Nulliparous Goats Research Articles

The use of oxytocin to cause cervical dilation for transcervical insemination in nulliparous goats: Improving pregnancy and kidding rates

To evaluate the effect of oxytocin as a cervical dilator, a study was carried out on nulliparous goats inseminated transcervically at the beginning of the breeding season. One hundred sixteen nulliparous goats with a mean live weight of 33.4±0.68kg and an age of 13.7±0.37months were used. The goats were exposed to active bucks of proven fertility for a period of 14 d in order to induce oestrus. One week later, the Ovsynch protocol was applied, which consisted of the application of 20mg of gonadorelin (Day Zero), 0.075mg of cloprostenol (Day 7) and of a second dose of 20mg of gonadorelin applied on Day 9. Artificial insemination (AI) was performed 16hr later. Three treatments were evaluated: T1=50IU saline, T2=25IU oxytocin; T3=50IU of oxytocin, intravenously applied 10-15min before AI. The time required to inseminate each treated goat from groups T2 and T3 was 49.56 and 56.25s, respectively, versus 85.78s needed for the goats from group T1 (p<.0001). In the T1 group of goats, the insemination catheter was inserted 2.1cm into the cervical canal and in goats from groups T2 and T3 it reached 3.41 and 3.77cm into the cervical canal, respectively (p=.02). Pregnancy rates and prolificacy (kids/doe) were higher (p=.02) for groups T2 (82.93%; 1.16) and T3 (76.92%; 1.21) respectively than for control goats (61.11%; 0.69). In conclusion, the intravenous administration of oxytocin led to greater dilation and depth of cervical penetration, obtaining higher pregnancy rates and prolificacy.

114 Short-term hormonal protocol efficiency either with or without equine chorionic gonadotrophin to promote oestrous synchronization in cyclic dairy goats

The use of equine chorionic gonadotrophin (eCG) in oestrous induction protocols is associated with antibody production against eCG. Moreover, there are important equine welfare issues involved in its production and the development of viable protocols without eCG in dairy goats is essential. The aim of this study was to assess oestrus and ovulatory responses of short-term oestrous synchronization protocol with or without eCG in nulliparous (NUL) and multiparous (MUL) dairy goats during the breeding season. On a random day of oestrous cycle (Day 0), Alpine (n=10 NUL and 10 MUL), Nubian (n=10 NUL and 10 MUL), and Saanen (n=10 NUL and 6 MUL) goats received 30μg of d-cloprostenol intramuscularly (IM) and an intravaginal sponge containing 60mg of medroxyprogesterone acetate, which was maintained for 6 days (Day 6). At 24h before sponge removal (Day 5), goats received IM 200IU of Novormon 5000 (G-eCG) or saline solution (G-Control). NUL and MUL goats of each breed were assigned equally into one of the two treatments. Transrectal ultrasonography was used to assess ovarian parameters, and teaser goats detected oestrus every 12h from sponge removal to ovulation or until 96h after sponge removal. The results are described as mean±s.e.m., and categorical results are presented as percentages. The normal distribution of the residues of all variables was determined by the Shapiro-Wilk test and for homoscedastic by Levene test. To evaluate interaction between treatments and parity order, the general linear model (GLM) was applied. Parametric variables were subjected to Student’s t-test. Nonparametric variables were analysed by Mann–Whitney test, Chi-squared test, and Fisher’s exact test. Values of P&amp;lt;0.05 were considered significant. According to the breed and parity order, Nubian and Saanen goats showed no difference (P&amp;gt;0.05) in reproductive parameters. Alpine goats had a longer (P&amp;lt;0.05) interval from sponge removal to onset of oestrus (SROE) in MUL (61±14.0h) than NUL (38.5±12.7h), longer interval from onset of oestrus to ovulation (IEOV) in NUL (33.5±11.9h) than MUL (19.5±13.4h), and the number of ovulations was greater (P&amp;lt;0.05) in MUL (2.2±0.9) than in NUL (1.3±0.5). In goats either receiving eCG or not, Alpine and Nubian goats had no difference (P&amp;gt;0.05) in SROE, IEOV, interval from sponge removal to ovulation (SROV), percentage of animals that ovulated, diameter of the ovulatory follicle, and number of ovulations. Saanen goats had a higher (P&amp;lt;0.05) percentage of animals that ovulated in G-eCG (87.5%) than G-control (25.0%). Regardless of parity order and breed, SROV was longer (P&amp;lt;0.05) in G-control (73.2±9.8h) than in G-eCG (65.1±10.2h), and the percentage of animals that ovulated was greater (P&amp;lt;0.05) in G-eCG (96.4%) than in G-control (67.9%). In summary, in short-term protocols for oestrous synchronization in cyclic dairy goats, the addition of eCG led to a shorter interval from sponge removal to ovulation and increased number of animals that ovulated. This research was supported by CNPq (310166/2012-8) and Embrapa (20.19.01.004.00.03.001).

