrier (OB) up the sides and partway across the top will reduce spoilage and waste. Researchers in Brazil captured multiple corn silage samples from eight different silos that were differently covered one side to the other. Half of the filled bunker had a sheet of 45-μm-thick OB film (PE + EVOH) lining the side and folding over the top by approximately 6.5 feet (see figure B). Over the top of the entire bunker was a standard (ST) 180-μm-thick polyethylene (PE) film. Central core silage samples were compared to samples from just below the surface from both the OB and ST sides (see figures A & B).
The quality profiles of the OB samples were very similar to the core samples in terms of pH, TDN (total digestible nutrients), mold concentration, and most other variables. In contrast, the ST samples had significantly higher pH, higher mold and yeast concentrations, and lower starch and TDN compared to the core samples. Silage samples closest to the walls showed the largest effect of the sealing system. Lining the bunker with OB film reduced aerobic spoilage on the shoulders, yielding higher quality feed that resulted in an estimate of 256 pounds more milk per ton of dry matter consumed. The authors recommend overlapping the OB film at least 200 cm (79 inches) on the top of the silage and weighting the top PE film (or tarp) particularly well at the walls.
SAFETY REMINDER: Silage faces are hazardous. Even a not-too-high, correctly shaved face can still collapse. No one who is not actively unloading from the feedout face should be anywhere in the area. A good rule of thumb is to stay at a distance of three times the height of the face. And don’t fill the bunker higher than the unloader can reach.
Sunrise, sunset. When to eat, when to sleep. Like people and plants (and microbes!), cows have a circadian pattern. Circadian rhythms are the physiological and behavioral changes that follow a predictable pattern over the course of a day.
In a recent study, the exact locations of 350 cows in a free-stall barn on a Danish dairy were tracked each second for 5 months using a real-time positioning system (GEA’s CowView). Cows were classified as resting (in a stall), feeding (at the feed bunk), or in alley (in the milking robot or otherwise not in a stall or eating). Each of these activities was weighted: resting was negative (-0.15), feeding was very positive (+0.34), and in alley was less positive (+0.12). Then these weights were applied to the number of hours each cow spent doing each activity, which resulted in an average activity level across the herd over the day (see solid lines in the figure for “normal” cows).
That cows have circadian rhythms, shaped by light-dark cycles and management activities (like stall cleaning), is no surprise. What is interesting, is that the researchers found that circadian patterns changed when a cow was feeling poorly (lameness or mastitis) or coming into heat (see dashed lines in the figure). Lame cows showed less overall activity level variation over the course of the day. Cows with mastitis showed higher activity during the day but lower activity into the evening.
What’s more interesting is that the shift in circadian pattern occurred 1 to 2 days before the farmer detected the abnormality. These results should be verified in other settings with additional diagnostic tools. However, monitoring circadian patterns of activity may serve as an early warning system for cows that may require additional attention.
We hate it when it happens, but sometimes cows (and heifers and calves) die on the farm. Along with the economic loss is the hit to morale. Mortality losses average 6-8% in U.S. dairy herds, which is higher than 40 years ago. Systematic collection and analysis of death information may help prevent other deaths in the future and improve overall welfare of the herd.
The Integrated Livestock Management program at Colorado State University’s vet school has a Certificate of Death form for dairy cattle. The purpose is to record detailed information about each animal’s death in order to improve overall health management. The form includes spots for the expected items like id, birth date, calving date, and death date, but also things like body condition score, days in milk, and calving ease score. The section for cause of death doesn’t have just one line, it has space to write in the conditions that led to the cow’s final demise. Did she have a metabolic imbalance? An infection? An injury from a piece of equipment? Identifying the timeline of contributing events allows for an assessment of health risks on the dairy. Causes that appear frequently in death certificates should serve as a call to action. The authors of the form advise using a coding system that allows for a more detailed cause of death to be included in the cow’s individual record.
The folks at Colorado State University have also written a Dairy Cattle Necropsy Manual that includes illustrated, step-by-step directions for conducting an on-farm necropsy. The manual has lots of photos of both normal organs and commonly found abnormalities. There is also guidance for taking tissue samples. When doing a “home” necropsy, take plenty of pictures for the subsequent conversation with your veterinarian.
Completing certificates of death for cows, heifers, and calves provides the necessary information for analyzing health management practices so that improvements can be made and mortality rate decreased. Information may be the only thing of value that comes from an animal’s untimely death. Let’s use it.
If you’re a customer of Portland General Electric or Pacific Power, Energy Trust of Oregon can help out with rebates and other financial incentives when you upgrade or make improvements to equipment.
Eligible items include installing a variable frequency drive on your pump or doing a green rewind on a motor that’s gone kaput rather than replacing it. Upgrading light fixtures and lighting controls, such as replacing incandescent bulbs with LEDs, will pay dollars per fixture when replaced. The list is long for irrigation-related improvements: from simple replacement of regulators, sprinklers, or gaskets to going to scientific irrigation scheduling, which uses soil moisture monitors, weather station data, and evapotranspiration rates to apply water only when it’s really needed.
Energy Trust of Oregon is an independent, nonprofit organization whose funding comes from utility customers (that may include you!) via the public purpose charge on their monthly bills.
Researchers from the University of Vermont and their collaborators are collecting (anonymized) information about how health insurance policies and programs affect farmers and their farming operation. If you’d like to increase their sample size and help contribute to the development of policy recommendations and training materials, the survey can be found here. Additional information about the survey, part of a project called Health Insurance, Rural Economic Development and Agriculture, can be found here.
Instruction and hands-on practice in artificial insemination in cattle will be offered in fall and winter. Classes will be held on campus at Oregon State University, with Shelby Filley and Adrienne Lulay as instructors. Indicate your interest in attending by filling out this form for the waiting list. (AI school is popular!) The exact dates are yet to be determined.
About 60 people took part in the clicker survey during the 2017 Oregon Dairy Farmers Association’s Annual Meeting (thank you!). If you’re curious about the results, read on. (Note that not every person answered every question. Also, the duller demographic results are not shown here.)
With regard to who was in the room and their primary roles on or off the farm, we have these results:
Here we have preferences for learning new information:
For those of you who are interested to see what your fellow ODFA members are interested in learning more about, here are the topics surveyed: