Sheep & Goat Research Journal. Volume 17, No. 1: 2001

Contents

Advantages of Multispecies Grazing: Perceptions of Idaho and Wyoming Producers
Author: K. Falxa, L.W. Van Tassell and J.P. Hewlett
Prickle Factor in Fleeces of Performance-tested Fine-wool Rams
Author: C.J. Lupton, D.F. Waldron and F.A. Pfeiffer
U.S. Lamb Demand
Author: T.C. Schroeder, R.J. Jerrick, R. Jones and C. Spaeth
Comparison of Three Measuring Techniques for Staple Length and Strength in U.S. Wool
Author: F.A. Pfeiffer and C.J. Lupton
Research Notes - Survival and Serum IgG Levels in Twin Born Lambs Supplemented with Vitamin E Early in Life
Author: P.G. Hatfield, J.T. Daniels, R.W. Kott and D.E. Burgess
Research Notes - Is There an Influence of Individual Rams on Ewe Prolificacy?
Author: A.L. Carr, W.C. Russell, R.H. Stobart, F.S. Hruby, P. Bulgin and G.E. Moss
Technical Notes - Enterprise Budgeting for Ewe Flock Operations
Author: A.L. Carr, W.C. Russell, R.H. Stobart, F.S. Hruby, P. Bulgin and G.E. Moss

Article Summaries

Advantages of Multispecies Grazing: Perceptions of Idaho and Wyoming Producers

Author: K. Falxa, L.W. Van Tassell and J.P. Hewlett

View PDF

Summary
This study reports findings of a survey aimed at examining whether complementarity in sheep and cattle pro­duction is recognized by producers and is an important factor in the maintenance of both enterprises by ranchers in ldaho and Wyoming. Over 80% of respondents felt their cattle and sheep enterprises had some degree of integration and comple­mented one another. This complementarity was created by the di­etary selection, grazing behavior and the social structure of sheep and cattle. While the sheep enterprise was the most labor intensive, labor and equipment re­quirements of the two enterprises were seen as being complementary. Profitabil­ity and cash flow additionally were aided by the diversification provided from main­taining both a sheep and cattle enterprise. The majority of producers felt that fluc­ tuations in prices and production be­tween sheep and cattle enterprises were somewhat offsetting. While 70% of re­spondents felt sheep had been histori­cally more profitable than cattle, more re­spondents assigned a higher probability that they would abandon the sheep busi­ness before the cattle business because of recent trends in the industry.

Key Words: Survey, Multispecies grazing, Complementary products, Diversification


Prickle Factor in Fleeces of Performance-tested Fine-wool Rams

Author: C.J. Lupton, D.F. Waldron and F.A. Pfeiffer

View PDF

Summary
Prickle factor (PF, % of fibers > than 30 µm) is an indicator of the relative comfort of wool fabrics worn next to the skin. Fiber diameter distributions were measured (with an Optical Fibre Diameter Analyser) in three consecutive years on core samples of unskirted fleeces from 524 fine-wool rams completing a central per­ fonnance test. These measurements were used to establish PF, average fiber diam­eter (AFD), SD, and CV in fleeces pro­duced under the unfavorable (from a wool fineness and uniformity perspective) test conditions and to determine relationships among PF and fiber fineness and vari­ability. As part of the normal performance test routine, AFD, SD, and CV were mea­sured on side and britch samples for each fleece. The AFD of side samples was used in the index of overall merit and AFD of side and britch samples constituted an independent rejection criteria for ram cer­tification. Core sample PF, AFD, SD, and CV averaged 5.5%, 22.3 µm, 4.4 µm, and 20.0"/o and ranged from 0.4 to 25.3%, 17.3 to26.8 µm 3.1 to 6.4 µm,and 15.2 to28.6%, respectively. The PF, SD, and CV did not differ among years (P > 0.05). It has been suggested that only wools having low PF (< 2%) be used in apparel worn next to the skin. Only eighteen percent of the fleeces were in this category. Stepwise multiple regression analysis was used to predict PF using all measured variables plus AFD squared (AFD') and differ­ences between side and britch AFD re­sulted in core AFD', core AFD, britch SD, core SD, side CV, and core CV enter­ing the equation. No other variable met the 0.01 significance level for entry into the model. Partial r2 values for the first three variables were 0.82, 0.10, and 0.03, respectively. This result was essentially unchanged when fleeces (349) having core, side, and britch AFD > 23.6, 24.9, and 27 .8 µm, respectively (i.e., from coarse, uncertifiable rams) were excluded from the analysis. Most of the variabil­ity in PF can be accounted for by core data alone, i.e., PF = 199.57 + 0.46*AFD' - l 9.33*AFD + 6.0 l *SI_) - l.O I *CV, r' = 0.94.

