Desempenho reprodutivo de bovinos na sub-região dos Paiaguás do Pantanal Mato-grossense. I. Efeito da suplementação mineral e da idade de desmama sobre a idade e o peso ao primeiro parto

The effects of mineral supplementation (common salt = CS, CS + dicalcium phosphate = SP and SP + micronutrients) and of weaning age (six, eight and ten months) on the age and weight at first calving of Zebu heifers were studied in the Paiaguás sub-region of the Pantanal Mato-grossense, Brazil. A completely randomized design was used. The experiment was conducted from February 1980 to November 1984. Age and weight as first calving were not influenced (P>0.05) by weaning age. Also mineral supplementation did not affect the age at first calving, but influenced weight at calving, which was about 30 kg higher (P0,05) pela idade à desmama dos animais. A suplementação mineral também não afetou a idade ao primeiro parto, mas influenciou os pesos à primeira cria, que foram aproximadamente 30 kg mais altos (P<0,01) nas novilhas suplementadas com fósforo, que naquelas que receberam somente sal comum. Concluiu-se que é viável a antecipação da desmama no Pantanal e da mesma forma, a suplementação com fósforo

The influence of the weaning age on the growth of heifers in the cowlands of Mato Grosso state

O estudo foi realizado no Pantanal Mato-grossense, com o objetivo de determinar a influência da idade de desmama no desenvolvimento de bezerras na fase de recria, em regime de pasto nativo. Foram utilizadas 88 unidades experimentais divididas em três ensaios experimentais com suplementações minerais diferentes. Cada ensaio foi composto por três tratamentos (seis, oito e dez meses de idade de desmama) num arranjo inteiramente casualizado. Não foram determinadas diferenças significativas nos três ensaios experimentais, entre os tratamentos (idades de desmama) no que se refere aos pesos médios alcançados aos 18 meses de idade. E possível concluir ser viável a desmama aos seis meses de idade em campos nativos, a partir da metade do período das cheias quando houver razoável quantidade e qualidade de pastagem associada a prática de everminação pós-desmama. Como não houve diferenças significativas nos pesos médios aos 18 e 24 meses de idade, é possível supor não existir influência da idade de desmama na idade à primeira cria.This work was carried out in order to determine the influence of the weaning age on the growth of heifers during growing period, when in native pasture. Eighty eight experimental units were divided into three experiments, each one with different mineral supplementations. Each trial was compounded by three treatments (six, eight and ten months old at weaning) in a completely randomized design. Statistical analysis showed no difference among treatments (age of weaning) in terms of weight gain at 18 months of age. It was concluded the viability of weaning at six months old in native pasture from the mid-period of inundation in presence of good amount and quality of pasture and associated a deworming programme. Since there was no statistical difference between 18 and 24 months of age, it is expected no influence of weaning at age on the first mating

Beef cattle mineral nutrition in the Brazilian Pantanal. III. Macronutrients survey on the lower Piquiri

Relatam-se resultados de análises de amostras de solo, plantas forrageiras e osso de bovinos coletadas no Baixo Piquiri, no Pantanal Mato-grossense, em três unidades de paisagem: campo cerrado, campo limpo e cerrado/mata. No solo, o pH médio foi de 5,5; os teores médios de cátions trocáveis foram: Al = 89 ppm; Ca = 142 ppm; Mg = 64 ppm; K = 58 ppm e Na = 5 ppm; o nível de P disponível foi de 13 ppm. Nas forrageiras nativas, os teores médios de P, K, Ca e Mg foram 0,21%, 1,52%, 0,21%e 0,18%, respectivamente. No osso, os níveis de Ca, Mg e P, em maio, foram de 39,3%, 0,65% e 17,8%. Os resultados encontrados não evidenciam deficiências minerais graves; entretanto, importantes componentes da dieta dos bovinos apresentam relação Ca: P de c. 0,7:1,0.Analytical results of soil, forage plant and cattle bone samples, taken on three physiognomic units ("campo cerrado" or savana grassland, "campo limpo" or open grassland, and "cerrado" woodland/forest), are reported for the lower Piquiri in the Brazilian Pantanal. Average soil pH was 5.5; average levels of exchangeable cations were Al = 89 ppm, Ca = 142 ppm, Mg = 64 ppm, K = 58 ppm and Na = 5 ppm; and available P = 13 ppm. In the native forage plants P, K, Ca and Mg levels (mean) were 0.21%, 1.52%, 0.21% and 0.18%, respectively. Average concentrations of Ca, Mg and P in bone, in May, were 39.3%, 0.65% and 17.8%. The data do not evidentiate serious mineral deficiencies, however important components of cattle diet presented Ca: P ratio of c. 0.7:1.0

Identification of genomic regions associated with feed efficiency in Nelore cattle

