ENERGY LEVEL AND STRATEGY OF FEEDING FOR DAIRY COWS IN THE DRY PERIOD

Djelovanje strategije hranidbe u suhostaju na proizvodnju i zdravlje istaživalo se u dva pokusa što su obuhvatila 80 i 96 mliječnih krava. U pokusu br. 1 ispitivalo se djelovanje razine energije (normalna i visoka (1.5 x N) i djelovanje dnevnog sagorjevanja kratkolančanih masnih kiselina (KLMK) u preživača (+ i -) u zadnja četiri tjedna suhostaja. U pokusu br. 2 uključeno je samo sagorjevanje KLMK. Šesnaest je krava zaklano radi ruminalnog pregleda. Sagorjevanje KLMK je inducirano davanjem 4.5 kg ječma u jutro i kabaste hrane (roughage) na večer. Nakon telenja koncentracija je postepeno povećavana do razine od 9 kg ST a sliaža trave bila ad lib. u obje skupine. Sagorjevanje KLMK povećalo je uzimanje silaže trave u prvih pet tjedana post parfum u pokusu br. 1, ali ne u pokusu br. 2. U pokusu br. 1 postojalo je međusobno djelovanje između razine hranjena i sagorjevanja KLMK na proizvodnju mlijeka, dok u pokusu br. 2 nije primijenjena nikakva razlika. U krava s pojačanim sagorjevanjem KLMK došlo je do rjeđe pojave ketoze i probavnih smetnji u prvom pokusu ali ne u drugom, te je postojala tendencija povećanja aktivnosti u mukozi rumena, no bez makroskopskih razlika. Zaključeno je da se sagorjevanjem KLMK ne postiže nikakvo ili samo neznatno pozitivno djelovanje u suhostaju na uzimanje hrane, proizvodnju, zdravlje i reprodukciju.The effect of feeding strategy in the dry period on performance and health was investigated in two experiments comprising 80 and 96 dairy cows. In exp. 1 the effect of energy level (Normal and High (1.5 x N) and the effect of a daily ruminal SCFA-burst (+ and -) in the last 4 weeks of the dry period were examined. In exp. 2. only SCFA-burst was included. Sixteen cows were slaughtered for ruminal examination. SCFA-burst was induced by allocating 4.5 kg barley in the morning and roughage in the evening. After calving concentrate was gradually increased to a level of 9 kg DM and grass silage was ad. lib in all groups. The SCFA-burst increased grass silage intake in the first 5 weeks post partum in exp. 1 but not in exp. 2. In exp. I there was an interaction between feeding level and SCFA-burst on milk production, while no difference between treatments were seen in exp. 2. The SCFA bursted cows had a lover incidence of ketose and digestive disorders in the first experiment but not in the second, and there was a tendency to increased activity in the ruminal mucosa but without any macroscopical differences. It is concluded that none or only small benefits are obtained from SCFA- bursts in the dry period on feed intake, performance, health, and reproduction

Nitrogen and sulphur management: challenges for organic sources in temperate agricultural systems

A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand