Birth weight (BW) (n =1277) and weaning weight (WW) (n = 1090) of calves, pregnancy rate (PR) (n = 1386), calf crop born (CCB) (n = 1386), calf crop weaned (CCW) (n = 1294), cow’s weight at palpation (CW) (n = 1474) and cow body condition score (BCS) (n = 1473) were evaluated from 1994 to 2006 in 143 F1 cows sired by Brahman (B), Boran (Bo) and Tuli (T) bulls and born to Angus and Hereford cows. Mouth scores (MS) (n = 139) were assigned to the remaining cows in 2004 and 2005. Fixed effects included sire breed of cow, dam breed of cow, and calf’s birth year/age of cow; random effects included cow and sire of cow. BW and WW were evaluated using the same model and adding gender for both and age for WW. All two-way interactions were tested for significance. Calf’s birth year/age of dam was significant for all traits (P < 0.05) except WW. BW for calves out of F1 B, Bo and T bulls were 35.08, 34.76 and 34.87 kg, respectively, and were not different. WW differed (P < 0.05) for calves out of F1 B, Bo and T cows (235.87, 221.10 and 208.35 kg, respectively). PR (0.922, 0.955 and 0.936, respectively), CCB (0.881, 0.931, 0.890, respectively), CCW (0.848, 0.898 and 0.869, respectively), did not differ among F1 B, Bo and T cows. CW when cows were 8- or 9-year old were 600.78, 514.63 and 513.14 kg, respectively, for F1 B, Bo and T cows, with those sired by B being heaviest (P < 0.05). BCS for B-, Bo- and T-sired cows were 5.23, 5.48 and 5.18, respectively, with F1 Bo cows having highest scores. Higher MS (P < 0.05) were assigned to Bo and B-sired cows (0.95 and 0.94, respectively) compared to T-sired cows (0.78), when both broken and solid incisors were scored 1, and smooth scored 0. When both smooth and broken were scored 0, and solid were scored 1, higher scores were assigned to B- (0.53) compared to T-sired cows (0.24), the Bo-sired cows being intermediate. Higher reproductive rates were found for Boran-sired cows, but Brahman-sired cows weaned heavier calves.

Birth weight (BW) (n =1277) and weaning weight (WW) (n = 1090) of calves, pregnancy rate (PR) (n = 1386), calf crop born (CCB) (n = 1386), calf crop weaned (CCW) (n = 1294), cow’s weight at palpation (CW) (n = 1474) and cow body condition score (BCS) (n = 1473) were evaluated from 1994 to 2006 in 143 F1 cows sired by Brahman (B), Boran (Bo) and Tuli (T) bulls and born to Angus and Hereford cows. Mouth scores (MS) (n = 139) were assigned to the remaining cows in 2004 and 2005. Fixed effects included sire breed of cow, dam breed of cow, and calf’s birth year/age of cow; random effects included cow and sire of cow. BW and WW were evaluated using the same model and adding gender for both and age for WW. All two-way interactions were tested for significance. Calf’s birth year/age of dam was significant for all traits (P < 0.05) except WW. BW for calves out of F1 B, Bo and T bulls were 35.08, 34.76 and 34.87 kg, respectively, and were not different. WW differed (P < 0.05) for calves out of F1 B, Bo and T cows (235.87, 221.10 and 208.35 kg, respectively). PR (0.922, 0.955 and 0.936, respectively), CCB (0.881, 0.931, 0.890, respectively), CCW (0.848, 0.898 and 0.869, respectively), did not differ among F1 B, Bo and T cows. CW when cows were 8- or 9-year old were 600.78, 514.63 and 513.14 kg, respectively, for F1 B, Bo and T cows, with those sired by B being heaviest (P < 0.05). BCS for B-, Bo- and T-sired cows were 5.23, 5.48 and 5.18, respectively, with F1 Bo cows having highest scores. Higher MS (P < 0.05) were assigned to Bo and B-sired cows (0.95 and 0.94, respectively) compared to T-sired cows (0.78), when both broken and solid incisors were scored 1, and smooth scored 0. When both smooth and broken were scored 0, and solid were scored 1, higher scores were assigned to B- (0.53) compared to T-sired cows (0.24), the Bo-sired cows being intermediate. Higher reproductive rates were found for Boran-sired cows, but Brahman-sired cows weaned heavier calves.

