Effect of various sources and levels of iodine, as well as the kind of diet, on the performance of young laying hens, iodine accumulation in eggs, egg characteristics, and morphotic and biochemical indices in blood.

Young hens were fed over a period of 150 d with 2 kinds of diets including corn and soybean meal or corn, soybean, and rapeseed meal. Diets were enriched with potassium iodide (KI) or potassium iodate (KIO3) as an I source in amounts equal to 1, 3, or 5 mg of supplemented I/kg of feed. The hen performance, egg quality, hematological and morphotic indices in blood, hepatic enzyme activity, lipid indices in blood serum as well as I accumulation in wet egg content were determined. Introduction of 00-variety rapeseed meal into the diet improved the laying rate and feed conversion (P < 0.05); however, better egg weight was noted by feeding the hens with a diet without rapeseed meal. Use of KI as an I source enhanced the egg weight. The increased I level in the diet had an equivocal influence on egg weight, improved the feed conversion per 1 kg of eggs, and decreased the proportion of damaged eggs. The use of corn, soybean, and rapeseed meal in hen diets significantly improved yolk color; similar results were noted after an increase in I levels in the diets after 3 mo of feeding. Hematological indices of hen blood demonstrated significantly higher red blood cells numbers and hemoglobin concentrations with the use of KI. The use of a diet containing rapeseed meal led to an enhancement of hepatic enzyme activity, especially of alkaline phosphatase (P = 0.007). Lipid metabolism indices were not influenced by the kind of diet or the I source or level. The accumulation of I in wet egg content was negatively influenced by the use of a diet containing rapeseed meal (P = 0.000). The application of KI as an I source enhanced (P = 0.003) the accretion of I in eggs after 5 mo of treatment. Enhanced I supply significantly increased accumulation of I in eggs (P = 0.000) after 3 and 5 mo of the experiment from 260 and 310 to 1,011 and 1,256 µg/kg of wet egg content, respectively.

The effect of MgSO4 addition and the increasing doses of calcium and phosphorus during ending drying period on the occurrence of hypocalcaemia and hypophosphataemia in dairy cows.

The aim of the presented study was the estimation of optimal Ca and P levels applied before calving together with anionic salt addition, as an element of hypocalcaemia and hypophosphataemia prevention. The experiment was carried out during the dry period on 48 cows with similar milk yield in the previous lactation. Cows were divided into four groups. In group I (control) the amount of minerals was in accordance to NRC standards. In experimental groups (groups II-IV), two weeks before calving, cows received 140 g/day/head of hydrated magnesium sulphate to achieve dietary cation-anion difference at the level of about 50 mEq/kg DM. In groups II and III cows received calcium carbonate (100 g/day) 10 days a.p. (antepartum) (group II), or 5 days a.p. (group III), while cows in IV group received dicalcium phosphate (100 g/day) for 5 days a.p. Application of MgSO4 x 7H20 significantly affected the urine pH of cows from group III and IV 4-5 d. before calving - 6.45 and 6.81, respectively. The acidification of urine was observed after calving in group IV (7.13). In cows from group II (100 CaCO3 10 days a.p.) urine pH decline was not found (7.97-7.75). In that group the incidences of hypophosphatemia were noted (blood serum inorganic P level 1.41-1.46 mmol/1). Addition of magnesium sulphate prevented hypocalcaemia occurrence -- 4-5 d. before calving the concentration of ionized Ca in blood serum was 1.11, 1.13 and 1.16 mmol/1 (respectively for group II, III and IV). Reproductive functions were significantly improved after the application of CaCO3 and CaHPO4 for 5 days a.p. in comparison with control and group II -- progesterone concentration in the blood serum on the 45th day of lactation was 1.396 - 1.409 versus 0.799 - 0.401. The correlation between progesterone and inorganic P level in serum was almost significant. Based on the obtained results a treatment optimal in prevention of hypocalcaemia and hypophosphataemia is the application of 50 g CaCO3 and 50 g of CaHPO4 for the last 5 days of the dry period together with MgSO4 x 7H20 given for 14 days a.p.

Chemical composition and biological value of spray dried porcine blood by-products and bone protein hydrolysate for young chickens.

The chemical composition of spray dried porcine blood by-products is characterised by wide variation in crude protein contents. In spray dried porcine blood plasma (SDBP) it varied between 670-780 g/kg, in spray dried blood cells (SDBC) between 830-930 g/kg, and in bone protein hydrolysate (BPH) in a range of 740-780 g/kg. Compared with fish meal, these feeds are poor in Met and Lys. Moreover, in BPH deep deficits of Met, Cys, Thr and other amino acids were found. The experiment comprised 7 dietary treatments: SDBP, SDBC, and BPH, each at an inclusion rate of 20 or 40 g/kg diet, plus a control. The addition of 20 or 40 g/kg of the analysed meals into feeds for very young chickens (1-28 d post hatch) significantly decreased the body weight (BW) of birds. Only the treatments with 40 g/kg of SDBP and SDBC showed no significant difference in BW as compared with the control. There were no significant differences between treatments and type of meal for feed intake, haematocrit and haemoglobin concentrations in blood. Addition of bone protein and blood cell meals to feed decreased the IgG concentration in blood and caused shortening of the femur and tibia bones. However, changes in the mineral composition of bones were not significantly affected by the type of meal used. The blood by-products, which are rich in microelements, improved retention of Ca and Cu only. In comparison to control chickens, significantly better accretion of these minerals was found in treatments containing 20 g/kg of SDBP or 40 g/kg of SDBC. Great variability in apparent ileal amino acid digestibility in chickens was determined. In this respect, some significant differences related to the type of meal fed were confirmed for Asp, Pro, Val, Tyr and His. In general, the apparent ileal digestibility of amino acids was about 2-3 percentage units better in chickens fed on diets containing the animal by products than in control birds.

The influence of administration of biotin and zinc chelate (Zn-methionine) to cows in the first and second trimester of lactation on their health and productivity.

In cattle, the prevention of diseases might be possible using dietary methods, with nutritional optimization of feed rations. For years significant influence has been associated with the addition of biotin, methionine and zinc (each given individually, or as chelate - Zn-methionine). The aim of this study was to evaluate the influence of biotin or biotin + Zn-methionine additives on the health and performance of cows, in the first and second trimester of lactation. This study was carried out in 3 groups of cows, 30 animals in each group. In the first group cows were fed the usual fodder used on the farm. In the second group biotin at 10 mg/day/cow was added. In the third group both biotin at 10 mg/day/cow and Zn-methionine at 5 g/day/cow were added. The administration of biotin increased the milk yield and reduced the occurrence of retained placenta, as well as endometritis puerperalis. However, the high doses of biotin suppressed ovulation and oestrus symptoms in the investigated cows (low progesterone levels on days 15, 21 and 45 after calving). Zn-methionine in comparison to biotin had a lower effect on the milk yield in the cows. Moreover, its supplementation improved the milk content, as well as some of the blood parameters; it also decreased the number of somatic cells in milk. The concurrent administration of biotin and zinc-methionine seemed to be a good method for the prophylaxis of subacute mastitis and for the improvement of the high yielding dairy cows' productivity.