Topical application of cervix with hyaluronan improves fertility in goats inseminated with frozen-thawed semen.

ObjectiveArtificial insemination plays an important role in genetic improvement in the goat farming system. The aim of this study was to investigate the effect of cervical application of hyaluronan (HA) on the fertility in goats after cervical artificial insemination using frozen-thawed (F-T) semen.MethodsAfter oestrous synchronisation with progesterone sponges and pregnant mare serum gonadotropin injection, both nulli- and multi-parous goats, were randomly allocated to 2 groups, and were inseminated with 0.25 mL of F-T semen (150×106 spermatozoa) twice at 52 h and 56 h after sponge removal. Prior to the insemination, goats in Group 1 only were given topical cervical HA application at 48 h after sponge removal. Site of insemination was recorded as os-cervix or intra-cervix or intra-uterus. Pregnancy was tested ultrasonographically 42 days after insemination. The data on pregnancy rates and percentage of animals according to the site of semen deposition were compared by Chi-square analysis.ResultsThe overall pregnancy rate was significantly (p<0.004) higher in goats with prior application to the cervix with HA (63.3%) than without (36.0%). Same pattern was observed in the pregnancy rates of nulli- and multi-parous goats in both the groups. Percentage of nulliparous goats according to the site of insemination in the HA group did not differ between first and the second insemination. However, in multiparous goats the percentage of animals inseminated intra-cervically was significantly increased (p≤0.05) between the first and the second inseminations.ConclusionThe results suggest that significantly higher fertility rate in the “HA goats” compared to the “without HA” group was because of deeper insemination facilitated by topical cervical application of HA. The deeper insemination into the cervical canal increase the rate of fertilisation when the cervical artificial insemination is performed.

Experimental Coxiella burnetii infection in non-pregnant goats and the effect of breeding

Q fever is a zoonosis caused by the intracellular bacterium Coxiella burnetii. In Europe, small ruminants are the main source of human Q fever. Small ruminant herds can be infectious during several lambing seasons. However, it is not clear how infection is maintained in a herd and what role non-pregnant animals play in the transmission of C. burnetii. We therefore inoculated nulliparous goats with C. burnetii, isolated from the outbreak of Q fever in the Netherlands, to gain a better understanding of the role of non-pregnant goats. Seroconversion and excretion of C. burnetii were monitored after inoculation. To study the effect of breeding on the excretion of C. burnetii, the goats were naturally bred and monitored during gestation and after lambing. Our results indicate that C. burnetii infection prior to breeding did not result in infection of the placenta nor did it affect the gestation length or the number of kids born. However, one of the ten does did excrete C. burnetii in the colostrum post-partum and the bacterium was detected in the mammary gland and associated lymph nodes at necropsy. This result indicates that non-pregnant goats might play a role in maintaining Q fever in a goat herd as persistent carriers of infection.

Effect of Continuous Administration of Enalapril Maleate on the Oocyte Quality and In Vitro Production of Parthenote Embryos in Nulliparous and Multiparous Goats Undergoing Serial Laparoscopic Ovum Pick-Up.

Simple SummaryOne of the main obstacles to the in vitro production of embryos in goats is the low ovarian response to hormonal treatments and low oocyte quality. Thus, several strategies have been performed to improve the reproductive performance of goats, including the development of new hormonal protocols as well as the use of other drugs that act directly or indirectly on reproductive function. In this experiment, we tested the use of a hormonal protocol aimed at maximizing the ovarian response and, in parallel, an angiotensin-converting enzyme (ACE) inhibitor was administered daily as an adjuvant. In recent years, the renin-angiotensin system has been shown to play an important role in reproductive function, especially in follicular development. We found that administration of the ACE inhibitor affected the ovarian response in multiparous goats, with more visible follicles, and had no effect on oocyte quality or during embryonic development, thus being a possible alternative to improve goat reproductive response.The aim of this work was to determine the effect of enalapril maleate administration, during oocyte recovery by serial laparoscopic ovum pick-up (LOPU), on the ovarian response and in vitro embryo production (IVP). Twenty cross-bred goats were allocated equally into two groups: Nulliparous and Multiparous. In each group, five animals were selected to receive daily doses of enalapril maleate during the hormonal protocol. Estrus was synchronized by a PGF2α analog, followed 48 h later by insertion of an intravaginal device with progesterone. Forty-eight hours after, a single dose of FSH/eCG was administered. The FSH/eCG doses were repeated three times, on every four day. Oocytes were recovered by LOPU 24 h after each FSH/eCG dose. Viable oocytes were matured in vitro, to be parthenogenetically activated and cultured for 72 h to the cleavage stage. The drug treatment increased the proportion of total follicles observed at LOPU (p < 0.01) in multiparous goats. In both parity groups, enalapril administration had no effect on the proportion or quality of oocytes recovered. Furthermore, the number of embryos cleaved was similar between the groups. Thus, enalapril maleate affected the ovarian response in multiparous animals only and had no effect on the oocyte quality or IVP.

