Universal Journal of Agricultural Research Vol. 5(4), pp. 209 - 212
DOI: 10.13189/ujar.2017.050401
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Study of the Environmental Effects on Holstein Cows' Milk Performance under Tunisian Conditions


S. Bedhiaf-Romdhani 1,*, M. Djemali 2
1 INRA-TUNISIA, Laboratory of Animal and Fodder Productions, Rue Hédi Karray, 1004 El Menzah, Tunisia
2 INAT-TUNISIA, Laboratory of Animal and Food Resources, 1082 City Mahrajène, Tunisia

ABSTRACT

Analyses of milk data of 74201 lactations from 327 Friesian dairy herds recorded during 1998-2009 and a total of 25,000 lactations from 156 Friesian dairy herds recorded during 1983-1987 under south Mediterranean environmental production conditions identified significant sources of variation by region, herd-year within region countries of origin, month of calving and days in milk for dairy cattle milk yield. The specific objective of this study was to quantify the effect of climate change by examining the effect of month of calving on milk yield of Friesian dairy cattle during two periods (1983-1987) and (1998-2009). In the first period, cows were North American Holsteins (2%), European Friesian (28%) and their progeny born and raised in Tunisia (70%). In the second period North American sired cows were (19%) and European sired cows were (14%). The effect of month of calving on milk yield was quantified by the least squares solutions obtained with the last month restricted to zero. In both periods, cows calving in the fall and early winter (September-January) yielded more milk than cows calving in spring (February-May) or summer (June-August). In the first period, cows calving in January yielded 384 kg more milk than cows calving in August. In the second period, the difference of milk yield between January and August was reduced to be only 220 kg. In the first period (1983-1987), least square means differences of milk yield from January to December (as a basis of comparison) were respectively, (113kg, -34kg, -76kg, -100kg, -189kg, -238kg, -246kg, -271kg, -160kg, 7kg, 35kg, 0). These differences were, respectively, in the second period (-47kg, 6kg, -30kg, -86kg, -203kg, -226kg, -267kg, -268kg, -177kg, -76kg, -47kg, 0). In the second period (1998-2009) and in relation to calving months, there is a clean tendency of a decrease in differences of total milk produced, between what is known in the first period (1983-1987) as traditional cool months and hot months which might be a climate change translation. This study showed how calving month effect on milk yield could be used over time as a measured indicator of climate changes.

KEYWORDS
Climate, Change, Friesians, Calving, Mediterranean

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] S. Bedhiaf-Romdhani , M. Djemali , "Study of the Environmental Effects on Holstein Cows' Milk Performance under Tunisian Conditions," Universal Journal of Agricultural Research, Vol. 5, No. 4, pp. 209 - 212, 2017. DOI: 10.13189/ujar.2017.050401.

(b). APA Format:
S. Bedhiaf-Romdhani , M. Djemali (2017). Study of the Environmental Effects on Holstein Cows' Milk Performance under Tunisian Conditions. Universal Journal of Agricultural Research, 5(4), 209 - 212. DOI: 10.13189/ujar.2017.050401.