SYNOPSES OF 2005 GRANTS
AWARDED BY JERSEY RESEARCH FOUNDATION

Andrew, Sheila A., University of Connecticut, Storrs, CT, The effects of extent of negative energy balance, plasma amino acids, retinol and retinol binding protein concentrations on the risk for developing mastitis during the transition period in high producing Holstein and Jersey cows.

The transition from late gestation to early lactation is the most metabolically challenging stage in the lactation cycle of a dairy cow. The risk for metabolic disorders and diseases, such as mastitis, increases for high producing dairy cows during this transition phase. It is estimated that the dairy industry loses over $1.5 billion a year due to health problems associated with this transition period, which is characterized by increased nutrient requirements for fetal growth, parturition, and the onset of milk production and a lag in increased feed intake that usually results in a period of negative energy balance (NEB). The immune system can also be impaired during this period due to the metabolic demands for milk production and the challenges of a prolonged state of NEB. Also, there is evidence that a reduction in plasma concentration of several lipid soluble vitamins, including retinol, increased the risk of mastitis. Plasma concentrations of these vitamins are typically reduced during early lactation. We recently completed a study to examine the effect of breed, energy status, and plasma metabolites on new intra-mammary infection in 10 Jersey and 10 Holstein periparturient dairy cows. We determined that Jersey cows maintained a higher plasma concentration of retinol from 2 weeks prepartum to 8 weeks postpartum compared to that of Holstein cows. Also, cows with greater plasma concentrations of retinol at 2 weeks prior to parturition tended to have a lower risk for developing a new intramammary infection.

During NEB, in addition to mobilization of tissue lipids there is an increase in oxidation of amino acids that support the energy requirement and cows may have a deficiency in protein during this time. This may result in a decrease in retinol binding protein which is the primary transporter of retinol from the liver to target organs and the synthesis of RBP is reduced when dietary amino acids are limiting. Thus it is postulated that a deficiency in ration protein during the transition phase may result in a reduction in retinol binding protein synthesis. This reduction in RBP may limit the availability of retinol for tissue needs and immune function.

It is hypothesized that since plasma retinol concentrations were greater for Jersey cows during the transition phase, then plasma amino acid and retinol binding protein concentrations will be greater for Jerseys compared to that of Holsteins. This will support the concept that Jersey cows do not generally experience as severe a negative energy balance as Holstein cows and thus do not experience as severe a negative protein deficiency. It is anticipated that the greater supply of amino acids will be available for retinol binding protein synthesis and enhance retinol status which will reduce the risk of mastitis for Jersey cows relative to Holstein cows. 

Using the plasma samples collected from the study described above, analyses of plasma amino acids, plasma retinol binding protein and plasma enzymes derived from the liver will be conducted to explain the relationship among plasma retinol, protein status, energy status and risk of mastitis. The following steps are proposed to be taken: Plasma concentrations of amino acids, retinol binding protein and enzymes associated with liver protein metabolism will be determined using plasma samples from the 20 cows from the completed study.

We will investigate the relationships among these variables, the NEB variables and the risk for developing an intramammary infection for each breed.

It is anticipated that there will be lower plasma retinol binding protein and amino acids in the cows that experience a greater NEB during the transition period and that this reduction is related to an increased risks for developing mastitis. In addition, it is anticipated that Holstein cows will have lower plasma concentrations of retinol binding protein and amino acids compared to that of Jersey cows. This will support the hypothesis that Jersey cows may be less susceptible to mastitis during the transition period.

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Ashwell, Melissa, North Carolina State University, Raleigh, NC, Why does some Jersey semen freeze and thaw better than others? A functional genomics approach to answering the age-old question.

Because inbreeding is an important issue with today’s Jersey population, the ability to preserve semen from genetically diverse bulls is paramount. Identification of all the genes important in sperm survival may provide important clues on how to improve cryopreservation technology so that semen from all genetically desirable Jersey bulls can be preserved.

