2002 * XIII * 6

I. Kübarsepp, O. Kärt, M. Henno.  
  Effect of dietary potassium and urea on milk mineral composition 325
Effect of dietary potassium and urea on milk mineral composition. The objective of the experiment was to study the influence of dietary cation-anion balance (DCAB) and urea as a source of rapidly degradable protein on secretion of milk minerals. In a 3×3 Latin square experiment with three mid-lactation Holstein cows, basal rations (0.71% K and 15.7% crude protein in DM) were supplemented with potassium carbonate and urea to the extent of 1.67% K (excess potassium) and 16.9% crude protein in DM (feeding urea). The experiment periods were 8 days in duration. Milk samples were collected on last two days of each experiment period. Dry matter intake was 16.4, 13.3 and 17.2 kg for the cows fed the basal ration (BR) and rations supplemented with potassium carbonate (K2CO3) and urea (urea), respectively. Feeding rations with markedly positive DCAB (~555 mekv/kg) depressed DM intake 18.6%. Adding urea to basal rations had no significant effect on DM intake. Milk yield was lower (P<0.01) for cows fed the rations with excess potassium, compared to the basal ration and ration with added urea. Adding potassium to basal rations decreased the calcium and especially magnesium content (−7.4 and −31.8%, respectively) of milk but increased milk potassium content. Magnesium and fat content in milk decreased and urea content increased significantly in the result of supplementing basal rations with urea.

Keywords: lactating cows, milk minerals, excess potassium, feeding urea, DM intake.

R. Leming, A. Lember.  
  Nutrient digestibility of barley-based diets supplemented with heat-treated rapeseed cake for growing pigs 331
Nutrient digestibility of barley-based diets supplemented with heat-treated rapeseed cake for growing pigs. The aim of the study was to investigate nutrient digestibility of barley-based diets supplemented with heat-treated rapeseed cake fed to growing pigs. The trial was carried out on five castrated male pigs according to 5×5 Latin Square design. Pigs had an average live weight of 46 kg at the start and 89 kg at the end of the experiment. Five experimental diets contained 76.5% of barley, 20% of commercial rapeseed cake produced at different temperatures (60 °C, 98/108 °C, 100/109 °C, 110/110 °C and 113/112 °C), 3% of minerals and vitamins and 0.5% of marker – chromium oxide (Cr2O3). Expeller-extracted rapeseed cake (EERC) was produced in AS Werol Tehased and cold-pressed rapeseed cake (CPRC) in a small farm factory. Compared to EERC, cold-pressed rapeseed cake contained more crude fat (EE) (19.4 vs. 10.3–11.1%), more metabolizable energy (15.8 vs. 14.7–14.8 MJ/kg) and less crude protein (CP) (30.6 vs. 36.8–37.6%) on dry matter basis. Digestibility of CP was highest (72%) in the diet where EERC had the highest (113/112 °C) processing temperature, while the lowest digestibility of CP (68%) was found in the diet where CPRC was used. Digestibility of EE was highest in the diets where CPRC and in the diet where EERC with the highest processing temperature was used (64 and 57%, respectively). Digestibility of dry matter, organic matter, N-free extract, crude fibre and gross energy was not significantly different across the diets.

Keywords: rapeseed cake, nutrient digestibility, heat-treatment, cold-pressed, pigs.

P. Lättemäe, U. Tamm.  
  The improvement of lucerne silage quality by using additives and lucerne-grass mixtures 337
The improvement of lucerne silage quality by using additives and lucerne-grass mixtures. Legumes, like lucerne are known to be difficult to ensile because they are highly buffering, have low sugars concentration, and often a low dry matter concentration. The previous results have shown that fermentation quality can easily be improved by using additives. When legume-grass mixtures are used, then theoretically the fermentation properties of silage material are improved. Different legume species differ in their ensiling proper-ties and also may affect fermentation. There are few data available about the ensiling different lucerne species and their mixtures.

In this ensiling study was used an American lucerne ‘WL 252 HQ’ and a local sort ‘Jõgeva 118’ as pure species or their mixtures with timothy grass. The grass sward was fertilised with P15 K50 fertilisers or not fertilised. The following additive treatments were used: untreated (negative control), Niben treated 5 l/t fresh matter (FM), AIV-2000 treated 5 l/t FM.

