Thesis (MScAgric)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Research conducted on beef cattle in Botswana investigated both growth and reproduction. These studies however, did not specifically determine the influence of the different environmental factors on growth in the Tswana and Composite beef cattle breeds. The establishment of a national beef herd recording and performance testing scheme requires knowledge on the appropriate adjustment methods of field data for the fixed effects such as sex of calf and age of dam. A fair comparison of birth and weaning weights between male and female calves, and calves born from young, mature and old dams will be derived from these adjustment factors. There is no information on adjustment factors for the Tswana and Composite cattle breeds in the country. Genetic parameters for growth traits in these breeds are not known and are needed for the implementation of the performance scheme in Botswana. The Composite breed resulted from a controlled crossbreeding programme using the Simmental, Brahman, Tswana, Tuli and the Bonsmara breeds. The Tswana animals are indigenous to the country and were sourced locally at the beginning of the growth evaluation trial in the two breeds. The objectives of the study were to use data collected from Tswana and Composite cattle breeds to estimate the influence of non-genetic factors on growth traits in the two breeds; to develop adjustment factors for the effects of sex of calf and age of dam; and to estimate genetic parameters (heritabilities and genetic correlations) for future genetic evaluations in both breeds. Data were collected over the period 1988 to 2006. A total of 2 257 records for the Composite breed and 5 923 records for the Tswana breed were available for analyses. Growth characteristics of interest in this study were birth weight (BW), weaning weight (WW), pre-weaning average daily gain (ADG1), 18 months weight (18MW) and post-weaning average daily gain (ADG2). Study 1 indicated that non-genetic effects of breed of calf, sex of calf, month and year of birth, previous parous state, weight of cow at parturition, age of dam, and age of calf at weaning significantly affected BW, WW, 18MW, ADG1 and ADG2 in both breeds. The Composite breed had higher BW, ADG1 and WW whereas the Tswana had higher ADG2 and 18MW. Pre-weaning growth rate increased with an increase in the age of the dam, reaching a peak in mature (5-12 years) cows and declined in cows 13 years and older. Conversely, post-weaning growth rates declined as age of dam advanced but increased in old (13 years and older) dams. Male calves were heavier than female calves for all the growth traits. Birth weight increased as calving season progressed whilst a decrease in WW was observed over the same period. Heifers gave birth to lighter calves when compared to mature multiparous dams. The Composite breed can therefore be considered for weaner production under ranch conditions while the Tswana can be reared under extensive systems due to its adaptability to the environment. Additive correction factors for effects of sex of calf and age of dam on BW and WW were studied separately for the Tswana and Composite in study 2. The least squares means procedure was used to derive age groups and the adjustment factors. The three age groups were young (4 years and below) dams, mature (5-12 years) dams and older (13 years and above) dams. Male calves were heavier than their female counterparts. The sex of calf adjustments for BW and WW were 2.75 and 8.21 kg in the Tswana, and corresponding values for the Composite 2.84 and 10.11 kg, respectively. Birth weight and WW increased as age of dam increased, reached maximum in mature dams and declined in older dams. Age of dam adjustment factors for BW in the 3, 4 and 13+ years age groups for the Tswana were 1.74, 0.96 and 1.87 kg, respectively. The corresponding values for the Composite were 2.28, 0.94 and 2.06 kg, respectively. Age of dam adjustment factors for weaning weight in the Tswana were 10.36 and 5.46 kg for age groups 3-4 and 13+ years, respectively. Adjustment factors for WW in the Composite were 13.84, 3.20 and 9.58 kg for age groups 3, 4 and 13+ years. The differences in adjustment factors obtained between the two breeds emphasize the need to compute and apply these factors within breed. Study 3 involved the estimation of genetic parameters for BW, WW, ADG1, 18MW and ADG2. Single-trait and multi-trait