Controlled Internal Drug Release Device Research Articles

Conception Rate in Dairy Cows Receiving a First or Repeatedly Used Controlled Internal Drug Release Devices in Timed Artificial Insemination Protocol

Controlled internal drug release (CIDR) devices for releasing progesterone have been used for reproductive management in dairy cattle. In order to minimize the cost, the devices can be reused upon disinfection after being used for 7-8 days. Therefore, the aim of this research is to compare the conception rate of dairy cows after the first, second, and third-use of CIDR devices timed following artificial insemination (TAI) protocol. A total of 783 cows receiving short-term hormonal protocol (9.5 days) by inserting CIDR for 7 day. At the initiation of the TAI protocol, cows were randomly assigned into three groups, (1st CIDR; n = 312), (2nd CIDR; n = 233), and (3rd CIDR; n = 238). Moreover, in each CIDR group, cows were subdivided into two types (primiparous and multiparous cows). Cows in all groups were inseminated on day 9.5 of the TAI protocol. Diagnosis of pregnancy was performed using ultrasound on days 30 and 60 after insemination. From the results, the 1st, 2nd and 3rd used CIDR devices did not significantly change the conception rates on days 30 (28.8% vs. 25.3% vs. 28.2%, respectively) and 60 (26.9% vs. 24.5% vs. 27.7%, respectively) post-TAI in dairy cows (P > 0.05). The embryonic loss did not differ among cows receiving the 1st, 2nd and 3rd used CIDR devices (6.7% vs. 3.4% vs. 1.5%, respectively) (P > 0.05). For each CIDR group, parity (primiparous and multiparous) did not alter conception rates on days 30 and 60 post-TAI and embryonic loss in dairy cows (P > 0.05). Our findings indicate that the CIDR device could be used for at least three times in the TAI protocol in primiparous and multiparous dairy cows.

389 Impact of a Controlled Internal Drug Release device on circulating and local concentrations of progesterone

Abstract Controlled Internal Drug Release (CIDR) devices have become an important component of reproductive management programs in many beef herds. When a CIDR is inserted into a cow, circulating concentrations of progesterone mimic a functional corpus luteum. Some data, however, suggest that concentration of progesterone following insertion of a CIDR might have negative consequences on fertility in Bos indicus animals. Therefore, the objective of this study was to determine the impact of a CIDR device on circulating and uterine tissue concentrations of progesterone. A blood sample and a uterine biopsy were collected from non-suckled postpartum cycling Brahman cows (n = 10; Cycling) during the midluteal stage. A blood sample and a uterine biopsy were also collected from non-suckled postpartum cycling Brahman cows (n = 9; CIDR) after a CIDR had been in place for 5 d. To collect uterine biopsies from CIDR cows, the uterine biopsy tool was placed inside a plastic covering, both were passed into the cervix of the cow before the tool was extended through the covering and into the uterus. After the biopsy was collected, the tool was carefully removed to prevent sample contamination. Blood samples were centrifuged, and serum was collected to determine concentrations of progesterone. Uterine biopsies were snap frozen until extraction. Biopsies were weighted, thawed, and homogenized in assay buffer. Samples were then extracted with methyl tert-butyl ether and resuspended in assay buffer. Serum concentrations are reported as ng/mL and uterine concentrations are reported as ng/g. Statistical analysis was performed using the GLM procedure in SAS with treatment (CIDR vs Cycling), tissue type (uterine vs serum) and their interaction included in the model. There was a significant effect of treatment (P = 0.0062), tissue (P = 0.0063) and a treatment by tissue interaction (P = 0.0068). Animals with a CIDR had greater concentrations of progesterone than Cycling animals (274.77 vs 4.37 ng, respectively). Uterine samples had greater concentrations of progesterone than serum samples (274.40 vs 4.74 ng, respectively). These increased concentrations of progesterone were mainly from CIDR uterine samples (543.24 ng/g) which had greater (P < 0.001) concentrations of progesterone compared with all other samples, which did not differ from each other (P > 0.98; CIDR Serum 6.29 ng/mL, Cycling Serum 3.2 ng/mL, and Cycling Uterus 5.54 ng/g). In summary, CIDRs increased circulating concentrations of progesterone sufficient to keep animals from exhibiting estrus, and were not different from cows in the midluteal stage of their cycle. Local concentrations in uterine tissue; however, were significantly greater when a CIDR was in place compared with uterine tissue collected during the midluteal phase. The implications of these significantly greater concentrations of progesterone in uterine tissue warrant further investigation.

Differing planes of nutrition alter serum and histotroph amino acid composition in nonpregnant, multiparous beef cows on day 3 of the estrous cycle.

