This paper discusses the following: Plant processed corn silage is a new technology that can improve corn silage quality and nutrient availability; Phosphorous levels in dairy cow rations can be reduced avoiding environmental risks and lower feed costs based on new research results; and Testing forages for digestible fiber can improve energy prediction and milk production.

Glucose is required by the lactating mammary gland to synthesize lactose, which is present in milk at essentially a constant percentage and is the primary controller of milk volume. As a result, dairy cows are subjected almost overnight to a nearly overwhelming increase in demand for glucose during early lactation compared with late gestation. Dry matter intake, and the potential dietary contribution to glucose supply of the cow, increases more slowly than does the demand for glucose after calving.

Diarrhea in neonatal calves is a continuing problem and source of economic loss to the cattle industry. The United States Department of Agriculture estimates that 6.6 percent of the annual dairy heifer calf crop dies as a result of diarrhea, with diarrhea being the leading cause of death in unweaned dairy heifers. Financial losses occur not only from calf mortality, but also from the cost of medication and labor needed to treat sick calves.

Blood lactate concentration provides information as to the adequacy of oxygen delivery, thereby providing a means of assessing the severity of cardiovascular or pulmonary dysfunction, monitoring the response to treatment, and formulating a prognosis for survival. Increases in blood lactate concentration have been categorized as mild (2.5 to 4.9 mM/L), moderate (5.0 to 9.9 mM/L), and severe (> 10 mM/L), with arterial blood lactate concentrations greater than 10 mM/L being associated with very high mortality rates. Studies in critically ill patients have shown an excellent correlation between blood lactate concentration in arterial blood, pulmonary arterial blood, central venous blood, and blood obtained from a peripheral vein, indicating that determination of the jugular venous blood lactate concentration would be clinically useful.

Illinois dairy farms will need solid economic data and interpretation to compete in the future. Return on investment can exceed 9 percent annually. Dairy managers must develop a production system and approach to meet life style, debt load, and economic goals. Farm production goals must be measuring and fine tuned to avoid loss of profit margin potential.

An article we wrote for the 1998 Illinois Dairy Report (Can Milk Fat be Beneficial to Your Health?) provided a brief description of conjugated linoleic acid (CLA), a minor component of milk fat. Briefly, CLA is a fatty acid that is synthesized in the rumen during biohydrogenation of linoleic acid (C18:2), the predominant fatty acid in vegetable oils. The pathway of biohydrogenation is C18:2 ? CLA ? trans 18:1 ? C18:0. Research conducted over the past ten years suggests there may be many health benefits from the consumption of CLA. Conjugated linoleic acid is an anti-carcinogen in many cell culture and animal models. It has positive effects on growth, the immune system, is anti-atherogenic and may improve glucose tolerance (help control diabetes).

Greetings from the Department of Animal Sciences.

Chemical hydrogenation of fats to make them more saturated is one technique for making dry fats for dairy rations. Increasing the degree of hydrogenation or saturation of fats increases their melting point, allowing them to remain solid under normal environmental temperatures. Increasing saturation decreases negative effects of fats on rumen fermentation, but decreases digestibility of the fatty acids in the fat sources. 

Supplemental fat in the diet of dairy cows might increase milk production because of increased energy intake or improved efficiency of energy utilization. Niacin has increased milk production, milk fat and protein percentages and yields by cows in some experiments but not in others. Reasons for the highly variable results when niacin was fed to cows might include differences in the energy (fat) composition of the diets. The objectives of this experiment were to determine the effects of a mixture of whole raw soybeans and animal fat fed with and without niacin on intakes of energy and fatty acids (FA), passage of energy and FA to the small intestine, absorption of energy and FA, and FA secretion in milk.

Fatty liver most commonly occurs around calving when cows are mobilizing large amounts of body tissue from adipose and muscle to offset the negative energy balance imposed by initiation of lactation and decreased feed intake. The liver takes up the mobilized non-esterified fatty acids (NEFA) from the blood in proportion to their concentration in blood. However, ruminant liver lacks the ability to export lipid to the same degree as uptake of NEFA.