analyses were used in the estimation of (co)variance components by fitting an individual animal model (AM) and the animal maternal model (AMM) for the two breeds. Direct heritabilities for BW, WW, ADG1, 18MW and ADG2 in the Tswana were 0.45, 0.32, 0.37, 0.31 and 0.31, respectively from a single-trait AM analysis. Fitting the AMM resulted in direct heritabilities of 0.31, 0.20 and 0.16 for BW, WW and ADG1, respectively, while the maternal heritabilities were 0.11, 0.15 and 0.21, respectively. For the Composite the direct heritabilities for BW, WW and ADG1 were 0.58, 0.32 and 0.30, respectively with single-trait AM. Partitioning using the AMM resulted in the direct heritabilities for BW, WW and ADG1 of 0.55, 0.17 and 0.14, respectively, while corresponding maternal effects were 0.09, 0.15 and 0.15, respectively. The genetic correlations between direct and maternal effects were positive and ranged from 0.20 to 0.89. When using the multi-trait analysis and fitting the AM, the direct heritabilities for the Tswana were 0.45, 0.37, 0.34, 0.39 and 0.31 for BW, WW, ADG1, 18MW and ADG2, respectively. Genetic correlations between the growth traits ranged from 0.16 to 0.97. Direct (and maternal) heritabilities for BW, WW and ADG1 were 0.31(0.11), 0.19(0.15) and 0.14(0.17), respectively, in the Tswana. Correlations between direct heritabilities for BW, WW and ADG1 ranged from 0.45 to 0.95, while maternal effects ranged from 0.12 to 0.99. The magnitude of the heritabilities indicates an existence of the opportunity to make genetic progress through selection in both breeds. Selection based on WW seems to be the ideal procedure to bring genetic improvement in the Tswana without detrimental long term effects. / AFRIKAANSE OPSOMMING: Navorsing wat op die vleisbeesrasse in Botswana gedoen is, het hoofsaaklik op beide groei en reproduksie gehandel. Hierdie studies het egter nie spesifieke gefokus op die bepaling van die invloed wat verskillende omgewingsfaktore op die groei van saamgestelde (d.i. Composite) en die Tswana vleisbeesrasse het nie. Die bepaling van ʼn nasionale vleisbees rekordhouding- en prestasietoetsskema verg kennis van die mees gepaste metode om velddata vir vaste effekte soos geslag van die kalf en ouderdom van die moeder aan te pas. Hierdie aanpassingsmetodes sal lei tot die regverdige vergelyking van geboorte- en speengewigte tussen manlike en vroulike diere, sowel as van kalwers gebore van jong, volwasse of ou moeders. Tans is daar geen inligting oor aanpassingfaktore vir die Tswana en saamgestelde vleisbeesrasse in Botswana bekend nie. Geen genetiese parameters vir groei-eienskappe vir geeneen van die rasse is beskikbaar nie en word benodig vir die implementering van die prestasie skema in Botswana. Die saamgestelde ras is die produk van ʼn beheerde kruisteeltprogram, wat onderskeidelik die Simmental, Brahman, Tswana, Tuli en die Bonsmara beesrasse ingesluit het. Die Tswana ras is inheems aan Botswana en vanaf plaaslike bronne vir die groei evaluasie studie bekom. Die doelwitte van die studie was eerstens die analisering van data wat van beide die Tswana en saamgestelde rasse ingesamel is, om die invloed van nie-genetiese faktore op die groei eienskappe te bepaal om ten einde aanpassingsfaktore vir die effek van geslag van die kalf en ouderdom van die moederdier te ontwikkel. ʼn Tweede doelwit was die bepaling van genetiese parameters (oorerflikhede en genetiese korrelasies) vir die gebruik in toekomstige genetiese evaluering van beide rasse. Data is vanaf 1988 tot 2006 ingesamel. ʼn Totaal van 2 257 waarnemings vir die saamgestelde ras en 5 923 waarnemings vir die Tswana ras is ontleed. Groei eienskappe wat in die studie ondersoek is, het geboortegewig (BW), speengewig (WW), voorspeen gemiddelde daaglikse toename (ADG1), 18-maand gewig (18MW) en naspeense gemiddelde daaglikse toename (ADG2) ingesluit. Studie een het aangedui dat nie-genetiese effekte van die ras van die kalf, die geslag van die kalf, maand en jaar van geboorte, vorige dragtigheidsstatus, koei se gewig met geboorte van kalf, ouderdom van die moederdier en die speenouderdom van die kalf het ʼn betekenisvolle invloed op BW, WW, 18MW, ADG1 en ADG2 van beide rasse gehad. Die saamgestelde ras het hoër waardes vir BW, ADG1 en WW gehad, terwyl die Tswana ras hoër waardes vir ADG2 en 18MW geopenbaar het. Voorspeense groeitempo het toegeneem met ʼn toename in die ouderdom van die moederdier, met ʼn piek in volwasse (d.i. 5-12 jaar ouderdom) moeders en ʼn afname in koeie 13 jaar en ouer. Omgekeerd het naspeen groeitempo afgeneem met ʼn toename in die ouderdom van die moederdier en weer begin toeneem vir ou (d.i. 13 jaar en ouer) koeie. Geboortegewig het toegeneem met die verloop van die kalfseisoen, terwyl ʼn afname in WW vir dieselfde periode aangeteken is. Verse het, wanneer hulle met volwasse koeie vergelyk is, het geboorte aan ligter kalwers gegee. Die saamgestelde ras kan dus oorweeg word vir die produksie van speenkalwers onder kommersiële intensiewe toestande, terwyl die Tswana ras, op grond van sy beter aanpassing by ekstensiewe omstandighede waar die moederlike invloed nie voorkom nie, vir produksie onder ekstensiewe omstandighede gebruik kan word. In studie 2 is die additiewe korreksie faktore vir die invloed van geslag van die kalf en moederouderdom op BW en WW apart vir die twee rasse bestudeer. Die geslag van die kalf x ouderdom van die moederdier interaksie was nie betekenisvol vir enige van die rasse nie. Dus kan geen aanpassing vir die ouderdom van die moeder binne geslagte vir enige van die twee rasse gemaak word nie. Die kleinste kwadraat gemiddeldes metode is gebruik om die ouderdomsgroepe en aanpassingsfaktore te bepaal. Die drie ouderdomsgroepe was jong (d.i. 4 jaar en jonger) koeie, volwasse (d.i. 5-12 jaar ouderdom) en ouer (d.i. 13 jaar en ouer) koeie. Daar is gevind dat manlike kalwers swaarders as hulle vroulike eweknieë is. Die aanpassingswaarde vir die geslag van die kalf vir BW en WW was 2.75 kg en 8.21 kg in die Tswana en 2.84 kg en 10.11kg vir die saamgestelde ras. Geboortegewig en WW het toegeneem met ʼn toename in die ouderdom van die moeder. Dit het ʼn maksimum bereik in volwasse koeie en afgeneem vir koeie ouer as 13 jaar. Die aanpassingsfaktore vir die ouderdom van die moederdier vir BW in die 3, 4 and 13+ jarige ouderdomsgroepe vir die Tswana ras was onderskeidelik 1.74 kg, 0.96 kg en 1.87 kg. Die ooreenstemmende waardes vir die saamgestelde ras was onderskeidelik 2.28 kg, 0.94 kg en 2.06 kg. Aanpassingsfaktore vir WW vir die Tswana ras was 10.36 kg en 5.46 kg vir onderskeidelik die 3-4 jaar en 13+ jaar en ouer ouderdomsgroepe. Aanpassingsfaktore vir WW in die Composite ras was 13.84 kg, 3.20 kg en 9.58 kg vir onderskeidelik die 3 jaar, 4 jaar en 13 jaar en ouer ouderdomsgroepe. Verskille in die onderskeie parameters vir die twee rasse beklemtoon die noodsaaklikheid vir die berekening en toepassing van die onderskeie aanpassingfaktore vir en binne elke ras. Studie 3 het die bepaling van die genetiese parameters vir BW, WW, ADG1, 18MW en ADG2 behels. Enkel- en multivariaat analises is gebruik vir die skatting van die (ko)variansie komponente deur ʼn direkte diermodel (AM) en ʼn dier-maternale model (AMM) vir die twee rasse te pas. Direkte oorerflikhede vir BW, WW, ADG1, 18MW en ADG2 vir die Tswana ras was onderskeidelik 0.45, 0.32, 0.37, 0.31 en 0.31, vir ʼn enkelvariaat AM analise. Die pas van ʼn AMM het direkte oorerflikhede van 0.31, 0.20 en 0.16 vir onderskeidelik BW, WW and ADG1 gegee, terwyl die maternale oorerflikhede onderskeidelik 0.11, 0.15 en 0.21 was. Vir die saamgestelde ras was die direkte oorerflikhede vir BW, WW en ADG1 onderskeidelik 0.58, 0.32 en 0.30 vir die enkelvariaat AM analise. Verdeling (partisie) van die AMM het direkte oorerflikhede vir BW, WW en ADG1 van onderskeidelik 0.55, 0.17 en 0.14 gegee, terwyl die ooreenstemmende maternale effekte onderskeidelik 0.09, 0.15 en 0.15 was. Die genetiese korrelasies tussen die drekte en maternale effekte was positief en tussen 0.20 en 0.89. Met die multivariaat analise en die pas van die AM, is direkte oorerflikhede van 0.45, 0.37, 0.34, 0.39 en 0.31 vir onderskeidelik BW, WW, ADG1, 18MW en ADG2, vir die Tswana ras bereken. Genetiese korrelasies tussen die groei eienskappe het gewissel tussen 0.16 tot 0.97. Direkte (en maternale) oorerflikhede vir BW, WW en ADG1 was onderskeidelik 0.31(0.11), 0.19(0.15) en 0.14(0.17), vir die Tswana ras. Korrelasies tussen die direkte oorerflikhede vir BW, WW en ADG1 het gewissel tussen 0.45 en 0.95, terwyl die maternale effekte tussen 0.12 en 0.99 gewissel het. Die grootte van die oorerflikhede dui op die moontlikheid van genetiese vordering wat deur seleksie in beide rasse gemaak kan word. Seleksie op grond van WW blyk die mees gepaste wyse te wees waarmee genetiese vordering binne die Tswana ras gemaak kan word, sonder enige langtermyn nadelige effekte.