Endometrial-derived uterine histotroph is a critical component of nutrient supply to a growing conceptus throughout gestation; however, the effect of nutritional plane on histotroph nutrient composition remains unknown in multiparous cows. We hypothesized that differing planes of nutrition would alter histotroph and serum nutrient composition in beef cattle. Thus, we evaluated serum and histotroph amino acid and glucose composition, and serum non-esterified fatty acids (NEFA) and blood urea nitrogen (BUN) in cows individually fed to maintain body weight (BW; 0 kd/d, n = 9; CON) compared with those losing moderate BW (-0.7 kg/d, n = 9; NEG). After 49 d of differing nutritional planes, cows were subjected to the 7-d CoSynch + controlled internal drug release device estrus synchronization protocol and then slaughtered on day 62. Blood serum (days 0 and 62) and uterine histotroph [day 62; from uterine horns ipsilateral and contralateral to the corpus luteum (CL)] were collected and analyzed for concentrations of amino acids, glucose, and NEFA. Performance characteristics, body composition via ultrasound (days 0 and 62), and carcass characteristics were collected. Body condition score, change in BW, average daily gain, dry matter intake, and gain:feed were decreased (P ≤ 0.05) in NEG vs. CON cows. There were no differences in body composition or carcass characteristics, except an increase (P ≤ 0.05) in dressing percentage in NEG cows due to differences in gut fill, consistent with study design. Serum NEFA increased (P ≤ 0.05) in the NEG group, but there were no differences between NEG vs. CON in glucose or BUN. Serum histidine increased (P ≤ 0.05) and alanine, isoleucine, and tryptophan decreased (P ≤ 0.05) in NEG vs. CON cows. Compared with that of the uterine horn ipsilateral to the CL, histotroph from the uterine horn contralateral to the CL had increased (P ≤ 0.05) isoleucine, asparagine, and proline concentrations in NEG cows, and decreased (P ≤ 0.05) tryptophan as a proportion of essential and total amino acids. There were no differences in glucose concentrations of histotroph contralateral or ipsilateral to the CL. Cow nutritional plane does alter serum and histotroph amino acid composition, although the presence of an embryo may be necessary to fully elucidate these changes. Differences in serum and histotroph tryptophan should be given consideration in future studies due to its importance as an essential amino acid in protein synthesis and bioactive affects.

Relationship between higher estrus-associated temperatures and the bovine preovulatory follicular fluid metabolome

IntroductionA higher estrus-associated temperature (HEAT) is a hallmark feature in sexually active females; however, its functional importance is unclear. Our objective was to examine the relationship between HEAT and the preovulatory follicular fluid metabolome. It was hypothesized that HEAT is functionally important as it affects fertility-related components in the preovulatory follicle.MethodsEstrus was synchronized in non-lactating Jersey cows. A Thermochron iButton temperature data logger was affixed to blank controlled internal drug release (CIDR) devices and intravaginally inserted after CIDR device removal. The follicular fluid was aspirated 14.9 h + 3.3 h after an animal first stood to be mounted. Regression models were performed using metabolite abundance and HEAT variables. Best-fit models were determined using backward manual selection (p < 0.05).ResultsA total of 86 metabolites were identified in cow follicular fluid samples. The vaginal temperature at first mount and when it was expressed as a change from baseline was positively related to the abundance of four metabolites (i.e., taurine, sn-glycerol 3-phosphate, glycine, and cysteine) and negatively related to one metabolite (i.e., serine). The vaginal temperature at the first standing mount was related to the differential abundance of two metabolites (i.e., jasmonate and N-carbamoyl-L-aspartate). Three metabolites were related to the maximum vaginal temperature (i.e., N-carbamoyl-L-aspartate, uracil, and glycodeoxycholate). When expressed as a change from baseline, the maximum vaginal temperature was related to the differential abundances of uracil, uric acid, and 6-phospho-D-gluconate. The time taken to reach maximum vaginal temperature was related to N-carbamoyl-L-aspartate, glycodeoxycholate, jasmonate, and tricarballylic acid. Pertaining to the combination of HEAT and its duration, the area under the curve associated with the time between the first increase in vaginal temperature and the maximum vaginal temperature was related to 6-phospho-D-gluconate, sulfolactate, guanidoacetic acid, and aspartate. The area under the curve associated with the time between the initial vaginal temperature increase and up to 10 h after a cow first stood to be mounted or when a cow’s temperature returned to baseline was related to the differential abundances of uracil, sn-glycerol 3-phosphate, methionine sulfoxide, and taurodeoxycholate.DiscussionOur findings support the notion that HEAT is related to changes in the preovulatory follicular fluid metabolites involved in energy metabolism, thermoregulation, and oxidative stress management.

Embryo yield and quality in superovulated Simmental donor cows following oral supplementation with different sources of omega-3 and omega-6 fatty acids

