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• An empirical relationship in the database suggested that dietary cation-anion difference affects the performance of lactating dairy cows.
• Maximum milk yield and feed intake were reached when dietary cation-anion differences were 35 and 40 meq/100g of feed dry matter, respectively.
• The effects of dietary cation-anion difference were likely mediated via modification of acid-base status in the cows.

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• Fertility is economically important.
• Genetic variability of fertility exists although heritability is low.
• A national evaluation of fertility ranking bulls on successful pregnancies of their daughters will be published early in 2003.

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• Within two months after calving, heifers in the control group produced the same 305-day projected milk yield as the heifers fed the accelerated calf program.
• Control heifers calved earlier and were slightly larger in frame, while weighing the same as the heifers who had been on the accelerated program.

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• If your dairy farm wasn’t planned and built to prevent water pollution, the farm may be a target for regulatory action.
• Some changes that you can make may greatly reduce the amount of pollutants leaving your farm, and possibly keep you out of trouble.
• Manage to keep storm runoff out of streams and daily wastewater during the times of low stream flow.

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• Holotrich protozoa in the rumen migrate towards glucose, fructose, probably citrate, and perhaps galactose.   No attraction towards malate, fumarate, succinate, arabinose, or xylose was noted.
• These protozoa help slow the fermentation of soluble sugars in the rumen by competing with bacteria for them; however, they apparently do not compete for organic acids or the other sugars tested.

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• Know your cost of producing milk
• Higher milk prices in 2001 resulted in total returns exceeding total costs
• Lower milk prices and higher feed costs will reduce profit margins in 2002

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• Abomasal (stomach) ulcers are frequently present in milk-fed dairy calves.
• The cause for abomasal ulcers in milk-fed dairy calves is unknown, but is probably related to diet.
• Dairy calves fed milk replacer twice a day have sustained periods of low abomasal pH.
• Feeding milk replacer more frequently than twice a day may decrease the prevalence of abomasal ulceration in suckling calves.

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• Individual animal identification is likely to become mandatory for production animals in the future.
• Rather than a regulatory burden, proper management and implementation of a national program will provide new opportunities in animal management, health traceback, and marketing.
• Current systems that rely only on physical tags are not adequate to meet all demands for high throughput, accurate individual identification.
• It is likely that RFID methods will replace physical tags and this new technology will provide more opportunities to monitor animals and enhance productive efficiency.

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• The CIDR is approved by FDA to synchronize estrus in dairy heifers.   It is an effective method that is convenient to use.
• Alterations of the protocol to improve efficacy are being evaluated; however, only the approved protocol—administration of PGF 2 " on day 6 and removal the next day—has been sufficiently tested.
• Utilization of estrus synchronization will facilitate the management of breeding heifers via AI.
• Approval for use in dairy cows is being sought.
• Additional uses of the CIDR are being created:   use with Ovsynch for AI or ET recipients, use with Ovsynch for treatment of cystic ovarian disease, treatment after insemination to enhance the establishment of pregnancy, and treatment for synchronization of the return estrus.

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• Feed costs have increased 10 to 15 percent resulting in 7 cents per pound of ration dry matter.
• Invitro digestible NDF, Milk 2000, RFQ, and fourth Penn State Box provide useful feed information.
• By-product feeds can be an economic alternative with lower quality forages and higher feed prices.

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• Reproductive efficiency has declined in the dairy industry.   Numerous factors have been implicated and include, but are not limited to, milk production, reproductive management practices, bST treatment, the environment, inbreeding, and reproductive diseases.
• Reproductive indices need to be modernized.   We should be more concerned with such indices such as “100-d in calf rate” or “% pregnant within 1, 2, or 3 cycles after the volunteer waiting period” combined with culling rate because the traditional indices are negatively affected by timed AI protocols even though they may improve reproductive efficiency.
• Reproductive record management needs greater utilization.
• Regardless of the cause, there are several reproductive technologies available to improve reproductive efficiency.   These technologies include first-service synchronization and timed AI , early pregnancy detection and synchronization of the return estrus for cows that don’t conceive to the first service, embryo transfer, and CIDR treatment..

