Consequences of elimination of the Rendement Napole allele from Danish Hampshire

An elimination programme was carried out to remove the dominant Rendement Napole mutation (RN(-) ) from Danish Hampshire pigs. We reasoned that during and after the elimination of the RN(-) allele, genetic gain of production traits decreased while rate of inbreeding in the population increased compared to the period prior to elimination. The hypothesis was tested by estimating the genetic gain in seven production traits and measuring the rate of inbreeding in the population prior to and during the elimination period. Genetic gain was reduced for quantitative traits daily gain(30-100 kg) and feed conversion ratio, while gain for ultimate-pH, lean meat percentage and slaughter loss were increased slightly. There were no changes in genetic gain for daily gain(birth-30 kg) and conformation. RN polymorphism affected several of the quantitative traits. The RN(-) mutation had a dominant effect on the traits daily gain(birth-30 kg) , daily gain(30-100 kg) , slaughter loss, lean meat percentage and ultimate-pH. It exhibited overdominance for feed conversion ratio and additive effect for conformation. Rate of inbreeding decreased during the elimination of RN(-) . Our findings indicate that the consequences of the elimination programme were not as serious as were feared and that a carefully designed preselection strategy may avoid unacceptable loss of genetic gain and excessive loss of genetic variation.     

Matrilinear hierarchy in the American black bear (Ursus americanus)

The American black bear (Ursus americanus) was long thought to be solitary and its social organization has not been well described. Here, we present new data on black bear social structure. The objectives of the study were to make detailed observations of the behavior of wild black bears to determine their social interactions and structure. We tested whether black bears interacted socially beyond mating and competing for resources, if black bears tracked relationships and interacted regularly even when resources were not limited, and whether the social structure of a population of black bears was based on a matrilinear hierarchy. We collected data by direct observation of bears from 1993 to 2014. Observations of 1210 social interactions at a provisioning site indicated that females compete and form matrilinear hierarchies. Dominant bears established a hierarchy for food, control of space, and control of younger bears. Post interaction scent marking took place, which suggested that dominant females were conditioning subordinates to their scent marks. Affiliative behavior occurred between related and unrelated bears and helped to establish the social structure of the bear community. Based on our data, human–bear conflicts can be reduced by behavioral modifications by humans when they encounter bears. Knowledge of bear behavior and the matrilinear hierarchy provide a basis for non-lethal management of bears that find themselves in a bear–human conflict situation.     

汉普夏血液含量对汉金杂种青年母猪生殖器官及排卵数的影响研究

汉金杂种猪１１头和纯金华猪３头按外血含量（６２．６％、３７．５％和０％）分为３ 组,对其生殖器官及排卵数进行了最小二乘协方差分析。结果表明外血含量３７．５％和６２．５％的母猪子宫体、子宫颈、阴道和前庭总重量大于金２华猪（Ｐ＝０．０７８）。外血含量为６２．５％的母猪排卵数少于金华猪（Ｐ＝０．０５８）。本研究表明汉普夏血液含量过高的青年母猪繁殖性能较差。