No description available.

Biological and therapeutic agents are used in food animal production to maintain animal health and well being, prevent and treat disease, and to maintain or enhance production. Concerns about the use of pharmaceutical agents in food animal production have been raised, especially in relation to food quality and safety. This study addressed the scarcity of information concerning the quantity of pharmaceuticals being used and the reasons for their use in sheep production. Additional goals included determining the sources of information used by shepherds in making treatment decisions and evaluating the economic impact that pharmaceutical usage has on sheep production. Thirty-nine Virginia sheep producers participated in this study of four months duration from March through September. After completing an initial questionnaire to determine flock and management characteristics, participants were asked to record all treatments with biological and therapeutic agents that occurred within their sheep flocks. A total of 14,310 treatments were recorded for a median of 1.5 treatments per sheep per month. Parasite control and vaccination were the most frequent reasons for treatment (64.9% and 15.2%, respectively) with vitamin/mineral supplementation being the next most common (8.8%). Price information was collected for 13,912 treatment events. An estimated total of $7,523.78 was spent on pharmaceutical treatment over the course of the study. This amounts to a cost of $0.63 per sheep per month of observation. Results of this study will enhance the ability of producers to evaluate treatment decisions, allow comparisons to be made between operations and provide a base of information for future research. / Master of Science

Genetic diversity and the effect of lamb and dam inbreeding on multiple traits were analyzed in an 11-yr closed population of sheep established in 1983 and remained closed after 1987, with 50% Dorset, 25% Rambouillet, and 25% Finnsheep breeding to determine selection response for spring fertility. The population had been randomly divided in 1987 into a fall-lambing selection line (S) of 125 ewes and 10 rams, fall-lambing environmental control line (E) of 55 ewes and 5 rams, and a spring-lambing genetic control line (G) of 45 ewes and 5 rams. Inbreeding effects were estimated from 2678 lambs and 556 dams present after the creation of the respective lines. The traits assessed were ewe spring-fertility, lambing date, lamb birth, 60 d, and 120 d weight, and lamb survival to 1, 3, and 14 d. Genetic diversity was assessed by estimating change in inbreeding per generation (ΔF) and effective number of breeding animals (N_e), and parameters derived from gene drop simulations and an iterative procedure developed by Boichard et al. (1997); effective number of founders (f_e), effective number of ancestors (f_a), founder genome equivalents (f_g), and two additional measures of genetic diversity (GD₁, GD2). In order to estimate the diversity available in S and G, three sets of animals from the end of the study and one set of animals at line formation were considered in each line: all lambs born (including dead lambs), all matings (including potential offspring, even if a lamb was not born), and all rams and ewes available at the end of the study and at line formation. At the time of line formation, most of the loss in diversity was due to unequal founder representation. The smaller population of G, as compared to S, caused a greater decrease in diversity due to bottlenecks at line formation. Very little diversity was lost due to additional drift by the time of line formation because selection had not occurred and a random mixing of founders was the goal. Allelic diversity decreased moderately; of the 322 founder alleles, there were 71% in S and 58% in G of rams and ewes (RE) that appeared in at least 50 runs of gene drop. By the end of the study in 1998, the amount of allelic diversity had decreased substantially. Of the alleles possible in RE at the end of the study in S and G, only 6 and 8 %, respectively, appeared in greater than 50 simulations of gene drop. The measures of f_e, f_a, and f_g revealed there was not much additional loss in diversity from the line founders to the end of the study due to unequal founder representation, but there was a larger amount of loss due to bottlenecks and additional drift. The diversity loss was similar, which was the goal of the selection study, when values for RE were compared in S and G. The effects of lamb and dam inbreeding were estimated from REML analysis. Effects of lamb or dam inbreeding were negative but not significant for lambing date or survival to 1, 3, or 14 d. Spring fertility was estimated to decrease by 0.70 ± 0.30 %/% inbreeding of the ewe (P < 0.01), which seems even greater since the average spring fertility was only 47.5 %. Effects of lamb inbreeding on birth, 60-d, and 120-d weights were -0.012 ± 0.006 (P < 0.05), -0.045 ± 0.020 (P < 0.05), and -0.130 ± 0.034 kg/% (P < 0.01), respectively. Dam inbreeding had smaller effects on birth, 60-d, and 120-d weights of -0.008 ± 0.010 (ns), -.033 ± 0.034 (ns), and -0.087 ± 0.056 (P < 0.1) kg/%, respectively. / Master of Science