A produção de bezerros de corte que atenda ao mercado consumidor é de extrema importância, uma vez que existem fatores capazes de influenciar o preço dos animais durante a sua comercialização. Desta maneira, foi desenvolvido o presente trabalho com o objetivo de avaliar a variação no preço de bezerros em relação ao preço do boi gordo, bem como os efeitos do grupo genético e do sexo de bezerros sobre os preços praticados em leilões no estado de Santa Catarina (SC). Foram avaliados 33.143 animais, constituindo 3.587 lotes em 47 leilões realizados entre os anos de 2009 e 2014. Os lotes de bezerros eram separados em machos (M) e fêmeas (F) e foram classificados em cinco grupos genéticos de acordo com o biotipo racial: britânicos e seus cruzamentos (BX); continentais e seus cruzamentos (CX); cruzamento entre britânicos e continentais (BC); zebuínos e seus cruzamentos (ZX) e cruzamento entre Bos taurus taurus e Bos taurus indicus (TI). Todos os preços nominais de comercialização foram deflacionados pelo índice geral dos preços – disponibilidade interna (IGP-DI), para maio de 2014. Os dados não atenderam aos pressupostos da análise de variância, sendo então, realizada uma análise não paramétrica a partir do teste de Friedman e Kruskall-Wallis (post-hoc de Dunn) com o auxílio do software SPSS 20.0. O preço pago pelos bezerros acompanhou a variação ocorrida no preço do boi gordo, sendo que no ano de 2014 o preço do bezerro atingiu seu maior valor nominal (R$ 5,36/kg; P<0,05). Os M são comercializados a preços 7,8% superiores ao das F, porém essa diferença foi influenciada pelo ano de análise, onde a menor diferença entre sexos ocorreu nos períodos de redução no preço do boi gordo em SC (2012 e 2013). Os M pertencentes ao grupo genético ZX e TI foram os que receberam menores preços (R$ 4,49/kg e R$ 4,64/kg, respectivamente) quando comparados aos outros grupos (P<0,05). Por outro lado, as bezerras do grupo BX receberam maiores preços a partir de 2011, em comparação aos grupos CX, BC, TI e ZX (8,1, 8,5, 14,7 e 16,5%, respectivamente). Assim, conclui-se que o preço dos bezerros acompanha a variação ocorrida no preço do boi gordo. Além disso, o sexo e diferentes grupos genéticos são fatores capazes de influenciar no preço de comercialização de bezerros na região de SC. Desta forma, os fatores que afetam o preço dos bezerros podem ser ajustados através da seleção genética. / The production of calves that attend consumer market is of utmost importance, as there are factors that can influence the price of animals during their marketing. This manner, it developed this study with the objective to investigate variation in calves price in relation to the price of cattle and the effects of genetic group and calves sex on prices at auctions in the state of Santa Catarina (SC). We evaluated 33.143 animals, representing 3.587 lots in 47 auctions from 2009 to 2014. The calves were classified according to genetic group: British breed or cross-breeding (BX); Continental breed or cross-breeding (CX); Zebu breed or cross-breeding (ZC); British and Continental cross-breeding (BC); Bos taurus taurus and Bos taurus indicus cross-breeding (TI). The lots were composed of male (M) and females (F) calves. Nominal sales prices were deflated for May 2014. The data did not meet the assumptions of analysis of variance and non-parametric analysis was performed from the Friedman test and Kruskal-Wallis test (post-hoc Dunn) with the SPSS 20.0 software. The years presenting low and high changes in the price of calves were similar to the variation in the price of beef cattle, and in 2014 the calf price reached its highest value (R$ 5.36; P<0.05). The M are sold at prices higher than F (average 7.8%) calves, but this difference was driven by year of analysis, where the closest approach occurred during periods of reduction in the price of live cattle in SC (2012 and 2013). The M of genetic group ZX and TI received on average lower prices (R$ 4.49 and R$ 4.64, respectively) compared to the other groups (P<0.05). On the other hand, the F heifers from BX group received higher average prices in 2011 compared to the CX group, BC, IT and ZX (8.1, 8.5, 14.7 and 16.5%, respectively). Thus, it was concluded that the price of calves accompanies the variation in the price of cattle. In addition, sex and different genetic groups are factors that impact on the market price of calves in the SC region. This way, the factors that affect the price of calves can be adjusted through genetic selection.

