Nutritional and ecological evaluation of dairy farming systems based on concentrate feeding regimes in semi-arid environments of Jordan

الملخص EN

The objective of this study was to evaluate the nutritional and ecological aspects of feeding systems practiced under semi-arid environments in Jordan.

Nine dairy farms representing the different dairy farming systems were selected for this study.

Feed samples (n = 58), fecal samples (n = 108), and milk samples (n = 78) were collected from the farms and analysed for chemical composition.

Feed samples were also analysed for metabolisable energy (ME) contents and in vitro organic matter digestibility according to Hohenheim-Feed-Test.

Furthermore, fecal nitrogen concentration was determined to estimate in vivo organic matter digestibility.

ME and nutrient intakes were calculated based on the farmer’s estimate of dry matter intake and the analysed composition of the feed ingredients.

ME and nutrient intakes were compared to recommended standard values for adequate supply of ME, utilizable crude protein, rumen undegradable crude protein (RUCP), phosphorus (P), and calcium (Ca).

Technology Impact Policy Impact Calculation model complemented with a partial life cycle assessment model was used to estimate greenhouse gas emissions of milk production at farm gate.

The model predicts CH4, N2O and CO2 gases emitted either directly or indirectly.

Average daily energy corrected milk yield (ECM) was 19 kg and ranged between 11 and 27 kg.

The mean of ME intake of all farms was 184 MJ / d with a range between 115 and 225 MJ / d.

Intake of RUCP was lower than the standard requirements in six farms ranging between 19 and 137 g / d, was higher (32 and 93 g / d) in two farms, and matched the requirements in one farm.