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The objectives of this study were to investigate genetic parameters of early growth traits, lifetime ewe productivity (total number born, number weaned and weight weaned per ewe lifetime production) and testis measurements in the Merino flock maintained at the Tygerhoek Experimental Farm. Non-genetic fixed factors influencing these traits were evaluated by using appropriate models. The influence of non-genetic factors on preweaning lamb survival rate and the effect of scrotal circumference on ewe fertility was also studied. Fixed effect models were fitted to the data using either Procedure GLM or CATMOD in SAS (1996) depending on the parameters being estimated. Variance components were estimated by Restricted Maximum Likelihood (REML) procedures, fitting an animal model. Records of 8310 lambs born from 2538 ewes and sired by 681 rams covering the period 1970 to 1998 were used in the analysis of birth weight (BW), weaning weight (WW) and preweaning average daily gain (ADG). All three traits were affected (p < 0.001) by type of birth of lambs (single, multiple), sex, year of birth of lambs, group of animals (selection, control) and age of dam at lambing (2- to 6-yr old). Male lambs and singles were heavier both at birth and weaning and grew faster (p < 0.001) than females and multiples, respectively. Non-selected animals were lighter than selected animals at birth and weaning with an inferior growth rate. BW increased with increasing dam age at lambing until a maximum of 3.7 kg was reached at 6-yr of age. However, WW and ADG reached a maximum at 4.5- and 4.2-yr of age, respectively. Variance components for BW, WW and ADG were estimated using Restricted Maximum Likelihood (REML) procedures. Four different animal models were fitted, differentiated by including or excluding maternal effects. The direct heritability estimates (h") ranged from 0.19 to 0.38, 0.25 to 0.40 and 0.26 to 0.40 for BW, WW and ADG, respectively. Estimates of direct heritability (h") were substantially higher when maternal effects were ignored. The direct heritability (h") estimate for BW decreased from 0.38 to 0.19 when both or either of the maternal effects, genetic or environmental, were fitted in the model. The h2 estimate for WW was 0.36 when both maternal effects were ignored from the model and decreased to 0.29 and 0.25 when maternal effects were fitted. A similar trend was observed for ADG. The maternal heritability (rn-) for BW ranged from 0.38 to 0.41 when only maternal additive genetic effects were fitted in the model, and decreased to 0.25 and 0.27 when the maternal permanent environmental effect (c") was fitted. The m" for WW and ADG ranged from 0.02 to 0.11 and from 0.01 to 0.10, respectively. The respective c2 estimates ranged from 0.05 to 0.10 and from 0.02 to 0.09. Moderate negative genetic correlations (ram) between direct and maternal additive genetic effects were observed in BW, while close to zero estimates were obtained for WW and ADG. The direct additive genetic correlation estimates between BW and WW and BW and ADG were 0.16 and 0.04, respectively. The corresponding maternal additive genetic correlation estimates were 0.93 and 0.60. The direct and maternal additive genetic correlation estimates between WW and ADG were 0.99 and 0.85, respectively. Data of 3272 lambing records collected on 818 ewes born from 689 dams and sired by 371 rams were used in the evaluation of ewe lifetime productivity (total number born, number weaned and total weight weaned). These records were collected from ewes born from 1969 to 1994 and gave birth from 1971 to 1999. Year of birth of ewe and ewe two-tooth liveweight