COVID-19 has changed all of our lives in one way or another. Our Four-State Dairy Nutrition and Management Conference (organized by Extension specialists from Iowa, Ill., Minn. and Wis.) was moved to a virtual format. The program was offered on June 10 this year. We surely missed not seeing in person the around 600 attendees that we see every June in Dubuque, IA. Hopefully we can see everyone, June 9-10, 2021. Crossing fingers for a more "normal" world by that time.
This conference is geared toward nutritionists’ interests, but some veterinarians and farmers also attend. There were various topics covered during the event, starting with the pre-conference symposium on amino acids in dairy diets sponsored by Adisseo, followed by 2 main sessions at the conference, one focusing on improving herd health and the other focusing on maximizing profit from bull calves. There were also 10 pre-recorded breakout sessions on various topics related to nutrition, management, and housing. For program details go to the conference website.
Highlights from several conference presentations
How do circadian rhythms affect milk production, components and feeding behavior?
Kevin Harvatine, Penn State University, discussed his research on how circadian rhythms impact cows. A circadian rhythm is a natural, internal process that regulates our biological processes. All dairy farms know that components drop in the summer. Using DHI records back to 2000, Kevin observed a very predictable seasonality of milk production and fat and protein percent. Key findings and take-home messages:
- Milk yield peaks in April, averaging about five pounds more than the fall.
- Components follow a different rhythm with lower milk fat (-0.34%) and milk protein (-0.20%) in the summer than the winter.
- Anticipate and expect a swing in components with a peak around the first of the year and a bottom around July 1.
- If milk fat and protein percentages are not increasing in late fall to early winter, investigate and try and determine the reason. If your annual fat test is 3.9%, you should expect a 4.1% fat in January and 3.7% in July to be normal.
In another experiment, they wanted to examine if different feeding regimes affected cow feeding behavior and performance. Cows’ natural feeding behavior is crepuscular, meaning that their natural pattern is to spend the most time eating shortly after dawn and shortly before dusk. Cows will naturally eat some during the day, while most of the night is spent resting and ruminating. Key findings and take-home messages:
- In confinement systems, the delivery of fresh feed is the biggest factor influencing periods of peak feed intake.
- When they compared once a day feeding in the morning, once a day feeding in the evening, and twice a day feeding with half the feed in the morning and half in the evening, peak feed intake corresponded with feeding times for all groups.
- Cows fed once daily in the evening had more of a slug feeding pattern, eating 50% more after evening feeding compared to cows fed once in the morning. The feeding pattern throughout the rest of the day was similar between the three groups.
- They concluded that potentially there is an increased risk of acidosis if a highly fermentable diet is fed once in the evening.
- Think not only about the diet presented but how the eating pattern may affect the rumen and risk of acidosis and milk fat depression.
- It is likely not beneficial in the summer to feed once in the evening believing cows will have to eat more of the fresh feed overnight. This may increase the risk of acidosis on some diets.
How does the feeding of colostrum and milk, and weaning strategies affect gut health and development?
Mike Steele, University of Guelph, presented a main session talk on nutritional regulation of gut health and development with a focus on colostrum and milk, and also a breakout session talk with a focus on weaning and beyond. Colostrum provides not only immunoglobulins, which are key for calf immune function but also various bioactive molecules and cells necessary for good health. Some key findings and take-home messages from their research:
- Delaying the first feeding of colostrum beyond 6 hours after birth will not only impact passive immune transfer but also negatively influence the colonization of beneficial bacteria in the calf intestine.
- The best innovation in calf feeding in recent years is the 3-L and 4-L bottles, which allow for feeding greater amounts of milk to our calves.
- Feeding transition milk from days 2 and 3 fresh cow milkings (or a combination of colostrum and whole milk on a 1:1 ratio) resulted in improved gut health and development compared to going straight from the first feeding of colostrum to whole milk or milk replacer.
- Feeding transition milk was very similar to feeding colostrum for those 3 days. Both have positive immunological and nutritional effects.
- Weaning calves results in large transformations of the gut.
- If feeding high levels of milk (8 or more quarts per day) wean after 8 weeks of age with a 2-week stepdown to reduce the impact of weaning on calf performance and health.
- Heifers offered a high plane of nutrition (85% concentrate) for 2 months post-weaning had improved reproductive development compared to heifers fed 70% concentrate.
What are the keys to prevent lameness in our dairy herds? What aspects of barn design help improve performance and health in automated milking systems (AMS)?
Nigel Cook, University of Wisconsin-Madison, presented a main session talk on steps to prevent lameness in dairy cattle. Steps include hoof care, disinfection and cow comfort. He also presented a breakout session on barn design in automated milking systems (AMS). Some key take-home messages:
- Trim hooves twice per lactation unless wear is an issue; restore a more upright claw angle; balance weight between the inner and outer claw.
- Use well-designed footbaths (10-12 ft long); footbath 4 milkings per week; use effective antibacterial solution; no more than 300 cow passes; all life stages (includes heifers)
- Poor cow comfort - standing up for too long - is a main factor in the development of sole ulcers.
- Deep bedded stalls with sand reduce the chronicity of lameness.
- Mattress herds must have excellent stall design; treat lameness cases promptly; allow lame cows to recover on a soft surface; and use effective footbathing. These will help reduce lameness in mattress herds.
- Heat stress negatively influences resting behavior contributing to lameness. Heat abatement is key!
- Aim for lying times of 11.5 to 12.5 hours per day.
- Rubber transfer lanes reduce hoof wear to and from the parlor. Rubber is not recommended in freestall barn alleys. Focus on stall comfort.
- Heifers can develop corkscrew claw syndrome. To prevent this problem bedded pack rather than freestalls is recommended up to at least breeding age; or use organic bedding rather than sand in freestalls; reduce headlock exposure; provide outdoor access.
AMS general design priorities: 55 cows per robot max, minimum of 2 AMS units per pen, deep loose bedding, sufficient feedbunk space per cow (24 inches), 24/7 fresh cow access to the robot for 10-21 days post-calving, and expert gating and flow modeling.