Why is peak milk important? • Increased milk yield. The vast majority of dairies generate the vast majority of their incomes through milk sales. The correlation between peak milk yield and actual 305-day milk production is highly positive. Each additional pound of peak milk should translate into an additional 200-280 lbs of milk in mature cows and 300+ lbs in first-calf heifers across the entire lactation. Conservatively, each one-pound increase in herd average peak milk production should generate at least 20,000 lbs more milk per 100 cows per year.
• Improved feed efficiency. This measure relates closely to improved income over feed costs (IOFC). Higher-producing cows typically have higher feed efficiencies, as each incremental increase in feed intake further dilutes maintenance feed requirements (and costs) and is more efficiently allocated to increased milk production.
Dr. Mike Hutjens reports that each 0.1 unit improvement in feed efficiency typically improves IOFC by 25-35 cents per cow per day. That equates with an income increase of $9,125 to $12,775 per 100 cows per year.
Related nutritional considerations
A primary objective for both transition and early-lactation cows is to maximize dry matter intake. Feed intake is influenced by a variety of factors in dairy cattle, and the predominant physiologic limitations vary with stage of production.
Based on research and a theory developed by Dr. Mike Allen and colleagues (the Hepatic Oxidation Theory, or HOT), transition and fresh cow intakes are primarily limited by elevated blood NEFA (non-esterified fatty acid) and/or blood/liver propionate levels, as they influence an increased rate of ATP production by the liver.
These considerations become less significant limiters of intake as the cow progresses through early lactation toward peak milk production. During this period, physical rumen fill (ruminal distension) is the primary limitation to additional dry matter intake.
From a ration formulation standpoint, this means targeting lower ration starch content and/or slower-versus-faster starch fermentability for fresh cows, as well as other strategies that will minimize rapid increases or fluctuations in propionate production. High and peak lactation rations should be more highly/rapidly fermentable and less filling (lower levels of physically effective NDF), but not to the extent where rumen health is jeopardized.
Excellent-quality, highly digestible forages, including BMR corn silage, should be prioritized for cows at this stage of lactation. A couple of studies have also shown improved milk production in early lactation in association with feeding BMR corn silage during the transition period.
Another ration strategy associated with improved fresh cow performance, as manifested by a decrease in metabolic disease incidence, is the feeding of dry cow diets with low energy densities.
Research by Dr. Jim Drackley and colleagues, among others, has demonstrated that over-consumption of energy during the dry period (the far-off dry period in particular) makes cows “behave metabolically” like fat cows during the transition period (lower dry matter intakes, greater risk of ketosis).
While there is some variation in the ease and consistency with which these diets are successfully implemented on-farm, the practical application generally agrees with the research when done correctly.
Related management factors
• Better transitions lead to higher peaks. Cow management considerations through the transition period (three weeks either side of calving) are arguably the most critical in this regard.
Several recent studies by Dr. Ken Nordlund and colleagues have demonstrated and reinforced the importance of adequate feedbunk space (at least 30 inches per cow), fewer pen moves or group changes, excellent cow comfort (sand bedding preferred) and astute fresh cow monitoring (focusing on appetite and attitude) as key components to better fresh cow performance.
• Beware lameness and mastitis. These are the two biggest profit-limiting conditions/diseases on the majority of dairies. When they occur during the transition period or in early lactation, expect more risk of a greater negative impact on cow performance and profitability.
• 4x or 6x milking of fresh group. If parlor usage time allows for it, this approach may help increase peak milk production and herd profitability. Keys to success with this strategy include ensuring fresh group pens are not overcrowded and verifying that total daily holding pen time won’t infringe upon cows’ time budgets to the point that daily lying time is compromised.
Research indicates that an increased milking frequency for the first 21-42 days of lactation can boost milk production, and a higher level of production can persist for the duration of lactation after returning to the normal 2x or 3x milking frequency for the herd. If implementing an increased milking frequency in fresh cows, be sure to also monitor teat ends and teat condition to ensure udder prep is good and that milking system settings are compatible with the increase in daily visits to the parlor.
• Heat abatement. Installing and using a climate-appropriate heat abatement system is a profitable strategy for almost every dairy, although the rate of return will vary by region and by facility. Many dairies focus on the lactating cow facilities when implementing cow cooling measures, but (aside from the possible exception of holding pen heat abatement) there is usually a greater proportional return on investment when dry and transition cows are effectively cooled.
• Dry cow body condition. Recognize that dry cows with excessive body condition (BCS >3.5) are at increased risk of metabolic disease after freshening because they don’t eat as well through the transition period and are more insulin-resistant. Appropriately conditioned (BCS 3.0-3.5) and thinner dry cows, on average, eat better through the transition period, which reduces their risk of fresh cow problems associated with negative energy balance.
• Adequate dry period length, especially for second-lactation cows. Recent prospective research indicates that mature dry cows can experience dry periods as short as 30-40 days without experiencing any decrease in milk production during the subsequent lactation.
However, although the data is limited, there appears to be a risk for lost milk in second-lactation cattle with dry periods that are too short. When employing a shortened dry period management strategy, remember to target at least 50-55 days dry for cattle entering their second lactation.
How to monitor with records
• Milk production in high or peak lactation groups can be monitored in those herds with daily milk weights, or by appropriate group identification as strings in DHIA testing.
• In larger herds (referenced because they more consistently provide adequate cow numbers for a meaningful sample size), evaluation of production for the group of cows 41-100 DIM should provide a reasonably accurate representation of current peak milk production.
• Recognize these measures (peak milk in particular) are somewhat insensitive, being influenced by lag, momentum and bias, as well as other herd-based variables including season of calving. Thus, they may not accurately reflect recent changes in performance.
Achieving and maintaining high peak milk production is closely tied to overall herd production and profitability. Focus on both nutrition-related and management-related strategies in order to maximize the opportunity to improve upon this key measure. PD
References omitted due to space but are available upon request to firstname.lastname@example.org .
R. Tom Bass
Technical Services and Nutritional Support
Renaissance Nutrition Inc.