affected (p < 0.001) the ewe reproduction traits investigated. Multiple born ewes were superior both in total number of lambs born and weaned than singles. Heritability estimates of 0.23, 0.17 and 0.20 were obtained for total number of lambs born (TLB), total number of lambs weaned (TLW) and total weight of lambs weaned per ewe lambing over four lambing opportunities (TWW), respectively. For total weight weaned per ewe lambing over the first lambing opportunity (TWWl) a heritability estimate of 0.02 was computed. Genetic correlation estimates of -0.10, 0.57 and 1.00 were obtained between TWW1 and TLB, TWW1 and TLW and TWWl and TWW, respectively. High and positive genetic correlations ranging from 0.61 to 0.92 were estimated between ewe lifetime reproduction traits. Data from 1380 rams born from 1986 to 1998 were used to investigate genetic parameters for scrotal circumference (SC), testis diameter (TD) and two-tooth liveweight (LW). The other objective of this study was to estimate the magnitude of the effect of SC on ewe fertility. Year of birth, selection group and LW were significant (p < 0.001) sources of variation both for SC and TD. Heritability estimates ranged from 0.29 to 0.40, 0.25 to 0.38 and 0.49 to 0.52 for SC, TD and LW, respectively. Adjustment for LW decreased heritability estimates of SC and TD by 11.0 and 8.0 %, respectively. The genetic correlation between SC and TD was unity. Rams with larger SC had a significant effect on ewe fertility (ewes lambing per ewe mated). Average survival rate from birth to 100 days of age was 0.79 and was influenced by lamb birth weight, year of birth, age of dam at lambing, type of birth (single, multiple) and sex of lambs. Lambs with a liveweight between 4.0 to 4.9 kg at birth showed the highest survival rate while lambs with a liveweight of:s 2.0 kg showed the lowest survival rate. / AFRIKAANSE OPSOMMING: '0 Genetiese studie van vroeë groei-eienskappe en ooiproduktiwiteit by Merinoskape: Die doel van die studie was om genetiese parameters VIr vroeë groei-eienskappe, ooileeftydsproduksie (totale aantal gebore, aantal gespeen en totale gewig gespeen) en testismaatstawwe in die Merinokudde van die Tygerhoek Navorsingstasie te beraam. Niegenetiese vaste effekte wat hierdie eienskappe beïnvloed, is met behulp van gepaste modelle geëvalueer. Die invloed van nie-genetiese faktore op voorspeense lamoorlewing en die invloed van skrotumomvang op ooivrugbaarheid is ook ondersoek. Vaste-effek modelle is, afhangende van die parameters wat beraam is, deur middel van of die GLM of CATMOD prosedures van SAS (1996) op die data gepas. Variansiekomponente is met behulp van die Beperkte Maksimum Aanneemlikheidsprosedure (REML), deur die passing van 'n dieremodel, beraam. Rekords van 8310 lammers wat tussen 1970 en 1998 van 2538 ooie gebore is en die nageslag van 681 ramme was, is vir die ontleding van geboortegewig (BW), speengewig (WW) en voorspeense daaglikse toename (ADG) gebruik. Al drie eienskappe is deur geboortestatus (enkeling, meerling), geslag, jaar van geboorte, groep (seleksie, kontrole) en ouderdom van die moeder met lamming (2- tot 6-jr oud) beïnvloed (p<0.001). Ramlammers en enkelinge was met beide geboorte en speen swaarder en het vinniger (p<O.OOI) as onderskeidelik ooilammers en meerlinge gegroei. Nie-geselekteerde lammers was ligter as dié van die seleksiegroep met beide geboorte en speen en het ook stadiger gegroei. BW het met toename in moederouderdom tot 'n maksimum van 3.7 kg by 6-jr oud ooie gestyg. Maksimum WW en ADG is egter by 3- en 5 jr oud ooie onderskeidelik bereik. Variansiekomponente vir BW, WW en ADG is met behulp van Beperkte Maksimum Aanneemlikheidsprosedures (REML) beraam. Vier verskillende modelle is gepas, waarin mateme effekte óf in- óf uitgelaat is. Die direkte oorerflikhede (h2 ) het van 0.19 tot 0.38, 0.25 tot 0.40 en 0.26 tot 0.40 vir BW, WW en ADG onderskeidelik gevarieer. Beramings van die direkte oorerflikheid (h2 ) was aansienlik hoër waar die mateme effekte geïgnoreer is. Die direkte oorerflikheidsberaming (h2 ) vir BW het vanaf 0.38 tot 0.19 verlaag toe beide of een van die mateme effekte, geneties of omgewings, in die model ingesluit is. Die h2 beraming vir WW was 0.36 toe beide mateme effekte geïgnoreer is en het tot 0.29 en 0.25 gedaal toe beide in die model gepas is. 'n Soortegelyke tendens is vir ADG waargeneem. Die mateme oorerflikheid (rrr') van BW het vanaf 0.38 tot 0.41 gevarieer waar slegs die direkte mateme effek gepas is maar tot 0.25 en 0.27 gedaal toe die mateme permanente omgewingseffek (c2 ) additioneel gepas is. Die m2 vir WW en ADG het onderskeidelik van 0.02 tot 0.11 en van 0.0 I tot 0.10 gewissel. Die ooreenstemmende c2 beramings het vanaf 0.05 tot 0.10 en vanaf 0.02 tot 0.09 gewissel. Matige negatiewe genetiese korrelasies (ram) tussen die direkte en mateme genetiese effekte is vir BW gevind, terwyl bykans zero beramings vir beide WW en ADG gevind is. Die direkte genetiese korrelasies tussen BW en WW en tussen BW en ADG was onderskeidelik 0.16 en 0.04. Die ooreenstemmende mateme genetiese korrelasies was 0.93 en 0.60. Die genetiese korrelasies tussen die direkte en mateme genetiese effekte tussen WW en ADG was onderskeidelik 0.99 en 0.85. Data van 3272 lamrekords van 818 ooie vanaf689 moeders en 371 vaders is vir die evaluasie van ooileeftydsproduktiwiteit (totale aantal gebore, aantal gespeen en totale speengewig) gebruik. Hierdie rekords is van ooie wat tussen 1971 en 1999 gelam het, versamel. Jaar van geboorte van die ooi en ooi-tweetandgewig het die reproduksie-eienskappe ondersoek, beïnvloed (p<O.OOI). Meerlinggebore ooie was beter as enkelgebore ooie ten opsigte van aantal lammers gebore en gespeen. Oorerflikheidsberamings van onderskeidelik 0.23, 0.17 en 0.20 is vir aantal lammers gebore (TLB), totale aantal lammers gespeen (TLW) en totale gewig oor vier lamgeleenthede gespeen (TWW), gevind. Vir totale gewig per ooi met die eerste lamgeleentheid gespeen (TWWJ), is 'n oorerflikheidsberaming van 0.02 bereken. Genetiese korrelasies van -0.10, 0.57 en 1.00 is onderskeidelik tussen TWW, en TLB, TWW, en TLW en TWW, en TWW beraam. Hoë en positiewe genetiese korrelasies wat tussen 0.61 en 0.92 gevarieer het, is tussen ooileeftydsreproduksie-eienskappe beraam. Data van 1380 ramme wat tussen 1986 en 1998 gebore is, is gebruik om genetiese parameters van skrotumomvang (SC), testisdeursnee (TD) en tweetandgewig (LW) te beraam. 'n Ander doel van die ondersoek was om die effek van SC op ooivrugbaarheid te ondersoek. Jaar van geboorte, seleksiegroep en LW was betekenisvolle (p<0.001) bronne van variasie vir beide SC en TD. Oorerflikheidsberamings het van 0.29 tot 0.40, 0.25 tot 0.38 en 0.49 tot 0.52 vir onderskeidelik SC, TD en LW gevarieer. Korrigering vir LW het die oorerflikhede van SC en TD met onderskeidelik 11.0 en 8.0 % verlaag. Die genetiese korrelasie tussen SC en TD was een. Ramme met hoër SC het 'n betekenisvolle invloed op ooivrugbaarheid (ooie gelam per ooie gepaar) gehad. Die gemiddelde oorlewingstempo vanaf geboorte tot 100 dae was 0.79 en is deur geboortegewig van die lam, jaar van geboorte, ouderdom van die ooi, geboortestatus (enkeling, meerling) en geslag van die lam beïnvloed. Lammers met 'n geboortegewig van tussen 4.0 en 4.9 kg het die hoogste oorlewingstempo gehad, terwyl lammers met 'n geboortegewig van ~2.0 kg die laagste oorlewingstempo gehad het.