The nutritive value of silage depended on the sort of lucerne and the mixture. American lucerne ‘WL 252 HQ’ resulted in higher protein concentration of herbage and total dry matter yield. The lucerne-grass mixture was superior because of the yields were higher. The silage quality was dependent on the use of additive, the sort of lucerne and the mixture. The both additives were similarly effective. There were interaction effects when using additives, different lucerne sorts and their mixtures. These factors need further investigations.

Keywords: lucerne, lucerne-grass mixture, legumes, silage, fermentation, silage quality, additive.

L. Nigul.  
  Investigations on the nutrial value of Triticale and barley in the diets for pigs 343
Investigations on the nutritional value of Triticale and barley in the diets for pigs. The chemical composition of Triticale and barley produced in Estonia was determined and used in the experiments with pigs. Average content of crude protein in Triticale samples (n=4) was 10.95% and 11.03% in the barley. The content of crude fibre was 2.30% and 5.30%, respectively. In the first experiment fattening performance was improved when barley was replaced partly or fully with Triticale in the diet. Increased level of Triticale in the diet for finishers proportionally decreased the fattening performance, however, did not affect the carcass quality. In the second experiment, where 50% of the barley in the diet was replaced with Triticale, fattening performance of weaners was affected significantly. The performance was even more worsened when barley was totally replaced with Triticale. Feeding weaners with the diet containing 15% of Triticale had similar performance data compared to barley-based diet. In the third experiment the diet containing 20% of Triticale worsened fattening performance of weaners compared to barley-based diet.

Keywords: Triticale, barley, weaners, growers, finishers, carcass quality.

T. Paaver, S. Kuusik, R. Gross, E. Mõttus, T. Tohvert.  
  Fatty acid composition of common carp flesh in Estonian fish farms 350
Fatty acid composition of common carp flesh in Estonian fish farms. Fatty acid composition of carp fillet from three Estonian fish farms was determined in three subsequent years. Significant differences were found between years and fish farms. In 1999 the content of omega3 acids was lower than in all fish farms in 1998. Carps reared at high density and fed intensively with grain had high content of lipids but these fish had lower proportion of PUFA and omega3 fatty acids in their fat. The proportion of PUFA and omega3 acids in the fats of fish from farm III, producing the most fatty fish was low (10 and 2.7%, respectively) compared to the fish reared on natural food (23% and 12%) in fish farm I. No differences were found between the fish given wheat as supplementary feed and fish kept on natural food in a test pond of fish farm I. This indicates the low proportion of grain in the food ration of carp in this fish farm. The main factor influencing the percentage of PUFA in carp flesh is the highly variable (38–53% in different fish farms and years) content of oleic acid.

Keywords: common carp, fatty acids.

E. Pärna, O. Saveli.  
  Genetic improvement of production and functional traits in Estonian holstein population 358
For the derivation of economic weights, a bioeconomical model of a closed herd which included the whole integrated production system of dairy breed was used. The total discounted profit for herd was calculated as the difference between all revenues and costs that occurred during the whole life of animals born in the herd in one year and that was discounted to the birth year of these animals. Revenues and costs connected with one generation of progeny of selected parents were discounted with a discounting rate 10% to the birth date of the progeny. Economic weights of milk yield, fat and protein content, daily gain, dressing percentage, feed conversion and net daily gain in bulls, calving interval, age at first breeding, interval between the first and last breeding of heifers and cow longevity were estimated under assumed quota on the milk production with given fat and protein content and non quota conditions for the Estonian Holstein. Milk quota had not any influence on the economic weights for beef performance traits, on feed conversion in bulls and on daily gain on fattening bulls, but influenced economic weight of milk yield and cow longevity. There were only minor differences in economic values of functional traits. In all cases discounted economic weights were lower than economic weights calculated without discounting. The standardised economic weights of the most considered traits made 3–8% of the economic weight for milk yield. Only feed conversion of bulls amounted up to 48% and cow longevity 22% of the economic value of milk yield. It was discounting that had a relevant impact on the economic weight of cow longevity. Selection gain in the first lactation was influenced neither by quota nor by discounting, but discounted total profit per closed herd decreased by 59%.Defining the breeding objective, milk production, content of milk components, interval between the first and last successful breeding of heifers, cow longevity and feed conversion rate of bulls should be included as the traits with the most higher economic value. Those traits should be included also to the selection index.
M. Raudseping, I. Bender.  
  The new tomato varieties 'Valve' and 'Mai' 364
The new tomato varieties ‘Valve’ and ‘Mai’. At the Jõgeva Plant Breeding Institute have been developed two new early-ripening, high yielding, disease resistant and with good flavour tomato varieties ‘Valve’ and ‘Mai’. These varieties are suitable for growing in unheated glass and plastic greenhouses.