To this end, two SAGE (serial analysis of gene expression) libraries will be produced; one from a Jersey bull with inferior post-thaw survival and a second from a Jersey bull with superior post-thaw survival. Dr. Mel DeJarnette will select appropriate semen samples using data collected in Select Sires’ Semen Evaluation Program (see attached letter). Total RNA will be isolated from 150 million sperm that has been cryopreserved using Select Sires’ standard protocols for commercially available semen. The SAGE libraries will be constructed using the protocol provided with the Invitrogen I-SAGE Long kit. A short fragment (SAGE tag) of every gene expressed in the frozen/thawed sperm will be sequenced and compared to public databases to identify the name and determine the function (if known) for each gene. The number of times each gene is sequenced provides information about the expression level of that gene. Data from the two libraries will be compared to identify genes that are differentially expressed, thereby providing a list of putative genes involved in or affected by the freezing and thawing process. Upon completion of this project, results will be published in a peer-reviewed journal and all SAGE tag data will be deposited into a public SAGE database. Expression levels of the candidate genes identified in this project will be evaluated in a larger set of bulls of interior and superior freeze/thaw capability at a later date.

DePeters, Edward J. and Michael A. Ballou, University of California, Davis, CA, Modifying Immune Response and Production Performance of Jersey Calves by Supplementing Milk Replacer with Fish Oil.

Recent reports indicate that morbidity and mortality rates among pre-weaned heifer Jersey calves are high. Jersey calves are born with all the components of the immune system intact; however, there are deficiencies in response to an infection that increase the risk of disease. Jersey calf mortality and the cost associated with treatment represent a huge loss to the industry; estimates across the entire dairy industry exceed $250 million annually. Data suggest that septicemia is the primary cause of mortality in Jersey calves and septicemia causes an over-reactive inflammatory response. 

The omega-3 fatty acids found in fish oils were found to attenuate an inflammatory response and increase survival in selected animal models. Supplementing milk replacer with the omega-3 fatty acids found in fish oils may provide a beneficial balance between a necessary versus an excess inflammatory response. Therefore supplementing young Jersey calves with fish oil may benefit immune function and enhance overall health and survival. Data also suggest that the health of pre-weaned calves affects the future productivity of that animal; therefore, enhancing the health of these calves early in life will benefit future production. Supplementing milk replacer with fish oil is a practical way to develop a management program that will increase the proportion of Jersey calves that survive through weaning and improve their production as lactating cows. 

Gould, Brian W., and Ed Jesse, and Bob Cropp, Wisconsin Center for Dairy Research, University of Wisconsin-Madison, Madison, Wisconsin, Evaluation of the Use of a New Cash-Settle Butter Futures and Options Contract by Dairy Farm Operators with Jersey Herds.

In early 2005 it is anticipated that the Chicago Mercantile Exchange (CME) will roll out a new cash-settled butter futures contract and related options contracts. This new futures contract will overcome a number of the shortcomings of the current butter contract. It will be smaller (20,000 pounds versus 40,000 pounds), cash-settle to the average NASS butter price (versus deliverable), trade each month (versus 5 months per year) and will use an electronic, 24/7 trading system (versus pit trading).

The proposed project will investigate the degree to which this new butter contract offers milk price risk management opportunities for Jersey dairy farms beyond what is available through the heavily-traded Class III milk contract. Because of higher fat tests, Jersey herds have a higher basis risk when using the Class III contract, which assumes 3.5 percent butterfat. The new contract could reduce basis risk by pricing butterfat production in excess of the 3.5 percent standard. This may require the use of a risk management strategy that incorporates a combination of the current Class III and proposed butter contracts.

