Genetic correlations between mature cow weight and productive and reproductive traits in Nellore cattle

We investigated genetic associations between mature cow weight (MW) and weaning weight (WW), yearling weight (YW), weight gain from birth to weaning (GBW), weight gain from weaning to yearling (GWY), weaning hip height (WHH), yearling hip height (YHH), scrotal circumference (SC), and age at first calving (AFC). Data from 127,104 Nellore animals born between 1993 and 2006, belonging to Agropecuária Jacarezinho Ltda., were analyzed. (Co)variance components were obtained by the restricted maximum likelihood method, applying an animal model in a multi-traits analysis. The model included direct genetic and residual effects as random effects, the fixed effects of contemporary group, and the linear and quadratic effects of animal age at recording (except for AFC, GBW, and GWY) and age of cow at calving as covariates (except for MW). The numbers of days from birth to weaning and from weaning to yearling were included as covariates for GBW and GWY, respectively. Estimated direct heritabilities were 0.43 ± 0.02 (MW), 0.33 ± 0.01 (WW), 0.36 ± 0.01 (YW), 0.28 ± 0.02 (GBW), 0.31 ± 0.01 (GWY), 0.44 ± 0.02 (WHH), 0.48 ± 0.02 (YHH), 0.44 ± 0.01 (SC), and 0.16 ± 0.03 (AFC). Genetic correlations between MW and productive traits were positive and of medium to high magnitude (ranging from 0.47 ± 0.03 to 0.71 ± 0.01). A positive and low genetic correlation was observed between MW and SC (0.24 ± 0.04). A negative genetic correlation (-0.19 ± 0.03) was estimated between MW and AFC. Selection to increase weight or weight gains at any age, as well as hip height, will change MW in the same direction. Selection for higher SC may lead to a long-term increase in MW. The AFC can be included in selection indices to improve the reproductive performance of beef cattle without significant changes in MW.     

Genetic parameters estimation for preweaning traits and their relationship with reproductive,productive and morphological traits in alpaca

The aim of this study was to estimate the genetic parameters for preweaning traits and their relationship with reproductive, productive and morphological traits in alpacas. The data were collected from 2001 to 2015 in the Pacomarca experimental farm. The data set contained data from 4330 females and 3788 males corresponding to 6396 and 1722 animals for Huacaya and Suri variants, respectively. The number of records for Huacaya and Suri variants were 5494 and 1461 for birth weight (BW), 5429 and 1431 for birth withers height (BH), 3320 and 896 for both weaning weight (WW) and average daily gain (DG) from birth to weaning, 3317 and 896 for weaning withers height (WH), and 5514 and 1474 for survival to weaning. The reproductive traits analyzed were age at first calving and calving interval. The fiber traits were fiber diameter (FD), standard deviation of FD (SD), comfort factor and coefficient of variation of FD and the morphological traits studied were density, crimp in Huacaya and lock structure in Suri, head, coverage and balance. Regarding preweaning traits, model of analysis included additive, maternal and residual random effects for all traits, with sex, coat color, number of calving, month–year and contemporary group as systematic effects, and age at weaning as linear covariate for WW and WH. The most relevant direct heritabilities for Huacaya and Suri were 0.50 and 0.34 for WW, 0.36 and 0.66 for WH, 0.45 and 0.20 for DG, respectively. Maternal heritabilities were 0.25 and 0.38 for BW, 0.18 and 0.32 for BH, 0.29 and 0.39 for WW, 0.19 and 0.26 for WH, 0.27 and 0.36 for DG, respectively. Direct genetic correlations within preweaning traits were high and favorable and lower between direct and maternal genetic effects. The genetic correlations of preweaning traits with fiber traits were moderate and unfavorable. With morphological traits they were high and positive for Suri but not for Huacaya and favorable for direct genetic effect but unfavorable for maternal genetic effect with reproductive traits. If the selection objective was meat production, the selection would have to be based on the direct genetic effect for WW but not on the maternal genetic effect that has been shown to have less relevance. Other weaning traits such as WH or DG would be indirectly selected.     

Electrophoretic assay of protein fractions,non-specific esterase fractions and acid phosphatase fractions in extracts from leaves and apple blossoms

Electrophoreograms of protein extracts from leaves of the variety Lord Lambourne, detached at the flowering period toward the end of April, differed quantitatively from electrophoreograms of protein extracts from leaves detached from shoots at the end of May and June. Electrophoreograms of protein extracts of leaves from juvenile seedlings, detached at the end of May and June, did not differ from electrophoreograms of protein extracts of leaves from shoots of the variety Lord Lambourne detached at the same period. Electrophoretic pattern of protein fractions and the fractions of non-specific esterase from leaves differed from the corresponding electrophoretic pattern of flowers quantitatively and in some areas even qualitatively; the pattern of acid phosphatase differed quantitatively. The results obtained are discussed in relation to organogenesis.     

Listeria antigens and their isolated protein fractions

Antigens have been obtained from standard Listeria strains 1 and 4a by alcohol precipitation, sonication and multiple freezing and thawing. From these antigens protein fractions, immunologically identical as shown by the precipitation test and immunoelectrophoresis and similar in their chemical composition, have been isolated. The immunogenic properties of the fractions are determined by the polysaccharide-protein complex represented by amino acids (proline, histidine, lysine) and monosaccharides (ribose, glucose, arabinose), common for the fractions of three antigens. In experimental studies on mice and rabbits the protein fraction has been shown to produce a protective effect. After receiving this fraction in three injections and the subsequent challenge with the suspension of Listeria culture in a dose of 500 million cells, the animals have been found to develop no Listeria infection. After autoclaving the protein fraction looses its immunogenic properties, but retains the specificity of chemical groups and produces an allergenic effect as shown in experiments on guinea pigs and rabbits.     

胡杨异形叶结构型性状及其相互关系

胡杨在个体生长发育过程中,叶形不断发生变化,植株上会逐年依次出现条形、披针形、卵形和阔卵形叶,且在同时具有这4种叶形的植株上,叶片在树冠中分布的顺序自上而下分别是阔卵形、卵形、披针形和条形。通过实验的方法对胡杨4种叶形叶片厚度、叶面积、比叶面积、叶片干重和干物质含量等5个结构型性状指标进行分析,研究不同叶形叶片的结构型性状与叶形(叶长/宽比值)之间的关系,以及各结构型性状指标间的相互关系。结果表明:叶片厚度、叶片干物质含量、叶面积和叶片干重与叶长/宽比值之间均呈明显负相关(P0.05);比叶面积随着叶长/宽比值的减小而逐渐减小,但二者相关性不明显,表明胡杨在个体发育过程中通过增加叶面积、叶厚度,减小比叶面积等方式来提高适应环境的能力。各结构型性状指标间相关性表现为:比叶面积与叶干物质含量和叶干重之间均呈明显负相关(P0.05),与叶厚度间呈极明显负相关(P0.01);叶片干重与叶厚度间呈明显正相关(P0.05);叶厚度与叶干物质含量之间、叶干重与叶面积之间均呈极明显正相关(P0.01),其它指标间无明显相关性。