In times of limited forage, dairy producers may need to feed diets lower in forage than is typical but would like to maintain milk production. In this study, two diets similar in neutral detergent fiber (NDF), starch, and crude protein with different amounts of forage were fed to 32 mid-lactation Holstein cows in a crossover design. The control diet (CON) contained high forage (55.5% of diet dry matter) with no supplemental fatty acids or amino acids. The low-forage diet (LF) contained 36.6% forage along with supplemental fat and rumen-protected methionine and lysine. As forage was removed from the LF diet, it was replaced with byproducts and high-moisture corn was replaced with dry corn. (4:42)
Dr. Lock added fat and amino acid supplements to the LF diet to not lose milk production. The fat supplement was a palmitic-acid-rich prill. Dr. Lock does not think the response would have been the same if a different fat supplement had been used. The LF diet was higher in fat and palmitic acid, but most other fatty acids were fairly similar between the two diets. (16:25)
Milk yields were similar between the two diets. Cows on the LF diet consumed about 1 kg more dry matter each day than CON-fed cows. Cows fed the LF diet also had higher milk fat and milk protein yields and content which led to an approximately 2 kg increase in energy-corrected milk compared to cows fed the CON diet. Dr. Lock believes the fat and amino acid supplementation were a key part of achieving these results, and they would not have seen the same response if those supplements had not been added to the LF diet. The LF diet spared around 5.5-6 kg of forage per day, and cows gained body condition. (22:03)
Dr. Weiss asks Dr. Lock to speculate if low-forage diets fed for longer periods would have negative health impacts. Dr. Lock feels that usually production would be negatively impacted by cow health issues, which was not the case here. However, if high-moisture corn had been used in the LF diet, he predicts they would have seen negative impacts. (27:18)
What about low-forage diets for early lactation cows? Dr. Lock suggests looking at diets in other parts of the world where forage is limited and see how dairy producers manage diets in those instances. He speculates that lower forage could be successfully implemented in early lactation cows after the fresh period. (31:09)
Dr. Weiss and Dr. Lock discuss the apparent improved digestibility of the LF diet given the increased production. While byproduct ingredients are often more fermentable in vitro, the results don’t always translate in vivo. Palmitic acid supplementation has been shown to improve fiber digestibility, so that may have happened in this experiment. (32:12)
On the protein side, we’ve moved away from talking about crude protein in the diet and toward amino acid concentrations. Dr. Lock would like to see the same trend in the industry for fat in the diet. A good leap was made recently from ether extract to total fatty acids, and he hopes to see individual fatty acids as the next step in that evolution. He recommends two questions be asked when considering a new fatty acid supplement. What is the fatty acid profile? What is the total fat content? The appropriate fatty acid profile is going to depend on the basal diet and what type of cow is being fed. Dr. Lock’s preference is a palmitic: oleic acid blend around 70:20 or 60:30 early in lactation, with a higher palmitic blend later in lactation. He expects the current work with different oilseeds to provide some good recommendations for feed ingredients to incorporate to increase dietary fat. (35:53)
As genetics continue to improve and nutrient requirements of cows continue to increase, is it conceivable that someday we are going to purposefully decrease fiber in the diet? While that may be the case, Dr. Lock reminds listeners that about half of milk fat comes from acetate and butyrate produced in the rumen, so fiber is still going to be critical. While we may lower the forage in a diet, forage quality is going to remain very important. (39:45)
The panel wraps up with their take-home messages from this paper. Clay looks forward to more research with a factorial design to further evaluate low-forage diets. Dr. Weiss reminds listeners there’s no one recipe for diets to achieve high yields of milk components. Lastly, Dr. Lock is excited about the future of research in this area and refining diet formulation in the area of fat supplementation. (43:21)
You can find this episode’s journal club paper from JDS Communications here: https://www.sciencedirect.com/science/article/pii/S2666910223001084
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By Balchem Animal Nutrition & Health