A two-pronged approach will be undertaken. The first general approach will examine the direct farm use of these contracts. This research effort will include separate analyses of alternative hedging and option strategies for Jersey milk producers in multiple component pricing markets and in high Class I markets where fat/skim milk pricing is used. The second general approach will focus on producers’ use of forward/minimum price contracts offered by their dairy plants where these programs are specifically designed for smaller dairy operations and based on the proposed cash-settle butter contract. 

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Jaster, Edwin H., California Polytechnic State University, San Luis Obispo, California, Evaluation of Growth and Performance of Jersey Calves Fed Milk Replacers and Starters Containing Different Amounts of Protein and Fat.

Nutrition and health of the young calf is crucial to maximize calf survival and growth rates. Traditionally, newborn calves after receiving colostrum where fed limited amounts of milk replacer (MR) in an effort to get them to consume dry feed, and potentially reduce the cost of feeding milk replacer. Results from recent research work at Cornell University and the University of Illinois indicate that body composition of calves can be altered by diet and that the nutrient requirement of young calves requires further elucidation. The experiment will be conducted at the Cal Poly University Dairy Farm, San Luis Obispo, CA. Twenty-four newborn Jersey calves will receive colostrum (4 l during first 24 h) for two days, navel dipped with iodine and placed in an individual calf hutch (1.22 x 2.44 m) and bedded with straw. Water will be available free choice (open pail) and separate from the starter container. Calves will be managed according to standard operation procedures at the Cal Poly Dairy Unit. Calves health will be monitored daily. Body temperature will be monitored daily during the first week, then only if calves are ill. Scour scores will be recorded daily. Scours will be treated primarily with oral electrolytes and milk replacer will not be withheld. Fecal consistency scores will be 1 = firm (normal), 2 = soft, pudding like, 3= runny, pancake batter, and 4 = liquid, splatters. 

The calves will be assigned randomly to 1 of 3 treatments. From d 3 to 42, calves in treatment 1 will be fed a standard MR (20% CP and 20 % fat) and an 18 % CP pelleted calf starter. Calves in treatment 1 will be fed 0.52 lbs. (236 g) of milk replacer and fed at constant rate of 4 pints (1.89 L) of warm (manufacturer’s recommendation) water per feeding with a nipple bottle. Milk replacer solution will be fed twice daily in two equal feedings at 0600 and 1800 h. Treatment 2 calves will be fed a MR (22 % CP and 22 % fat) and 18 % CP grain starter. Treatment two calves will be fed the same amounts of milk replacer and schedule as treatment 1. Treatment 3 calves will be fed a MR (30 % CP and 25 % fat) and 25 % CP grain starter. During week one, calves in treatment 3 will be fed 0.62 lbs. (281 g) of MR with 4.6 pints (2.13 L) of warm water per feeding twice daily. During week 2 to 6 calves will be fed 0.75 lbs. (340 g) of MR with 5.5 pints (2.6 L) of warm water per feeding twice daily. Results of this study will provide new information on performance of Jersey calves fed milk replacer and starter with different amounts of protein and fat. 

Kerr, David E., and Ravi S. Pareek, The University of Vermont, Burlington, VT, Breed differences in mastitis resistance.

Mastitis is an inflammatory reaction of the mammary gland, usually due to a microbial infection, and its prevalence is alarming high. The long-term goal of the proposed research is to improve the ability to breed dairy cows with enhanced resistance to mastitis. Selective breeding over the last hundreds of years has resulted in breeds of cattle that produce vastly different quantities of milk and milks with substantially different compositions. Milk of Jersey cows is characterized by its relatively high percentage of protein and fat in comparison to Holsteins, whereas Holstein cows generally produce more milk. In addition, there exists a body of anecdotal accounts of breed differences in resistance to mastitis. The Jersey and certain European breeds are thought to be more resistant to mastitis than Holsteins. However, very few scientific studies have evaluated this phenomenon, and thus the goal of the proposed research is to evaluate differences between Jersey and Holstein breeds of cattle in parameters related to their ability to resist mastitis. It is well documented that the increase in milk somatic cell count (SCC) seen during mastitis is due primarily to a large influx of neutrophils into the gland. Our central hypothesis is that breed differences exist in the SCC response to infection. We aim to test this hypothesis and to ascertain if such a difference is due to differential responsiveness of neutrophils, or to differential secretion of neutrophilattracting signals into milk.

