Branislav Zivkovic

Heritability, phenotypic and genetic correlations of the growth intensity and meat yield of pigs.

The five year study included two genotypes of gilts of performance tested gilts, Swedish landrace and crosses F1 generation SLxLY. Of total number (n=3600), 1709 animals were genotype SL and 1891 animals were genotype SLxLY. Measuring of back fat thickness in the loin part (FT1), between 3rd and 4th lumbar vertebrae, 7cm laterally to the back line; back fat thickness (FT2) and depth of the musculus longissimus dorsi (MLD) between the 3rd and 4th rib from the rear, 7cm laterally to the back line. Assessment of meat yield was done using the ultrasonograph apparatus Piglog 105. In regard to meat yield indicators, medium heritability values were established for FT1 h 2 =0.461, and high values for FT2 h 2 =0.639, and for meat yield h 2 =0.633. Low heritability was established for depth of MLD (h 2 =0.105), life daily gain (h 2 =0.110) and age at the end of test (h 2 =0.103). Established phenotypic correlations between fat thickness FT1 and FT2 were strong (rp=0.638); between fat thickness and meat yield very strong (rp=-0.880 to -0.895), and between fat thickness and MLD very weak and negative (rg=-0.103 to -0.216). Genetic correlations were stronger than phenotypic, so between fat thickness FT1 and FT2 the correlation was complete/full (rg=0.930), also between fat thickness and meat yield (rg=-0.979 to -0.982), whereas the correlation between fat thickness and MLD was strong and negative (rg=-0.627 to -0.653). Heritability values for fat thickness and meat yield show that these traits have high level of heritability and are transfered to the progeny, whereas the level and strength of their dependance show that by decreasing the fat thickness positive influences is exhibited on meat yield, and that by increasing of depth of MLD also the meat yield is increased.

The effects of different pre-mixtures in nutrition of sows and piglets

In the last ten years we have been witnesses to import of numerous premixes produced by various producers and of different quality in regard to concentration of ingredients which are their main components. There is relatively few data on the effects of their nutritive value in pigs, so this research was carried out with objective to verify the effects of several different imported premixes and those produced according to domestic concept, in nutrition of sows, suckling piglets and weaned piglets. Research was performed on private farm in the vicinity of Sabac in Serbia. Obtained results showed that there was no significant difference in losses of body masses and food consumption in sows during lactation period. Nutrition of suckling piglets using mixture which contained adequate premix of domestic production improved the growth rate by 7.6%. Cost of food when domestic premixes were used in nutrition of sows and piglets was by 5.3% lower, and value of realized piglets by approx. 26.0% more favourable when domestic premixes were used in nutrition of sows and suckling piglets. Piglets in rearing were fed mixtures containing imported premixes showed no significantly important effect on gain, but had poorer feed conversion by 6.2% compared to animals fed diets containing domestic premix. Domestic premix in mixtures reduced the cost of mixtures by 3.4% and reduced the cost of gain of piglets in rearing by 9.9% compared to nutrition with diets containing imported premixes. In general, obtained results shoed that use of both types of compared premixes can be recommended, but it is more economically efficient to use domestic premixes in nutrition of sows and piglets.

Probiotic Beta Plus in nutrition of sows and piglets

Effects of the use of probiotic Beta Plus in nutrition of gestating and lactating sows, suckling piglets, weaned piglets were investigated. Obtained results showed that: introduction of Beta Plus in concentrations of 0.1% in diets had an effect which was characterized by: - smaller losses of body mass of sows during lactation period, by 21.8%, - shorter service period of sows, by 2.95 days, - more weaned piglets, 0.20 piglets/litter, and - better gain, by 6.69%, and more favorable feed conversion ratio, by 0.9% in weaning piglets Generally we recommend the use of probiotic Beta Plus in nutrition of sows, suckling piglets and weaned piglets.

PREBIOTICS IN NUTRITION OF SOWS AND PIGLETS

The effects of prebiotic Bio Mos (0.2%) used in nutrition of gestating and sows in lactation, as well as Bio Mos (0.5%) and fructo- oligosaccharides (0.4%) used in nutrition of suckling piglets were investigated. Obtained results showed that the introduction of additives in mixtures influenced: greater food intake of sows in lactation by 13.75 %, by 14.7% more born piglets and by 3.6% heavier piglets at birth, greater litter weight by 3.1 % at weaning and better intake of pre-starter by 6.7% per litter during lactation. In general, obtained results showed that the use of investigated prebiotic Bio Mos and fructo- oligosaccharides are recommended for use in nutrition of sows and suckling piglets.

Effect of genotype and order of farrowing on variation of fertility traits in pigs

Investigations were carried out in single pig herd. It included 9 genotypes of sows (4 breeds and 5 groups of crosses of different crossing combinations) and 25.040 of their litters. Traits such as size of litter of Swedish Landrace sows (18.511 litters) and crosses of Fl generation (4651 litters) obtained by crossing of Swedish Landrace (SL) sows and boars of Large White breed (LW) were especially investigated. Second part of the investigation related to effect of sire (SL, LW and D) and dam breed (SL and SLxLW) on average demonstration and variability of number of live born piglets in first seven farrowings. Standard mathematical-statistical methods were applied in order to evaluate average demonstration and variability of the trait litter size. Effect of parent genotype and order of farrowing on variability of traits was evaluated using the variance analysis. Testing of differences in average values was carried out using t-test. Results of the variance analysis (table 2) show that sow genotype and order of farrowing had highly significant effect (P< 0,01) on investigated traits. In investigated herd and between investigated sow-genotypes average number of live born piglets (from 8.50 to 10,37), still born piglets (from 0,30 to 0,79) and reared piglets (from 6,75 to 8,44). Only the difference of average values for number of still born piglets between sows SL and SLxLW had no statistical significance. Investigation of the effect of dam and sire breed on average demonstration and variability of number of live born piglets per farrwoings (table 4) indicates that sows of SL breed mated with boars of LW breed produced more liveborn piglets compared to sows of SL breed mated with SL boars in all farrowings (from +0,30 to +0,69 piglets). These sows, from fourth to seventh farrowing farrowed more than 11 live piglets, which means that individual heterosis effect was displayed (3 to 7%). Mating of sow crosses of F1 generation (SLxLW) with boars of Durroc breed caused no increase of number of live born piglets in litter compared to rearing in pure breed (except in 3rd farrowing) or two breed crossing.