Owing to contradictory results with respect to the yield and quality of embryos after supplementation with omega-3 fatty acids, this study sought to determine the effect of an oral supplement containing sources of omega-3 and omega-6 fatty acids on the ovarian response and embryo quality after superovulation. Cows were allocated to receive one of three oral supplement regimens. In the control (CO) group (n = 9), cows were fed a control supplement without fatty acids. The cows in the soybean oil (SO) (n = 8) and linseed oil (LO) (n = 8) groups received supplements containing SO or LO, respectively. Supplements were administered for 28 days, commencing 7 days before the onset of estrus synchronization until the day of embryo collection. The estrous cycle of all cows was synchronized by inserting a controlled internal drug release (CIDR) device (progesterone 1.38 g), followed by the administration of estradiol benzoate 2.5 mg. The CIDR device was withdrawn 7 days after insertion, followed by intramuscular administration of dinoprost 25 mg. Superovulation was induced via the administration of 152 mg of follicle-stimulating hormone (Folltropin-V) in tapered doses, starting 72 h before CIDR withdrawal. The embryos were collected 6 days after artificial insemination. The estrous response, onset of estrus after CIDR withdrawal, and number of ovulations were similar among the experimental groups (p > 0.05). The mean number of transferable embryos (grades 1 and 2) was higher in the LO group compared to the CO group (9.0 vs 3.2; p < 0.05). Although the number of transferable embryos (grades 1 and 2) was greater in the LO group than that in the SO group, the difference was not statistically significant (9.0 and 4.4; p > 0.05). In conclusion, oral supplementation with LO for 28 days increased the yield of transferable embryos, which could potentially improve the profitability of embryo transfer programs in cattle.

Validation of indwelling vaginal sensor to monitor body temperature in ewes

Remote-sensing technology facilitates longitudinal collection of body temperature during periods of hot or cold environmental stress without human interference, producing high-frequency measurements whilst reducing labour and stress to the animal. A pilot study was conducted to validate an improved, minimally invasive method for the continual measurement of vaginal temperature (VT) in female sheep. A silicon mould of a modified controlled internal drug release (CIDR) device (Zoetis Animal Health, Parsippany), was manufactured to securely house a temperature logger (Micro-T 16-bit; Star Oddi, Iceland) and allow direct contact at the collection site. These temperature-sensing CIDR devices were validated against manual rectal temperature (RT) measurements collected from 15 mature, non-pregnant, non-lactating Merino ewes. Rectal temperature was measured from each individual, six times per day in 2-h intervals for 14 consecutive days. The simultaneous measures of VT and RT did not differ significantly within each ewe (P > 0.05) and demonstrated a moderate linear relationship (R2 = 0.62, P < 0.05). The mean (± SEM) difference between RT and VT was small (0.010 ± 0.004 °C), with a 95% confidence interval of − 0.26 to 0.29 °C. Additionally, the coefficient of variation was lower on average for VT (0.49%) compared to RT (0.59%). Differences among paired readings were likely due to interval variation as well as penetration depth, air influx and faecal temperature when collecting RT. The initial silicone manufacturing costs were high (2200 AUD), with each unit costing 1.25 (AUD) thereafter; however, the temperature-sensing CIDR device was an effective and efficient research tool for the remote monitoring of body temperature. While further validation of these devices within extensive grazing environments is warranted, the collection and analysis of longitudinal physiological data from ewes has the potential to improve a variety of management aspects related to extensively grazed ewes maintained and joined in harsh conditions.

Follicular wave emergence and fertility following estrogen based synchronization regimen in anestrus buffaloes (Bubalus bubalis)

The study was undertaken to study the follicular changes around the time of new wave emergence following estradiol-17 (E-17) + controlled internal drug release (CIDR) based synchronization in 30 anestrus buffaloes. The animals were divided in two Groups, viz. Group I and II. In Group I (n=20), on day 0 (beginning of experiment), buffaloes were administered CIDR device (1.38 g P4) and concurrently received 1.5 mg estradiol-17 in 1.5 ml canola oil (i. m.). On day 9, CIDR was removed and a prostaglandin (PG) 2 analogue (500 μg, i. m.) was administered. On day 11, buffaloes were administered gonadotropin releasing hormone (GnRH) analogue (20 μg, i.m.) and inseminated twice at 12 h and 24 h following GnRH injection. Group II (control, n=10) received the CIDR-based protocol except the administration of estradiol at the time of CIDR insert. Ovaries were examined for follicular wave emergence, ovulation of dominant follicles at estrus and subsequent conception at 45 days of insemination. The mean diameter of largest follicle was reduced from 8 mm (0th day) to 4 mm on the day of wave emergence (WE), i.e. day 4 in Group I but day 6 in control. The mean number of 4-5 mm follicle was 5.7 in Group I and 4.8 in control on the days of WE. Ovulation and conception rates achieved were 85 vs 60% and 47 vs 30% respectively. In conclusion the new wave emergence was induced earlier by estradiol-17 administered along with CIDR which ultimately resulted in more ovulation and conception rate in buffalo. Estrogen based protocols might be adopted to improve fertility in anestrum buffaloes.

Use of GnRH for Synchronization of the Follicular Wave in Assisted Reproductive Technologies in Sheep: A Preliminary Study.

