GENETIC CONSIDERATIONS FOR BEEF CATTLE PRODUCTION IN CHALLENGING ENVIRONMENTS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0220729
• Multistate No.: S-1045
• Project Start Date: Oct 1, 2009
• Project End Date: Sep 30, 2014
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF THE VIRGIN ISLANDS
(N/A)
ST. CROIX,VI 00850

Performing Department
Research & Land Grant Affairs

Non Technical Summary
It has been documented that beef cattle performance has impacted diseases and external parasites. However, it is less well documented as to what extent resistance to these is influenced by genetics. Because external parasites tend to develop resistance to pharmaceuticals used for their control, any genetic means of reducing the susceptibility of cattle to infestation would be of value to the cattle industry. This information could be utilized by producers to identify genetic types that express resistance with a subsequent increase in herd productivity being achieved at a lower cost. The 13 states in the Southern region account for 14 million beef cows (42.3% of the nation's beef cow inventory) and 406,200 producers (48.9% of the nation's cow-calf producers). A variety of breeds and crosses are utilized in this region. Direct selection using estimated breeding values may represent a strategy for improvement of traits related to cow reproductive success and calf survival. Summer conditions are often stressful throughout the South. Analyses of traits using data from across the region would permit accumulation of substantial numbers necessary for appropriate assessment and would expand application of results throughout this critical production area. Improving beef cattle performance through genetic selection traditionally involved observing physical characteristics of an animal, choosing the "best" individual, and using them as parents to produce the next generation. Progress with this type of selection was generally slow because the true genetic value was unclear until performance of the individual's progeny could be measured. Development of DNA marker and SNP (single nucleotide polymorphisms) technologies has allowed for the addition of a new selection tool, which creates the opportunity to evaluate individuals based on their genotypes from a DNA sample. This information gives producers the ability to make selection decisions much earlier in the growth and development period to identify economically efficient animals. Numerous populations of cattle of known genetic background need to be evaluated for genetic markers to understand their utility across the entire industry. Over the past two decades black has become the preferred color of feedlot and slaughter cattle in the U.S. As a result, the black gene has been incorporated into a number of previously red breeds such as the Simmental, Limousin, Gelbvieh, etc. Studies showed rather dramatic (up to 0.5 degrees) lower body temperatures while under heat stress for white (dilute-colored Charolais crossbred) as compared to black feedlot steers. This advantage is comparable to the effect of the Slick hair gene for heat tolerance. The combined effects on heat tolerance of cattle that are both light colored and slick-haired have never been evaluated. There is no information available on the pasture growth of cattle varying in coloration and hair coat length. Also, if a specific coloration, hair length, or coloration-hair length combination results in increased tick or fly resistance, it could have a major impact on the genetic types utilized in crossbreeding programs for the southern region.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
304	3310	1080	20%
305	3310	1020	60%
306	3310	1110	20%

Knowledge Area
305 - Animal Physiological Processes; 306 - Environmental Stress in Animals; 304 - Animal Genome;

Subject Of Investigation
3310 - Beef cattle, live animal;

Field Of Science
1110 - Parasitology; 1080 - Genetics; 1020 - Physiology;

Keywords

beef cattle

cattle

environment

ticks

calf production

breed

genotype

phenotype

hair coat

body temperature

Goals / Objectives
Estimation of genetic variation associated with susceptibility/resistance to specific measures of disease stress in cattle managed on forage. Characterize diverse, tropically adapted beef breeds in subtropical and temperate areas of the United States with emphasis on cow fertility and productivity in comparison to Bos indicus influenced breeds and types. Establish a DNA bank for characterization of molecular markers, genetic parameter estimation and future discovery of genes that influence economically important traits in pedigreed beef cattle populations. Evaluation of relationships between hair coat and production traits in beef cattle breed types.

