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The paper presents experimental results concerning the age importance of the first freshening of the ewes belonging to the Botosani Karakul breed. Some females were mated at an early age (8-9 months old) and others at the normal physiological age (16-18 months old). The influence of early pregnancy and of the one in due time on the production parameters (body weight, body growth and milk production and their evolution, bodily dimensions, lamb pelt features) and reproduction indicators (heat apparition rhythm, their manifestation rate, freshening number in order to the pregnancy be installed, fecundity, prolificacy) was yearly pursued next to 3.5-4 years old. The experimental results point out that the age of the first freshening in the Botosani Karakul sheep (early mating or mating at normal physiological age) does not influence or unsignificantly influences the morpho-production parameters and reproduction indices of the adult animal. But, forwarding the reproduction activity of ewes with an year, a gain of lamb number and of milk production is obtained on the whole productive period of ewes, thus contibuting to streamlining the economic situation of sheep farms specializated for the lamb pelt production.

The paper proposes a simplified formula to estimate the milk production in sheep. The formula is based on using the polynomial of Hermite interpolation of 0 degree. The result constitutes a control value for the milk production parameter. This value is well correlated with the correctly calculated value by a polynomial interpolation of superior degree.

The paper describes some associative aspects of various biochemical-genetic markers with the reproduction activity in ewes of the Botosani Karakul breed. The two most important reproduction parameters (fecundity and prolificacy) were analyzed according to the genotypes or phenotypes of polymorph systems (haemoglobin, transferrin, albumin and blood potassium) of females. The relationship between reproduction data and genetic markers in ewes was quantified both for each genotype (phenotype) and for each mating couple type made up depending on the genotype (phenotype) of the couple partners (homozygous x homozygous, homozygous x heterozygous or heterozygous x heterozygous). All these associative aspects and their results are discussed for each polymorph genetic system. The ewes which are heterozygous at different genetic marker loci are more fertile and more prolific than the ewes which are homozygous at the levels of these loci. The highest conception and lambing rates resulted from the mating couples in which both partners were heterozygous and the least lambs were obtained from the mating couples in which both partners were homozygous; the fertility and prolificacy had intermediate values in heterogeneous mating couples (heterozygotes x homozygotes) but they were nearer to the case in which both mating couple partners were heterozygous. The sheep breeding field can benefit by the contribution of biochemical-genetic markers to optimize the selection criteria with a view to increasing the reproduction capacity of this species.

In the last ten years the milk lambs were very demanded on the west European market, especially at the beginning of December and early spring. In this researches was followed the growing speed evolution on crossbreed Charollais x Merinos de Transilvania lambs, from lambing to weaning (70 days). Mother sheep were well prepared before get trough a normal nutrition, depending on the phase of gestation and adequate sheltering conditions. At lambing, sheep had a very good condition and a normal milk production. Crossbreed lambs had maternal milk on ad libitum and from the age of 10 days got in separated enclosures, quality after-grass and granulated combined feeder with 14% PDI in the first 30 days and 12% between 30- 70 days. After the evaluation of the growing speed it was determined that lambs from single lambing, both sexes (F-female, M-male), realize a growing speed, between lambing to weaning (70 days) superior (370g/day), the ones from twin lambing (F-F couple 286g/day, F-M couple 299g/day, M-M couple 302g/zi). The growing speed is significantly higher (p < 0.01) in 30-70 days period, compared with 10-30 days period, both in lambs from single and twin lambing. On the base of this study, we suggest that for obtaining milk lambs with a higher body weight and quality meat, realization of crossbreed lambs between breeds Charollais and Merinos de Transilvania, is opportune. This should be raised with maternal milk and strong feeder, at least until the age of 70 days.

The associative analysis of the potassium phenotypes with the quantitativeproduction traits in adult sheep of the Botoşani Karakul breed pointed out theproduction superiority of the HK phenotype in rams concerning the both bodyweight and wool production. The ewes with HK phenotype are slightly moreproductive than the LK ewes concerning the wool production. The productionsuperiority of the LK phenotype was found in females for body weight and totalmilk quantity. Statistically, the difference values of the quantitative productionsbetween the two potassium phenotypes are very close to the 5% significancethreshold in the adult rams and insignificant in the adult ewes. The utilization ofthe kalium system in sheep breeding of the Botoşani Karakul breed forquantitative productions must be made with accuracy because the association ofthe LK phenotype with the qualitative features of the lamb pelts and with thehealth status is better than with the HK phenotype.

In the paper it emphasizes the importance of inheritance of colour variation and ofbreeding problems, important traits affecting the price of the production fur traits.It is therefore an attempt to highlight those aspects which can make an impact onthe improvement in Karakul pelt production. From an economic point of view, ithas been shown by various authors that within different colours, the pelt price ispredominantly determined by curl type, pattern score, hair quality score and hairlength traits. Traits such as pelt thickness and hair thickness are also correlated tothe price, though their contributions are minimal. It was furthermore indicated thatthe relative weight for pattern score becomes less important and for hair qualityscore it becomes more important with a decrease in curl development. Propertiessuch as colour intensity become more important in the coloured pelts.