| Well-maternal behavior is the key to the cubs’ survival and adaptation, so the maternal behavior is closely related to the benefits of animal industry. Because of the maternal behavior is affected many factors, it is hard to observe the well-maternal behavior under the scale breeding conditions. Our experiment was to test113sheep,99of them were used to observe the maternal behavior. We used the PCR-SSCP to select the PRLR gene exon10, ER-β gene and DRD2gene, which were the candidate genes for the maternal behavior, observed the relevance between the three polymorphisms of sequences and ewes’maternal behavior. In addition, the experiment used the biological statistic method to study the difference between primiparous and multiparous ewes’maternal behavior, to find the performance rules of Hu sheep’s maternal behavior and develop suitable management measures for its growth and breeding. The results were followed as these:1. Length of labour was longer in primiparous ewes’delivery relative to multiparous ewes’, and the relationship was significantly different for twin litters(0.01<P<0.05), but there were no significantly difference for single and multiple lambs of two groups(P>0.05). Primiparous ewes were more likely to abandon a lamb and steal a lamb(0.0≤P≤0.05).There was no significant difference in behaviors of searching, grooming and trampling lambs between two groups(P>0.05). Nursing behavior and refused to nursing behavior had very significant difference between two groups (P≤0.01). Significant difference was found in7d weight of lambs between two groups (0.01<P≤0.05). Therefore, primiparous ewes were more likely to show negative maternal behavior than multiparous ewes.2. Single nucleotide polymorphisms of the nucleotide sequence of PRLR gene exon10, ER-β gene exon2and DRD2gene exon2were found by using PCR-SSCP technique. Compared with the original sequence, the genotype AA had no change. Sequencing revealed two mutations (337Câ†'T and339Câ†'T) of PRLR gene in the genotype AB in comparison to the genotype AA. The two mutations resulted in an amino acid change of Proâ†'Ser. Sequencing revealed two mutations (284Câ†'T and339Câ†'T) of PRLR gene in the genotype BB, the former mutation resulted in an amino acid change of Proâ†'Leu, and the latter mutation was a silent mutation. One mutation (97Câ†'T) was detected in ER-β gene exon2, and one mutation (85Câ†'T) was found in DRD2gene exon2, but they did not cause any amino acid change.3. The analysis of genetic diversity level within populations indicated that only PRLR gene could be selected for maternal traits (licking, nursing, trampling and refusing to feed lamb behaviors) in the populations. For grooming and nursing behaviors, the results showed that the observations of the three genotypes were decreased gradually. It was seen that there was no significant difference between observations for grooming and trampling behavior of AA and AB genotypes individuals (P>0.05), but it had a extremely significant difference (P≤0.01) and a significant difference (0.01<P≤0.05) compared with BB genotype respectively. Significant differences were found in nursing behavior among AA and AB genotypes individuals (0.01<P≤0.05), but the difference between this two genotypes and BB genotype was very significant (P≤0.01). No obvious difference was found in three genotypes for the behavior of refusing to feed young sheep (P>0.05). As the result showed, the partial sequences of PRLR gene exon10had polymorphisms and there was some correlation between PRLR gene and maternal behaviors. The result of clustering analysis showed that AB and BB genotypes individuals were distributed in two categories. The results suggested that difference of maternal behavior could occur in the same genotypes and the allele A might be an advantageous gene. |
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