Health-Related Outcomes and Molecular Methods for the Characterization of A1 and A2 Cow's Milk: Review and Update.

A new trend in cow's milk has emerged in the market called type A1 and A2 milk. These products have piqued the interest of both consumers and researchers. Recent studies suggest that A2 milk may have potential health benefits beyond that of A1 milk, which is why researchers are investigating this product further. It is interesting to note that the A1 and A2 milk types have area-specific characteristics compared to breed-specific characteristics. Extensive research has focused on milk derivatives obtained from cow's milk, primarily through in vitro and animal studies. However, few clinical studies have been conducted in humans, and the results have been unsatisfactory. New molecular techniques for identifying A1 and A2 milk may help researchers develop new studies that can clarify certain controversies surrounding A1 milk. It is essential to exercise extreme caution when interpreting the updated literature. It has the potential to spread panic worldwide and have negative economic implications. Therefore, this study aims to investigate the differences between A1 and A2 milk in various research areas and clarify some aspects regarding these two types of milk.

Economics of treatment with GnRH agonist 7-14 days after artificial insemination in repeat breeder lactating dairy cows.

This study looked at the effectiveness and financial benefits of treating repeat breeder (RB) dairy cows with the GnRH agonist gonadorelin 7-14 days after artificial insemination (AI). A total of 188 healthy dairy cows (2.4 ± 1.3 lactations) with an average milk yield of 42.1 ± 6.8 kg milk/day, at 179 ± 38.4 days in milk with 3.8 ± 1 AIs were divided into two groups, experimental (E group, n = 98) and control (C group, n = 90). The GnRH agonist gonadorelin was given 7-14 days after AI to the E group to evaluate the embryo survival in RB cows. The control group did not receive any treatment. Recorded pregnancy rates and cumulative pregnancy rates were superior in the E group (49% and 64.3%) compared with the C group (37.8% and 55.5%). The interaction between therapy and RB had a significant impact on the pregnancy rate and accessory corpus luteum (CL), according to a binary logistic regression study. The UW-DairyRepro$ decision support tool utilized in this experiment demonstrated that by implementing this approach, the net present value can be increased by US dollars (US$)30.2/RB cow/year. Thus, the single therapy with GnRH agonist gonadorelin between 7 and 14 days after AI enhanced the potential for a second CL in repeat-breeder pregnant cows, presumably favouring embryo survival.

Mastitis impact on high-yielding dairy farm's reproduction and net present value.

Poor udder health can have a negative impact on milk production and reproductive performance, which reduces the net present value (NPV) of dairy farms. The aim of this study is therefore to investigate the relationship between clinical mastitis and NPV and the financial impact of impaired reproductive function. For this purpose, 473 dairy cows were included in our study, 146 cows with clinical mastitis (CM group) and 327 clinically healthy cows (CH group) from a high-yielding dairy farm in Romania, milking approximately 780 dairy cows with an average milk production of 46 kg milk/day. We found that, in contrast to CH cows, CM cows had a significantly lower conception rate at first service (58.2% vs. 41.7%, p < 0.05), third service (45.3% vs. 30.2%, p < 0.05), and total services (49.2% vs. 36.4%, p < 0.05). However, this positive effect was not observed for the average days open, which were significantly lower in CM cows than in CH cows (112 ± 4.3 days vs. 142 ± 3.1 days, p < 0.05). The fact that the non-pregnant CH cows had higher somatic cell counts (>400,000 SCC/mL) in their milk around artificial insemination (AI) and 1 month earlier than the pregnant cows (<250,000 SCC/ml) supports the idea that poor uterine health affects the reproductive activity of high-yielding cows. However, by using the UW-DairyRepro$ decision support tool, we found that despite the impairment of reproductive function in dairy cows, the largest negative impacts on NPV are still the cost of milk loss (US$14,439.4/farm/year) and treatment costs (US$4,380/farm/year). We considered the costs associated with poor reproductive function in the CM group (US$3,577/farm/year) as an additional cost of mastitis. Finally, it appears that the impact of mastitis on reproduction is associated with a lower chance of conception than it is with a daily risk of services.

Intraovarian Injection of Reconstituted Lyophilized Growth-Promoting Factor Extracted from Horse Blood Platelets (L-GFequina) Increases Oocytes Recovery and In Vitro Embryo Production in Holstein Cows.