Goat incubator: Can bovine oocytes be matured in the uterine horn of a goat?

We used a goat as a live incubator, along with associated nonsurgical embryo transfer techniques, to perform ex situ (in vivo) maturation of bovine oocytes. Immature bovine cumulus-oocyte complexes (COCs) aspirated from 3-8 mm follicles from slaughterhouse ovaries were randomly split into two groups for in vitro (IVM; n = 38) and ex situ maturation (ESM; n = 40). IVM was performed for a period of 24 h at 38.5 ºC and with 5% CO2 in the air of maximum humidity. For ESM, a presynchronized nulliparous goat (12 months old) received 40 immature COCs in the uterine horn apiece, via the transcervical route. After 24 h the structures were retrieved through uterine flushing. Analyses of nuclear maturation and lipid quantification were performed on oocytes from both groups. Fluorescent intensity was compared using the Student’s t-test. Forty-seven percent of the structures were recovered after uterine flushing (19/40). The nuclear maturation rate was 94.5% (18/19) and 81.6% (31/38) for the ESM and IVM groups, respectively. In vitro-matured COCs contained more lipid droplets, expressed as a higher amount (p &lt; 0.05) of emitted fluorescent light than ex situ-matured COCs (858 ± 73 vs. 550 ± 64 arbitrary fluorescence units, respectively). This is the first report to associate nonsurgical embryo transfer techniques and a goat as a live incubator for the maturation of bovine oocytes. We conclude that bovine oocytes can progress meiotically in the uterus horn of a goat and that transcervical transfer of bovine oocytes to a goat’s uterus could present an alternative to nuclear maturation.

INCIDENCE OF HYDROMETRA IN GOATS AND THERAPEUTIC EFFECTS

The presence of hydrometra was analyzed on five dairy goat farms (one Saanen and four Alpine) in a period of one to three years, from 2013 to 2016. Total of 3,355 goats were scanned by ultrasound for pregnancy diagnosis after breeding season or out-of-season upon hormonal synchronization. Overall incidence of hydrometra was 1.37%. One farm of Saanen goats demonstrated statistically higher incidence of hydro/pyometra as compared to other four Alpine farms (3.25% vs. 0.56%; p &lt;0.001). Seasonal synchronization of anestric goats and occasional outof-season synchronization in nulliparous Saanen goats probably contributed to higher incidence of this pathological condition (7/67; 10.45%), thus leaving unclear if this results can be attributed to breed affinity and/or to intensive reproductive management. Treatment with double prostaglandin injections and antibiotic treatment of hydrometra/pyometra resulted in relatively good conception rate of 64% (16/25). In conclusion, regular ultrasonography 40-70 days after mating or insemination is of crucial importance for intensive farm reproductive management on large dairy goat farms. After the treatment, significant percentage of goats with hydrometra can be successfully rebred.

Relationship of foetal number and parity in Barbari goats to plasma profile of caprine pregnancy-associated glycoprotein (caPAG) during gestation and the early postpartum period

This study was conducted to characterise pregnancy-associated glycoprotein (caPAG) in peripheral plasma during gestation and postpartum periods of nulliparous and multiparous does with one or two foetuses using a caPAG specific two-step sandwich ELISA system. Earliest time-points for detection of pregnancy and foetal number with appropriate cut-off values were identified. Plasma samples from 15 pregnant (multiparous: n = 8; nulliparous: n = 7; during pregnancy and postpartum period) and six non-pregnant (during oestrous cycle) goats were collected and analysed. Mean caPAG concentration was greater than the threshold for pregnancy detection (S-N = 0.40) on d22, peaked on d45 and remained unchanged until parturition. From d45 until parturition, caPAG concentration in multiparous does with two foetuses was 1.4 to 1.8 fold greater (P < 0.001) than those with one foetus. For the ELISA, 0.83 (S-N) was the most appropriate cut-off to differentiate does with two from those with a single foetus with an overall sensitivity and accuracy of 88.9% and 84.7%, respectively. Circulating caPAG concentration in multiparous goats was greater (P < 0.05) compared with nulliparous goats during the early pregnancy and postpartum periods. After parturition, caPAG concentrations markedly decreased and were basal within 14 days postpartum. In conclusion, using the caPAG specific ELISA, results indicated there were unique gestational and postpartum profiles for caPAG concentrations that are affected by number of foetuses and parity of the doe. The marked decrease in concentration of caPAG following parturition indicates there would not be compromising of the detection of subsequent pregnancies in goats using this technique.