Project Methods
Objective 1c. Tick counts will be obtained from calves at weaning and at yearling age using photographs of the animals. Data will be analyzed using genetic type, sex, time of year and location in the model to evaluate differences in tick counts. Objective 2. The following data for heifers and cows will be collected: (1)Breed, (2)Sire/sire breed and dam/dam breed of cow,(3) birth date, (4)Mating information, (5)Predominant forage in pastures, (6)Sire/sire breed of calf, (7)Calving date, (8)Calving difficulty (1=normal;2=easy pull;3=hard pull; 4=caesarian section; note the abnormal presentation of calf),(9)Calf vigor issues (1=normal; 2=weak but nursed without assistance; 3=weak and assisted to nurse;add any notes), (10)Birth weight, (11)Weaning date,(12)Weaning weight, (13)Date of death and reason for cow or her calf, (14)Date of culling and reason, and (15)Occurrence and notes related to any health issue.These data will be used to construct reproductive traits of calf survival (to various ages), calf crop born and calf crop weaned; occurrence of calving difficulty or inadequate newborn vigor, calving interval; and weaning weight per cow exposed. Objective 3. DNA samples will be collected from pedigreed populations of cattle (purebred and crossbred) from various units throughout the Southeastern United States in conjunction with all objectives. Whole blood or tissue samples will be taken from each animal including calves dead at birth. Data on each animal will include individual, sire, and dam identification, breed or breed type, and location. Phenotypic information will be collected on each animal based upon the type of performance data required for objectives 1, 2, and 4. A catalogue of information including phenotypic data and DNA samples from the different locations will be assembled and updated annually. Objective 4. Bull and heifer calves will be evaluated at weaning and up to a year of age. Heifers will be evaluated at first breeding and cows will be evaluated at the start of the breeding season each year. At each time point rectal temperature, and surface temperature if possible, will be measured. Respiration rate will be determined by visual observation. Animals will also be scored for hair coat type and color. Hair coat luster and length will be evaluated using a numerical scoring system. Hair coat luster will be evaluated using the following 5-point scale: 1=glossy, healthy appearance; 2=slightly glossy with patches of dull; 3=intermediate between glossy and dull; 4=mostly dull, some indication of unthriftiness; and 5=dull and unthrifty. Hair length score will be evaluated using the following 5-point scale: 1=short; 2=shows some winter growth; 3=intermediate in length; 4=long in places, but intermediate in others; and 5=long. Hair samples will be clipped from an area 2 in x 4 in over the rump, the ribs and the shoulder and analyzed for total dry weight and number.

Progress 10/01/09 to 09/30/14

Outputs
Target Audience: The target audience for this project includes cattel producers in the USVI and wider Caribbean region as well as producers in the southeast US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Through workshops, seminars and conference presentations. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? A method to evaluate external pasite burdens (ticks)on cattle was developed and is being incorprated into herd mamagement and subsequent research projects and cows and calves. it was determined that the vast majority of cows in the UVI herd posess the slick hair gene and display the slick phenotypoe so mimimal selection pressure is being placed on this trait.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Huson, H.J., E.S. Kim, R.W. Godfrey, T.A. Olson, M. McClure, C.C. Chase, R. Rizzi, A.M. OBrien-Perez, C. Van Tassell, J.F. Garcia, T.S. Sonstegard. 2014. Genome-wide association study and ancestral origins of the slick-hair coat in tropically adapted cattle. Frontiers in Genetics, 5:101. doi: 10.3389/fgene.2014.00101
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Godfrey, R.W. and A. J. Weis. 2013. Production traits of spring- and fall-calving Senepol cows in the tropics. J. Anim. Sci. Vol. 91(E-Suppl. 2):417.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Godfrey, R.W. and A. J. Weis. 2013. Evaluation of hair coat, tick burden and production traits of Senepol cows in the tropics. J. Anim. Sci. Vol. 91(E-Suppl. 2):417.

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Beef cattle producers in tropical areas. The information will be incorporated into workshops or training programs offered. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Data will be collected on cows and calves at calving weaning and breeding during 2014.

Impacts
What was accomplished under these goals? Senepol cows (n = 56) calving in the spring of 2013 on St. Croix were evaluated for hair coat phenotype, tick burden, weight and condition score (1 = thin, 9 = fat) at calving and weaning. Senepol calves born in spring 2013 on St. Croix were evaluated for weight, hair coat phenotype and tick burden at weaning (n = 33). Hair coat was scored using 1 = slick, 2 = rough and 3 = hairy. Tick burden was scored using 1 = clean, 2 = light, 3 = moderate and 4 = heavy. There was no difference between calving and weaning in cow weight (586 vs. 603 kg, respectively), condition score (6.45 vs. 6.3, respectively), tick score (1.7 vs 1.7, respectively). At calving cows had rougher hair coat than at weaning (1.6 vs 1.2, respectively). At weaning heifers and bulls had similar weight (211 vs. 216 kg, respectively), coat score (2.2 vs 2.7, respectively) and tick burden (1.6 vs 1.5, respectively).