Sire and family effects were evaluated for calf growth, udder and teat conformation, and reproduction traits in 2- to 4- yr-old cows from the McGregor Genomics Project. Cows were produced by embryo transfer (ET) and natural service (NS) from the same 4 F1 Nellore-Angus sires, and were analyzed separately. Sire of cow was significant for calf birth weight (P = 0.014) among ET cows, but not NS cows. Among NS families, calves from cows out of Brahman-Hereford dams were 2.0 kg heavier (P = 0.064) at birth than calves from cows out of Brahman-Angus dams. Sire of cow accounted for variation in weaning weight (P = 0.006) and preweaning ADG (P = 0.005) of calves from ET dams, but not NS dams. Family nested within sire also accounted for variation (P = 0.061) in weaning weights of calves from ET dams. Sire of cow was significant for average teat length in ET (P < 0.001) and NS (P = 0.013) cows. Sire of cow was significant for average teat diameter (P = 0.022) among NS cows. Sire of cow also affected udder support score (P = 0.002), cow disposition at calf birth (P = 0.002), and cow weight at weaning (P = 0.045) in ET cows. Family and cow age also accounted for variation in cow disposition at calf birth (P = 0.015, P = 0.041, respectively) and cow weight at weaning (P = 0.001, P < .001, respectively) among ET cows. Calf year of birth also affected (P < .001) cow weight at weaning among ET cows. For NS dams, calf year of birth (P = 0.012), cow age (P < .001), and parity nested within cow age (P = 0.005) affected cow weight at weaning. Although reproduction data were not formally analyzed, there appear to be substantial differences for calving rate and average calving date among these cow families. Data from this project will be used for identification of genetic markers for these cow productivity traits.

Darbo tikslas: ištirti karvių genomo nestabilumo ryšį su pieno produktyvumu. Darbo uždaviniai: 1. Surinkti ir išanalizuoti mokslinę literatūrą apie galvijų chromosomų skaičiaus ir struktūros pakitimus bei jų ryšį su produktyvumo savybėmis. 2. Paruošti karvių chromosomų preparatus. 3. Ištirti chromosomų skaičiaus ir struktūros pakitimus aukšto ir žemo produktyvumo pieninėms karvėms. 4. Apskaičiuoti chromosomų skaičiaus ir struktūros pakitimų dažnį ir spektrą aukšto ir žemo produktyvumo pieninėms karvėms. 5. Nustatyti ryšį tarp chromosomų skaičiaus ir struktūros pakitimų ir pieno produkcijos kiekio. Darbo metodai: mokslinės literatūros, straipsnių, statistinių duomenų analizė. Praktinėje dalyje atlikti karvių chromosomų tyrimai. Rezultatai aptarti juos apibendrinus. Darbe remtasi įvairiais užsienio ir lietuvių moksliniais darbais, straipsniais, tyrimų medžiaga, darbe analizuojama tema. Darbo objektas: citogenetinė analizė atlikta 20 karvių iš LSMU VA praktinio mokymo ir bandymų centro, 10 aukšto produktyvumo karvių ir 10 žemo produktyvumo karvių. Tyrimai atlikti standartiniu citogenetiniu metodu. Rezultatai ir aptarimas: žemo produktyvumo karvės turėjo žymiai daugiau chromosominių pakitimų. Daugiausiai chromosomų struktūros pakitimų, t.y. 37,5 proc., sudaro spragos vienoje chromatidėje (S1), 15,6 proc. – spragos abiejose chromatidėse (S2), 17,2 proc. – chromatidžių trūkiai (D1), 9,4 proc. – fragmentai (F). Mažiausią dalį chromosomų struktūros pakitimų, t. y. 3,1 proc. sudaro... [toliau žr. visą tekstą] / The Object of the work: cytogenetic analysis was performed on 20 cows from LSMU VA practice and research centre, 10 productive cows and 10 unproductive cows. The research was performed by standard citogenetical laboratory. The aim of the work: to evaluate the influence of chromosomal aberrations on cow high productivity. The tasks of the work: collect and analyze scientific literature on bovine chromosome number and structure of the environment and their relationship with performance traits. Prepared bovine chromosome preparations. To investigate the chromosome number and structure changes in high and low productivity of dairy cows. Calculate the number of chromosomes and structural changes in the frequency and range of high and low productivity of dairy cows. Determine the relationship between chromosome number and structure changes and milk production levels. The results and their discussion: after the examination of the unproductive cows the structural and numeral variations of chromosomes were identified. Most part of structural variations in chromosomes, i.e. 37,5 proc., consisted of gaps in one chromatid (S1), 15,6 proc.of gaps in both chromatids (S2), 17,2 proc. of cracks in chromatids (D1) .There were 10,9 proc. of poliploidies (P) found in numeral variations of chromosomes. There were also identified both the structural and numerical variations of chromosomes after examining the productive cows. These structural variations of chromosomes were identified: 34,6 proc... [to full text]

