Recipient Organization
MISSISSIPPI STATE UNIV
(N/A)
MISSISSIPPI STATE,MS 39762
Performing Department
Animal & Dairy Science
Non Technical Summary
The Southern region (AL, AR, FL, GA, KY, LA, MS, OK, NC, SC, TN, TX, VA) of the United States accounts has 11.8 million beef cows (40% of the nation's beef cow inventory; USDA, 2014). This region has environmental constraints that require animal adaptation to hot, humid conditions, reduced forage quality, and parasitic loads. Producers have used American Brahman to provide adaptation, as highly productive cattle of European origin lack adaptation to these conditions. However, there are production challenges associated with the use of Brahman, including low production and fertility as purebreds, oscillating (year to year) reproduction rates as young cows, and substandard and variable beef quality. Improved beef cow fertility is desired throughout the Southern Region in most herds.Two broad areas of improvement that would greatly benefit cow-calf producers in this region include: 1) improvement of production and reproduction of Brahman, and 2) improvement of adaptation in cattle of European origin. On a much broader scale, these improvements can be applied to other U.S. and many global regions. These efforts would impact several SAAESD Priority Areas, including Goal 1 (an agricultural system that is highly competitive in the global economy) and several of its priorities including Integrated and sustainable agricultural production systems, Value-added plant and animal genes in conventional breeding and molecular biology, and Health and well-being of food animals, as well as Goal 4 (greater harmony between agriculture and the environment) and its priority of Integrated pest management systems, including biologically-based tactics. This proposed project fits into these priorities particularly well as increased productivity in tropical and subtropical regions of the world is critical to increased global food security. Most of the funded beef cattle work addresses production in temperate areas and is not concerned with adaptation. Most individual university-based research in the South has been curtailed due to the limiting budget environment, including reduction of beef cow research populations. Failure to address this results in inefficient use of a substantial amount of forage resources in the Southern Region that are not suitable for human food crop production, and a large group of producers with little research support for activities important to their productive and economic well-being.It is appropriate to approach such issues from a multi-state perspective primarily to fully exploit the increasingly limited resources available for research at individual locations; this is especially important from a genetic perspective, as combined sample size facilitates appropriate hypothesis testing. Key areas of beef cattle production system efficiency such as adaptability and reproduction, including their component traits, need to be assessed in the different sub-environments within the region. These traits are the least characterized in beef cattle research, especially among those types and breeds of cattle in the region; results will therefore have potential for impact in similar areas of the world extending into the tropics. This multi-state project will also facilitate the cellular and molecular scientific characterization of these traits, and provide for unique research resources that can be utilized to study numerous scenarios that impact sustainable beef production in the US. It is also likely that these resources will attract potential for additional research partnerships beyond the Southern Region, including international possibilities. Additionally, capitalizing on the multi-state groups extension resources will allow for wide dissemination of impactful research to a broad geographical area, which will increase the impact of this research on profitability and sustainability of beef cattle operations in the southern United States.The states comprising the Southern region produce approximately 40% of the cattle that enter the U.S. beef chain, with a large proportion possessing some Brahman inheritance. Breeds of cattle have in many cases changed dramatically, especially in relation to other breeds, since original characterization efforts (Cundiff et al., 2004). Therefore, the proposed Brahman objective serves also as an up-to-date evaluation of current bloodlines and type of Brahman cattle used in the United States today, and will be used then to compare to previous scientific characterization of the breed. Particularly, traits relative to Brahman reproduction have been characterized to a very limited extent, and joint work offers an excellent opportunity to assess reproduction on a whole animal basis and serve as a basis for investigation of component traits of reproduction within the breed.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
Estimate genetic variation associated with animal health using classical animal breeding and genomic techniques to facilitate sustainable beef cattle production systems.
Meta-analyses of economically important traits of cow productivity and fertility to assess breed and production system combinations.
3.Documentation of genetic components pertaining to heat tolerance adaptive traits in sustainable beef cattle production systems.