Key Words: Prickle factor, Wool, Ram performance testing


U.S. Lamb Demand

Author: T.C. Schroeder, R.J. Jerrick, R. Jones and C. Spaeth

View PDF

Summary

Understanding major determinants of, and trends in consumer demand for lamb is critical for the industry to develop appropriate production and marketing strat­egies. Little research has empirically de­termined aggregate lamb demand. This study estimates a quarterly lamb demand model to assess major determinants over time. Per capita lamb consumption appears to be more responsive to lamb price than previous studies have concluded. When retail lamb price increases, comparable percentage declines in per capita consumption are likely. Beef is a signifi­cant substitute for lamb suggesting continued efforts to make lamb price com­petitive with other meats is important. Lamb demand tends to decline when consumer incomes and associated lifestyles change. This suggests that, in order to increase lamb demand, lamb products that are compatible with high-income con­sumer lifestyles are essential.

Key Words: Lamb demand, Demand index, U.S. lamb demand


Comparison of Three Measuring Techniques for Staple Length and Strength in U.S. Wool

Author: F.A. Pfeiffer and C.J. Lupton
View PDF

Summary

Twenty-nine consignments of greasy wool in Texas warehouses were used to compare three measuring techniques for staple length (SL) and strength (SS) and to assist the U.S. wool industry in deciding which techniques to adopt for commercial testing. Samples (-IO lb/lot) were obtained using a bale grab sampler and were subsampled at the Texas Agricultural Experiment Station (TAES) Wool and Mohair Research Laboratory (WMRL) to provide three sets of comparable subsamples. One complete set of subsamples (29 subsamples x 65 staples/ subsample = 1,885 staples) was sent to the Australian Wool Testing Authority (AWTA) for measurement using the Automatic Tester for Length and Strength (ATLAS) while another set was sent to SGS Wool Testing Services (SGS) in New Zealand for testing with the Agritest Staple Breaker Model 2. A third set was measured at WMRL using the American Society for Testing and Materials (ASTM) manual method for SL and an Agritest Staple Breaker (manual model) for SS. Each testing lab used the same wool base and vegetable matter base values to convert "greasy" to "clean" SS. Paired t tests and linear regression analyses were conducted to test for differences and calculate r values between test methods. Warehouse personnel provided visual estimates of SL. Mean values of SL determined by AWTA and the visual assessments were not different (3.20 and 3.21 in, respectively, P > 0.05; r2 = 0.63). Measurements of SL made by SGS and WMRL were not different (3.07 and 3.12 in, respectively, P > 0.05; r2 = 0.74) but were shorter (P < 0.05) than the AWTA and visual results. Mean values of variability in staple length (CV) were not different (P > 0.05) among the three measuring techniques. The AWTA and SGS means of SS were not different (32. I and 31.8 N/ktex [a textile measure of strength, newtons per kilotex, literally kilogram­ force per unit of staple thickness expressed in ktex, kg per km], respectively, P > 0.05; r = 0.41). The WMRL meanvalue, 41.7 N/ktex, for SS was greater (P < 0.05) than the other two labs, which strongly suggests that either the manual instrument and/or the WMRL technique produced excessively high values. Further testing incorporating a broader cross-section of U.S. wools is required before an authoritative recommendation can be made to the U.S. wool trade.

Key Words: Staple length, Staple strength, Wool


Research Notes - Survival and Serum IgG Levels in Twin Born Lambs Supplemented with Vitamin E Early in Life

Author: P.G. Hatfield, J.T. Daniels, R.W. Kott and D.E. Burgess
View PDF

Key Words: Lambs, Vitamin E, Lamb survival, Immunoglobulin G

Lamb mortality is a major factor limiting profitability in sheep operations. Estimates of pre-weaning losses range from 15 to 51% (Rook, 1997), with mortalities as high as 35% considered normal for large sheep operations (Rowland et al., 1990). Rowland et al. (1990) also reported that 50% of mortality occurs in the first 24 hours of life.