In the present study samples from four native Turkish Cattle Breeds / South Anatolian Red (n= 48), East Anatolian Red (n= 34), Anatolian Black (n= 42) and Turkish Grey (n=46) and elite bulls of Holstein (n=21) were genotyped with respect to two milk production enhancer genes, Prolactin (PRL) and Diacylglycerol acyltransferase (DGAT1), and one disease (Complex Vertebral Malformation) causing gene (SLC35A3). A allele frequency for PRL gene, believed to be positively associated with the milk yield in cattle, ranged between 0.5645 (Anatolian Black) - 0.7558 (South Anatolian Red). K allele frequency which is thought to be related with the milk fat content in cattle varied between 0.7794 (East Anatolian Red) - 0.9250 (Anatolian Black). Complex Vertebral Malformation gene was not observed in any of the examined individuals (n= 164), hence, SLC35A3 locus was monomorphic. Pairwise Fst values based on the two polymorphic loci revealed that breeds are not significantly different from each other with respect to these two genes. Correlations, but weak, between the PRL A allele frequency and milk yield and similarly DGAT1 K allele and milk fat content was observed, Principle Component Analysis generated two compound axis based on the two polymorphic loci. Positions of the breeds on the first axis were correlated with the milk fat content of the breeds, perfectly. Again, positions of the breeds on the second axis were correlated with the milk yield of the breeds. Furthermore, PCA revealed that both A of PRL and K of DGAT1 genes seemed to have contributions in milk yield Results are believed to be useful for the management efforts of Turkish native cattle breeds.

The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37 percent); though it was reduced (26.9±2.64 percent) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04 percent) and standing (20.8±4.63 percent) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40 percent) and not kicking than the ND steers that were more vocal (20–60 percent) and kicking (> 5 percent). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2 percent) pre-slaughter than those in TG2 (23.9 percent). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5 percent), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24 percent). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear.

A produção de bezerros de corte que atenda ao mercado consumidor é de extrema importância, uma vez que existem fatores capazes de influenciar o preço dos animais durante a sua comercialização. Desta maneira, foi desenvolvido o presente trabalho com o objetivo de avaliar a variação no preço de bezerros em relação ao preço do boi gordo, bem como os efeitos do grupo genético e do sexo de bezerros sobre os preços praticados em leilões no estado de Santa Catarina (SC). Foram avaliados 33.143 animais, constituindo 3.587 lotes em 47 leilões realizados entre os anos de 2009 e 2014. Os lotes de bezerros eram separados em machos (M) e fêmeas (F) e foram classificados em cinco grupos genéticos de acordo com o biotipo racial: britânicos e seus cruzamentos (BX); continentais e seus cruzamentos (CX); cruzamento entre britânicos e continentais (BC); zebuínos e seus cruzamentos (ZX) e cruzamento entre Bos taurus taurus e Bos taurus indicus (TI). Todos os preços nominais de comercialização foram deflacionados pelo índice geral dos preços – disponibilidade interna (IGP-DI), para maio de 2014. Os dados não atenderam aos pressupostos da análise de variância, sendo então, realizada uma análise não paramétrica a partir do teste de Friedman e Kruskall-Wallis (post-hoc de Dunn) com o auxílio do software SPSS 20.0. O preço pago pelos bezerros acompanhou a variação ocorrida no preço do boi gordo, sendo que no ano de 2014 o preço do bezerro atingiu seu maior valor nominal (R$ 5,36/kg; P<0,05). Os M são comercializados a preços 7,8% superiores ao das F, porém essa diferença foi influenciada pelo ano de análise, onde a menor diferença entre sexos ocorreu nos períodos de redução no preço do boi gordo em SC (2012 e 2013). Os M pertencentes ao grupo genético ZX e TI foram os que receberam menores preços (R$ 4,49/kg e R$ 4,64/kg, respectivamente) quando comparados aos outros grupos (P<0,05). Por outro lado, as bezerras do grupo BX receberam maiores preços a partir de 2011, em comparação aos grupos CX, BC, TI e ZX (8,1, 8,5, 14,7 e 16,5%, respectivamente). Assim, conclui-se que o preço dos bezerros acompanha a variação ocorrida no preço do boi gordo. Além disso, o sexo e diferentes grupos genéticos são fatores capazes de influenciar no preço de comercialização de bezerros na região de SC. Desta forma, os fatores que afetam o preço dos bezerros podem ser ajustados através da seleção genética. / The production of calves that attend consumer market is of utmost importance, as there are factors that can influence the price of animals during their marketing. This manner, it developed this study with the objective to investigate variation in calves price in relation to the price of cattle and the effects of genetic group and calves sex on prices at auctions in the state of Santa Catarina (SC). We evaluated 33.143 animals, representing 3.587 lots in 47 