How strong is the evidence linking stress reactivity with future health and disease outcomes?—A systematic review of prospective evidence

The objective of this study was to determine the estrous response and the moment of ovulation and fertility after a progesterone (P4) priming plus human chorionic gonadotropin (hCG) administration in multiparous and nulliparous goats. Therefore, two experiments were conducted during non-breeding season (April and May, 26° N) and all the animals received a single injection of 20 mg of P4 and 100 IU of hCG 24 h later. In Experiment 1, 13 multiparous and 9 nulliparous goats were subjected to estrus detection twice a day from P4 administration, and their ovaries were scanned by transrectal ultrasonography every 12 h from the onset of estrus to determine ovulation. The proportion of goats in estrus did not differ between multiparous and nulliparous females. The onset of estrus (60.5 ± 12.4 h vs. 52.0 ± 5.2 h after hCG administration) and the moment of ovulation (91.5 ± 10.3 h vs. 85.3 ± 11.5 h) were also similar in multiparous and nulliparous goats. In Experiment 2, a total of 299 multiparous and nulliparous goats managed under intensive (n = 112 and 41 goats, respectively) or extensive (n = 85 and 61 goats, respectively) production systems were divided to receive a fixed-time artificial insemination (FTAI) with fresh semen at 60 or 72 h after hCG administration. The pregnancy rate did not differ significantly between multiparous and nulliparous goats in both production systems. Nonetheless, in the intensive system pregnancy rate was affected by the moment of insemination (P < 0.05). In this system, the pregnancy rate was higher in goats inseminated at 60 h than in 72 h (55.6%, 44/79 vs. 35.1%, 26/74, respectively; P < 0.05). On the contrary, in the extensive system the pregnancy rate was not affected by the time of insemination (29.4%, 23/78 vs. 22.0%, 15/68). To conclude, both the ovulatory response and the pregnancy rate after a single P4 injection plus hCG was similar between multiparous and nulliparous goats during anovulatory season. Although the pregnancy rate was not affected by the time of insemination in the extensive production system, under intensive conditions FTAI should be performed at 60 h after hCG treatment.

Use of injectable progesterone and hCG for fixed-time artificial insemination during the non-breeding season in goats

The objective of this study was to determine the estrous response and the moment of ovulation and fertility after a progesterone (P4) priming plus human chorionic gonadotropin (hCG) administration in multiparous and nulliparous goats. Therefore, two experiments were conducted during non-breeding season (April and May, 26° N) and all the animals received a single injection of 20 mg of P4 and 100 IU of hCG 24 h later. In Experiment 1, 13 multiparous and 9 nulliparous goats were subjected to estrus detection twice a day from P4 administration, and their ovaries were scanned by transrectal ultrasonography every 12 h from the onset of estrus to determine ovulation. The proportion of goats in estrus did not differ between multiparous and nulliparous females. The onset of estrus (60.5 ± 12.4 h vs. 52.0 ± 5.2 h after hCG administration) and the moment of ovulation (91.5 ± 10.3 h vs. 85.3 ± 11.5 h) were also similar in multiparous and nulliparous goats. In Experiment 2, a total of 299 multiparous and nulliparous goats managed under intensive (n = 112 and 41 goats, respectively) or extensive (n = 85 and 61 goats, respectively) production systems were divided to receive a fixed-time artificial insemination (FTAI) with fresh semen at 60 or 72 h after hCG administration. The pregnancy rate did not differ significantly between multiparous and nulliparous goats in both production systems. Nonetheless, in the intensive system pregnancy rate was affected by the moment of insemination (P < 0.05). In this system, the pregnancy rate was higher in goats inseminated at 60 h than in 72 h (55.6%, 44/79 vs. 35.1%, 26/74, respectively; P < 0.05). On the contrary, in the extensive system the pregnancy rate was not affected by the time of insemination (29.4%, 23/78 vs. 22.0%, 15/68). To conclude, both the ovulatory response and the pregnancy rate after a single P4 injection plus hCG was similar between multiparous and nulliparous goats during anovulatory season. Although the pregnancy rate was not affected by the time of insemination in the extensive production system, under intensive conditions FTAI should be performed at 60 h after hCG treatment.

