Cody B. Scott

Observations of Sheep Foraging in Familiar and Unfamiliar Environments: Familiarity with the Environment Influences Diet Selection

Abstract We determined if familiarity with a pasture decreased the importance of social interactions in food selection and choice of foraging location by lambs with different dietary preferences. Lambs in three treatments (18 lambs per treatment) were reared separately for 2 months and exposed daily to a 1-ha experimental pasture (Treatment 1), to a 0.5-ha pasture with similar forage species to those in the 1-ha experimental pasture (Treatment 2), or reared in confinement and not allowed to graze (Treatment 3). Half of the lambs in each treatment were fed milo ( Sorghum bicolor ) and half were fed wheat ( Triticum aestivum ) daily for 2 months to condition preferences for milo and wheat, respectively. During testing, subgroups of three lambs that were conditioned to prefer milo and three that were conditioned to prefer wheat (three subgroups per treatment) were exposed simultaneously to the 1-ha experimental pasture to determine if social influences affected food selection when milo and wheat were placed at opposite ends of the pasture (100 m apart). We found: (1) subgroups of lambs familiar with the pasture typically consumed different foods, depending on whether they preferred milo or wheat; (2) subgroups of lambs naive to the pasture typically foraged together on the same food; (3) preferences for either milo or wheat persisted for animals familiar with the experimental pasture, whereas lambs naive to the pasture acquired preferences for both foods. Thus, these results suggest social factors can override food preferences in a novel environment, but food preferences may be more influential in food selection in a familiar environment.

Sire Influence on Juniper Consumption by Goats

Abstract Goats avoid eating redberry juniper (Juniperus pinchottii Sudw.) when other palatable forages are available but will increase intake of juniper when exposed to the plant for several days. Intake of redberry juniper also differs among breeds and individual goats. Selection based on foraging habits could further improve juniper intake. The purpose of this study was to determine the influence of sires on juniper consumption. Heritability of redberry juniper intake was assessed for 3 years (1997, 1998, 2000) by placing male Boer-Spanish cross goats from 4–8 sires (the number of sires differed among years) in individual pens and feeding juniper (200 g) daily for 2 hours over 5 to 10 days. Feeding juniper was done after weaning kid goats each year. Juniper intake was similar among sire groups within years. Heritability of juniper consumption was low (11%) across the 3 years of this study. Goats increased juniper intake daily while in individual pens. These results suggest that an acceptance of juniper by goats can be conditioned through exposure to the plant after weaning, and that juniper consumption does not appear to be a highly heritable trait.

Supplements Containing Escape Protein Improve Redberry Juniper Intake by Goats

Abstract Redberry juniper (Juniperus pinchotii Sudw.) is a common invasive plant species in west-central Texas. Goats will consume redberry juniper, but intake is limited by monoterpenoids found in the plant. Previous research has shown that goats will increase juniper intake through 1) conditioning and 2) protein supplementation. This study compared intake of juniper when goats received different protein supplements either with or without protein sources that are high in amino acids that escape digestion in the rumen. Recently weaned Boer-cross goats (n  =  47) were randomly placed into five treatments. Treatments 1, 2, 3, and 4 received a protein supplement and juniper for 1 h daily for 14 d, along with a basal diet of alfalfa pellets (2% body weight). Treatment 5 received only a basal diet of alfalfa pellets and juniper. All supplements were formulated to be isonitrogenous (37% crude protein [CP]). Treatment 1 contained cottonseed meal (high CP escape value), treatment 2 contained cottonseed meal and distillers dried grain (higher CP escape value), treatment 3 contained soybean meal (low CP escape value), and treatment 4 contained soybean meal and distillers dried grain (moderate CP escape value). Refusals of juniper, supplements, and alfalfa were weighed daily to determine intake. Supplementation with 1) cottonseed meal, 2) soybean meal, or 3) soybean meal and distillers dried grain did not influence (P > 0.05) juniper intake. Conversely, goats supplemented with cottonseed meal and distillers dried grain ate more (P < 0.05) juniper than goats receiving only alfalfa, possibly because of increased escape of glucogenic amino acids. We contend that supplementation with feeds high in protein escape values should increase juniper intake on rangelands.