auctions from 2009 to 2014. The calves were classified according to genetic group: British breed or cross-breeding (BX); Continental breed or cross-breeding (CX); Zebu breed or cross-breeding (ZC); British and Continental cross-breeding (BC); Bos taurus taurus and Bos taurus indicus cross-breeding (TI). The lots were composed of male (M) and females (F) calves. Nominal sales prices were deflated for May 2014. The data did not meet the assumptions of analysis of variance and non-parametric analysis was performed from the Friedman test and Kruskal-Wallis test (post-hoc Dunn) with the SPSS 20.0 software. The years presenting low and high changes in the price of calves were similar to the variation in the price of beef cattle, and in 2014 the calf price reached its highest value (R$ 5.36; P<0.05). The M are sold at prices higher than F (average 7.8%) calves, but this difference was driven by year of analysis, where the closest approach occurred during periods of reduction in the price of live cattle in SC (2012 and 2013). The M of genetic group ZX and TI received on average lower prices (R$ 4.49 and R$ 4.64, respectively) compared to the other groups (P<0.05). On the other hand, the F heifers from BX group received higher average prices in 2011 compared to the CX group, BC, IT and ZX (8.1, 8.5, 14.7 and 16.5%, respectively). Thus, it was concluded that the price of calves accompanies the variation in the price of cattle. In addition, sex and different genetic groups are factors that impact on the market price of calves in the SC region. This way, the factors that affect the price of calves can be adjusted through genetic selection.

Made available in DSpace on 2014-06-11T19:32:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-08-19Bitstream added on 2014-06-13T20:24:30Z : No. of bitstreams: 1 vieirajunior_lc_dr_botfmvz.pdf: 285770 bytes, checksum: ea4f695dd363af526d84a17d75b2cab3 (MD5) / Avaliou-se o potencial e viabilidade metodológica da análise de isótopos estáveis de 13C/12C, 15N/14N e 18O/16O no sangue e plasma de bovinos de corte criados em diferentes sistemas de produção no Brasil. Os tratamentos consistiram em três sistemas de alimentação de bovinos de corte, sendo: em pasto (PA), em sistema de confinamento de animais recriados (CAR) e confinamento de animais desmamados (CAD). Foram utilizados para análise do plasma 16 bovinos, sendo 6 do PA, 4 do CAR e 6 do CAD. Já para análise do sangue foram utilizados 14 bovinos, sendo 4 do PA, 5 do CAR e 5 do CAD. Para o sangue e também para o plasma, houve distinção para todos sistemas avaliados assumindo maior representatividade na separação o elemento Carbono. Para análise da diferenciação entre os sistemas avaliados, é fundamental a participação dos 3 elementos: Carbono, Nitrogênio e Oxigênio. Para análise isotópica visando a caracterização dos sistemas de produção, recomenda-se o sangue como tecido a ser utilizado. / It was evaluated the potential application of stable isotopes methodology of 13C/12C, 15N/14N e 18O/16O in blood and plasma of beef cattle raised under three different production systems in Brazil. Treatments consisted of production systems: pasture (PA), yearling feedlot (CAR), and fed calves feedlot (CAD). For plasma, it was utilized a total of 16 samples (6 of PA, 4 of CAR and 6 of CAD). In addition, for blood it was used 14 samples (4 of PA, 5 of CAR and 5 of CAD). In both types of tissue it was possible to observe production systems differentiation, assuming greater representatively separation of Carbon element. For differentiation of production systems it is highly recommended the inclusion of Carbon, Nitrogen and Oxygen in the analysis. Based on the results, it is recommended to analyze blood for production systems differentiation by stable isotope technique

Orientador: Mário de Beni Arrigoni / Coorientador: Cyntia Ludovico Martins / Banca: Carlos Ducatti / Banca: Paulo Roberto Meirelles / Banca: Rodrigo Dias Lauritano Pacheco / Banca: Danilo Domingues Millen / Resumo: Avaliou-se o potencial e viabilidade metodológica da análise de isótopos estáveis de 13C/12C, 15N/14N e 18O/16O no sangue e plasma de bovinos de corte criados em diferentes sistemas de produção no Brasil. Os tratamentos consistiram em três sistemas de alimentação de bovinos de corte, sendo: em pasto (PA), em sistema de confinamento de animais recriados (CAR) e confinamento de animais desmamados (CAD). Foram utilizados para análise do plasma 16 bovinos, sendo 6 do PA, 4 do CAR e 6 do CAD. Já para análise do sangue foram utilizados 14 bovinos, sendo 4 do PA, 5 do CAR e 5 do CAD. Para o sangue e também para o plasma, houve distinção para todos sistemas avaliados assumindo maior representatividade na separação o elemento Carbono. Para análise da diferenciação entre os sistemas avaliados, é fundamental a participação dos 3 elementos: Carbono, Nitrogênio e Oxigênio. Para análise isotópica visando a caracterização dos sistemas de produção, recomenda-se o sangue como tecido a ser utilizado. / Abstract: It was evaluated the potential application of stable isotopes methodology of 13C/12C, 15N/14N e 18O/16O in blood and plasma of beef cattle raised under three different production systems in Brazil. Treatments consisted of production systems: pasture (PA), yearling feedlot (CAR), and fed calves feedlot (CAD). For plasma, it was utilized a total of 16 samples (6 of PA, 4 of CAR and 6 of CAD). In addition, for blood it was used 14 samples (4 of PA, 5 of CAR and 5 of CAD). In both types of tissue it was possible to observe production systems differentiation, assuming greater representatively separation of Carbon element. For differentiation of production systems it is highly recommended the inclusion of Carbon, Nitrogen and Oxygen in the analysis. Based on the results, it is recommended to analyze blood for production systems differentiation by stable isotope technique / Doutor