Abstract\ud \ud Background\ud Feed efficiency is jointly determined by productivity and feed requirements, both of which are economically relevant traits in beef cattle production systems. The objective of this study was to identify genes/QTLs associated with components of feed efficiency in Nelore cattle using Illumina BovineHD BeadChip (770 k SNP) genotypes from 593 Nelore steers. The traits analyzed included: average daily gain (ADG), dry matter intake (DMI), feed-conversion ratio (FCR), feed efficiency (FE), residual feed intake (RFI), maintenance efficiency (ME), efficiency of gain (EG), partial efficiency of growth (PEG) and relative growth rate (RGR). The Bayes B analysis was completed with Gensel software parameterized to fit fewer markers than animals. Genomic windows containing all the SNP loci in each 1 Mb that accounted for more than 1.0% of genetic variance were considered as QTL region. Candidate genes within windows that explained more than 1% of genetic variance were selected by putative function based on DAVID and Gene Ontology.\ud \ud \ud Results\ud Thirty-six QTL (1-Mb SNP window) were identified on chromosomes 1, 2, 3, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25 and 26 (UMD 3.1). The amount of genetic variance explained by individual QTL windows for feed efficiency traits ranged from 0.5% to 9.07%. Some of these QTL minimally overlapped with previously reported feed efficiency QTL for Bos taurus. The QTL regions described in this study harbor genes with biological functions related to metabolic processes, lipid and protein metabolism, generation of energy and growth. Among the positional candidate genes selected for feed efficiency are: HRH4, ALDH7A1, APOA2, LIN7C, CXADR, ADAM12 and MAP7.\ud \ud \ud \ud Conclusions\ud Some genomic regions and some positional candidate genes reported in this study have not been previously reported for feed efficiency traits in Bos indicus. Comparison with published results indicates that different QTLs and genes may be involved in the control of feed efficiency traits in this Nelore cattle population, as compared to Bos taurus cattle.CNPqCAPE

Genomic structure and marker-derived gene networks for growth and meat quality traits of Brazilian Nelore beef cattle

Abstract\ud \ud Background\ud Nelore is the major beef cattle breed in Brazil with more than 130 million heads. Genome-wide association studies (GWAS) are often used to associate markers and genomic regions to growth and meat quality traits that can be used to assist selection programs. An alternative methodology to traditional GWAS that involves the construction of gene network interactions, derived from results of several GWAS is the AWM (Association Weight Matrices)/PCIT (Partial Correlation and Information Theory). With the aim of evaluating the genetic architecture of Brazilian Nelore cattle, we used high-density SNP genotyping data (~770,000 SNP) from 780 Nelore animals comprising 34 half-sibling families derived from highly disseminated and unrelated sires from across Brazil. The AWM/PCIT methodology was employed to evaluate the genes that participate in a series of eight phenotypes related to growth and meat quality obtained from this Nelore sample.\ud \ud \ud Results\ud Our results indicate a lack of structuring between the individuals studied since principal component analyses were not able to differentiate families by its sires or by its ancestral lineages. The application of the AWM/PCIT methodology revealed a trio of transcription factors (comprising VDR, LHX9 and ZEB1) which in combination connected 66 genes through 359 edges and whose biological functions were inspected, some revealing to participate in biological growth processes in literature searches.\ud \ud \ud Conclusions\ud The diversity of the Nelore sample studied is not high enough to differentiate among families neither by sires nor by using the available ancestral lineage information. The gene networks constructed from the AWM/PCIT methodology were a useful alternative in characterizing genes and gene networks that were allegedly influential in growth and meat quality traits in Nelore cattle.This study was conducted with funding from EMBRAPA (Macroprograma1,\ud 01/2005) and FAPESP (process number 2012/23638-8). GBM, LLC, LCAR and\ud MMA were granted CNPq fellowships. We thank Sean McWilliam, Marina R. S.\ud Fortes, Edilson Guimaraes, Robson Rodrigues Santiago, Roselito F. da Silva,\ud Fernando F. Cardoso, Flavia Aline Bressani, Wilson Malago Jr., Avelardo U. C.\ud Ferreira, Michel E. B. Yamaguishi and Fabio D. Vieira for the help and\ud technical assistance. The authors would like to acknowledge the\ud collaborative efforts among EMBRAPA, University of Sao Paulo and CSIRO

Cattle reproductive performance in the Paiaguas subregion of the Brazilian Pantanal. 4. Effect of calf weaning age on breeding cows

Efeitos da idade de desmama sobre o desempenho reprodutivo de vacas de cria foram estudados de 1979 a 1984 no Pantanal Mato-Grossense. Em delineamento inteiramente casualizado, 300 vacas foram distribuídas num fatorial 3 x 3. Os tratamentos foram três idades de desmama (6, 8 a 10 meses) com três suplementos minerais. As vacas foram inicialmente sorteadas para a suplementação mineral e posteriormente, ao parto, para a idade de desmama. Cada grupo consistia de 100 vacas e 10 touros e era rotacionado mensalmente em três invernadas de pastagem nativa. Aplicou-se a análise de regressão múltipla "stepwise", relacionando-se o intervalo entre partos (IP) à desmama, suplementação mineral (SM), ano do parto, peso à fecundação, mês do parto (linear a quadrático) e peso à desmama. O IP médio foi, de 599 ± 120 dias. Com exceção da SM, todas as variáveis influenciaram (P < 0,01) o IP. As taxas de natalidade foram de 62%, 61% a 55% nas desmamas aos 6, 8 e 10 meses, respectivamente.Effects of weaning age on reproductive performance of breeding cows were studied from 1979 to 1984 in the Brazilian Pantanal. Three hundred cows were randomly assigned to a 3 x 3 factorial. Treatments were three calf weaning ages (6,8 and 10 months) and three mineral supplements. Cows were first assigned to mineral supplementation, then, at calving, animals within each group were randomized to calf weaning age. Each group comprised 100 cows and 10 bulls. Groups were kept in three native pasture areas where groups were rotated monthly. Data were analyzed by Stepwise Multiple Regression. Calving interval was regressed on weaning age, mineral supplement, year of parturition, weight at conception, linear and quadratic effect of month of parturition and cow weight at weaning. Average calving interval was 599 t 120 days. All variables influenced (P < 0,01) calving interval, except mineral supplement. Calving rates were 62%, 61% and 55%, for weaning at 6, 8 and 10 months, respectively