Wpływ nawozenia NPK, B, Cu, i ZN na plon zielonki szarłatu (Amaranthus cruentus L.) oraz jej wartość jako paszy dla kur

W doświadczeniu polowym z nawożeniem szarłatu (Amaranthus cruentus L.) dawkami 290 i 435 kg NPK·ha⁻¹ oraz borem (2 lub 4 kg B·ha⁻¹), cynkiem (5 lub 10 kg Zn·ha⁻¹) lub miedzią (5 lub 10 kg Cu·ha⁻¹) uzyskano plony zielonki wynoszące od 7,24 do 11,29 t s.m. z ha. Wzrost dawki NPK z 290 do 435 kg·ha⁻¹ zwiększył plon o 21,5%. Spośród badanych mikroelementów (B, Cu, Zn) największą efektywność plonotwórczą wykazał bor zwiększając plon suszu zielonki średnio o 15,7%. Doświadczenie żywieniowe wykazało, że przydatność paszowa suszu nie była wyraźnie uzależniona od stosowanego nawożenia. Kury tolerują 8% dodatek suszu z liści szarłatu w mieszance paszowej, ale zużywają więcej paszy w przeliczeniu na 1 jajo przy gorszej nieśności i jakości jaj. Ponadto stwierdzono, że jaja pochodzące od tak żywionych ptaków miały słabiej zabarwione żółtka.In field experiment on amaranth (Amaranthus cruentus L.) with 290 and 435 kg·ha⁻¹ NPK fertilization rates and application of boron (2-4 kg·ha⁻¹), copper (5-10 kg·ha⁻¹) or zinc (5-10 kg·ha⁻¹) the yields of green matter ranged from 7.24 to 11.29 t DM per ha. The increase of NPK rate from 290 to 435 kg·ha⁻¹ gave the yield by 21.5% higher. From among the studied microelements, boron showed the highest green matter yielding effect, by 15.7% on average. Feeding trial conducted on the layers showed that the nutritive value of dried green fodder was not markedly affected by applied fertilization. The hens tolerated 8% supplement of amaranth leaves to feed mixture. However, in such a case the feed consumption per 1 egg increased, at worsened laying performance and poorer eggs quality. Moreover, the yolks of egss from hens fed with such a mixture, were less intensively coloured

Effects of housing, perches, genetics, and 25-hydroxycholecalciferol on keel bone deformities in laying hens

Several studies have shown a high prevalence of keel bone deformities in commercial laying hens. The aim of this project was to assess the effects of perch material, a vitamin D feed additive (25-hydroxyvitamin D(3); HyD, DSM Nutritional Products, Basel, Switzerland), and genetics on keel bone pathology. The study consisted of 2 experiments. In the first experiment, 4,000 Lohmann Selected Leghorn hens were raised in aviary systems until 18 wk of age. Two factors were investigated: perch material (plastic or rubber-coated metal) and feed (with and without HyD). Afterward, the hens were moved to a layer house with 8 pens with 2 aviary systems. Daily feed consumption, egg production, mortality, and feather condition were evaluated. Every 6 wk, the keel bones of 10 randomly selected birds per pen were palpated and scored. In the second experiment, 2,000 Lohmann Brown (LB) hens and 2,000 Lohmann Brown parent stock (LBPS) hens were raised in a manner identical to the first experiment. During the laying period, the hens were kept in 24 identical floor pens but equipped with different perch material (plastic or rubber-coated metal). The same variables were investigated as in the first experiment. No keel bone deformities were found during the rearing period in either experiment. During the laying period, deformities gradually appeared and reached a prevalence of 35% in the first experiment and 43.8% in the second experiment at the age of 65 and 62 wk, respectively. In the first experiment, neither HyD nor the aviary system had any significant effect on the prevalence of keel bone deformities. In the second experiment, LBPS had significantly fewer moderate and severe deformities than LB, and rubber-coated metal perches were associated with a higher prevalence of keel bone deformities compared with plastic perches. The LBPS laid more but smaller eggs than the LB. Again, HyD did not affect the prevalence of keel bone deformities. However, the significant effect of breed affiliation strongly indicates a sizeable genetic component that may provide a basis for targeted selection