Catarrhal mastitis by &lt;i&gt;Staphylococcus simulans&lt;/i&gt; in a nulliparous goat

The present paper is a case report of a one-year old nulliparous Alpine Goat belonging to a dairy goat farm in semi-arid region of Brazil. Both glands were naturally infected by α-hemolytic Staphylococcus simulans and evolved similar clinical signs. The mammary glands presented an acute catarrhal mastitis with systemic clinical signs that responded positively to treatment with gentamicin associated with amoxicillin. The present report suggests the importance of the pathogenic potential of non-aureus Staphylococci strains (NAS) as a cause of clinical mastitis also in nulliparous animals. The isolate showed resistance to tetracycline and contained staphylococcal toxin production genes (sec, sec and TSST-1). Moreover, it has been reported that Staphylococcus simulans is an emerging pathogen in humans causing cutaneous and osteoarticular infections, mainly in those in close contact with farm animals. To the best of our knowledge, this is the first report of a clinical mastitis in a nulliparous goat caused by Staphylococcus simulans.

Reproductive seasonality in Saanen goats kept under tropical conditions.

This study aimed to verify the reproductive seasonality in Saanen goats from distinct parity orders (nulliparous, primiparous, and pluriparous) throughout an entire year in the Southeast Region of Brazil. In addition, it was also verified the influence of environmental indexes, metabolic profile, body weight, and social interactions on the reproductive seasonality of these animals. Forty Saanen goats kept under intensive system at latitude 22° 52' 30″ s and tropical photoperiod (11-13h of light per day) were used. Every 15days, blood from 24 animals (8 animals per group) was collected for assessment of serum progesterone levels. Monthly, environmental data (rainfall index, maximum and minimum temperature, and time of natural daylight) and blood were collected to evaluate the metabolic profile. Weighting and body condition score measurement were also carried out every 2months. There was no difference in body weight and body condition score in primiparous and pluriparous goats. Nulliparous goats showed natural breeding season in the winter season while the primiparous and pluriparous goats remained cyclical in autumn and winter season. Regardless of the parity order, all goats showed a seasonal anestrus in the spring season. From December, social interactions were able to reestablish, in distinct degrees, the cyclical state in the goats. Likewise, environmental and weight indexes had low and moderate influence, respectively, on the reproductive seasonality in the Saanen goats kept under tropical conditions.

Post-translational modification of a chimeric EPO-Fc hormone is more important than its molecular size in defining its in vivo hematopoietic activity

BackgroundRecombinant erythropoietin (EPO) has been marketed as biopharmaceutical for anemia and chronic renal failure. Long-acting EPO variants that aimed at achieving less frequent dosing have been generated, either by the addition of glycosylation sites or increasing its molecular weight. MethodsThe hEPO cDNA linked to the human IgG Fc fragment was cloned as a single codifying gene on the pAdtrack-CMV vector, yielding the recombinant adenoviral genome. For in vitro and in vivo expression assays cervical cancer cell line (SiHa) and nulliparous goats were used, respectively. The hematopoietic activity of EPO-Fc, expressed as the differential increment of hematocrit was evaluated in B6D2F1 mice. NP-HPLC of the 2AB-labeled N-glycan was carried out to profile analysis. ResultsThe direct transduction of mammary secretory cells with adenoviral vector is a robust methodology to obtain high levels of EPO of up to 3.5mg/mL in goat's milk. SiHa-derived EPO-Fc showed significant improvement in hematopoietic activity compared to the commercial hEPO counterpart or with the homologous milk-derived EPO-Fc. The role of the molecular weight seemed to be important in enhancing the hematopoietic activity of SiHa-derived EPO-Fc. However, the lack of sialylated multi-antennary glycosylation profile in milk-derived EPO-Fc resulted in lower biological activity. ConclusionsThe low content of tri- or tetra-antennary sialylated N-glycans linked to the chimeric EPO-Fc hormone, expressed in the goat mammary gland epithelial cells, defined its in vivo hematopoietic activity. General significanceThe sialylated N-glycan content plays a more significant role in the in vivo biological activity of hEPO than its increased molecular weight.

Estrous and ovarian responses following the administration of different insulin doses following progestagen-cloprostenol treatment in mated does during the dry season

Thirty-nine nulliparous and cyclic free-ranging Anglo-nubian goats were synchronized using 60mg MAP intravaginal sponges for 10days and 50μg cloprostenol treatment, 48h before sponge removal (SR). Goats were allocated to 3 groups with 13 animals in each group. The treatment groups, Insulin 0.14 and Insulin 0.20 were treated subcutaneously, for 3 consecutive days – beginning 48h before SR, with 0.14IU/kg BW/day or 0.2IU/kg BW/day of a long-acting insulin, respectively. The Control group received a 0.5ml saline solution (s.c.). The goats were monitored for the occurrence of estrus and mated at the onset of estrus and 24h later. Transrectal ultrasonography was used to monitor the ovarian follicular dynamics, ovulation rate and diagnose pregnancy. Blood samples were collected from 48h before SR to the 12th day of pregnancy for plasma insulin determinations. Insulin administration exhibited an increase (p<0.05) in animals with plasma insulineamia. Insulin treated goats recorded a higher (p<0.05) ovulation rate, when compared to saline control treated goats (1.7±0.23 vs 1.0±0.21). Nulliparous does from the Insulin 0.14 group recorded large follicles at 0, 12 and 18h of the estrous period (p<0.05), a more efficient synchronization of ovulation (p<0.05) and larger size CLs (p<0.05). It was concluded that administration in insulin induced a positive effect on ovarian response in nulliparous goats. Furthermore, in these animals the reproductive performance appeared to be independent of the increase of insulin dosage.

Assessment of luteal function in goats by ultrasonographic image attribute analysis

The aim of this study was to evaluate the potential of luteal echotexture (mean pixel value and heterogeneity), as a tool for assessing luteal function during different phases of the estrous cycle in Toggenburg goats. Sonographic evaluations of the ovaries were performed daily in nulliparous goats ( n = 21), using a 5 MHz linear rectal probe, commencing at estrus (day 0). Blood samples were collected daily for plasma progesterone RIA and images recorded on VHS tape and then digitized in TIFF format at a resolution of 1500 × 1125 pixels. A representative elementary area (REA) of 5625 pixels (0.31 cm 2) of these images was analyzed using custom-developed software, for mean pixel value and heterogeneity. Mean plasma progesterone, luteal area and pixels all reached maximum values at approximately days 13 and 14, during luteogenesis. Luteolysis was characterized by an abrupt decrease in blood progesterone concentration following ovulation, and a gradual decline in luteal area and pixel values. The luteal tissue area was positively correlated with plasma progesterone concentration during both luteogenesis ( r = 0.63; P < 0.05) and luteolysis ( r = 0.50; P < 0.05). Weak correlations were recorded between the mean pixel value and luteal tissue area during luteogenesis ( r = 0.34; P < 0.05) and luteolysis ( r = 0.26; P < 0.05). Similarly, weak correlations between the mean pixel value and plasma progesterone concentration were recorded during luteogenesis ( r = 0.24; P < 0.05) and luteolysis ( r = 0.37; P < 0.05). The pixel heterogeneity was not correlated with luteal tissue area or the plasma progesterone concentration at any stage of the estrous cycle. The results show the association between the corpus luteum echotexture and steriodogenic function to be weak and the present ultrasound technology, to have limited potential in evaluating luteal function in goats.

23 INDUCTION OF ESTRUS IN CYCLIC ALPINE GOATS WITH SHORT-TERM PROGESTAGEN PROTOCOLS WITH OR WITHOUT eCG ADMINISTRATION

Depending on the season, estrus can be efficiently induced using male effect, melatonin implants, light controlled programs, prostaglandin, progestagens, and gonadotrophins. The eCG is the most used hormone employed in estrus induction protocols in goats. However, as eCG is a foreign protein, a humoral immune response (i.e. antibody formation) is displayed in goats, which tends to reduce the efficiency of eCG when successively administered. The objective of this study was to evaluate the possibility of omitting the administration of eCG to induce estrus in Alpine goats during the breeding season in herds submitted to successive hormonal estrus induction. This study was done in April (local breeding season) of 2009 in Florestal/MG, Brazil. Nulliparous (n = 10) and pluriparous (n = 10) Alpine goats were equally assigned to receive (Day 0) MAP 60 mg intravaginal sponges (Progespon®, Schering Plough Animal Health, São Paulo, Brazil) for 6 days and 50 μg D-cloprostenol (Ciosin®, Schering Plough Animal Health) i.m. with (T1) or without (T2) 200 IU of eCG (Novormon 5000®, Schering Plough Animal Health) i.m. 24 h before sponge removal. Transrectal ultrasound (5 MHz probe, Aloka SSD 500®, Tokyo, Japan) was done at 12-h intervals until 72 h after sponge removal. All goats underwent timed AI 55 h after sponge removal according to expected ovulation (Menchaca et al. 2007 Anim. Reprod. Sci. 102, 76-87). Statistical analysis was performed using all tests at the 95% confidence interval (SAEG® program, Funarbe, Viçosa, Brasil). Data are reported as percentage or mean ± SD. The following results for T1 or T2 animals (respectively) were observed: estrus response (80 and 80%), goats ovulating (80 and 100%), interval from sponge removal to estrus onset (46.0 ± 17.0 and 53.5 ± 18.1 h) and to ovulation (58.8 ± 6.2 and 66.0 ± 9.8 h), interval from estrus onset to ovulation (26.0 ± 8.5 and 26.0 ± 0.7 h), diameter of ovulatory follicles (7.1 ± 0.6 and 7.4 ± 0.9 mm), number of ovulations (1.7 ± 0.8 and 1.8 ± 0.9 h), intervals from sponge removal to insemination (56.9 ± 2.3 and 58.2 ± 1.2 h) and from estrus onset to insemination (10.9 ± 14.5 and 4.6 ± 16.1h) and pregnancy rate (20 and 40%). Eight goats were inseminated at 17 to 23 h after estrus onset, which resulted in 50% pregnancy rate, and the other 2 pregnant goats were inseminated without being detected in estrus. In Brazil, dairy goats are inseminated with frozen-thawed semen 12 to 24 h after estrus onset or 42 to 55 h after sponge removal. Thus, for Alpine goats, this study suggests that earlier AI time should be avoided. However, under heat detection, AI at 18 to 24 h can be indicated. Ovarian ultrasonography of goats submitted to estrus induction gives great information of ovulation time relative to device removal and to estrus onset, which can optimize AI efficiency. In herds with successive estrus induction this kind of information could indicate an error in the common times currently used in AI programs in goats in Brazil. Financial support: Embrapa Goats and Sheep, CNPq and FAPEMIG.