Breeding of tomatoes was started in 1945 at the Jõgeva PBI. The varieties suitable for growing in outdoor conditions was the objective of the first period. The next period started in 1968 with breeding of the varieties suitable for growing mainly for unheated and plastic greenhouses.

A lot of varieties from many countries have been studied in various collection trials during the years.

The best varieties, perspective breeds and hybrids have been used in breeding of new varieties. The breeding method has been crossing and continual selection of breeding material.

The variety ‘Valve’ (N 1621) was selected from cross between the hybrid variety’Verlioka’F1 (Russia) and local breed N 941. Crossing was made in 1990. Mother of the local breed N 941 was local variety ‘Koit’. Breeding of variety ‘Koit’ was started in 1946. It was taken to the Official Variety List in 1968. Variety ‘Valve’ is semideterminate, with generative growth which ends after 6. or 7. fruit cluster. Plant is medium sized. Foliation is semierect. Leaf is rather broad with medium length, intensity of green colour is medium. Inflorescence is uniparous or multiparous. Fruit is medium sized, average weight of 90–95 g. Shape of fruit is variable, from rounded up to oblong. Ripening fruit is light green. Ripe fruit is red. The variety `Valve’ is early-ripening, with high yielding, resistance to leaf mold (Fulvia fulva (Cke) Cifferi) and resistance to cracking of fruits.

The variety ‘Mai’ (N 1653) was selected from the cross of the local breed (N 1581) and local hybrid (N 1638) F1. Crossing was made in 1993. The variety ‘Mai’ is determinate and with generative growth. Pose of leaf is horizontal. Leaf is short with medium width. Plant is with slow regeneration of side shoots. Inflorescence is multiparous. Fruit is round and small, average weight of 60–65 g. Dominate number of locules is 2. Ripening fruit is light green. Ripe fruit is red. The variety ‘Mai’ is early-ripening, disease resistance and resistant to cracking of fruits.

Keywords: breeding, continual selection, crossing, hybrid, local breed, variety.

V. Rosenberg, P. Talvoja.  
  On the nature of the alternations (spindle-, pear-, etc. shaped) in potato tubers and the viroid-infection 369
On the nature of the alternations (spindle-, pear-, etc. shaped) in potato tubers and the viroid-infection. The spindle-shaped potato tubers have previously been spread in the southern regions. In the plants of the Research Centre EVIKA, the Potato Spindle Tuber Viroid (PSTV) has been determined in Denmark in one of the variety ‘Vigri’ meristem clone. Later on, the PSTV-infection was determined in Estonia, in one of the variety ‘Kondor’ meristem clone.
In Estonia, the tubers with the disease symptoms have been ascertained in the variety ‘Ando’. The meristem clone of the variety ‘Ando’ with the supposed PSTV-infection was susceptible to the late blight, which caused the yield decrease up to 4–5 times. The yield, from the tubers with the disease symptoms, revealed 41.8–47.8% of the tubers with the same disease symptoms. The rest were assessed as externally healthy. In studying the disease, it is necessary to apply the methods of PSTV diagnosis and to avoid the planting of the tubers with the disease symptoms.

Our objective was to study the external symptoms of the damaged plants and tubers and to determine the presence of the PSTV.

Keywords: potato spindle tuber viroid, spread, harmful, disfigured tubers, late blight, yield.

  This year's fifth issue of the Journal of Agricultural Science had misleading mistake. M. Järvan et. al article "Effect of liquid nitrogen fertilizer and rare earths on spring wheat" completed the target-financed research topic number 0110193s98 context.