Simple SummaryThe present study aimed to set up a short-term protocol for synchronization of follicular wave emergence in sheep, concomitant with estrus synchronization, which would improve ovarian response in assisted reproductive technologies. Administration of a single dose of gonadotrophin-releasing hormone (GnRH), concomitant with the insertion of a progesterone-loaded controlled internal drug release (CIDR) device, caused regression of gonadotrophin-dependent follicles in all test sheep, with 70% of them initiating a new follicular wave and the remaining showing non-dominant follicles.The present study aimed to set up a short-term protocol for synchronization of follicular wave emergence in sheep, concomitant with estrus synchronization, which would improve ovarian response in assisted reproductive technologies. Administration of a single GnRH dose, concomitant with the insertion of a progesterone-loaded CIDR device, caused regression of gonadotrophin-dependent follicles ≥4 mm in all the GnRH-treated sheep and in around 80% of the controls treated only with CIDR (p < 0.05). Similar percentages of ewes lost all follicles (around 70%) or only the largest one (around 30%) in both groups. Hence, 54.1% and 70% of the sheep lost all large follicles and initiated a new follicular wave in the control and GnRH groups, respectively (p < 0.05). The remaining sheep showed follicles that were still not dependent of luteinizing hormone (LH). So, in fact, all the sheep had non-dominant follicles after treatment. In conclusion, a treatment including GnRH at CIDR insertion would offer a time- and cost-efficient protocol for inducing follicular turnover and synchronizing a new follicular wave at any stage of the estrous cycle.

Synchronization and resynchronization strategies to improve fertility in dairy buffaloes

Dairy buffalo has an integral role in the sustenance of economics due to its substantial contribution in milk and meat industry, however, the reproduction in this species is challenging. During the last decade, our laboratory conducted a series of experiments to encapsulate the solutions of the problems through optimizing pre- and post-insemination interventions in dairy buffaloes. In an unique study, we proposed that timing of ovulation with reference to the onset of standing heat during spontaneous estrus is delayed, and subsequently re-framed the traditional AM-PM rule (AI after 12 h of standing heat) to AM-AM or PM-PM (AI after 24 h of standing heat) to achieve the optimum fertility using frozen thawed semen in dairy buffaloes. Pregnancy per AI (P/AI) varied substantially either via injecting single shot of prostaglandin (PG) F2α to perform AI at detected estrus or applying standard ovsynch protocol for timed AI (TAI) in buffaloes. However, estrus response, and P/AI remained similar either with used or new controlled internal drug release device in dairy buffaloes. Additionally, the incorporation of estradiol benzoate in progesterone (P4) based protocol resulted in controlled emergence of follicular wave and increased the estrus intensity in buffaloes. Thereafter, we fine-tuned P4-based protocols to optimize the ovulation window for TAI either using GnRH or human chorionic gonadotropin (hCG) or equine chorionic gonadotropin that ultimately improved the fertility in dairy buffaloes. Although, these hormonal interventions resulted in decent fertility, yet it was consistently being compromised due to early or late embryonic losses in dairy buffaloes. Administration of hCG or GnRH on d 7 or 23 or 25 post AI has been proved beneficial to enhance the embryonic survival in buffaloes. Recently, resynchronization program as an aggressive reproductive management approach has been tested that served as a dual-purpose tool to increase overall herd fertility and reduce embryonic losses at commercial buffalo farm operations. Taken together, we concluded that the solutions to the problems of reproductive function are now clearly available with acceptable fertility, however, their application to the small holder buffalo farming remains challenging.

Synchronization of Estrus and Ovulation Using CIDR and Prostaglandin for Improving Pregnancy Rate of Repeat Breeder Egyptian Buffaloes

To synchronize estrus and ovulation for improving pregnancy rate (PR) of repeat-breeder buffaloes, Controlled Internal Drug Release (CIDR) + prostaglandin (PGF2α) was used before service of repeat breeder buffaloes. Total of 20 cyclic lactating buffalo-cows (4-7 years, 400-500 kg, non-pregnant up to 90-postpartum day) and 10 cyclic buffalo-heifers (2.5-4 years, 350-400 kg, not conceived after 3 services) were used in this study. In the 1st group, a CIDR was inserted for 9 days, regardless reproductive status, and then animals were intramuscularly injected with PGF2α 24 h prior to CIDR removal. In the 2nd group, control animals were used at the same interval. Animals in heat were naturally served and blood samples were collected on different days post-service for serum P4 determination. Pregnancy was diagnosed on day 25 post-service. Results showed that overall mean of PR was higher (P<0.01), while serum P4 at estrus was lower (P<0.001) in CIDR than in control, but both parameters were not affected significantly by animal type or CIDR x animal type interaction. Serum P4 at estrus was lower (P<0.05) in pregnant than in non-pregnant, regardless treatment or animal type. At the following post-service days, serum P4 showed the same trend of change, being higher (P<0.001) in CIDR than in control animals and in pregnant than in non-pregnant animals, regardless animal type. It could be concluded that the random usage of CIDR device for 9 days and prostaglandin F2α injection 24 h pre-CIDR withdrawal can be applied to improve pregnancy rate of repeat breeder Egyptian buffaloes.

