Central New York’s 2015 Dairy Day focused on breeding stronger and healthier dairy herds through genetic improvement, reproductive results and calf management.
Dr. Curt Van Tassell, Research Geneticist, ARS, USDA, from Beltsville, MD, spoke to attendees about using genomics for testing and predicting future traits in dairy herds.
“We’re using DNA information to supplement performance data to predict genetic values,” Van Tassell explained. “We’ve been collecting data for 100 years, so we have an incredible historic collection of data.”
Van Tassell estimates that the genetic merit of well over 16 million dairy cows has been obtained since 1960 with involvement from all breed organizations.
Data collected includes records of identification, lactation, daily yields, reproduction events, calving difficulty scores, stillbirth scores, growth, disease resistance and other data significant to the dairy cattle industry.
Genetic data banks also evaluate individual genes influencing traits such as mastitis resistance, milk, fat and protein concentrations to accurately predict successful mating programs.
“Significant genetic gains in productive life are being achieved by selecting sires whose daughters produce more, conceive faster, calve easier, and live longer than their contemporaries.”
Van Tassell said using genetic markers would also determine other economically significant traits, such as health, mastitis, ketosis, displaced abomasum and even lameness.
Recently, scientists have produced “genetically engineered cows” that carry a gene known to provide some protection against bovine tuberculosis, a serious, chronic disease, contagious to a large group of other mammals, including humans, world-wide. A genome editing and modification tool was used by scientists to perform this feat and although all resulting cows were not resistant to the tuberculosis-causing pathogen, many were able to resist the disease, while others displayed minimal symptoms. This trait for resistance to bovine tuberculosis was shown to be passed from the genetically modified cow to her offspring.
Van Tassell remarked that with genome editing nucleotides can be added, deleted and/or replaced.
Parasite tolerance studies are also underway to “better understand livestock biology of parasite resistance through a combination of quantitative genetics, marker-assisted selection, genome annotation, and gene expression analyses.”
Van Tassell reported about 30 percent of young bulls have been geonotyped by breeders since 2013 and he commented that there is an increase in collection of data for health traits.
Prices for top genomic tested animals can be very high resulting in increased interest in leasing versus selling bulls.
Van Tassell says reliability in females has also increased because of the program and the current trend with elite breeders is to follow selection and mating programs. Embryo producers are especially interested in these programs.
The question remains as to whether there will be more inbreeding because of the genetic trait selection. “The jury is still out on that,” Van Tassell said.
Dr. Julio Giordano, DVM, MS, PhD, Dairy Cattle Biology and Management, Cornell Animal Science spoke to attendees about consistently getting top results in dairy herd reproduction.
“We do have herds that have outstanding performance,” Giordano pointed out. “It is possible!”
In a word “management” is the key to speedy and successful reproduction performance. “Management includes everything, genetics, healthy cows, cow welfare, good facilities, a lot of things need to be done right.”
Giordano emphasized time is important for lactation in dairy cows; therefore efficient breeding strategy should be used. “The 21 day pregnancy rate is the most important parameter that we use today to measure reproductive performance.”
Pointing out that reproductive performance is compatible with current production systems, Giordano stated, “Recent research data and experience working with commercial dairies indicate that a proactive, systematic, and consistent reproductive management program conducted by committed personnel who prioritize attention to detail, usually leads to successful reproductive performance of the dairy herd — regardless of the approach and the level of technology utilized.”
Estrus detection (ED) is one issue that is problematic and Giordano showed charts with statistics telling that 30 percent of cows failed to show heat or failed to ovulate — or both. “There’s no technology that will deal with that.”
Giordano reported on the use of automated activity-monitoring (AAM) systems, comparing statistics on before and after the implementation of AAM, between herds managed with AAM and herds managed with timed artificial insemination (TAI), timed strategy in using hormones and other programs.
“Programs aimed at maximizing the insemination of cows after a detected estrus can be successful,” he said. “However, they should be coupled with a synchronization of ovulation protocol for timed A.I. (TAI) to assure timely insemination of all cows. On the other hand, for farms that need — or prefer — to rely more on synchronization of ovulation protocols, there are options to increase the fertility of first, as well as second, and subsequent TAI services.”
Giordano said these strategies are available to producers and can be successfully implemented by all dairy farms.
Dr. Mike Van Amburgh, Cornell Animal Science, spoke to attendees about ongoing studies and updates on the Lactocrine Hypothesis and the effect of colostrum on calves through infancy, growth stage and reproduction.
Studies testing the Lactocrine Hypothesis for maternal programming indicate that colostrum has more purpose than providing immunoglobulins (IgG). Colostrum also provides hormones, short-chain fatty acids, enzymes and maternal leukocytes. It stimulates gut maturation and helps develop functional tissue, provides hormones that enhance absorption, and possibly effects feed efficiency.
Van Amburgh stated calves receive “information” from colostrum that has been “short circuited” by man’s intervention. He stated that data from other species suggest that other developmental functions are also being affected by not providing enough colostrum and there is “no substitute for liquid feed, milk or milk replacer during the first six weeks” of the calf’s life. Colostrum from the mother — not a colostrum replacer — provides essential life long effects for the calf. “Enhanced protein accretion (lean growth) during the neonatal period has long lasting implications,” Van Amburgh said.
Studies show that heifer calves provided with their mother’s colostrum as soon as possible after birth, followed with high levels of milk or milk replacer, have rapid growth in the first two months of life and an increased milk production when entering the milking herd.
For more information on dairy issues contact Dairy Specialist Dave Balbian, coordinator of CNY Dairy Day at email@example.com .