448 RELATION BETWEEN GESTATIONAL AGE AND ULTRASONOGRAPHIC MEASUREMENTS OF CONCEPTUS PARAMETERS IN ANGLO-NUBIAN GOATS RAISED IN THE BRAZILIAN SEMIARID REGION

The aim of this study was to determine the relation of gestational age with embryonic/fetal measurements in goats through the real-time ultrasound method. Ultrasonographic examinations began on the 25th day after first mating in eight Anglo-Nubian nulliparous goats, using a Falco 100 ultrasound scanner fitted to 6/8 MHz linear-array and 3.5 MHz convex probe. On recorded scanning images, the embryonic vesicle diameter (EVD) and crown-rump length (CRL), head length (HL), bi-parietal diameter (BPD), thoracic diameter (TD), umbilical cord diameter (UCD), long axis of heart (LAH), and short axis of heart (SAH) and placentomes of embryo/fetus were measured using computer software. The relationships between gestational age and each parameter of the ultrasonic measurements were expressed as straight-line equations and plotted as linear regression using Statistica 7.0 software, being statistically significant at a level of P &lt; 0.05. Mean values were correlated to fetal age, and inverse regression equations were created for each parameter. Results obtained showed the following values: EVD (r = 0.94), CRL (r = 0.94), HL (r = 0.74), BPD (r = 0.70), TD (r = 0.88), UCD (r = 0.73), LAH (r = 0.77), SAH (r = 0.80), and placentome (r = 0.71). Additionally, embryonic size increased from the first detection of the embryo to the end of the study. In conclusion, the ultrasonographic technique is a reliable method to estimate gestational age through the embryonic/fetal measurement once its increase follows a linear regression standard. CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brasil).

Effect of parity and progesterone priming on induction of reproductive function in Saanen goats by buck exposure

The response to the buck effect and the use of progesterone priming was studied in Saanen goats during the non-breeding season (April and May) in northern Mexico (26° N). Forty goats were assigned randomly in equal numbers ( n = 10) to four treatment groups in a 2 × 2 factorial arrangement. Treatment consisted of two dosages of progesterone (P4) (0 or 5 mg) and two categories of goats, nulliparous and multiparous. Both parity groups were exposed to sexually active bucks previously exposed to a long-day photoperiodic scheme (16 h light day − 1 ). All multiparous goats (20/20) displayed estrous behavior within the first 10 days of buck exposure, while 70% (14/20) of the nulliparous goats showed estrus ( P > 0.05). During the first five days of buck exposure, the percentage of unprimed goats in estrus was 70% points lower than the primed goats, although progesterone priming did not affect the occurrence of estrus (90% vs 80%; P > 0.05) after 10 days of buck stimulus. The time to onset of estrus was four days shorter ( P < 0.05) in P4-treated goats compared with controls. Pregnancy rate did not differ between primed and unprimed goats (80 vs 60%; P > 0.05), but this variable was higher ( P < 0.05) in multiparous than nulliparous goats (95 vs 45%). It was concluded that it is possible to induce fertile estrus in Saanen goats during the non-breeding season in northern Mexico using sexually active bucks. The use of progesterone priming can accelerate the response of goats to the buck stimulus although it was ineffective in improving the pregnancy rate of goats. Additionally, a higher proportion of the multiparous goats got pregnant compared with the nulliparous goats induced to estrus by the buck stimulus.