Inicialmente, foram analisados dados peso-idade do nascimento até 100 meses de idade, de vacas de quatro grupos genéticos (G): Nelore (NEL), ½Canchim + ½Nelore (CN), ½Angus + ½Nelore (AN) e ½Simental + ½Nelore (SN), pertencentes a Embrapa Pecuária Sudeste, São Carlos. Os animais considerados neste estudo nasceram de 1998 a 2001 (Ano), na primavera e outono (EP), e foram criados em sistema de produção intensiva, recebendo três níveis de suplementação pós-desmama (M): 0, 1,5; 3,0 kg/animal/dia de concentrado. O objetivo neste estudo foi comparar diferentes modelos não-lineares para estimar o crescimento, e avaliar a influência de efeitos de ambiente e grupo genético sobre os parâmetros estimados. Os modelos não-lineares: Brody, Gompertz, Logístico, Von Bertalanffy e Richards foram ajustados por mínimos quadrados ordinários e ponderados, considerando a variância normal e ponderada pelo inverso dos pesos em diferentes períodos. Foi usado o procedimento NLIN do SAS. Os modelos Brody e Von Bertalanffy convergiram para todos os G, havendo, entretanto, leve superioridade do Brody ponderado. Na comparação do ajuste dos modelos considerando o uso do inverso da variância os modelos mostraram-se mais adequado. As estimativas dos parâmetros peso assintótico (A) e taxa de maturidade (k) do modelo de Brody ponderado foram analisadas por meio de modelo que, além do efeito médio global, incluiu os efeitos de G, M, EP e as interações entre estes efeitos. Houve diferenças significativas das curvas de crescimento médias para os G. Na análise individual dos parâmetros A e k estimados através do modelo Brody ponderado, verificou-se que A foi influenciado (P<0,05) por G e EP e k foi influenciado (P<0,05) por M, fornecidos aos animais durante quatro meses após desmama. Melhorias no manejo alimentar resultaram em menor variação na forma das curvas de crescimentos e em altas taxas de maturidade. Na segunda parte, verificou-se a qualidade do modelo Brody, ponderado pelo inverso das variâncias dos pesos, quanto ao ajuste peso-idade como também a influência das estimativas do peso à maturidade (A) e da taxa de maturidade (k) sobre características produtivas das vacas NEL, CN, AN e SN. Foram organizados 10 grupos contemporâneos (GC), com concatenação dos efeitos Ano-EP-M para cada G. Utilizando-se um modelo misto com efeitos de G e GC, foi incluído, alternadamente covariáveis linear e quadrática de A e k, na análise das características produtivas: peso à desmama dos bezerros (PD); número (ND8) e kg (KD8) de bezerros desmamados em até 8 anos de permanência da vaca no rebanho; relação PD/peso da vaca ao parto (PD_PVP); relação PD/peso da vaca à desmama do bezerro (PD_PVD); relação PD/unidade metabólica da vaca (PV0,75) à desmama do bezerro (PDW). Houve diferença significativa (P<0,05) da curva de crescimento entre os grupos genéticos (G) e também entre os grupos de contemporâneos (GC) dentro de G. Verificou-se que estas características foram, em geral, influenciadas (P<0,01) tanto pelos efeitos linear e quadrático de A quanto pelos efeitos linear e quadrático de k. / Initially, were analyzed weight-age data from birth to 100 months of age from cows of four genetic groups (G): Nellore (NEL), ½Nellore + ½Canchim (CN), ½Angus +½Nellore (AN) and ½Simmental + ½Nellore (SN), of a experiment carried out at Embrapa Southeast Cattle Research Center, State of São Paulo, Brazil. The animals considered in this study were born from 1998 to 2001 (Year) in spring and fall (EP), and were managed in intensive production system and submitted to three of levels of supplementation post-weaning (M): 0, 1.5 and 3.0 kg/animal/day of concentrate. The objective of this