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• Bulk tank milk cultures are a valuable management tool for any size dairy.
• A consistent mastitis control program is the best defense against all mastitis.
• Bulk tank milk bacteria counts can not be used to predict the number of infected quarters in a herd

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• Effective and appropriate antibiotic treatment protocols for mastitis are needed.
• Antibiotic susceptibility testing has been used to guide treatment decisions in cows with clinical mastitis, however, it is uncertain whether antibiotic susceptibility test results can accurately predict treatment success.
• Ant ibiotic susceptibility testing was of no value in predicting duration of clinical mastitis or bacteriologic cure rate in 121 episodes of mastitis, except for mastitis episodes caused by gram-positive bacteria treated only with intramammary cephapirin.

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• Wide variations in manure starch content, fecal pH, and fecal dry matter were measured in fresh cows.
• Routine manure laboratory analysis did not provide useful information to evaluate rumen digestion or manure changes.

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• Presynchronizing cows before the voluntary waiting period improves responses to ovsynch.
• Initiating bST simultaneously with the first GnRH injection in the ovsynch protocol enhances pregnancy rates.  

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• BST injections under the skin of the neck significantly increased milk production in early and late lactation cows, as well as first and second or greater lactation cows.
• An additional 2-5 pounds of milk per day for up to 10 days post injection could cover any potential increase in labor.

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• The chemical composition of corn grain and corn silage produced from a corn line tolerant to Roundup ® (NK603) is substantially equivalent to that of its non-transgenic control line.
• Production of milk and milk components are not different when cows are fed Roundup ®-tolerant corn as grain or silage compared with its non-transgenic corn line.
• The stable insertion into corn of the gene that confers tolerance to Roundup ® (event NK603) does not affect its nutritional value for lactating dairy cows.

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• Sphingomyelin may help prevent and decrease the severity of colon cancer.
• Holsteins have greater concentrations of sphingomyelin in milk fat compared to Jerseys, but whole milk concentrations are similar.
• Cows in late lactation have higher whole milk sphingomyelin concentrations than cows in early lactation.
• Cows in 1 st, 2 nd or 3 rd lactation have higher milk fat concentrations of sphingomyelin than cows in later lactations.

We are once again pleased to share the annual summary of the important work that our faculty, staff, and students have done in the field of dairy cattle research. The past year has been marked by accomplishments that contribute to both the scientific stature of our department and to improvements in practices of dairy producers in Illinois, the U.S., and throughout the world. This combination of scientific merit and relevance to the industry make the University of Illinois dairy program one of the national leaders in both education and research. Our outreach programs in dairy are also strong and have established leadership in our college in the use of online instruction as a tool for delivering state-of-the-art knowledge to dairy producers around the globe.

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• Maintaining dry matter intake at calving is critical.
• Drenching cows can be a tool to improve nutrient intake.
• Feed additives can minimize metabolic disorder.

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• Microarray technology is a new molecular tool that allows simultaneous analysis of thousands of genes in a tissue from an organism.   We are the first research group in the world to apply this advanced technology to problems of dairy cattle genetics, physiology, and nutrition.
• New insights into animal development, health and disease, and metabolism during different times in the lactation cycle or during growth could be gained by evaluating gene expression in key tissues.
• In our current experiment, data on expression profiles of genes in the liver of dairy cows during the transition period should provide new information on the efficacy of different dry period nutritional strategies on lactation performance.

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• Soyhulls can supply 20 to 30% of the dry matter intake of midlactation cows producing about 66 pounds of milk/day.
• When more than 30% of the diet is soyhulls differences in the source of energy, amounts of fiber and nonstructural carbohydrates digested, and in the site of digestion within the digestive tract may cause a shortage of either the proper source and (or) amount of energy required for maximum milk production.
• Replacing a portion of the corn in the diet with soyhulls may help to reduce feed costs when soyhulls can be purchased at a more competitive price than corn.

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• Dairy producers who utilize off-farm services may reduce investment per cow and     allow more time to specialize in operating the dairy enterprise.
• Contracting off-farm inputs must be equitable for both buyer and seller.
• Forage contracts require accurate yield measurements or reasonable estimates by weighing some or all of the loads and using moisture tests to determine dry matter yields.