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  =  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−1) for 12 mo. Two pastures housed conditioned goats, and two pastures housed naive goats at a moderate stocking rate (1 animal unit · yr−1 · 8 ha−1). 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.

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

Abstract In the southwestern United States, redberry (Juniperus pinchotii Sudw.) and ashe (Juniperus ashei Buchholz) juniper are two invasive species that dominate some rangelands. Goats will consume up to 30% of their diet in juniper, but it is unknown if sheep will accept juniper to the same extent. The objectives of this study were to determine if sheep can be conditioned to consume juniper and to compare intake among different breeds. Rambouillet (n = 10), Suffolk (n = 10), and Dorper-cross (n = 10) lambs were randomly placed in individual pens for 31 d. A basal diet of alfalfa pellets (2.5% body weight [BW]) and juniper were fed. Juniper was fed each morning from 0800 to 0830 hours. The basal diet was fed for the remainder of the day. Intake of each was measured daily. Following the first 17 d, the basal diet was reduced to 2% BW for 7 d and then reduced to 1.5% BW for the final 7 d. Serum aspartate transaminase (AST), gamma glutamyltransferase (GGT), blood urea nitrogen (BUN), creatinine, and bilirubin levels, and live body weight were measured to assess any adverse physiological effects from juniper consumption. In a second trial, lambs were again fed alfalfa (2.5% BW) and juniper. One half of the lambs were also fed a 36% protein supplement to determine if supplementation with protein sources that escape rumen degradation would improve juniper consumption. Lambs received alfalfa, juniper, and protein supplement for 22 d with intake of each recorded daily. Intake of juniper was similar (P > 0.05) among breeds of sheep. Lambs readily consumed juniper and increased (P < 0.05) intake of juniper as the amount of alfalfa fed was reduced. Weight change was also similar among treatments. Protein supplementation did not improve juniper consumption. We contend that sheep will consume a diet consisting of 24% juniper without experiencing any adverse effects.

Short-Term Mesquite Pod Consumption by Goats Does Not Induce Toxicity

Abstract Goats, unlike cattle, disperse few viable mesquite (Prosopis glandulosa Torr.) seeds in feces. However, there is some evidence that goats may suffer from toxicosis from overingestion of mesquite pods. We assessed the likelihood that short-term ingestion of mesquite pods would induce toxicosis in goats. Twenty-four goats were randomly allocated to one of four treatments with treatments fed different concentrations (0%, 30%, 60%, or 90% of the diet) of whole mesquite pods fed with alfalfa pellets. The mixture of mesquite pods and alfalfa pellets was fed for 12 d to 14 d. Because there were only 12 pens available for the study, two trials were used so that all 24 goats could be housed in individual pens. Intake, serum metabolite levels, and fecal output were measured to assess physiological status. In Trial 1, intake and fecal output decreased on days 12 through 14 for goats consuming a diet of 90% mesquite pods. In the second trial, intake and fecal output were similar across days of feeding within each treatment, but the trial only lasted 12 d. Serum metabolite levels remained within normal levels irrespective of the amount of mesquite pods in the diet in both trials. Goats appear to be able to consume mesquite pods on a short-term basis without experiencing toxicosis.

