scholarly journals Genetic dissection of reproductive performance of dairy cows under heat stress

2020 ◽  
Vol 51 (4) ◽  
pp. 511-520 ◽  
Author(s):  
A. Sigdel ◽  
L. Liu ◽  
R. Abdollahi‐Arpanahi ◽  
I. Aguilar ◽  
F. Peñagaricano
2016 ◽  
Vol 187 ◽  
pp. 146-150 ◽  
Author(s):  
Simin Khorsandi ◽  
Ahmad Riasi ◽  
Mohammad Khorvash ◽  
Saeid Ansari Mahyari ◽  
Farhad Mohammadpanah ◽  
...  

Author(s):  
T. Penev ◽  
D. Dimov ◽  
N. Vasilev ◽  
J. Mitev ◽  
Tch. Miteva ◽  
...  

Abstract. The goal of this review is to consider and discuss the scientific literature related to the effect of heat stress (HS) on reproductive performance in dairy cows and opportunities to reduce its effects. The information in literature shows that the HS topic in dairy cows began to be discussed in the 1970s. As genetic progress related to productivity increases, the requirements for cows also increase, including for their reproduction performance. In the present review, a significant array of scientific papers is examined, as a result of which it is established that HS has a multifaceted effect on reproduction in dairy cows. The main role for the negative impact of HS is the effect of high ambient temperature on the hypothalamic-pituitary-ovarian axis. As a result, hormonal changes occur in the body of cows, which affect the behavior of cows in estrus, the development of follicles in the ovaries and the survival of the embryo in the uterus. These changes affect the main elements of cattle breeding such as length of days open interval, conception rate, number of inseminations required for conception. To mitigate the negative impact of HS on cows, methods have been developed for better estrus detection, for microclimate control, as well as for hormonal treatment of cows in order to increase reproductive performance. Although some progress has been made in each of the measures, HS still poses a serious reproductive problem for dairy cows, especially in the countries with warmer climates. This provokes the interest of many scientists around the world who seek to offer a solution/mitigation to this problem.


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.


Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 197
Author(s):  
Hiroaki Okawa ◽  
Missaka M.P. Wijayagunawardane ◽  
Peter L.A.M. Vos ◽  
Osamu Yamato ◽  
Masayasu Taniguchi ◽  
...  

This study investigated the efficacy of intrauterine infusion of a chitosan solution (CHT) on uterine recovery in early postpartum dairy cows with or without endometritis, and their subsequent reproductive performance. In Experiment 1, cows with endometritis at 3 weeks postpartum were administered CHT (n = 5) and prostaglandin F2α (PGF2α) (n = 4). Untreated cows (n = 7) served as the control group. In Experiment 2, 18 cows with a normally recovered uterus at the fresh cow check (mean, 35 days postpartum) were assigned to the CHT (n = 10) and control (n = 8) groups, and intrauterine infusion was conducted in the CHT group. Overall, in Experiment 1, the percentage of polymorphonuclear leukocytes significantly declined in the CHT group (32.3 ± 10.2 to 5.5 ± 2.4, p < 0.05) from week 3 to week 5, but no decline occurred in the PGF2α and control groups. In Experiment 2, the CHT and control groups showed no significant differences in reproductive parameters, suggesting the absence of adverse effects of CHT on fertility. These results suggest that intrauterine infusion of CHT in the early postpartum period effectively accelerates uterine recovery from endometritis and might be a suitable replacement for PGF2α administration.


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