Establishing and Grazing Native Warm Season Grass: How Average Daily Gain and Internal Parasite Burden are Affected in Weaned Lambs

View the project final report

Commodities

• Agronomic: grass (misc. perennial)
• Animals: sheep

Practices

• Animal Production: animal protection and health, feed/forage, grazing management, parasite control
• Crop Production: cropping systems

The purpose of this project is to establish an economical and sustainable way to handle small ruminant internal parasites burden on weaned lambs.  Internal parasites are one of the biggest problems facing sheep producers in the South.  The main internal parasite of economic importance is Haemonchus Contortus or better known as Barber Pole Worm.  Young lambs are affected by internal parasites after they are weaned from their mothers.  Especially weaned lambs who spend their time grazing on pastures.  LeeDer Farm typically lambs in early spring, between February-March, and lambs are weaned two and three months after birth.  This results in lambs being weaned on pastures during May and June when growth of pastures is usually abundant, but also at a time when internal parasites have access to lush growth with plenty of moisture.  Weaned lambs on pasture, if not closely watched, can quickly become anemic and can die from overload of internal parasite burden.  This is of economic importance because severely infected lambs can mean poor weight gain and reduced performance, or worst case scenario is death loss which means lost income to the producer. 

In the Katahdin Hair Sheep breed there has been significant importance and genetic selection placed on parasite resistance.  We have purchased some breeding stock from two well known Katahdin producers, in GA and VA, who have been selecting for parasite resistance for at least 15 years.  This has allowed us to have reduced death loss in weaned lambs from internal parasite burden and purchasing the genetically proven parasite resistant ewe lambs was another tool in our toolbox.

Some common ways to handle internal parasite burden in the South are to put weaned lambs on a dry lot and feed them for 60 days, selling them directly to market a few weeks after they’re weaned to avoid economic loss from anemic lambs, and worm the entire flock every few weeks while on pasture to avoid anemic lambs and death loss.  Every option listed has its advantages and disadvantages according to the producer’s market and annual cost of production for the ewe flock.  LeeDer Farm uses rotational grazing with rest periods from 30-45 days and some small amount (~1% of body weight) of 16% Lamb Grower feed with Coccidiostat for 30 days after weaning to prevent reduced performance from Coccidiosis.  Even with these two measures there are always some poor performers that become anemic and need producer intervention.  The last resort measure in our flock is to pull out those anemic lambs and worm them separately if verified anemic via FAMACHA score and visual inspection of body condition. They are then put back in with the weaned lamb flock and marked in our performance records as culls to be taken to market and not used as breeding stock. Starting in 2020, LeeDer Farm has pulled fecal samples at weaning and sent them to a State Vet Diagnostic Lab for a McMasters Quantitative Fecal Egg Count.  Lambs were all wormed with Cydectin after the fecal sample was taken, the day of weaning, to set all lambs on an equal plane of parasite burden.  Then fecal samples were pulled again roughly six weeks after the first sample for McMaster Quantitative Fecal Egg Count.  This also allowed us to verify what we were seeing visually in the pastures in regard to those lambs showing a higher parasite burden than the average FEC for the contemporary group.  This method was chosen after researching some previous SARE grant results involving Fecal Egg Counts and from our mentorship with Lee Wright of Rolling Spring Farms in VA.

This project has the potential to improve the quality of life for future small ruminant producers by providing an environmentally sustainable model while potentially improving the economic profitability of livestock operations.  Native Warm Season Grasses have been shown to require minimal commercial inputs of fertilizer and can be established in a variety of pH and fertility ranges.  Their deep root systems offer drought proofing for producers that can lead to improved stand longevity and less annual costs due to re-establishing perennial stands.  Less commercial inputs and drought resilience can lead to improved economic profitability which is a win for all small ruminant producers and creates less dependency on the conventional model of high inputs.  It also has the potential for environmental benefit if grazing small ruminants on Native Warm Season Grasses proves to lessen the need for anthelmintics/chemical dewormers.  Less use of dewormers can improve the soil organism diversity in the soil by having less detrimental effect on things such as dung beetles.  This could also benefit in marketing future farm products by giving consumers a more naturally raised product with lesser chemical inputs in the production process.

The problem of weaned lambs on pasture in the South is being severely infected with barber pole worms and affecting economic profitability.  This is through death loss of lambs, reduced weight gain, and getting to market later than planned.  Going to market later may affect economics of an operation due to less lambs going to market during prime market days such as ethnic holidays where prices tend to be higher per pound.