Consumption of Salt Cedar and Willow Baccharis by Boer-Cross Goats☆

ABSTRACT Both salt cedar (Tamarix ramosissima Ledeb.) and willow baccharis (Baccharis salicina Torr. & Gray) are readily invading rivers, streams, and lake basins throughout Texas. Both outcompete desirable vegetation and reduce biodiversity. The purpose of this study was to determine if goats would consume either plant and if protein supplementation would improve intake. In Trial 1, 36 recently weaned Boer-cross goats were randomly allocated to four treatments. Treatments included feeding salt cedar, willow baccharis, both, or neither plant. Goats were fed salt cedar and/or willow baccharis for 1 h daily for 14 d with intake measured daily. All goats were also fed alfalfa pellets (2% body weight [BW]) throughout the trial to meet maintenance requirements. Goats ate more (P < 0.05) salt cedar than willow baccharis and increased intake of salt cedar over the 14 d of feeding. In Trial 2, 20 recently weaned Boer-cross goats were randomly allocated to two treatments. One treatment received a protein supplement (37%) daily in addition to salt cedar. The other treatment did not receive any additional protein. Regardless of treatment, all goats received alfalfa pellets (2.5% BW) to meet maintenance requirements. Both groups increased intake of salt cedar over 10 d of feeding. Protein supplementation did not improve intake of the plant. Given a choice, goats will consume more salt cedar than willow baccharis and will readily consume the plant. Protein supplementation will not improve intake of the plant, but goats will increase intake of the plant when fed the plant at weaning.

Intake of Salt Cedar by Two Different Breeds of Sheep

ABSTRACT Salt cedar (Tamarix spp.) readily invades and dominates riparian areas and lake basins throughout the western United States. Traditional control efforts (chemical and mechanical control) are expensive and provide limited long-term control. The salt cedar leaf beetle (Diorhabda elongata) provides a method of biological control through reduction in cover. However, population establishment of leaf beetles in some locations is often difficult because of environmental conditions. In previous research, goats readily consumed salt cedar, offering an alternative method of reducing salt cedar cover. For this study, we determined if sheep would consume salt cedar and consume a similar amount as goats. Twelve Rambouillet and 12 Suffolks lambs were fed salt cedar once daily (Trial 1) and three times daily (Trial 2). Intake of salt cedar by sheep was compared between breeds and with intake of salt cedar by goats (n = 10). Salt cedar was fed once a day in Trial 1 for 30 min over 15 d. Intake was recorded daily for individual animals. In Trial 2, salt cedar was offered three times daily for 13 d with intake recorded. There were no differences (P > 0.05) between breeds of sheep. In addition, sheep consumed more salt cedar than goats except on the last day of the study. When salt cedar was offered three times daily, both breeds of sheep increased intake and gained weight over the 13 d of feeding in Trial 2. By the end of the study, intake appeared to still be increasing. Collectively, these results illustrate that both Rambouillet and Suffolk sheep will consume a similar amount of salt cedar as goats and will provide another species of livestock that can be potentially used to reduce salt cedar cover.

Juniper Consumption Does Not Adversely Affect Meat Quality in Boer-Cross Goats

Abstract Goat browsing can be used as an alternative brush management option for redberry (Juniperus pinchotii Sudw.) and ashe (Juniperus asheii Buch) juniper instead of more expensive and invasive brush control methods, assuming consumption of juniper does not adversely affect the marketability of offspring. Some wildlife species reportedly retain juniper flavor when consumed. We determined if juniper consumption affected meat quality or flavoring of Boer-cross kid carcasses. Twenty recently weaned, Boer-cross wethers were randomly assigned to one of four treatments with treatments fed different amounts of juniper (0%, 10%, 20%, 30% juniper in the diet). All goats were fed juniper for 28 d at the Angelo State University (ASU) Management, Instruction, and Research Center. All goats were also fed a feedlot ration to meet maintenance requirements (2% body weight). Juniper intake varied (P < 0.05) between all treatments (0%, 10%, 20%, 30%) primarily because treatments were fed different amounts of juniper. Following a 28-d trial, goats were harvested at the ASU Food Safety and Product Development Laboratory. Carcass characteristics including live weight, hot carcass weight, dressing percentage, loineye area, body wall fat thickness, and leg circumference were similar (P > 0.05) among treatments. Sensory characteristics including tenderness, juiciness, flavor intensity, off-flavor, and overall acceptability were also similar (P > 0.05) among treatments. Landowners can utilize goats as a biological management tool without adversely affecting goat meat quality or flavoring.