study was to compare different nonlinear models to fitted growth curves, of beef cattle females, and to evaluate of environmental and genetic group effects on the estimated parameters. The nonlinear models: Brody, Gompertz, Logistic, Von Bertalanffy and Richards were fitted by ordinary least squares and weighted by the inverse of the variances of the weights in different periods. It was used the NLIN procedure of SAS. The parameters asymptotic weight (A) and maturing rate (k) obtained from model of Brody were analyzed by a mixed linear model that, besides the overall mean effect, included the effects of G, M, EP, and the interactions among these effects. The Brody and Von Bertalanffy models converged for all genetic groups, although slight superiority of the weighted Brody. Comparing the goodness of fit of these models, the use of the inverse of variances showed more efficient than the adjust of the models considering normal variances. Individual analysis of A and k estimated the model weighted Brody, the A parameter was influenced (P <0.05) by genetic group and season of birth and k was influenced (P <0 05) for levels of supplementation to the animals. Improvements in feeding supplementation resulted in less variation in the shape of growth curves and rates of maturity. In the second part of the work, it was evaluated the goodness of the Brody model, weighted by the inverse variance weights, in the adjust of weight-age data, and also analyzed the influence of the maturity weight (A) and maturing rate (k) estimates for traits cows productivity. Were organized 10 contemporary groups (CG) with concatenation of effects Year- EP-M for each G. Considering a mixed model with effects of G and CG (10 contemporaneous groups organized by concatenation Year-EP-M effects), linear and quadratic covariate effects of A and k, were added, alternately, for the analysis of the following traits: weaning weight of calve (WW), number (NW8) and kg (KW8) of calves weaned over 8 years of the cow in the herd; WW/weight of the cow at calving (WW_WC); WW/cow weight at weaning of calf (WW_WWC); and WW/metabolic unit of the cow (PV0,75) at weaning of the calf (MW). There was significant difference (P<0.05) of the growth curve among the genetic groups and also among contemporary groups within G. It was found that the production traits were, in general, influenced (P<0.01) by both linear and quadratic effects of A and k.

Inicialmente, foram analisados dados peso-idade do nascimento até 100 meses de idade, de vacas de quatro grupos genéticos (G): Nelore (NEL), ½Canchim + ½Nelore (CN), ½Angus + ½Nelore (AN) e ½Simental + ½Nelore (SN), pertencentes a Embrapa Pecuária Sudeste, São Carlos. Os animais considerados neste estudo nasceram de 1998 a 2001 (Ano), na primavera e outono (EP), e foram criados em sistema de produção intensiva, recebendo três níveis de suplementação pós-desmama (M): 0, 1,5; 3,0 kg/animal/dia de concentrado. O objetivo neste estudo foi comparar diferentes modelos não-lineares para estimar o crescimento, e avaliar a influência de efeitos de ambiente e grupo genético sobre os parâmetros estimados. Os modelos não-lineares: Brody, Gompertz, Logístico, Von Bertalanffy e Richards foram ajustados por mínimos quadrados ordinários e ponderados, considerando a variância normal e ponderada pelo inverso dos pesos em diferentes períodos. Foi usado o procedimento NLIN do SAS. Os modelos Brody e Von Bertalanffy convergiram para todos os G, havendo, entretanto, leve superioridade do Brody ponderado. Na comparação do ajuste dos modelos considerando o uso do inverso da variância os modelos mostraram-se mais adequado. As estimativas dos parâmetros peso assintótico (A) e taxa de maturidade (k) do modelo de Brody ponderado foram analisadas por meio de modelo que, além do efeito médio global, incluiu os efeitos de G, M, EP e as interações entre estes efeitos. Houve diferenças significativas das curvas de crescimento médias para os G. Na análise individual dos parâmetros A e k estimados através do modelo Brody ponderado, verificou-se que A foi influenciado (P<0,05) por G e EP e k foi influenciado (P<0,05) por M, fornecidos aos animais durante quatro meses após desmama. Melhorias no manejo alimentar resultaram em menor variação na