A produção de bezerros de corte que atenda ao mercado consumidor é de extrema importância, uma vez que existem fatores capazes de influenciar o preço dos animais durante a sua comercialização. Desta maneira, foi desenvolvido o presente trabalho com o objetivo de avaliar a variação no preço de bezerros em relação ao preço do boi gordo, bem como os efeitos do grupo genético e do sexo de bezerros sobre os preços praticados em leilões no estado de Santa Catarina (SC). Foram avaliados 33.143 animais, constituindo 3.587 lotes em 47 leilões realizados entre os anos de 2009 e 2014. Os lotes de bezerros eram separados em machos (M) e fêmeas (F) e foram classificados em cinco grupos genéticos de acordo com o biotipo racial: britânicos e seus cruzamentos (BX); continentais e seus cruzamentos (CX); cruzamento entre britânicos e continentais (BC); zebuínos e seus cruzamentos (ZX) e cruzamento entre Bos taurus taurus e Bos taurus indicus (TI). Todos os preços nominais de comercialização foram deflacionados pelo índice geral dos preços – disponibilidade interna (IGP-DI), para maio de 2014. Os dados não atenderam aos pressupostos da análise de variância, sendo então, realizada uma análise não paramétrica a partir do teste de Friedman e Kruskall-Wallis (post-hoc de Dunn) com o auxílio do software SPSS 20.0. O preço pago pelos bezerros acompanhou a variação ocorrida no preço do boi gordo, sendo que no ano de 2014 o preço do bezerro atingiu seu maior valor nominal (R$ 5,36/kg; P<0,05). Os M são comercializados a preços 7,8% superiores ao das F, porém essa diferença foi influenciada pelo ano de análise, onde a menor diferença entre sexos ocorreu nos períodos de redução no preço do boi gordo em SC (2012 e 2013). Os M pertencentes ao grupo genético ZX e TI foram os que receberam menores preços (R$ 4,49/kg e R$ 4,64/kg, respectivamente) quando comparados aos outros grupos (P<0,05). Por outro lado, as bezerras do grupo BX receberam maiores preços a partir de 2011, em comparação aos grupos CX, BC, TI e ZX (8,1, 8,5, 14,7 e 16,5%, respectivamente). Assim, conclui-se que o preço dos bezerros acompanha a variação ocorrida no preço do boi gordo. Além disso, o sexo e diferentes grupos genéticos são fatores capazes de influenciar no preço de comercialização de bezerros na região de SC. Desta forma, os fatores que afetam o preço dos bezerros podem ser ajustados através da seleção genética. / The production of calves that attend consumer market is of utmost importance, as there are factors that can influence the price of animals during their marketing. This manner, it developed this study with the objective to investigate variation in calves price in relation to the price of cattle and the effects of genetic group and calves sex on prices at auctions in the state of Santa Catarina (SC). We evaluated 33.143 animals, representing 3.587 lots in 47 auctions from 2009 to 2014. The calves were classified according to genetic group: British breed or cross-breeding (BX); Continental breed or cross-breeding (CX); Zebu breed or cross-breeding (ZC); British and Continental cross-breeding (BC); Bos taurus taurus and Bos taurus indicus cross-breeding (TI). The lots were composed of male (M) and females (F) calves. Nominal sales prices were deflated for May 2014. The data did not meet the assumptions of analysis of variance and non-parametric analysis was performed from the Friedman test and Kruskal-Wallis test (post-hoc Dunn) with the SPSS 20.0 software. The years presenting low and high changes in the price of calves were similar to the variation in the price of beef cattle, and in 2014 the calf price reached its highest value (R$ 5.36; P<0.05). The M are sold at prices higher than F (average 7.8%) calves, but this difference was driven by year of analysis, where the closest approach occurred during periods of reduction in the price of live cattle in SC (2012 and 2013). The M of genetic group ZX and TI received on average lower prices (R$ 4.49 and R$ 4.64, respectively) compared to the other groups (P<0.05). On the other hand, the F heifers from BX group received higher average prices in 2011 compared to the CX group, BC, IT and ZX (8.1, 8.5, 14.7 and 16.5%, respectively). Thus, it was concluded that the price of calves accompanies the variation in the price of cattle. In addition, sex and different genetic groups are factors that impact on the market price of calves in the SC region. This way, the factors that affect the price of calves can be adjusted through genetic selection.