Successful artificial insemination using semen frozen and stored by an ultrafreezer in the Majorera goat breed

The semen of five Majorera breed bucks was collected and processed to reach a final concentration of 200 × 10 6 spermatozoa/straw in the extender containing 4% of glycerol and 12% of egg yolk. Two freezing techniques were assessed: (LN) straws were frozen and stored in liquid nitrogen, and (ULF) straws were frozen and stored in the ultra-low freezer at −152 °C. Semen quality (sperm motility, acrosome integrity and abnormal sperm cells percentages) was determined for different storage times (1, 30, 90 and 365 days of cryopreservation). Thereafter, 150 Majorera goats were assigned to four experimental groups: for groups LN-1 ( n = 40) and LN-6 ( n = 35), the goats were transcervically inseminated with frozen-thawed semen stored for 1 and 6 months in liquid nitrogen, respectively, while for groups ULF-1 ( n = 40) and ULF-6 ( n = 35), the goats were transcervically inseminated with frozen-thawed semen stored for 1 and 6 months in an ultra-low freezer at −152 °C, respectively. The pregnancy rate was determined by transabdominal ultrasound scanning; in addition, the kidding rate and prolificacy were recorded at parturition. In vitro results showed that the freezing protocol did not affect sperm quality with similar values for up to 1 year of cryopreservation. The kidding rates were not significantly different between experimental groups (43.6%, 38.5%, 42.8% and 40.0% for groups LN-1, ULF-1, LN-6 and ULF-6, respectively). In all experimental groups, the kidding rate and prolificacy were significantly higher ( p < 0.01) in multiparous than in nulliparous goats. Therefore, the in vitro results and fertility trials confirmed the efficiency of the ULF technique for freezing and storage of goat semen.

313 ASSESSMENT OF LUTEAL FUNCTION IN TOGGENBURG GOATS BY COMPUTER-ASSISTED IMAGE ANALYSIS

Computer-assisted image analysis is a technological extension of reproductive ultrasonography and allows the quantitative assessment of the luteal echotexture, which is related to changes in histological features and, consequently, to steroidogenesis. The aim of this study was to determine the efficiency of luteal echotexture evaluation as a tool to assess luteal function in different phases of the estrous cycle in Toggenburg goats. Nulliparous goats (n = 21), 8 months in age, 33.52 ± 1.22 kg of body weight, and body score condition of 3.5 ± 0.07 (1 to 5 scale), which showed estrus within a 48-h period during the natural breeding season (March and April), were used. After estrous detection (Day 0) and mating, ovarian sonographic evaluations were performed daily using a portable ultrasound device (Aloka SSD 500, Aloka Co.) equipped with an adapted linear transrectal 5-MHz probe. The examinations were preceded by blood sample collections, which were stored until radioimmunoassay for progesterone (P4). Images were recorded in VHS tapes, then digitized to TIFF files (resolution of 1500 × 1125 pixels) using a video capture board. A representative elementary area of 5625 pixels (0.31 cm2) was defined for the luteal tissue according to the criterion proposed by Van den Bygaart and Protz 1999. Computer-assisted analyses were performed using custom-developed software (Quantporo®). Each pixel received a numeric value ranging from 0 (black) to 255 (white). Luteal echotexture and plasma P4 data were analyzed by ANOVA, and differences among means were determined by Tukey’s test. Correlations were established by Pearson’s correlation method. Results are shown as mean ± SEM. Corpora lutea size increased progressively (P &lt; 0.001) until Day 9, when it reached the maximum area (1.26 ± 0.32 cm2). No increase in size was detected on the subsequent days (P &gt; 0.05). Plasma P4 levels increased until a maximum value on Day 9 (6.31 ± 0.46 ng mL–1), and no increase was observed further (P &gt; 0.05). In nonpregnant animals (n = 7), luteolysis was characterized by an abrupt decrease in plasma P4 concentration, which dropped to values lower than 1 ng mL–1 24 h after the onset of the process, whereas luteal area decreased gradually. Plasma P4 concentration was correlated to luteal area during luteogenesis and luteolysis (r = 0.63 and r = 0.50, respectively; P &lt; 0.05). Mean pixel value showed a progressive increase during luteogenesis and reached the maximum value on Day 13 (54.33 ± 1.83). During corpus luteum (CL) regression, mean pixel value decreased to lower values 48 h after the onset of natural luteolysis (P &lt; 0.05). Through both luteogenesis and luteolysis, positive correlations were observed between mean pixel values and luteal area (r = 0.34 and r = 0.26, respectively; P &lt; 0.05) and also between mean pixel values and plasma P4 concentration (r = 0.24 and r = 0.37, respectively; P &lt; 0.05). Pixel heterogeneity was not correlated to luteal area nor plasma P4 levels. These results suggest an association between CL echotexture and steroidogenic function; therefore, the quantitative assessment of the pixel brightness has a potential to be used for luteal function evaluation in goats. FAPEMIG and CAPES.