The purpose of this study was to determine the impact of intraovarian injections of a reconstituted lyophilized growth-promoting factor extracted from horse blood platelets (L-GFequina) on the number of ovarian follicles, the recovery of cumulus−oocyte complexes (COCs), and embryo development to the blastocyst stage in Holstein cows. Thus, 12 Holstein cows were assigned to three protocols. According to the number of punctured follicles in protocol 1, ovum pick-up (OPU) was conducted on days 6 and 14 of the cycle (day 0 = estrus). In protocol 2, every large follicle (more than 7 mm) was removed, and 1 mL of L-GFequina was intraovarian injected (day 0). Two days later, equine chorionic gonadotropin (eCG) was administered, and OPU sessions were conducted on days 6, 10, and 14. The same ovarian stimulation procedure as that in protocol 2 was performed in protocol 3, except that equine L-GFequina was not supplied. OPU was carried out on days 6 and 10 of the cycle. The results indicate that the intraovarian injection of L-GFequina significantly (p < 0.05) increased the number of OPU sessions per cycle, the recovery of cumulus−oocyte complexes (COCs), and the production of blastocysts. In conclusion, an intraovarian injection of L-GFequina can improves OPU-IVEP results in Holstein cows.

Platelet-rich plasma in animal reproductive medicine: Prospective and applications.

Platelet-rich plasma (PRP) is the fraction of the plasma enriched with a platelet level above baseline, and it plays an essential role in tissue regeneration. The attention to PRP as unconventional therapy has increased during the past two decades. In animals, applications of PRP showed various degrees of success in a wide range of medical applications, from musculoskeletal injuries to ovarian insufficiency. Therapeutic applications with PRP in farm animals are still scarce, but the promising results offered by several studies are expected to trigger more interest in its application by both veterinarians and farmers. In this review, we highlight some efforts made in the field of animal reproduction regarding the use of PRP to potentiate the ovarian hypofunction, treat endometritis, improve the follicular development, oocyte competence and uterine environment for embryo implantation as well as restore testicular and erectile function in male, and as a treatment for mastitis.

Economics of Rebreeding Nonpregnant Dairy Cows Diagnosed by Transrectal Ultrasonography on Day 25 after Artificial Insemination.

Pregnancy rates of Holstein cows showed a substantial decline in the past years, which caused intensive TAI programs for nonpregnant cows to shorten the period between unsuccessful insemination and the next attempt on the same cow. Although many studies examined the improvement in pregnancy rates following TAI, only a few examined the economic impact of such programs. In this study, we look at the feasibility of reproductive programs that included early pregnancy diagnosis performed by transrectal ultrasonography 25 days after artificial insemination (AI) and TAI of nonpregnant cows. This resulted in the following two TAI programs: a modified OvSynch program with a second PGF2α treatment at 24 h interval (GPPG, n = 100) and a modified OvSynch program with an intravaginal progesterone-release device inserted between days 0−7 (PRID + GPPG, n = 100). Cows included in the TAI programs recorded an improvement in the cumulative pregnancy rate (67% vs. 53%; 69% vs. 53%) compared to those in which this strategy was not applied (p < 0.05). An economic analysis was performed using a decision-support tool to estimate the net present value (NPV; USD/cow/year). The analysis revealed a difference in NPV of 89.6 USD/cow/year between the programs (rebreeding the nonpregnant cows following the TAI program vs. AI at detected estrus). In summary, rebreeding the nonpregnant cows after early negative pregnancy diagnosis (25 days after AI) using this strategy can improve the cumulative pregnancy rate and profitability of dairy farms.

Ovarian cysts, an anovulatory condition in dairy cattle.

Ovarian cysts are one of the most common ovarian dysfunctions in dairy cattle, which can lead to a considerable economic loss through its high incidence and can reduce the reproductive performance. Anestrus is the most significant clinical sign observed in dairy cattle suffering from this condition. For diagnosis, most of the veterinarians use a combination of methods, from ultrasonography as an additional approach to trans-rectal palpation and symptomatology when assessing ovarian cysts. Although the Ovsynch treatment seems to be preferred, the pregnancy rate after this treatment is relatively low. Despite such reports on dairy cattle ovarian cysts, the data is insufficient to validate all the characteristics of this condition. This review summarizes what the literature has so far provided from definition to treatment of ovarian cysts in dairy cattle.