Although various procedures to synchronize estrus and ovulation, prostaglandin F2" (PGF2") is the only compound approved for use in dairy cattle. Gonadotropin releasing hormone (GnRH) is approved for the treatment of cystic ovarian disease. Recently, researchers have used a procedure first developed for the treatment of cystic ovarian disease to sychronize estrus and ovulation. This procedure, known as the OvSync procedure, has been demonstrated to be as effective as breeding upon the detection of estrus. The purpose of this study was to determine if efficacy of the OvSynch procedure could be improved if used concurrently with a intravaginal progesterone insert (IPI; aka-CIDR).

With the increasing public interest in environmental regulation for livestock operations comes the need for producers to have a well documented livestock waste management plan. Current Illinois law requires all livestock operations over 1000 animal units to have a written manure nutrient management plan. However, it is a good management decision for all livestock producers to prepare a manure plan. Producers who have a top-notch plan can improve their profits while protecting the environment and have a stronger defense in case of a pollution complaint.

Increasing the rumen-undegradable protein of soybean meal without making it unavailable to the cow has been the goal of many different treatments. Heat treatment first reduces the solubility of protein in soybean meal and then, if prolonged or excessive, reduces the availability of its amino acids to the animal. Protein solubility is often assessed using a dilute KOH solution. Amino acid availability is sometimes evaluated by measuring the ability of a protein to support the growth of rats or poultry; however, in vitro methods are also available to estimate it.

resulting from lameness arise not only from the cost to treat clinical cases but also from decreased milk production, decreased reproductive efficiency and premature culling. New York researchers estimate the total cost of lameness per 100 cows per year to be nearly $9000. The average incidence was 30 cases per 100 cows per year with a case fatality rate of 2 percent, involuntary culling rate of 20 percent, and increase in average days open of 29 days. The National Animal Health Monitoring System (NAHMS) Dairy 96 study revealed that 15 percent of the reason that dairy cows were culled for slaughter was due to lameness or injury.

a-Lactalbumin (a-LA) is a major whey protein of bovine milk and is essential for the biosynthesis of lactose in the mammary gland. Within the mammary epithelial cell, a-LA complexes with membrane bound ß1,4-galactosyltransferase to form the enzyme lactose synthase. Lactose synthase synthesizes lactose which is released into the milk along with a-LA. Lactose then draws water in the milk through osmosis. Because of its association with lactose production, a-LA is thought to play a role in regulating milk volume. With a-LA as its key regulator, an increase in lactose production should theoretically cause a proportional increase in milk volume. Bleck and Bremel discovered a variation in the control region of the a-LA gene. The A variant of this gene is only found in Holstein cattle while other breeds studied all contained the B variant. Through milk production trait analysis, they showed that this a-LA variant is associated with significant differences in milk production within Holsteins.

Dairy cows in the north Lincoln Avenue dairy barn at the University of Illinois were monitored for any influence of bedding type on the cow's comfort. Specifically, the objective of the project was to evaluate potential differences in how the cows used the stalls or any changes in size or appearance of the cow's hocks.

First, criteria needs to be established for evaluating how many bulls should be used in a 200-cow dairy herd. As a geneticist, I believe that the focus should be on the response to selection. Four components comprise response to selection and are 1) accuracy of evaluation, 2) intensity of selection, 3) genetic variability, and 4) generation interval. A breeder should want to increase the first three and reduce the generation interval to maximize the response to selection. A dairy producer will also want to focus on costs of the genetic improvement, but I will not address the costs in detail.

There are five stages of mammary development: fetal, prepubertal, postpubertal, pregnancy, and lactation. Hormones and nutrition play critical roles in the development of the mammary gland. Feeding regimens with varying nutrient levels during critical phases of mammary gland development in heifers can optimize lactational performances by taking advantage of normal patterns of mammary growth.

In 1997 Illinois dairy farmers volunteered to participate in measuring the quality, yield, and performance of BMR corn silage compared to their elite corn silage hybrids. Review the 1998 Dairy Report (page 71 and 72) to review agronomic results. In the winter and spring of 1998, control and BRM corn silage samples were collected and analyzed for starch content (by Dairyland Labs) and in vitro digestibility and silage composition (by Michigan State University).