Our approach will include an in vivo experiment to examine the whole animal response to an intramammary infusion of lipopolysaccharide (LPS), a component of the E. coli cell wall. In particular we will monitor the influx of neutrophils into one mammary quarter that has been infused with LPS. Milk for the other three quarters will be co-mingled and serve as a negative, within animal, control. In addition to SCC, milk will be analyzed for interlukin-8 (IL-8), a potent chemoattractant, and acute response proteins including lactoferrin, haptoglobin, and serum amyloid to attempt to identify components in milk that cause the neutrophil influx. This whole animal approach will be followed up by an in vitro experiment to compare the ability of Jersey and Holstein neutrophils to migrate towards infection related signals. The chemokine IL-8 will be used as a standard chemoattractant in a chemotaxis assay that we have recently established in our laboratory. Furthermore, we will examine the chemoattractant ability of milk obtained from the control and LPS infused quarters. This functional assay seems ideal to test the overall activity of milk obtained from mastitic quarters.

This proposal will initiate studies to examine if years of selective dairy cattle breeding have resulted in selection of genotypes that have enhanced resistance to mastitis. Greater knowledge of the genes involved in the infection response will allow for more precise selection of superior dairy animals.

Seykora, A.J., L.B. Hansen, D.G. Johnson, J.G. Linn, B.J. Heins, University of Minnesota, St. Paul MN, Comparison of Jersey-Holstein Crossbred and Pure Holstein Two-year-old Lactating Cows for Feed Efficiency, Fertility, Calving Ease, Stillbirths, Postpartum Complications, Production, and Economic Merit.

Larger ongoing study: Holstein heifers and cows in two research herds, each with approximately 100 lactating cows, were mated to either Jersey or Holstein sires for two years (2000-2002). Fifty percent of all cows and heifers were mated to Jersey sires and the other 50% to Holstein sires. Service sires were selected from the active A.I. sires and ranked near the top of the respective breeds for Lifetime Net Merit. Approximately 90 Jersey-Holstein females and 90 purebred Holsteins born from September 2001 to June 2003 will be compared for a number of economically important traits throughout their lives. Currently, all production, health, and fertility information is collected on these animals. 

Fertility of Jersey-Holstein crossbreds vs. purebred Holsteins portion of study: This proposal would help fund the continued collection of blood samples of Jersey-Holstein crosses and purebred Holsteins at 49, 56, and 63 days in milk and analysis approximately 900 blood samples for progesterone levels. This analysis will determine of cows are cycling by 60 days postpartum. This time period was chosen because it is the beginning of the breeding period in most dairy herds. This information will be combined with other fertility information that is being collected including: all observed heats, conception rates, days open, results of veterinarian reproductive checks, reproductive culls and body condition scores.

Of the Holsteins and Jersey – Holstein crosses that freshened last fall as part of this study, the Holsteins averaged 171 days open and Jersey-Holstein crosses averaged 161 days open. The crosses also had a slightly higher first service conception rate. The progesterone profiles will help to determine the causes of the fertility differences.

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Van Tassell, Curtis P., and Tad S. Sonstegard, USDA-ARS, Beltsville, MD, Characterization of Single Nucleotide Polymorphism (SNP) Genetic Markers in Jersey Cattle.

Genetic markers based on single nucleotide polymorphism (SNP) information are becoming the genetic marker system of choice in cattle for research and application by industry. There are two main reasons for the increased importance of SNP markers in cattle. First, the availability of SNP markers has increased substantially with completion of a bovine genome sequence draft. Second, SNP markers are well suited for high-throughput studies due to advances in automation that have been facilitated by research projects in the field of human genomics.