Impact of Type and Dose of Recombinant Human Follicle Stimulating Hormone on Embryos Production in Dairy Cows and Their Relationship with AMH Concentration

The study was investigated to compare the effectiveness of Folltropin and two products (Fostimon and Menogon) of a recombinant human follicle stimulating hormone (rhFSH) on ovarian super-stimulation and embryo production in dairy Holstein cows. Two different doses for each super-ovulatory product were investigated. The relationship between the levels of Anti-Mullerian Hormone (AMH) in the blood serum before super-stimulation initiation and ovarian response and embryos production were also evaluated. At random stage of the estrus cycle, the donor cows were received intra-vaginal controlled internal drug release device (CIDR) and injected with 100μg of gonadotropin-releasing hormone (GnRH). On fourth day of CIDR insertion, cows were divided according to the product types of superovulatory hormones into three equal main groups. According to hormonal dose, each main group was re-divided into two equally sub-groups; low and high dose. Superovulatory hormones was injected IM as decreasing doses; 40%, 30%, 20% and 10% of the total dose twice daily for 4 days. On day 7, CIDRs were removed and each cow received 2 doses of PGF2α with 12hr interval. Based upon heat detection, donor's cows were inseminated with frozen semen three times 8-10hrs interval and concurrent with 100μg GnRH injection at first insemination. Non-surgical embryos recovery was performed on day's 7-8 post insemination and ovarian super-stimulation was checked using sonography to estimate ovarian response. Recovered embryos were morphologically evaluated as grades. Twelve embryos collected from Menogon donors group were transferred to six recipient's cows. The mean numbers of CL, recovered embryo/ova, fertilized ova and transferable embryos are significantly (P<0.01) higher in Folltropin and Menogon treated cows than Fostimon group. Donor cows treated with high doses of Folltropin and Menogon showed higher means for transferable and freezable embryos. Three recipients (50%) who received embryos appeared pregnant and one of them born calf. Significant positive correlations were reported between AMH on one side and CL, total ovarian response, transferable and freezable embryos on the other side, and cows having AMH≥230ng/L exhibited significant higher means. In conclusion: Menogon can be used as rhFSH for embryos production with transferable quality. AMH can be used as indicator to helpful select cow's candidates as donors. More studies are needed using Fostimon accompanied with different levels of LH.

Effect of dried distiller's grains plus solubles in postpartum diets of beef cows on reproductive performance of dam and heifer progeny.

Forty-eight primiparous and multiparous cows were fed a silage-based total mixed ration (TMR; CON), a TMR with 2.5 kg/d DM dried distiller's grains plus solubles (DDGS; MID), or a TMR with 4.7 kg/d DM DDGS (HIGH) from 8.5 ± 4 to 116 ± 4 d postpartum (DPP). All diets were formulated to be isocaloric for a postpartum ADG targeted at 0.22 kg, whereas CP exceeded requirements in both diets containing DDGS. Blood samples were collected from dams at 7- and 21-d intervals for progesterone concentration (resumption of cyclicity) and plasma urea nitrogen, respectively. A weigh-suckle-weigh procedure was used to measure milk production, and samples were collected for milk composition and fatty acid profile. A 5-d Co-Synch + controlled internal drug release (CIDR) protocol was used, and cows were bred (97 ± 4 DPP) by timed AI (TAI). Ultrasonography was used for measurement of the largest antral follicle at TAI and pregnancy diagnosis. Nineteen days after TAI, cow and calf pairs were managed as a single group until weaning and exposed to natural mating for a total of a 60-d breeding season. Starting at weaning, blood samples were collected from heifer offspring at 7-d intervals for progesterone concentration used as an indicator of puberty. A 5-d Co-Synch + CIDR protocol was used, and heifers were bred by TAI. Transrectal ultrasonography was used for measurement of the largest antral follicle at TAI and antral follicle count (AFC) at CIDR device insertion as well as pregnancy diagnosis. There were no differences in dam ADG ( = 0.364); however, DMI decreased with increasing DDGS ( < 0.0001), resulting in an increased feed efficiency ( = 0.042). Milk fat and lactose tended to increase with the addition of DDGS in the diet ( ≤ 0.055), and milk urea nitrogen increased ( < 0.001). There were no differences in resumption of cyclicity ( = 1.00) or diameter of the largest antral follicle ( ≥ 0.372). Timed AI pregnancy rates were not different with the addition of DDGS in the diet ( ≥ 0.174). Heifer ADG was reduced with DDGS during late lactation ( = 0.031). Heifer AFC had a tendency to increase with increasing DDGS ( = 0.081), with no impacts on dominant follicle diameter at TAI ( = 0.161). Heifer TAI pregnancy rate also was not different among treatments ( = 0.508). Overall, feeding 4.7 kg/d DM of DDGS to dams during early lactation increases feed efficiency of the dam, with minor statistically significant effects on dam or heifer offspring reproduction.