Supplemental vitamin E given orally to the ewe during late gestation has been shown to decrease lamb mortality (Kott et al., 1998). In addition, when lambs were injected with vitamin E shortly after birth, Gentry et al. (1992) noted an increase in lamb serum immunoglobulin G (IgG) concentration that could be indicative of enhanced immune function.

(Besser and Gay, 1994). However, no advantages in survival or lamb body weight gain were observed when supple­mental vitamin E was given to lambs at birth (Gentry et al., 1992; Williamson et al., 1996).


Research Notes - Is There an Influence of Individual Rams on Ewe Prolificacy?

Author: A.L. Carr, W.C. Russell, R.H. Stobart, F.S. Hruby, P. Bulgin and G.E. Moss
View PDF

Key Words: Ram, ewe, prolificacy, lambing rate

Previous studies have shown that ram introduction near the onset of the breeding season stimulates the initiation of estrous cycles (Sebastian and Inskeep, 1988)and ram libido influences flock conception and flock lambing rates (Fitzgerald, 1992). Twin- and triplet-born rams produce more multiple births than single-born sires (Hodgson et al., 1965; Vakil et al., 1968; Botkin et al., 1988), an effect generally attributed to increased libido (Fitzgerald, 1992) and serving capacity (i.e. testis size; Snowder et al., 1981). Sexual behavior also varies among individual rams (Price, 1987; Fitzgerald and Perkins, 1993; Alexander et al., 1999) and among males of other species (Meisel and Sachs, 1994).

Ovulation rate and prolificacy of ewes are characterized as being lowly heritable characteristics (Botkin et al., 1988) inherent to a ewe's reproductive cycle. In spite of t h is generalization, limited data (Hodgson et al., 1965; Botkin et al., 1988; Burfening and Davis, 1996) and emperical observations support a role for the male in influencing prolificacy of individual ewes. The observation that clitoral stimulation advanced timing of ovulation in cows (Randel et al., 1973) supports the concept that stimuli associated with mating may influence time and perhaps rate of ovulation in spontaneously ovulating species such as cattle or sheep. Alternatively, in vitro fertilization studies with rabbits led to the conclusion that semen from selected bucks differentially influenced embryo survival in vivo (Burfening and Ulberg, 1968). More recently, "service sire" was indicated as a significant source of variation for number of lambs born per ewe exposed (Burfening and Davis, J 996) and a paternal effect on initiation and length of the S-phase of embryo development was reported for bulls (Eid et al., 1994). Therefore, the precedence for a sire effect on number of off­ spring born to individual ewes exists, but mechanisms through which such an effect may be mediated remain an enigma.


Technical Notes - Enterprise Budgeting for Ewe Flock Operations

Author: A.L. Carr, W.C. Russell, R.H. Stobart, F.S. Hruby, P. Bulgin and G.E. Moss
View PDF

Enterprise budgeting is a tool producers can use to evaluate current and alternative enterprises for profitability. Enterprise budgets are typically completed for operations that are not undergoing significant change. This ignores any transition or implementation phase necessary to make changes or start an entirely new enterprise. While some changes may take several years to implement, others can be accomplished in one production period. EweCost is a tool that assists sheep producers in analyzing current and potential future alternative operating procedures for an ewe flock. The end point in this enterprise is feeder lambs and wool.

The EweCost program is divided into four sections; 1) revenue calculation and inventory check, 2) enterprise operating costs, 3) enterprise ownership costs, and 4) results. To save space, only a portion of the results and input are presented here. Not shown are inputs required for the leasing analysis, sensitivity tables that vary prices, weights and weaning percentage from the results section, graphs showing breakdowns of income and expense and the results of the share and cash lease analysis. While there is extensive use of color in the software, some information that color is designed to enhance is lost when printed in black and white. Information the user is either allowed or required to enter is displayed in blue text and outlined in double lined boxes. Numbers or labels outside of a double lined box are calculated or fixed and cannot be changed.