No description available.

Mountain sheep (Ovis canadensis mexicana) in the Pusch Ridge Wilderness (PRW), Santa Catalina Mountains, Arizona have abandoned historic habitat and now occupy 44 km². I used univariate analyses to quantify differences of physiographic and vegetational variables between abandoned habitat and habitat that is still used by mountain sheep. A discriminant function model characterized the magnitude of the differences between the 2 habitats. Habitat that supports mountain sheep has less human disturbance and is more open with more side oats grama (Bouteloua curtipendula), red brome (Bromus rubens), brittle bush (Encelia farinosa), and forb cover, but less ground cover, bush muhly (Muhlenbergia porteri), and turpentine bush (Haplopappus laricifolius) than habitat that was abandoned by mountain sheep. Fire is important in still used habitat because it reduces tall plants that obstruct mountain sheep vision. Human disturbances should be minimized in mountain sheep habitat.

The purpose of this study was to evaluate the economic aspects of farm flock sheep production in Utah. Using 1979 as a base year, costs and returns were calculated from data obtained from twenty- six Utah farms. Characteristics that typify the states· farm flock sheep production, at this writing, with regard to: 1) the farm flock producers and 2) the farm flock enterprise, were presented. Various models were dev eloped and examined using Multiple Regression and Linear Programming analytical techniques. Multiple Regression was us ed to estimate the effects that different variables had on the profitability of the sheep enterprise. The most significant variables were found to be: 1) the number o f years each producer has been involved in sheep production and 2) number of years rams are retained for breeding purposes. Linear Programming was used to maximize the relative net returns between : 1 ) a traditional method of farm flock sheep production in Utah. 2) an accelerated production program where three lamb crops are produced in two years, and 3) an intensive program where two lamb crops are produced in one year. The accelerated lambing program producing three lamb crops in two years consistently demonstrated the highest relative net return. Recommendations of future related research were also included.

Abstract not available

Bibliography: leaves 175-196. The influence of starch in grain-based diets on fat development in cattle and sheep is investigated.

Expression of membrane-type matrix metalloproteinases (MT) and tissue inhibitors of matrix metalloproteinases (TIMP) was evaluated in sheep embryos and uterus during the pre- and peri-implantation periods. Embryos and uterine samples were surgically collected from ewes on days 9, 11, 13, and 15 of pregnancy (n=3 ewes/day) and of the estrous cycle (n=2 ewes/day). Total RNA was extracted and RT-PCR were performed using primers specifically designed from published human, mouse, and bovine complete cDNA sequences for MT-1, -2, -3, and -5, and TIMP-1, -2 and -3. Multiplex PCR were performed on uterine samples for each gene at optimal cycles and temperatures with 18S rRNA as the internal standard. For embryos, PCR were conducted for 40 cycles at optimal temperatures. MT-1, -2, -3, and -5 were observed in pregnant and nonpregnant uterus during all days of collection. No difference (P>0.10) was observed in MT-1 or -2 expression due to day of collection. However, pregnant uterus expressed more (P=0.096) MT-1 than nonpregnant uterus, whereas expression of MT-2 was greater (P<0.05) in nonpregnant compared to pregnant uterus. No differences (P>0.10) in MT-3 expression were observed due to pregnancy status, however Day 9 and 11 expressed more MT-3 than Day 15. Uterine MT-5 expression was not different (P>0.10) between pregnant and nonpregnant females, however Day 15 uterus expressed less (P<0.05) MT-5 then Day 11 and 13 uteri. TIMP-1 expression was greater (P<0.05) in pregnant compared to nonpregnant uterus, but did not differ (P>0.10) by day of collection. TIMP-2 did not differ (P>0.10) by pregnancy status or day of collection but the interaction was significant (P<0.05). TIMP-2 expression was greatest in Day 9 pregnant uterus and least in Day 9 nonpregnant uterus. No difference (P>0.10) was observed in expression of TIMP-3 due to day of collection or pregnancy status. Embryos expressed MT-3 and -5 during Days 9-15 of development, however, MT-1 and -2 were not detected. The presence of MT and TIMP in the endometrium suggests these proteins may play important roles in regulating extracellular matrix degradation and activating other matrix metalloproteinases for endometrial remodeling and preparation for implantation. Embryonic MT may participate in the processes of embryonic expansion, elongation and attachment. / Graduation date: 2002