<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The objective is to study the effect of heat stress on milk yield (MY) relative to milking records (n=18178) of native Holsteins (n=187), in the region of Ghardaia, according to periods of HS, using the temperature-humidity index (THI). With THI >72 during 07 months in the study area, which significantly (P&lt;0.001) decrease the MY (-15.5% corresponding to 21.73 kg). Also, calving periods led to a significant drop (P &lt; 0.001) in overall MY (7030.35 kg) of the order of (-14.6%), and over the lactation length (353.43 d), which explains 41% of the variations in MY. In addition, the non-significant effect (P=0.212) of the lactation range on the increase in MY, moreover, the lactation length shows a non-significant (P = 0.108) decrease (-4.68%) during heat stress (HS). Furthermore, the significant effect (P &lt;0.001) of the interaction (Milking frequency × THI) on MY, when THI variates from &lt; 74 to > 84, with regression of (-16.82% and -08.82%) of the MF (2X and 3X), respectively. Again, the NH cow is less sensitive to hyperthermia, so THI explains only 2% of the variation in MY levels. Thus, NH in arid regions have the ability to acclimatize to Saharan environmental conditions.</p>
</abstract>

The objective is to study the effect of heat stress on milk yield (MY) relative to milking records (n=18178) of native Holsteins (n=187), in the region of Ghardaia, according to periods of HS, using the temperature-humidity index (THI). With THI >72 during 07 months in the study area, which significantly (P<0.001) decrease the MY (-15.5% corresponding to 21.73 kg). Also, calving periods led to a significant drop (P < 0.001) in overall MY (7030.35 kg) of the order of (-14.6%), and over the lactation length (353.43 d), which explains 41% of the variations in MY. In addition, the non-significant effect (P=0.212) of the lactation range on the increase in MY, moreover, the lactation length shows a non-significant (P = 0.108) decrease (-4.68%) during heat stress (HS). Furthermore, the significant effect (P <0.001) of the interaction (Milking frequency × THI) on MY, when THI variates from < 74 to > 84, with regression of (-16.82% and -08.82%) of the MF (2X and 3X), respectively. Again, the NH cow is less sensitive to hyperthermia, so THI explains only 2% of the variation in MY levels. Thus, NH in arid regions have the ability to acclimatize to Saharan environmental conditions.

Effect of Temperature-Humidity-Index on Milk Performances of Local Born Holstein Dairy Cows Under Saharan Climate

Département de sciences agronomiques, Faculté des sciences de la nature et de la vie et sciences de la terre, Université de Ghardaia

Université Kasdi Merbah -Ouargla (Algérie), Laboratoire de Bio ressources sahariennes

Archiva Zootechnica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The objective is to study the effect of heat stress on milk yield (MY) relative to milking records (n=18178) of native Holsteins (n=187), in the region of Ghardaia, according to periods of HS, using the temperature-humidity index (THI). With THI >72 during 07 months in the study area, which significantly (P 84, with regression of (-16.82% and -08.82%) of the MF (2X and 3X), respectively. Again, the NH cow is less sensitive to hyperthermia, so THI explains only 2% of the variation in MY levels. Thus, NH in arid regions have the ability to acclimatize to Saharan environmental conditions.

The objective is to study the effect of heat stress on milk yield (MY) relative to milking records (n=18178) of native Holsteins (n=187), in the region of...

Effect of Temperature-Humidity-Index on Milk Performances of Local Born Holstein Dairy Cows Under Saharan Climate

Data publikacji: 30 gru 2021

Zakres stron: 24 - 36

DOI: https://doi.org/10.2478/azibna-2021-0010

Słowa kluczowe
Algerian Northern Sahara, THI, native Holsteins, husbandry practices, dairy performance

© 2021 Ioannis Chrysikos, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Effect of Temperature-Humidity-Index on Milk Performances of Local Born Holstein Dairy Cows Under Saharan Climate

Data publikacji: 30 gru 2021

Zakres stron: 24 - 36

DOI: https://doi.org/10.2478/azibna-2021-0010

Słowa kluczoweAlgerian Northern Sahara, THI, native Holsteins, husbandry practices, dairy performance

© 2021 Ioannis Chrysikos, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Słowa kluczowe
Algerian Northern Sahara, THI, native Holsteins, husbandry practices, dairy performance