Manipulation of reproductive seasonality using melatonin implantation in Anglo-Nubian does treated with controlled internal drug release and equine chorionic gonadotropin during the nonbreeding season

The objective of this study was to compare the efficiency of hormonal treatments on ovarian activity and reproductive performance in anestrous Anglo-Nubian does during the nonbreeding season (February to May). A total of 48 multiparous does were divided into 2 groups (24 lactating does and 24 dry does). In each group, animals were allocated randomly into 2 equal subgroups (12 does each). In the first subgroup, does received a single 18-mg melatonin implant for 42 d followed by a controlled internal drug release (CIDR) device for 19 d in conjunction with 500 IU of equine chorionic gonadotropin (eCG) i.m. on the day of CIDR device removal. The second subgroup received CIDR combined with eCG in parallel with the first subgroup. Melatonin implantation induced a luteotrophic effect, expressed as an increasing number of corpora lutea, increased serum progesterone concentration, and reduced estradiol concentration. Regardless of treatment, dry does showed greater value of progesterone concentration. With the advancement of day of treatment, number of total follicles, small follicles, and medium follicles tended to increase to the greatest values at the day of CIDR device insertion. Furthermore, at day of mating, the numbers of large follicles reached the greatest value, which was associated with the lowest value of the number of corpora lutea. At day of mating, serum progesterone concentration achieved the lowest value, which increased until d 56 of pregnancy. The estradiol:progesterone ratio showed the opposite trend. The detrimental effect of reproductive seasonality, expressed as cessation of estrus behavior and fertile mating during the nonbreeding season, was successfully alleviated by the CIDR-eCG protocol. Furthermore, melatonin implantation in conjunction with the CIDR-eCG protocol enhanced conception rate and fecundity at d 28 of pregnancy and prolificacy at d 56 of pregnancy compared with does that were not implanted. Interestingly, does that failed to conceive did not come to heat again. In conclusion, the beneficial effect of melatonin implantation in conjunction with the CIDR-eCG protocol on the luteotrophic effect was reflected in the increasing number of corpora lutea, increasing progesterone concentration, and decreasing estradiol concentration. Furthermore, conception rate, prolificacy, and fecundity were improved compared with does that were not implanted during the nonbreeding season.

Effect of steroid hormones on the innate immune response induced by Staphylococcus aureus in the goat mammary gland.

The objective of this study was to compare the dynamics of innate immune components after intramammary infusion of Staphylococcus aureus (SA) under conditions of high oestrogen and high progesterone in goats. In one group ("E-group"), controlled internal drug release (CIDR) devices were inserted intravaginally from days -11 to -4. Prostaglandin F2α was administered immediately after removal of the CIDR device at day -3, and then oestradiol benzoate (E) was injected intramuscularly once a day from days -2 to 3. Heat-inactivated SA was then administered via intramammary infusion to the left udder at day 0, whilst only saline was infused to the right udder as a control. In a second group ("P-group"), CIDR devices were inserted intravaginally from days -3 to 7 and SA was infused at day 0 in the same way as in the E-group. The milk yield and the concentration of innate immune components (somatic cell count (SCC), lactoferrin (LF), S100A7 and goat ß-defensin 1 (GBD-1)) in the milk were measured. Milk yield decreased drastically in both SA and control udders in the E-group, whereas the P-group exhibited increased milk yield in both SA and control udders. SCC increased after SA infusion in both E- and P-groups, although it was higher in the E-group than in the P-group. There was no significant change in LF concentration in the E-group, but a decrease was observed in the P-group. Concentrations of S100A and GBD-1 were significantly increased after SA infusion in the E-group but not in the P-group. These results suggest that E enhances the innate immune response induced by SA in the goat mammary gland. This effect may be due to the reduction in milk yield and upregulation of innate immune components.

Inducing sub-luteal circulating concentrations of progesterone and persistent follicles in Holstein heifers and non-lactating cows using a modified CIDR device

Reducing progesterone from Controlled Internal Drug Release (CIDR) devices may allow for the comparison of contrasting steady state concentrations of progesterone (P4) in non-lactating dairy cows and heifers. This technical study was designed to determine if circulating P4 concentrations from the CIDR device could be reduced in cattle via ethanol extraction, and if reduced steady state concentrations of P4 would increase the percent of cows and heifers that developed a persistent follicle. Holstein heifers and non-lactating cows were treated with Ovsynch (100μg GnRH, 7 d later, 25mg dinoprost tromethamine, 2 d later, 100μg GnRH) to initiate a new cycle. Only heifers and cows that synchronized were included in this study. On d 7 of the newly induced estrous cycle, animals were assigned to three treatments all treated with new CIDRs as follows: CIDR-N, CIDR that was not manipulated; CIDR-W, CIDR immersed in water, or CIDR-E, CIDR immersed in a mixture of equal parts water/ethanol. All heifers and cows received 25mg dinoprost tromethamine at time of treatment to ensure regression of the d 7 corpora lutea (CL). Only data from heifers and cows having morphological CL regression observed with ultrasonography on d 1 and 2 following treatment, and with basal P4 concentrations (<0.15ng/mL) on d after CIDR removal, were considered in the final analyses (n =30). CIDR-E had lower circulating concentrations of P4 during the treatment period compared to CIDR-N and CIDR-W in cycling heifers and non-lactating cows and a significant interaction of treatment x d from CIDR insertion was observed. CIDR-W had lower P4 compared to CIDR-N in heifers, but not in cows. With the three treatments combined, non-lactating cows had lower circulating concentrations of P4 than heifers. The 1st wave dominant follicle became atretic followed by a new wave of follicles in 4 of 5 non-lactating cows and heifers treated with CIDR-N compared to 1 of 12 in the CIDR-E and 3 of 13 in CIDR-W treatments during the 7 d treatment period. In summary, reduced steady state serum concentrations of progesterone from a CIDR device resulted in continued growth of persistent follicles in cows and heifers compared to a non-manipulated CIDR device.

Presynchronization with CIDR improved the efficiency of ovsynch in the cyclic and acyclic Postpartum Pluriparous Cows

The postpartum period is considered an important period in the reproductive life of dairy cows. This study was aimed to evaluate the effect of progesterone (P 4 )-CIDR supplementation in the course of Ovsynch regimens in postpartum Holstein-Friesian dairy cows. Eighty Holstein Friesian dairy cows were used. All animals were gynaecologically examined for uterine involution and ovarian resumption by rectal ultrasound scan. Those with history of endometritis, caesarean section, dystocia, retained placenta, acute mastitis, lameness or other unhealthy were excluded. Fifty-two cows were cyclic and twenty eights were non-cyclic. Animals were divided into three synch-regimens. The 1 st group (N=27), used as a control, is the ovsynch regimen only in which the animals were treated with GnRH-PGF 2α -GnRH (GPG), the 2 nd group (N=26) in which the GPG was presynchronized with controlled internal drug release (CIDR) device before (CIDR-GPG), and the 3 rd group (N=27) in which CIDR device was incorporated into GPG, after the first GnRH injection (G-CIDR-PG). Blood samples were collected 5 times (day -7, 0, 7, 14 and 50) for measuring P 4 using enzyme-immunoassay (EIA) technique. Ultrasound examinations were performed on days -7, 0, 7 and 9 for following up the ovarian changes, and repeated at 35, 45 and 50 days post-insemination for pregnancy diagnosis. Conception rate was variable among groups. It was increased by 69.23, 51.85 and 40.74% in CIDR-GPG, G-CIDR-PG regimens treated groups and GPG-control group, respectively. The conception rate was higher in the cyclic versus acyclic GPG group (44.4 vs. 33.3 %). On the other hand, acyclic cows were highly responsive than cyclic cows in CIDR-GPG group (70.0 vs. 68.8%) and G-CIDR-PG group (55.6 vs. 50.0%). In conclusion, we recommend that the CIDR-GPG regimen is improving fertility and conception rate in postpartum dairy cows.

Efficacy of repeatedly used CIDR device in cattle reproduction: a metaanalysisreview of progesterone concentration and conception rate

n order to reduce estrus synchronization cost, utilization of residual progesterone (P4) in the used controlled internal drug release (CIDR) device upon sanitization can be possible. Two datasets were compiled from 8 and 7 research articles involving 3434 (2653 heifers + 771 lactating cows + 10 ovariectomized cows) and 7301 cattle (3879 heifers + 3422 lactating cows) to evaluate blood P4 concentration and conception rate, respectively, in response to repeatedly used CIDR devices after sanitization via autoclaving and disinfection. As the number of CIDR usages increased, blood P4 concentration decreased linearly (y = -0.484X + 3.135, R2 = 0.99, P < 0.001). Blood P4 concentration (1.52 vs. 2.20 ng/mL; P < 0.002) and conception rate (40.76 vs. 32.96%, P < 0.05) for lactating cows were lower than those for heifers. The sanitization method did not affect blood P4 concentration, but reused CIDR device subjected to disinfection was associated with reduced conception rate. In summary, depending upon the initial P4 load (1.38-1.90 g), the CIDR device could be used twice in lactating cows and four times in heifers after autoclaving to achieve target blood P4 concentrations.

23 THE EFFECT OF WITHDRAWAL TIMING OF CONTROLLED INTERNAL DRUG RELEASE (CIDR) ON EWE REPRODUCTIVE PERFORMANCE

This study was carried out using 80 multiparous Awassi ewes during breeding season to compare the effects of controlled internal drug release (CIDR) withdrawal time on ewe fertility. Ewes were equally and randomly allotted into 4 groups (n = 20/group). Ewes had a CIDR inserted for 3, 6, 9, or 12 days with intramuscular administration of 300 IU of equine chorionic gonadotropin (eCG) at withdrawal time. Oestrus was detected using vasectomized ram starting 12 h after CIDR withdrawal and repeated every 12 h up to 84 h. Blood samples were collected from all groups at the time of CIDR withdrawal for measuring of oestradiol (E2) and progesterone (P4) serum concentrations using commercial ELISA kits and micro-titrimetric plates. Timed insemination was performed 48 h post CIDR withdrawal in all groups. Pregnancy was diagnosed by ultrasonography at day 23 post-insemination and confirmed at day 35. Comparisons among groups were evaluated using Chi Square (χ2) test in all measured parameters except hormones levels, which analysed by repeated-measures analysis of variance (ANOVA), using SAS (SAS Institute Inc., Cary, NC, USA). A difference was considered significant at P &lt; 0.05 level. The results revealed that the retention, vaginal discharge and drawstring breakage rates after CIDR removal were insignificantly differed between all groups. On the other hand, pregnancy rate was significantly (P ≤ 0.05) higher in 9-d and 6-d groups (68.4 and 60%, respectively) than the 3-d group. While, no significant difference was detected between 12d group and other groups. The heat detection rate was significantly (P ≤ 0.05) higher in 12d group (100%) than 6-d and 3-d groups (80 and 45%, respectively). While, no significant difference was detected between 12-d and 9-d groups in heat detection rate. P4 was significantly higher in the 12-d group (13.4 ± 3.06 ng mL−1) than other groups. While E2 was significantly lower in the 12-d group (1.6 ± 0.06 pg mL−1) than other groups. These results indicated that withdrawal of CIDR devices after 9 days are efficient in synchronizing oestrus in ewes and provided higher pregnancy rate.