My proposed solution is to establish a Native Warm Season Grass (NWSG) pasture for weaned lambs.  The NWSG pasture will consist of mostly Big Bluestem, Little Bluestem, and Indiangrass.  These native plants are more sustainable because they require minimal, if any, fertilization and are prolific growers once established.  They are also more drought tolerant, which is more common during hot summers in the South, because of deeper root systems.  Each species has different maturity rates and can help to establish vigorous growth during the entire warm season growing period.  NWSG’s grow more erect and the average growth point is around six inches above the soil surface.  The proposed research is that the taller growing grasses will allow the weaned lambs to graze at head height or slightly higher heights and avoid grazing so close to the ground where the Barber Pole Worm is more commonly found.  NWSG establishment is more common in cattle operations, but the proposed research is to investigate the effectiveness of their use in small ruminant operations, specifically with sheep.  The other proposed benefit of establishing NWSG pastures for weaned lambs is better weight gains both from reduced internal parasite burden and from grazing nutritious warm season grass versus cool season perennial forage Tall Fescue KY-31 variety.  It has been well documented that KY-31 variety Tall Fescue creates performance issues in livestock in climates such as the Southeast, due to the fungal endophyte located within the plant.  While the fungal endophyte gives the plant improved drought tolerance and survivability it also can cause poor livestock performance when it is consumed in large amounts by livestock.  Common symptoms in livestock are delayed hair shedding and heat stress, along with reduced weight gain while grazing this KY-31 variety during hotter summer months.  Giving the weaned lambs a grass that doesn’t cause these performance symptoms could lead to higher overall weight gains and growing marketable lambs  (60-75 lb. live weight) sooner.  This would be particularly helpful in hitting the target market dates around ethnic holidays such as Ramadan, commonly beginning and ending in the months of May and June.  The other economic benefit would be reduced lamb deaths due to reduced internal parasite burden.

To test this hypothesis, it will take two years to get final results.  The first year, 2021, will be used to establish and maintain a Native Warm Season Grass (NWSG) mix pasture of roughly 1.25 acre in size.  This will require eradicating any cool season perennials and other weeds from the existing pasture.  NWSG mix will be established via no-till methods and with help from Jason Smith, NC Wildlife Resource Commission Biologist.  Jason brings a wealth of NWSG knowledge and experience with many years helping producers establishing successful NWSG plantings in North Carolina.  He will assist with drill calibration and NWSG seeding recommendations for the planting.  He will also monitor initial establishment growth and any further recommendations in year two.  In Jason's experience the first year should be used for establishing a good root system and monitoring plant competition and its effects on survivability.  

In year two, 2022, a contemporary group of lambs will be separated at weaning time.  The contemporary groups will consist of roughly 40 lambs total.  One group will be put on the established NWSG pasture and rotationally grazed with electric netting and temporary water tanks.  Another group will be divided and rotationally grazed on our base cool season perennial KY-31 Tall Fescue with a mix of warm season annual forbs and weeds/grasses.  Electric netting will also be used and temporary water tanks.  Breeding groups of lambs will be sired by at least two different Rams.  Contemporary groups will be comprised of lambs from both sires to avoid bias and more inconclusive results due to poor on-farm testing setup. 

Lambs from both groups will be weaned the same day, weighed on our W100 Gallagher weight scale for performance records, FEC sample taken, and then wormed with Prohibit (Levamisole) sheep drench before exiting the sheep working system.  Prohibit was recommended because it only lasts about 48 hours in the sheep’s system and therefore there is no long residual effect that may skew FEC data.  I later found out from Dr. Andrew Weaver, NCSU Small Ruminant Extension Specialist, that this is standard protocol in many other FEC/Parasite Resistance studies as well to use the shorter active life Prohibit wormer.  Prohibit wormer is negligible cost and will be incurred by LeeDer Farm during the study.  All lambs will be kept together as one group for 14 days and fed 1% body weight a 16% lamb grower feed, with coccidistat, to start everyone on an equal playing field.  The lamb grower feed will be given 6 times in the 14 day equalization period.

After 14 days, each contemporary group will be weighed again, wormed with Prohibit, second FEC sample taken, and divided and placed in their respective NWSG or Cool Season Perennial pasture.  Each group will be fed the same sheep mineral and have full access to cool, clean water from our pressurized watering system.  Actual weights will be conducted every 2 weeks during the testing period, mainly on Saturdays or Sundays, due to our full-time job responsibilities.  Weights will be taken for 2 months (~60 days post-weaning), resulting in at least six different weight recordings.  During the grazing trial FEC samples will be conducted at two week intervals for both groups to see if there is any statistical difference between the two groups.  This will result in six FEC samples during the testing period to hopefully show further proof of reduced parasite burden while grazing NWSG pastures in the immediate post-weaning period of lambs.  Dr. Andrew Weaver, NCSU Small Ruminant Extension Specialist, will help with FEC sampling analysis and statistical analysis of results at the end of the study.  Lastly, forage will be tested for protein levels, species composition, and TDN levels before lambs enter the pastures to get a representative comparison.  Dr. Deidre Harmon, NCSU Extension Livestock Specialist, will assist with species composition and forage sampling during the trial.  Species composition will be important in the NWSG contemporary group to determine if the lambs performed better due to other species besides NWSG.