Effective Fiber: Differences in Actual and Predicted peNDF

The goal in formulating and feeding dairy rations is to match the ration on paper to the ration the cow actually eats. Moisture changes in forages, forage changes, inaccurate scales, and lax mixing procedures are some of the reasons they are not the same. We can send in a TMR sample to the lab to measure protein , fiber, starch, mineral content, etc. to see how close the formulated ration and the TMR actually are. But how effective is this fiber in the rumen? Most ration programs give an estimate of peNDF (physical effective NDF). This estimation uses fiber levels of our feed ingredients to predict the ration contribution to an adequate rumen mat in the rumen. PeNDF predictions gives us an idea of changes in fiber contribution, but not a good measure of actual peNDF. We can use the Penn State Particle Separator to give use an actual peNDF value. There are three different versions with different calculations for each one. Measuring actual peNDF in TMRs 3 “screen” – 2 Sieves and a pan Add calculated percentage of top two sieves  plus 20% of bottom pan  and multiply by  the NDF of ration 4 “screen” – 3 sieves  (3rd sieve is a fine screen) and a pan Add calculated percentage of top two sieves plus 30% of 3rd sieve and multiply by NDF of the ration 4 “screen” with new 3rd sieve having 0.16 inch (4 mm) openings. This new screen was designed to measure peNDF. Add calculated percentage of top 3 screens and multiply by NDF of ration How close is the actual to the predicted?  If the actual peNDF is significantly lower than predicted peNDF, cow performance may be enhanced...

Adding Methionine to Lactating Dairy Rations

The benefits of adding methionine to dairy lactating rations to enhance milk and milk protein production has been known for many years. The return on investment of this inclusion was usually measured by the cost of the methionine against the potential return from milk protein production.  The value of milk protein has varied greatly over the last few years. The value of this milk protein is at a low point, which has many questioning the value of adding methionine, and some reducing the amount of supplementation. Additional research has shown the value of feeding dairy cows methionine pre- and post-freshening. Research shows it improves immune function during the critical transition period. A presentation at the 2016 Four-State Nutrition Conference by Dr. Phil Cardoso of the University of Illinois highlighted the beneficial effects of methionine supplementation during the later stages of follicle growth and early embryo development. Supplemented cows had lower early embryonic death (primarily between day 21-61). “Supplementation of cows with methionine during the final stages of follicular development and early embryo development, until Day 7 after breeding, lead to lipid accumulation changes in the embryos and resulted in differences in gene expression in the embryo.  Methionine supplementation seems to impact the preimplantation embryo in a way that enhances its capacity for survival because there is strong evidence that endogenous lipid reserves serve as an energy substrate. The lower pregnancy losses from cows fed methionine enriched diets suggest that methionine favors embryo survival, at least in multiparous cows. Further studies are needed to corroborate whether supplementation with methionine would have a beneficial impact on embryo survival and if these...

Trace mineral supplementation in dairy rations

It has been a common practice to reduce the amount of trace minerals (VTM) in lower producing or late lactation cows because of the belief that these cows have a lower requirement than high producing cows. They do have a lower requirement, but not necessarily a lower concentration in their diet. These trace minerals include iron, manganese, zinc, copper, cobalt, chromium, and selenium. High producing cows (with higher dry matter intakes) can utilize more of the trace minerals from feedstuffs. Cows with lower dry matter intakes that are fed reduced levels of VTM do not have the same opportunity to make up the difference as higher producing cows. Post fresh cows fed a lactating diet but only consuming two thirds of the intake may be short of requirements. Here is what we need to do to ensure the cows are receiving the right levels of VTMs: Use wet chem analysis on forages to get accurate levels. Cobalt, chromium and selenium levels are not tested. High ash forages (soil contamination) may give higher levels of trace minerals, but they may not be as available. Other minerals, like high sulfur levels with copper, may be antagonistic and limit their absorption. This may require feeding higher levels to compensate, or using a more available source. Feed 1.2-1.5 times NRC requirements to ensure adequate levels. Diets are limited to .3 ppm added supplemental selenium. Selenium yeasts will have more available selenium than inorganic forms. Feeding bentonite can inhibit absorption and may require higher feeding levels. To answer the question, does it cost more to overfeed or underfeed trace minerals, the answer is to...

6 tips for minimizing heat stress on your dairy

Minimizing heat stress is a goal of every dairyman. Tunnel or cross ventilated barns have given us a cow comfort standard that we can try to attain in many barns. There have been improvements in air movement and sprinkler systems in most dairies. But what else can we do?  1. Feeding more digestible forages. Low quality forages stay in rumen longer and produce more heat than high quality forages. Target these mineral levels in summer: Potassium                          >1.5% Sodium                                 .4-.55% Chloride                                <.35 DCAD                                   At least 300 meq/Kg 2. Lowering stocking density.  If possible, especially in pre- and post-fresh pens. This will help reduce metabolic disease incidence. 3. Provide shade. Cows under stress are light sensitive and bunch up in areas away from sunlight.  Shade cloth on outside walls or lowering the lower curtain can allow cows to spread out. 4. Feed multiples time a day. Feeding multiple times a day will keep fresh feed in front of cows and ensure adequate feed at night as cows will eat more in cooler temperatures. 5. Water. Waterers need to be cleaned more often in hot weather. Access to water immediately after milking is more important than ever. 6. Bovine BlueLite. Bovine BlueLite lowers body temperature and assists in rehydration. This can be fed all summer...

Accurate cow descriptions fine-tune rations for improved performance

The dairy cow’s ability to produce more milk is dependent on the quality of the ration and how much she consumes of it. We have made great strides in improving forage quality, ration formulation and cow comfort. Ration modeling programs (CNCPS) use information from multiple sources to predict cow performance. Improvements in these programs make it imperative that we have accurate inputs to get our expected predictions. However, one of the most obvious and overlooked is the cow itself and her environment. Dry matter intake and rate of passage are calculated based on the cow’s body weight and milk production. Forage quality also impacts these numbers, but forage laboratories provide us with accurate evaluations of their contribution. Most of us are guilty of using default body weights for all groups of dairy cattle. However, correct weights will lead to more accurate production predictions (milk and/or growth). This can impact ration formulation. The amount of starch needed in a ration may change due to rate of passage differences. This may allow us to confidently fine tune a ration with lower MUN levels. The stage of lactation also affects intake. Are we describing our pens of cows correctly? Fresh pens can change dramatically in days in milk and production. Body weight loss can be used to predict energy needs of these cows.   Up-to-date days in milk, milk weights, and body condition scores in all pens allow our ration programs to assist us in producing the correct ration. Even a one-group TMR herd will still benefit from an accurate description of the herd. Air temperature, wind speed, lot conditions, and walking distance will...