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In times of limited forage, dairy producers may need to feed diets lower in forage than is typical but would like to maintain milk production. In this study, two diets similar in neutral detergent fiber (NDF), starch, and crude protein with different amounts of forage were fed to 32 mid-lactation Holstein cows in a crossover design. The control diet (CON) contained high forage (55.5% of diet dry matter) with no supplemental fatty acids or amino acids. The low-forage diet (LF) contained 36.6% forage along with supplemental fat and rumen-protected methionine and lysine. As forage was removed from the LF diet, it was replaced with byproducts and high-moisture corn was replaced with dry corn. (4:42)
Dr. Lock added fat and amino acid supplements to the LF diet to not lose milk production. The fat supplement was a palmitic-acid-rich prill. Dr. Lock does not think the response would have been the same if a different fat supplement had been used. The LF diet was higher in fat and palmitic acid, but most other fatty acids were fairly similar between the two diets. (16:25)
Milk yields were similar between the two diets. Cows on the LF diet consumed about 1 kg more dry matter each day than CON-fed cows. Cows fed the LF diet also had higher milk fat and milk protein yields and content which led to an approximately 2 kg increase in energy-corrected milk compared to cows fed the CON diet. Dr. Lock believes the fat and amino acid supplementation were a key part of achieving these results, and they would not have seen the same response if those supplements had not been added to the LF diet. The LF diet spared around 5.5-6 kg of forage per day, and cows gained body condition. (22:03)
Dr. Weiss asks Dr. Lock to speculate if low-forage diets fed for longer periods would have negative health impacts. Dr. Lock feels that usually production would be negatively impacted by cow health issues, which was not the case here. However, if high-moisture corn had been used in the LF diet, he predicts they would have seen negative impacts. (27:18)
What about low-forage diets for early lactation cows? Dr. Lock suggests looking at diets in other parts of the world where forage is limited and see how dairy producers manage diets in those instances. He speculates that lower forage could be successfully implemented in early lactation cows after the fresh period. (31:09)
Dr. Weiss and Dr. Lock discuss the apparent improved digestibility of the LF diet given the increased production. While byproduct ingredients are often more fermentable in vitro, the results don’t always translate in vivo. Palmitic acid supplementation has been shown to improve fiber digestibility, so that may have happened in this experiment. (32:12)
On the protein side, we’ve moved away from talking about crude protein in the diet and toward amino acid concentrations. Dr. Lock would like to see the same trend in the industry for fat in the diet. A good leap was made recently from ether extract to total fatty acids, and he hopes to see individual fatty acids as the next step in that evolution. He recommends two questions be asked when considering a new fatty acid supplement. What is the fatty acid profile? What is the total fat content? The appropriate fatty acid profile is going to depend on the basal diet and what type of cow is being fed. Dr. Lock’s preference is a palmitic: oleic acid blend around 70:20 or 60:30 early in lactation, with a higher palmitic blend later in lactation. He expects the current work with different oilseeds to provide some good recommendations for feed ingredients to incorporate to increase dietary fat. (35:53)
As genetics continue to improve and nutrient requirements of cows continue to increase, is it conceivable that someday we are going to purposefully decrease fiber in the diet? While that may be the case, Dr. Lock reminds listeners that about half of milk fat comes from acetate and butyrate produced in the rumen, so fiber is still going to be critical. While we may lower the forage in a diet, forage quality is going to remain very important. (39:45)
The panel wraps up with their take-home messages from this paper. Clay looks forward to more research with a factorial design to further evaluate low-forage diets. Dr. Weiss reminds listeners there’s no one recipe for diets to achieve high yields of milk components. Lastly, Dr. Lock is excited about the future of research in this area and refining diet formulation in the area of fat supplementation. (43:21)
You can find this episode’s journal club paper from JDS Communications here: https://www.sciencedirect.com/science/article/pii/S2666910223001084
Please subscribe and share with your industry friends to invite more people to join us at the Real Science Exchange virtual pub table.
If you want one of our Real Science Exchange t-shirts, screenshot your rating, review, or subscription, and email a picture to [email protected]. Include your size and mailing address, and we’ll mail you a shirt.
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