The availability of such a high-density array of SNP genotypes will facilitate a number of research areas that are extremely relevant to AJCA. The first area impacted would likely be enhanced fine mapping of QTL and gene discovery for traits of economic importance in Jersey cattle. Another logical area of investigation that becomes tractable with a large number of SNP genotypes is the investigation of genomic regions that are sensitive or robust to inbreeding. Identification of these regions would facilitate eventual strategies for marker-assisted management of breed diversity at the genomic level. Additional applications of these markers are limited only by the imagination of researchers and breeders.

Already a large number of putative SNP have been identified within and across breeds as a part of the bovine genome project. For Jersey breeders to better utilize the genome information generated, a more complete characterization of potential SNP is necessary. To initiate this effort that ultimately will allow investigation of genetic diversity across breeds, a number of research groups have been identified to generate SNP genotypic data for as many as 2000 cows representing up to 80 breeds of cattle and evolutionarily related species. 

The SNP characterization portion of the bovine genome project requires an initial investment of an estimated $250,000 to develop a genotyping assay that will generate 10,000 SNP marker genotypes per animal, and assay development is done once for each set of 10,000 SNP markers. These initial set-up costs will be covered in a variety of ways, including genome sequencing funds (Baylor), supplementary government funds (Alberta and Norway), and competitive grants (Australia and New Zealand – funding proposed). Animals selected for genotyping will be determined through a “funded sponsorship” with costs of generating between 13,000 and 23,000 SNP markers being estimated at $1,000 per animal.

The purpose of this proposal is to obtain funding to cover the expected costs of generating the 13-23,000 SNP marker genotypes from 25 Jersey animals. The PI will work with AJCA staff to identify the best portfolio of 25 animals to represent the breed. Genotyping costs are expected to total approximately $25,000 and cost for obtaining DNA for the portfolio of representative animals is difficult to predict. A series of trade offs will almost certainly have to be made between “ideal” animals and the cost of DNA (i.e., semen). As an example, it would be ideal to include Duncan as one of the 25 animals to be genotyped, but because of the very limited availability and extremely high cost, it is probably unrealistic to include Duncan in this collection. This almost certainly true when one considers that 50 units of semen would be needed for an animal to be part of the panel! As an alternative, more widely available and more inexpensive relatives of Duncan would be logical choices in his absence. The PI has carried out a similar process as part of a smaller SNP project that is being generated as a parentage verification and animal identification panel.

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Weigel, Kent A., and John A. Lucey, University of Wisconsin, Madison, WI, Cheese Yield Potential of Milk From Holstein and Crossbred Jersey X Holstein Dairy Cows.

Ninety percent of milk produced in Wisconsin is used for cheesemaking. The yield of cheese produced from each pound of milk is directly related to the concentration of casein and fat in milk. Cheesemakers in Wisconsin currently import milk powder and milk concentrates to increase the casein content in cheesemilks. Holstein cattle outnumber Jersey cattle by roughly 30:1 on Wisconsin farms today, although milk produced by Jersey cattle has a much higher fat and protein content. Crossbreeding could make a rapid and permanent change, although little is known about its impact on milk composition and cheesemaking potential. We will study milk composition, coagulation properties, and cheesemaking potential of milk from Jersey x Holstein crosses (50% Holstein / 50% Jersey cows and 75% Holstein / 25% Jersey cows) at four different times of the year over two complete lactations to account for seasonal and lactational influences. Results will be compared with milk from pure Holstein (control) cows on the same farms. We will determine concentrations of seven major milk proteins using high performance liquid chromatography, and coagulation properties will be measured using dynamic rheometry. Cheese yield potential from each sample will be estimated using the Van Slyke prediction equation. The economic impact of these two types of crossbreds will be determined from the producers' and cheesemakers' perspectives.

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