Project Methods
Objective 1. Estimation of genetic variation associated with animal health using classical animal breeding and genomic techniques to facilitate sustainable beef cattle production systems.Objective 1.1 External ParasitesFly count data collection will begin in May or June, and will continue until the end of summer when a decline in fly numbers is observable. High-resolution photos of the animals head, neck, body and legs will be taken once per week early in the morning (between 0600 and 1000 h) during the coolest time of the day.Tick counts will be obtained from bull and heifer calves at weaning and at yearling age. Heifers will also be evaluated at first breeding. Cattle will be evaluated prior to any treatment (dip or spray) to remove external parasites. Tick counts will be conducted as a visual, subjective observation. Tick burden will be scored using 1 = clean, 2 = light, 3 = moderate and 4 = heavy.Objective 1.2 Eye and facial pigmentation associated with animal healthWe will use photographs and digital quantification software to determine proportion of eyelid with pigmentation. Each animal will have one photo to identify the animal (primarily have used tag or brand), one of full face straight on to clarify markings, one of eye straight across on left side, one of eye aiming up (to characterize the eyelid under the upper eyelashes) on the left side, one of eye straight across on right side, and one of eye aiming up on the right side.Objective 1.3 Udder conformationTeats and udder will be evaluated according to Beef Improvement Federation udder scoring guidelines (BIF, 2010). Teat length will be evaluated as the distance from the base of the udder to the distal end of the teat, and teat diameter will be measured at the midpoint of that distance. Teat shape will be scored on a 1 to 9 scale such that low scores from one to three will indicate a conical or funnel shape in that the diameter of the teat being greater near the base of the udder than at the distal end of the teat. High scores from 7 to 9 indicated the opposite: bulbous or balloon shaped teats in which the teat is narrower at the base of the udder that at the middle or distal end. Teat shape scores from 4 to 6 will indicate a teat that was cylindrical (diameter near the base of the udder was about the same as that at the distal end of the teat).Teat placement on the udder will be evaluated as the relative positioning of pairs of teats with 4 subjective scores. Side placement scores are assigned for the 2 left and 2 right quarters; lateral placement scores are assigned for the 2 front quarters and the 2 back quarters.Udder balance scores will be assigned to describe the relative size of the fore quarters as compared to the rear quarters.Udder support scores will be assigned to assess the strength of udder attachment.Objective 2. Meta-analyses of economically important traits of cow productivity and fertility to assess breed and production system combinations.The following data will be collected for heifers and cows: (1) Breed of cow, (2) Sire ID/sire breed and dam ID/dam breed of cow, (3) cow birth date, (4) Mating information (natural or artificial insemination; single or multiple sires; number of cows per bull; season or insemination date(s), (5) Predominant forage in pastures (fescue 0 = no; 1 = yes), (6) Sire/sire breed of calf, (7) Cow:bull ratio, (8) Body condition score (date and stage of production), (9) Palpation status (0 = non-pregnant; 1= pregnant), (10) Calving status (0 = no; 1 = yes), (11) Weaning status ( 0= no; 1 = yes), (12) Calving date (calving season, spring or fall), (13) Calving difficulty (1 = normal; 2 = easy pull; 3 = hard pull; 4 = caesarian section; 5 = abnormal presentation, note the abnormal presentation of calf), (14) Calf vigor issues (1 = normal; 2 = weak but nursed without assistance; 3 = weak and assisted to nurse; add any notes), (15) Calf birth weight, (16) Calf weaning date, (17) Calf weaning weight, (18) Cow temperament at calving, (19) Date of death and reason/notes for cow or her calf, and (20) Date of culling and reason/notes for cow and/or her calf leaving herd.Objective 3. Documentation of genetic components pertaining to heat tolerance adaptive traits in sustainable beef cattle production systems.1. Cows, calves, and yearlings will be evaluated each spring starting in March and assessed every 28 days until July for hair coat characteristics. At each evaluation animals will be visually inspected for amount of winter hair shed and shedding pattern.2. Hair shedding will be evaluated using a numerical scoring system. A score of 1 = completely shed or slick (100% shed); 2 = 75% shed; 3 = 50% shed; 4 = 25% shed; and 5 = 0% shed or full winter coat. For shedding pattern a score of 1 = slick, shedding complete; 2 = animal has shed off to below the middle of the rib cage; 3 = slick strip covers the full topline and the back of the hindquarters; 4 = a completely slick strip down the topline of the animal; and 5 = no evidence of shedding, even down the topline.3. Cow data will be collected for assessment of the influence of shedding type on production characters. These will include breed, breed type, and pedigree information on each animal for genetic analysis. Cow performance data will include cow weights, body condition scores, reproductive records and performance of their calves from birth to weaning.Objective 4. Investigation of early cow-life performance (first four parities) affecting lifetime production in Brahman and Brahman × Angus cows.Objective 4.1. Comparison of cow reproductive ability as success/failure after the first insemination and at calving.1. Calving and weaning dates will be recorded and those cows that calve and wean will be assigned values of 0 and 1 indicative of failure and success, respectively.2. Females will be first exposed to bulls at 12, 18, or 24 mo age.Objective 4.2. Comparison of preweaning calf nursing ability and its effect on survival and weaning weights.1. Calf vigor will be recorded for calves born alive using a subjective score assigned by the attending herdsman: 1 = normal vigor, 2 = less than normal vigor, but calf nursed on its own, 3 = score of 2 but calf required special assistance to nurse.2. Calf nursing ability will also be assigned when calves are weighed and processed at birth: 1 = calf nurses normally, 2 = calf has poor nursing instinct (dummy calves that cannot find udder, and nurse the brisket).3. Dystocia will be assessed with a subjective score: 1 = normal birth; 2 = difficult birth but was not assisted; 3 = difficult birth that required minor assistance; 4 = difficult birth requiring major assistance or caesarean section.4. Udder scores, including 1 to 9 subjective evaluation of udder suspension and teat size (Beef Improvement Federation Guidelines, 2009) will be recorded for each cow at parturition in conjunction with Objective 1.5. Herdsmen notes about the birth or unusual conditions at birth will be considered in the construction of dependent variables for analysis.Objective 4.3. Comparison of cow-calf productivity in terms of calf preweaning gains and calf postweaning ultrasound measurements.1. Birth and weaning weight will be recorded for all calves, and ADG will be constructed from those weights and age at weaning.2. Ultrasound measurement of fat thickness over the 12th rib, loin muscle area, and loin muscle % intramuscular fat will be recorded between 365 to 467 days of age.Objective 4.4. Comparison of carcass traits and meat quality.Steers at some locations will be slaughtered and carcass data will be recordedand will include (a) slaughter weight, (b) hot carcass weight, (c) adjusted 12th rib fat thickness, (d) loin muscle area, (e) kidney, pelvic, and heart fat, (f) USDA marbling score (g) USDA quality grade, and (h) USDA yield grade.