We initially evaluated effects of replacing CSH with air-dried redberry juniper leaves in Rambouillet lamb feedlot diets (Whitney and Muir 2010). In this trial, a maximum of 30% juniper leaves was included in a mixed diet that fed for 28 days; lambs were transitioned onto a mixed diet containing 15% juniper. No negative effects on animal health were reported but replacing 50% of the CSH with redberry juniper leaves increased lamb growth performance. We concluded, “that redberry juniper leaves can effectively be used as a roughage source and can replace all of the CSH in lamb feedlot rations, but may reduce intake and consecutively growth at greater inclusion levels”
The same lambs from Whitney and Muir (2010) were evaluated for wool, carcass, meat fatty acids, and sensory panel traits (Whitney et al., 2011). We concluded: “that air-dried juniper leaves can effectively replace cottonseed hulls in lamb feedlot rations. However, increasing concentration of juniper increased saturated fatty acids, which have been negatively associated with human health and greater off-flavor.”
Results from Whitney and Muir (2010) led to a trial in which mixed diets containing ground juniper leaves and small stems were fed to lambs (Whitney et al., 2014). Whitney et al. (2014) evaluated effects of using redberry juniper in wether lamb diets. Lambs were individually fed DDGS-based diets where 0% (0JUN), 33% (33JUN), 66% (66JUN), or 100% (100JUN) of the oat hay was replaced by juniper. Results indicated that replacing all of the ground oat hay with ground juniper in lamb growing and finishing diets is not detrimental to animal performance or health.” The same lambs from Whitney et al. (2014) were evaluated for carcass characteristics, adipose tissue fatty acid composition, and sensory panel traits (Whitney and Smith, 2015). We concluded, “…Replacing all of the oat hay with juniper resulted in similar carcass characteristics and greater sensory characteristics of lamb chops. According to industry standards, all lambs had acceptable carcass characteristics; however, taking all carcass, fatty acid, and sensory characteristics into consideration, lambs fed diets with a combination of oat hay and ground juniper (33JUN and 66JUN) seemed to have produced the most acceptable carcasses and lamb chops. Results also suggested that ground redberry juniper is as valuable as ground oat hay in lamb feedlot diets with potential for greater value if premiums are received for greater HCW and LM area and enhanced sensory characteristics. It is apparent that DDGS and ground juniper should be given greater consideration as dietary ingredients in lamb feedlot diets.”
Between 2010 and 2014, we modified and developed a new assay to evaluate how various feeds and plant secondary compounds affect internal parasite function in the rumen (Whitney et al., 2011). We then began to evaluate the effects of Juniperus spp. on reducing internal parasite (Haemonchus contortus) larvae viability (Armstrong et al., 2013) and fecal egg shedding. The conclusion of Armstrong et al. (2013): “Dried and fresh juniper material reduced larval motility, but only dried juniper increased IVM efficacy. The reduction in IVM efficacy due to larvae initially being incubated in OIL was exactly opposite of what was expected and is currently unexplainable. Further in vivo research is warranted to determine if feeding dried juniper in mixed feeds to sheep and goats can reduce in vivo H. contortus motility, fecal egg shedding and increase IVM efficacy. Numerous benefits such as re-instating non-effective synthetic anthelmintics by increasing their efficacy would be realized if feeding sheep and goats dry juniper can weaken larvae in the host prior to drenching.
We took this knowledge, applied it to a field setting, and published, “The use of redberry juniper (Juniperus pinchotii) to reduce Haemonchus contortus fecal egg counts and increase ivermectin efficacy” (Whitney et al., 2013). Conclusion: “Compared to lambs fed a control diet, results indicated that feeding lambs mixed diets containing 30% redberry juniper leaves and stems can at times, reduce fecal egg counts without any IVM treatment. Results also indicated that feeding lambs a juniper-based diet before treating with IVM, increased IVM efficacy by 65% as compared to lambs fed a control diet. However, this reduction is not enough to suggest that this practice provides effective anthelmintic control. At times, feeding the juniper-based diet negatively affected growth rate but this is mainly attributed to nutritional differences between the diets. Feeding juniper-based diets throughout the year, increasing percentage of juniper and CP in the diet, using fresh vs. dried juniper, or replacing juniper with ingredients that contain greater concentrations of secondary compounds, has potential to increase IVM efficacy enough to justify its use in flocks with IVM-resistant trichostrongyles. Other classes of anthelmintics with different modes of action, need to be evaluated and exact mechanisms involved in increasing IVM efficacy by feeding bioactive compounds need to be further investigated. Being able to reinstate ineffective synthetic anthelmintics would be extremely beneficial to small ruminant parasite management.”
In 2017, we published Whitney et al., 2017; “Substituting ground woody plants for cottonseed hulls in lamb feedlot diets: Growth performance, blood serum chemistry, and rumen fluid parameters.” We concluded, “Results suggested that even though lamb DMI was reduced during Period 1 when growing diets contained 30% J. pinchotii, J. monosperma, J. virginiana, and P. glandulosa, rumen fluid parameters were not negatively affected and all lambs fed woody-based diets remained healthy throughout the trial. Due to the physical characteristics of the woody-based diets, lamb growth performance would probably increase if a small amount of ground hay was included. Ground woody products are unique in that they are not subject to seasonal feed pricing and availability, require no inputs by man to establish and grow, and are the only feed ingredients that can increase rangeland forage production after harvest. Therefore, the development of a commercialized industry to supply ground woody products for livestock production is warranted.”
The same lambs from Whitney et al. (2017) were evaluated for carcass characteristics, adipose tissue fatty acid composition, and sensory panel traits. We concluded, “Minimizing input costs associated with feeding livestock is important, and furthermore, utilizing raw materials that might otherwise be thought of as pastoral waste has the potential to provide an opportunity for finishing ruminants. The research reported here indicated that lambs can be finished on a diet with 30% of the diet as ground juniper or mesquite as a source of roughage without negatively affecting carcass traits, fatty acid composition, or sensory traits.”
We also completed a beef cattle feedlot trial, “Substituting hammermilled Juniperus spp. for chopped alfalfa hay in steer feedlot diets.” Conclusions of this trial: “Although the differences in nutritive value between alfalfa and juniper resulted in a reduction in DMI, and thus growth rate of steers as juniper increasingly replaced alfalfa in steer diets, such replacement was shown to be feasible. Observations from this experiment coupled with appropriate valuation of production in a given scenario will allow prediction of the ingredient pricing offset (relative to alfalfa) required to achieve economic viability. Because the price of juniper would be viewed as a cost reduction to land reclamation or rehabilitation, its price would likely be stable; this would enhance its viability as a substitute ingredient during times when the price of other roughage ingredients increases due to competition or scarcity, as often occurs during drought.”