Thesis (MSc. (Animal breeding and genetics )) --University of Limpopo, 2006 / The objective of this study was to estimate genetic parameters for weekly body weight of feed intake of individually fed beef bulls at centralized testing stations in South Africa using random regression models (RRM). The model for cumulative feed intake included the fixed linear regression on third order orthogonal Legendre polynomials of the actual days on test (7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77 and 84 day) for starting age group and contemporary group effects. Random regressions on third order orthogonal Legendre polynomials were included for the additive genetic effect of the animal and the additional random effect of weaning-herd-year (WHY) and on fourth order for the additional random permanent environmental effect of the animal. The model for body weights included the fixed linear regression on fourth order orthogonal Legendre polynomials of the actual days on test for starting age group and contemporary group effects. Random regressions on fourth order orthogonal Legendre polynomials were included for additive genetic effects and additional uncorrelated random effects of the WHY and the permanent environment. The residual effects for both traits were assumed to be independently distributed with heterogeneous variance for each measurement period. Variance ratios for additive genetic, permanent environment and WHY for cumulative feed intake at different days on test ranged from 0.07 to 0.10, 0.53 to 0.77 and 0.14 to 0.37, respectively. Variance ratios for additive genetic, permanent environment and WHY for weekly body weights at different test days ranged from 0.26 to 0.29, 0.37 to 0.43 and 0.26 to 0.34, respectively. Estimates of genetic correlation among the same trait (body weight or feed intake) measured at different test days were generally high (>0.80) for any give test pair. The WHY had a significant contribution in variation of performance of bulls on test, despite the 28-day adjustment period. RRM provided the opportunity to study changes in genetic variability within the studied traits over time. Random Regression Models could be used in the National Genetic Evaluation of beef bulls at central performance testing stations in South Africa.

Feedlot performance, carcass merit and chemical composition were compared using Waguli , Brangus, Hereford x Tuli and Wagyu x Crossbred Gene Combination (CGC) breeds. Steers were penned in the following manner: 6 Waguli steers, 6 Hereford x Tuli, 6 Wagyu x CGC and 8 Brangus. There was a significant difference (P<0.05) between Brangus and Waguli for ADGs. F:G was lower (P<0.05) for Hereford x Tuli compared to the other crossbreeds. A heavier final weight was observed (P<0.05) for the Wagyu x CGC than all other crossbreds. There was a significant difference (P<0.05) for REA between Wagyu x CGC and Hereford x Tuli and Waguli. Wagyu x CGC had higher shear force values (SFV) (P<0.05) than all other crossbreeds. Cost of gain was lower (P<0.05) for Hereford x Tuli compared the other breeds. Hereford x Tuli also had less protein (P<0.05) than to the other breeds.A second study was conducted comparing limit feeding (LF) vs. full feeding (FF) strategies. 23 steers and 27 heifers were penned by sex and were randomly assigned a treatment; 4 pens received the LF treatment and 4 were FF. ADG was lower (P<0.05) for LF and FF heifers compared to both LF and FF steers. Dressing percentage was lower (P<0.05) for LF steers compared to LF and FF Heifers. LF heifers YG was higher (P<0.05) compared to FF steers. Quality grades were higher (P<0.05) for LF and FF heifers compared to LF and FF steers. REA /cwt was significantly higher (P<0.05) for FF heifers compared to LF and FF steers. SFV were11lower (P<0.05) for FF heifers compared to LF and FF steers. A significant difference (P<0.05) in cost of gain was noted between LF steers and the rest, also between LF heifers and FF steers. Primal cut price/cwt was significantly lower (P<0.05) for LF heifers compared to FF steers. Lipid percentage was higher (P<0.05) LF heifers compared to FF steers. Moisture percentage was lower (P<0.05) for LF heifer compared to the other groups.