Publications

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Data was collected on hair coat and tick burdens of Senepol cows and calves at weaning and as yearlings (calves only). A subjective score for tick burden and hair coat type was developed for use in this project. PARTICIPANTS: Animal Science Program staff TARGET AUDIENCES: Cattle producers; scientists studying animal physiology, parasites and heat tolerance. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The proportion of cows scored as hairy, rough or slick was 1.3, 17.1 and 89.6 %, respectively. The proportion of cows that had clean, light, moderate or heavy tick burden scores was 32.5, 10.6, 37.5 and 19.4%, respectively. Lactating cows had a higher tick score than non-lactating cows but there was no difference in hair score. There was no difference in hair score or tick score between pregnant and non-pregnant cows. Slick cows were heavier and had higher CS than non-slick (rough or hairy) cows. There was no difference in BW or CS between cows with (tick score 2, 3 or 4) or without (tick score 1) ticks. The proportion of calves with clean, light, moderate or heavy tick burden scores was 43.3, 37, 12.6 and 7.1%, respectively. Tick score was lower at weaning than as yearlings, but there was no difference in hair score. There was no difference in tick score at weaning between SL and NSL calves but NSL calves had higher tick scores than SL calves as yearlings. At weaning SL calves were heavier than NSL calves but not as yearlings. Weaning weight was higher in clean calves than it was in calves with a high tick burden. Clean calves had a greater ADG at weaning than did calves with a high tick burden. There was no difference in yearling BW between calves that were clean or had a high tick burden. Clean calves had a greater ADG at yearling than did calves with a high tick burden. Tick burden had no influence on cow BW or CS, but slick cows were heavier and had higher CS than non-slick cows further supporting the hypothesis that slick cattle are more suited to the tropical environment. Tick burden can have a greater influence than hair coat phenotype on Senepol calf weights up through yearling age.

Publications

• No publications reported this period

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Data was collected on hair coat and tick burdens of Senepol cows and calves at weaning and as yearlings for calves from a single calf crop. A subjective score for tick burden and hair coat type was developed for use in this project. PARTICIPANTS: Animal Science Program staff and undergraduate students supported by grant funds TARGET AUDIENCES: Cattle producers; scientists studying animal physiology, parasites and heat tolerance PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Calves (n = 59) were evaluated for tick burned and coat score at weaning and at a year of age (n = 59). There was no difference in tick burden among calves at weaning or at a year of age. Calves with a smoother coat had higher tick burdens than calves with a rough coat. Calves with lower tick burdens had a higher average daily gain from birth to weaning than claves with a high tick burden (0.9 vs. 0.4 kg per day). There was no difference in tick burden of cows (n = 88) at weaning between coat types, pregnant or lactating cows. Further data will be collected to evaluate the relationships among of coat type, tick burden and gain of claves and cows over time.

Publications

• No publications reported this period

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: A student being supported by other funds conducted a research study as part of this project and a summary of the data was prepared and submitted for presentation as an abstract at the Southern Section of the American Society of Animal Science meetings held in Feb 2011. PARTICIPANTS: Animal Science Program staff and undergraduate students supported by grant funds. TARGET AUDIENCES: Cattle producers; scientists studying animal physiology and heat tolerance. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Tropically adapted Senepol and crossbred (Charolais X Angus X Senepol) calves were used. Thermal imaging of the left and right side of each calf was done in a shaded pen to determine temperature of areas over the shoulder, ribs and rump. Thermal images of the left and right eye and rectal temperature (RT) were taken while the calf was restrained in a chute. Hair was shaved over the ribs and thermal imaging was used to determine the temperature of shaved and unshaved areas. Across breeds, RT and eye temperature were higher than shaved, unshaved, rump, rib or shoulder temperatures. Temperature of the shaved area was higher in crossbred than in Senepol calves. Eye temperature and RT were positively correlated in Senepol but not crossbred calves. RT was correlated with temperature of the shaved and unshaved areas in Senepol and crossbred calves. Eye temperature was correlated with temperature of the shaved and unshaved areas in Senepol and crossbred calves. Temperature of the shaved area was correlated with temperature of the unshaved area in Senepol and crossbred calves. Senepol and crossbred calves had similar body temperatures in tropical conditions. Data on the hair traits is being analyzed and will be reported at a later date.

Publications

• MacAuley, A.L., A.J. Weis and R.W. Godfrey. 2010. Hair coat traits and body temperature of Senepol cows based on phenotype and genotype for the slick hair gene. J. Anim. Sci. 88(Suppl. 1):21.