Alfalfa is an important component of dairy rations and can be a profitable cash crop. High quality alfalfa can reduce feed costs and increase profitability. The key management strategy in producing high quality alfalfa forage is knowing when to select the optimum harvest date for the first cutting. Second and successive cuttings should then be harvested every 28 to 30 days thereafter. A common approach to determining the optimum harvest date for quality and quantity is by observing the growth stage of the plants. There is a direct correlation between the morphological development of the plant and the quality and quantity of alfalfa harvested. It is well documented that alfalfa nutrient quality decreases as the plant matures from the vegetative stage to full flower. At the same time, the pounds of plant material harvested per acre increases as the plant matures. The optimum harvest date is a compromise between the feed quality and the tonnage produced. Producers need to monitor the first cut alfalfa growth in order to determine the optimum harvest date. To assist alfalfa producers in monitoring plant growth and quality, University of Illinois Extension specialists conducted an Illinois "scissor clip" project on eighteen fields in eight regions throughout the state during spring 1998. This project is supported by a Partnership Illinois grant.

The intake of feed is a major factor limiting milk production in early lactation. Feed, animal, management, and environmental factors are known to alter the intake of lactating dairy cows. Increased and more consistent day-to-day consumption of feed is also important in minimizing the incidences of ketosis and displaced abomasum.

A new method of pregnancy detection has been advertised. This method involves the assay of serum samples collected 12 to 48 hours after insemination. The manufacturer (Concepto Diagnostics of Knoxville, TN) reports that it “is a unique immunoassay to identify the open cow within 12-48 hours of breeding. The test is conducted only on serum samples using the monoclonal-polyclonal antibody ‘dip stick’ methodology with gold as the indicator. This is not an absolute diagnosis of open cows. There are approximately 4 percent false positive results in serum samples collected 12-24 hours” after insemination. Because the manufacturer does not identify the compound being assayed and because no early conception factor has been reported in the scientific literature, the authors purchased kits and evaluated the assay on a group of cows synchronized with the “OvSync” procedure.

The feed intake and milk production of dairy cows is reduced during times of heat stress. Heat stress itself is a function of time, temperature, and humidity, because cows rely on water evaporation via sweating and panting to dissipate an excess of heat they have generated metabolically or absorbed from the environment. It is less clear how increased milk production, a result of genetic selection and improved management over the years, has affected the response of cows to heat stress. Even less is known about heat stress in early lactation. Our objective was to study, for a few cows in early lactation, as many of the relevant variables as possible during heat stress in a farm setting.

As dairy herds expand, having adequate labor to pay attention to the important details of heat detection and artificial insemination (AI) becomes a larger problem. The time available to observe the cows in estrus often becomes inadequate to detect cows in estrus accurately. Furthermore, it is often more difficult to detect cows in estrus when they are constantly on slippery concrete surfaces often found in large herds. Consequently, some large dairy herds have turned away from AI and are letting genetically unproven “jumper” bulls run with the dairy herd. Although at first this may seem like an easy solution, this approach has many disadvantages.

Economically important traits in dairy cattle such as milk, fat and protein yields and disease resistance are polygenic traits (i.e., influenced by many genes). The identification of these genes, termed quantitative trait loci (QTL), or closely linked genetic markers would allow genetic selection on the basis of both an individual's breeding values and on genotype using "marker-assisted" breeding programs. In the future, molecular identification of QTL may be used to develop pharmacological and transgenic approaches to enhance production or disease resistance.

Johne's disease was identified more than a century ago, yet remains a common and often a costly infectious disease of dairy cattle. In spite of this, many U.S. dairy producers are unfamiliar with Johne's disease. The recent National Animal Health Monitoring System (NAHMS) Dairy '96 Study report showed that 45 percent of dairy producers were either unaware of Johne's disease or recognized the name but knew little else about it. This lack of familiarity has hindered control and prevention of Johne's disease in this country. Efforts are currently underway to change this state of awareness.

Diarrhea in neonatal calves is a major source of economic loss for the cattle industry, being the leading cause of death in dairy and beef calves in the United States. Financial losses occur not only from calf mortality, but also from the cost of medication and labor needed to treat sick calves. One of the major goals of treatment is increasing cardiac output and correcting dehydration, through administration of oral electrolyte solutions and/or intravenous fluids. Because of the expense associated with conventional methods for administering intravenous fluids, such treatment is usually reserved for severely dehydrated calves (> 8% dehydration). An accurate, practical, and inexpensive method for predicting cardiac output and the need for intravenous fluids in calves with diarrhea would therefore be of value in guiding treatment.