forma das curvas de crescimentos e em altas taxas de maturidade. Na segunda parte, verificou-se a qualidade do modelo Brody, ponderado pelo inverso das variâncias dos pesos, quanto ao ajuste peso-idade como também a influência das estimativas do peso à maturidade (A) e da taxa de maturidade (k) sobre características produtivas das vacas NEL, CN, AN e SN. Foram organizados 10 grupos contemporâneos (GC), com concatenação dos efeitos Ano-EP-M para cada G. Utilizando-se um modelo misto com efeitos de G e GC, foi incluído, alternadamente covariáveis linear e quadrática de A e k, na análise das características produtivas: peso à desmama dos bezerros (PD); número (ND8) e kg (KD8) de bezerros desmamados em até 8 anos de permanência da vaca no rebanho; relação PD/peso da vaca ao parto (PD_PVP); relação PD/peso da vaca à desmama do bezerro (PD_PVD); relação PD/unidade metabólica da vaca (PV0,75) à desmama do bezerro (PDW). Houve diferença significativa (P<0,05) da curva de crescimento entre os grupos genéticos (G) e também entre os grupos de contemporâneos (GC) dentro de G. Verificou-se que estas características foram, em geral, influenciadas (P<0,01) tanto pelos efeitos linear e quadrático de A quanto pelos efeitos linear e quadrático de k. / Initially, were analyzed weight-age data from birth to 100 months of age from cows of four genetic groups (G): Nellore (NEL), ½Nellore + ½Canchim (CN), ½Angus +½Nellore (AN) and ½Simmental + ½Nellore (SN), of a experiment carried out at Embrapa Southeast Cattle Research Center, State of São Paulo, Brazil. The animals considered in this study were born from 1998 to 2001 (Year) in spring and fall (EP), and were managed in intensive production system and submitted to three of levels of supplementation post-weaning (M): 0, 1.5 and 3.0 kg/animal/day of concentrate. The objective of this study was to compare different nonlinear models to fitted growth curves, of beef cattle females, and to evaluate of environmental and genetic group effects on the estimated parameters. The nonlinear models: Brody, Gompertz, Logistic, Von Bertalanffy and Richards were fitted by ordinary least squares and weighted by the inverse of the variances of the weights in different periods. It was used the NLIN procedure of SAS. The parameters asymptotic weight (A) and maturing rate (k) obtained from model of Brody were analyzed by a mixed linear model that, besides the overall mean effect, included the effects of G, M, EP, and the interactions among these effects. The Brody and Von Bertalanffy models converged for all genetic groups, although slight superiority of the weighted Brody. Comparing the goodness of fit of these models, the use of the inverse of variances showed more efficient than the adjust of the models considering normal variances. Individual analysis of A and k estimated the model weighted Brody, the A parameter was influenced (P <0.05) by genetic group and season of birth and k was influenced (P <0 05) for levels of supplementation to the animals. Improvements in feeding supplementation resulted in less variation in the shape of growth curves and rates of maturity. In the second part of the work, it was evaluated the goodness of the Brody model, weighted by the inverse variance weights, in the adjust of weight-age data, and also analyzed the influence of the maturity weight (A) and maturing rate (k) estimates for traits cows productivity. Were organized 10 contemporary groups (CG) with concatenation of effects Year- EP-M for each G. Considering a mixed model with effects of G and CG (10 contemporaneous groups organized by concatenation Year-EP-M effects), linear and quadratic covariate effects of A and k, were added, alternately, for the analysis of the following traits: weaning weight of calve (WW), number (NW8) and kg (KW8) of calves weaned over 8 years of the cow in the herd; WW/weight of the cow at calving (WW_WC); WW/cow weight at weaning of calf (WW_WWC); and WW/metabolic unit of the cow (PV0,75) at weaning of the calf (MW). There was significant difference (P<0.05) of the growth curve among the genetic groups and also among contemporary groups within G. It was found that the production traits were, in general, influenced (P<0.01) by both linear and quadratic effects of A and k.