Feeding Redberry Juniper (Juniperus pinchotii) at Weaning Increases Juniper Consumption by Goats on Pasture

Abstract

Redberry (Juniperus pinchotii Sudw.) and ashe (Juniperus ashei Buchh.) juniper dominate rangelands throughout central Texas. Our objective was to attempt to improve the efficacy of goats as a biological control mechanism for juniper through behavioral training. Conditioning sheep and goats to increase the palatability of chemically defended plants can be a useful tool in brush control. Previous research illustrated that goats can be conditioned to consume more juniper while in individual pens when foraging choices are limited. To test whether this creates a longer-lasting increase in juniper preference, we determined if goats would continue to consume juniper on pasture for one year after being fed juniper in individual pens for 14 d. Female Boer-cross goats (n 5 40) were randomly divided into two treatments: conditioned and naive to juniper. At approximately 12 mo of age, conditioned goats were placed in individual pens and fed redberry juniper 1 h daily for 14 d, while naive goats received only alfalfa pellets to meet maintenance requirements. After the pen-feeding phase of the study, goats were placed in one of four pastures (10 goats ? pasture 21) for 12 mo. Two pastures housed conditioned goats, and two pastures housed naive goats at a moderate stocking rate (1 animal unit ? yr 21 ? 8 ha 21). Bite count surveys were conducted twice per month, while herbaceous standing crop and monoterpene levels were measured once per month. Juniper preference varied monthly; however, conditioned goats consistently ate more (P , 0.05) juniper than naive goats except for April, when the study began, and March, when the study ended. When selection of herbaceous forages decreased, conditioned goats increased selection of juniper, while naive goats increased selection of other palatable shrubs. Seasonal changes of monoterpene levels in juniper had no apparent effect on juniper preference. We contend that feeding juniper at weaning will increase use of the plant in grazing situations. Resumen Juniperus pinchotii Sudw y J. ashei Buchh son dominantes en pastizales naturales del centro de Texas. Nuestro objetivo fue intentar mejorar la eficacia del pastoreo de caprinos como mecanismo de control biológico de Juniperus mediante entrenamiento de comportamiento ingestivo. El condicionamiento de ovejas y cabras para que incrementen la palatabilidad de plantas que contienen defensas químicas podría ser una herramienta útil en el control de especies arbustivas. Trabajos de investigación previos demostraron que se puede condicionar un incremento en el consumo de Juniperus en cabras mantenidas en bretes individuales cuando las opciones de forrajeo son limitadas. A fin de determinar si este protocolo crea un incremento duradero en la preferencia de Juniperus, determinamos si las cabras continuarían consumiendo Juniperus en condiciones de pastoreo durante un añ o luego de haber recibido Juniperus en bretes individuales por 14 días. Hembras cruza Boer (n 5 40) se dividieron al azar en 2 tratamientos, uno condicionado y el otro sin experiencia p...

Using Experience and Supplementation to Increase Juniper Consumption by Three Different Breeds of Sheep

“…These results are similar to the results with goats; feeding juniper in individual pens increased intake over time (Bisson et al 2001;Ellis et al 2005;Dunson et al 2007). In addition, goats continue to consume juniper when released on pasture (Dietz et al 2010).…”

“…Thus, it seems probable that 1) sheep will consume juniper even when alternate forages are available, and 2) sheep will increase consumption as forage quantity declines. Indeed, goats will increase intake of juniper on pasture situations as forage availability declines (Dietz et al 2010). Goats that were conditioned to consume juniper in the same manner increased intake, whereas naïve goats increased intake of other shrubs in the pasture.…”

“…The amount of juniper offered was initially limited to 50 g because overingestion can lead to the formation of condition food aversions. Other studies have illustrated that aversions to juniper can be avoided if the amount of juniper offered is increased slowly over a 14-d feeding trial (Dunson et al 2007;Dietz et al 2010). Thereafter, alfalfa was fed from 0900 until 0800 hours the following day.…”

“…Goats will consume juniper on pasture after conditioning a preference for the plant in individual pens (Dietz et al 2010). Goats increase intake of juniper after feeding the plant 14 d after weaning (Bisson et al 2001;Ellis et al 2005;Dunson et al 2007).…”

“…By the end of the 14-d feeding trials, juniper typically accounts for 30% of their diet. Feeding more juniper initially or increasing the amount of juniper offered too quickly results in the formation of conditioned food aversions and avoidance of juniper (Dietz et al 2010).…”