Effect of protein supplementation and forage allowance on the growth and reproduction of beef heifers grazing stockpiled tall fescue.

Stockpiled tall fescue can provide adequate winter forage for beef cattle, although unsupplemented replacement heifers may display marginal performance before breeding. The objective of this study was to determine if protein supplementation and/or additional forage improves growth and reproductive performance of replacement heifers grazing stockpiled fescue. Cattle averaging 272 ± 1.59 kg were stratified by BW and then randomly assigned to 1 of 4 plots within a pasture replication. Treatment combinations were assigned in a 2 × 2 factorial arrangement and included 1) a conservative forage allocation ("normal," targeting 85% forage use) and mineral supplement (normal forage allocation with mineral supplement [FM]), 2) normal forage allocation with protein tub (FT), 3) more liberal forage allocation ("extra," targeting 70% forage use) and mineral supplement (extra forage allocation with mineral supplement [EM]), and 4) "extra forage allocation with protein tub (ET). Treatments were administered for 8 wk from early November to early January. Heifers were fed fescue hay for 1 wk before breeding in late January. Heifers were synchronized with the 7-d CO-Synch + controlled internal drug release device protocol and inseminated in late January. Heifers were checked for pregnancy by ultrasonography at 35 and 90 d after AI. Main and interaction effects between the 2 treatments were determined. Total supplement intake was greater for protein tub than mineral supplement (0.36 vs. 0.11 kg·heifer·d, respectively; < 0.0001), and the additional dietary protein in the tub groups resulted in greater serum urea N concentrations ( < 0.0001; 8.15 vs. 10.4 mg/dL for mineral and protein tub, respectively). Forage utilization efficiency was greater for normal than extra forage allocation (74.7 vs. 65.8%, respectively; < 0.0001). Main effects of both treatments on ADG were significant ( < 0.0001; 0.28, 0.43, 0.43, and 0.51 kg·heifer·d for FM, FT, EM, and ET, respectively). There was an interaction effect of the 2 treatments on change in BCS ( < 0.05; 0.12, 0.10, 0.18, and 0.31 for FM, FT, EM, and ET, respectively). Reproductive tract scores, pelvic area, and AI pregnancy rates were not different between treatments ( > 0.05). Overall, feeding a protein supplement or providing extra forage increased gain and interacted to increase BCS but did not have an effect on reproductive performance. Supplementing with protein and providing extra forage are strategies that can increase gain in heifers, which could aid heifers in reaching puberty before estrous synchronization.

Manipulation of Fertility in Crossbred Dairy Cattle Using Controlled Internal Drug Release Device Combined With Prostaglandin and Equine Chorionic Gonadotrophin

Simplifying and improving our understanding of the protocols for inducing or synchronizing estrus is important for improving management of dairy cattle. This study evaluated the estrus response and conception rate of crossbred (Holstein Friesian X Zebu) dairy cows (n=75) and heifers (n=47) assigned to a 10-day controlled internal drug release (CIDR) device – prostaglandin F2-alpha (PGF2α) – equine chorionic gonadotrophin (eCG) based estrus synchronization protocol. Animals were assigned to three groups (a) anestrus (n=62), (b) repeat-breeders (n=11) and (c) silent estrus (n=46), according to their reproductive history, per rectal palpation, and progesterone concentrations determined by On-Farm enzyme-linked immunosorbent assays (ELISA) in milk (lactating cows) or serum (dry cows and heifers). For each animal, a CIDR device (containing 1.38g progesterone) was inserted into the vagina and allowed to remain in-situ for 10 days. On Day 8 after device insertion, a dose of 500µg of PGF2α was administered intramuscularly (IM). On Day 10 (device removal), 500 IU of eCG was given IM. Animals were inseminated or mated 48 and 72 hrs post device removal. Pregnancy was assessed 20-24 days post insemination by measurement of progesterone in milk/serum and pregnancy was confirmed by per rectal palpation and/or ultrasonography 44-90 days post insemination. Overall estrus response and conception rates were 97.5% and 78.3%, respectively, with no significant differences in parity, pre-treatment reproductive status and farming system (smallholder vs organized commercial farms). Conception rate after induced/synchronized estrus was 82.9% and 72.1% in cows and heifers, respectively, with an overall calving rate of 94.4%. In conclusion, the present study has shown high estrus response and conception rate in crossbred dairy cattle using this CIDR - PGF2α - eCG based estrus synchronization protocol. Application of this protocol is highly recommended to enhance fertility of dairy cattle in the study area, and this could readily be applied to other regions.