scholarly journals The relationship between the number of consecutive days with heat stress and milk production of Holstein dairy cows raised in a humid continental climate

2019 ◽  
Vol 102 (9) ◽  
pp. 8537-8545 ◽  
Author(s):  
V. Ouellet ◽  
V.E. Cabrera ◽  
L. Fadul-Pacheco ◽  
É. Charbonneau
2009 ◽  
Vol 2009 ◽  
pp. 63-63
Author(s):  
S Khalajzade ◽  
N Emam Jomeh ◽  
A Salehi ◽  
A Moghimi Esfandabadi

Milk production is significantly decreased by thermal stress. The survival and performance of an animal during heat stress periods depend on several weather factors, especially temperature and humidity. Researchers reported dramatic decreases in milk production as temperature rose above 30 degree of centigrade. Very high environmental temperature is common during the summer months in Iran. Rectal temperature is as indicator of heat tolerance and has been the most frequently used physiological variable for estimating heat tolerance in cattle. Some dairy cows are more heat tolerant and productive when subjected to heat stress. Identification and selection of heat stress resistant cattle offers the potential to increase milk yield in tropical environment. The aim of the present study was to estimate genetic parameters of heat tolerance and its relationship to milk production in Holstein Dairy Cows in Iran.


Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 722
Author(s):  
Jang-Hoon Jo ◽  
Jalil Ghassemi Nejad ◽  
Dong-Qiao Peng ◽  
Hye-Ran Kim ◽  
Sang-Ho Kim ◽  
...  

This study aims to characterize the influence of short-term heat stress (HS; 4 day) in early lactating Holstein dairy cows, in terms of triggering blood metabolomics and parameters, milk yield and composition, and milk microRNA expression. Eight cows (milk yield = 30 ± 1.5 kg/day, parity = 1.09 ± 0.05) were homogeneously housed in environmentally controlled chambers, assigned into two groups with respect to the temperature humidity index (THI) at two distinct levels: approximately ~71 (low-temperature, low-humidity; LTLH) and ~86 (high-temperature, high-humidity; HTHH). Average feed intake (FI) dropped about 10 kg in the HTHH group, compared with the LTLH group (p = 0.001), whereas water intake was only numerically higher (p = 0.183) in the HTHH group than in the LTLH group. Physiological parameters, including rectal temperature (p = 0.001) and heart rate (p = 0.038), were significantly higher in the HTHH group than in the LTLH group. Plasma cortisol and haptoglobin were higher (p < 0.05) in the HTHH group, compared to the LTLH group. Milk yield, milk fat yield, 3.5% fat-corrected milk (FCM), and energy-corrected milk (ECM) were lower (p < 0.05) in the HTHH group than in the LTLH group. Higher relative expression of milk miRNA-216 was observed in the HTHH group (p < 0.05). Valine, isoleucine, methionine, phenylalanine, tyrosine, tryptophan, lactic acid, 3-phenylpropionic acid, 1,5-anhydro-D-sorbitol, myo-inositol, and urea were decreased (p < 0.05). These results suggest that early lactating cows are more vulnerable to short-term (4 day) high THI levels—that is, HTHH conditions—compared with LTLH, considering the enormous negative effects observed in measured blood metabolomics and parameters, milk yield and compositions, and milk miRNA-216 expression.


2007 ◽  
Vol 2007 ◽  
pp. 148-148
Author(s):  
A. Heravi Moussavi ◽  
M. Danesh Mesgaran ◽  
T. Vafa

Reproduction and milk production are the principal factors that are influencing dairy farm profitability. The dairy industry in Iran has changed dramatically in the last decade. The shift toward more productive cows and larger herds in Iran is associated with a decrease reproductive efficiency (Heravi Moussavi et al., 2004). Increased knowledge about the principal causes of reduced fertility is essential. The root cause of the declining fertility is probably a combination of a variety of physiological and management factors that have an additive effect on reproductive efficiency. Dairy cattle are inseminated and pregnancy is established while dairy cows are lactating. Based on the analyses of large datasets, there is clearly an antagonistic relationship between milk production and reproduction in dairy cattle (Lucy, 2001). It was shown that the hazard ratio for cumulative first 60-day milk yield and conception in high producer cows was 8 percent less than the others and also high milk yield was a risk factor for several reproductive disorders (Grohn and Rajala-Schultz, 2000). The objective of this study was to evaluate the effect of first 60-day cumulative milk yield on days open in Iranian Holstein dairy cows.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 389-389
Author(s):  
Andrea Dahnae del Rio-Aviles ◽  
Abelardo Correa-Calderon ◽  
Leonel Avendaño-Reyes ◽  
Milton G Thomas ◽  
R Mark Enns ◽  
...  

Abstract Summer season in northwest Mexico is characterized by hot-humid weather conditions that lead to heat stress and affect physiological and productive performance of lactating Holstein cows. Mineral supplementation has been proposed as strategy to alleviate negative effects of heat stress in dairy cattle. Thus, the objective of this study was to evaluate the effect of an injectable mineral supplement on physiological variables and milk production in Holstein cows managed during summer. Sixteen cows were randomly assigned to 1 of 2 experimental groups: Mineral-treated (TRT; n = 8) or control (CON; n = 8). The TRT group received 3 injections of Fosfosan® (10 ml, i.m., Virbac, Uruguay), on days 0, 7 and 17, considering summer onset as day 0 (June 21st), whereas group CON was untreated. Physiological variables such as respiratory rate (RR), vaginal temperature (VT) and skin-surface temperature (SST), were registered twice a week (0500-1700 h) during 6 weeks. Ambient temperature and humidity were collected to calculate the daily temperature and humidity index (THI). Data were analyzed using a mixed model with repeated measures, which included fixed effects of treatment, time and treatment*time, and sire as random effect. According to the THI, Holstein cows were exposed to heat stress during the experiment (&gt;72 units). Cows in the TRT group showed higher (P &lt; 0.05) milk production than CON cows (17.93±0.47 vs 17.02±0.51 kg/day) and lower (P &lt; 0.01) VT (39.14±0.11 vs 39.46±0.15 °C). Relative to CON cows, treated cows also had lower RR (63.16±0.65 vs 64.47±0.76 breaths/min) and lower SST (33.75±0.15 vs 34.02±0.16 °C). All physiological variables showed a significant effect of time (P &lt; 0.01). In conclusion, mineral supplementation during summer appears to improve physiological and productive performance in heat-stressed milking dairy cows; therefore, we suggest to consider this management as strategy to reduce negative effects of summer and heat stress on the dairy industry in northwest Mexico.


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