scholarly journals Sex ratio and size structure of Micropogonias furnieri (Desmarest, 1823) (Perciformes, Sciaenidae) in Sepetiba Bay, Rio de Janeiro, Brazil

2003 ◽  
Vol 63 (4) ◽  
pp. 559-566 ◽  
Author(s):  
R. N. Vicentini ◽  
F. G. Araújo
Keyword(s):  
Sex Ratio ◽  
Size Structure ◽  
Reproductive Potential ◽  
Outer Zone ◽  
Size Class ◽  
Cycle Period ◽  
Chi Square ◽  
Sepetiba Bay ◽  
Chi Square Test ◽  
Micropogonias Furnieri

Sex ratio and size structure constitute basic information in assessing reproductive potential and estimating stock size in fish populations. One hundred fifty-one individuals of Micropogonias furnieri caught by experimental otter trawls, in three zones (inner, central, and outer) of Sepetiba Bay between October 1998 and September 1999 were examined. Males outnumbered females (1.3:1.0) in all zones but no significant differences were detected. Only in the outer zone (5.0:1.0) were male/female rates significantly different according to the chi-square test. No temporal differences were observed in sex ratio. Fish size ranged from 81 to 244 mm total length (TL) with significant differences in 155 to 185 mm TL size classes, where males predominated, and a slightly higher number of females were observed for the smaller size class (TL = 95-150 mm). Size distribution varied according to the zone, with juveniles predominating in the inner and adults in the outer zone. Spatial difference in size structure observed in this study indicates that the inner bay is a rearing ground during the first life-cycle period, and movement toward the sea occurs as fish increase in size.

scholarly journals KOMPOSISI UKURAN, PERBANDINGAN JENIS KELAMIN, DAN TINGKAT KEMATANGAN GONAD IKAN TODAK BERPARUH PENDEK (Tetrapturus angustirostris) DI SAMUDERAHINDIA

2017 ◽  
Vol 3 (2) ◽  
pp. 123
Author(s):  
Dian Novianto ◽  
Budi Nugraha ◽  
Andi Bahtiar
Keyword(s):  
Indian Ocean ◽  
Sex Ratio ◽  
Size Composition ◽  
Maturity Stage ◽  
Chi Square ◽  
Male And Female ◽  
Level Ii ◽  
Chi Square Test ◽  
The Indian Ocean ◽  
Tuna Longline

Ikan todak berparuh pendek atau ikan tumbuk atau shortbill spearfish (Tetrapturus angustirostris) merupakan salah satu hasil tangkapan sampingan rawai tuna. Informasi mengenai ikan todak berparuh pendek seperti komposisi ukuran, perbandingan kelamin, dan tingkat kematangan gonadsangat terbatas. Tulisan ini bertujuan untuk menyajikan data dan informasi mengenai aspek biologi ikan todak berparuh pendek yang merupakan hasil tangkapan sampingan dari rawai tuna yang beroperasi di Samudera Hindia. Penelitian ini dilakukan pada bulan September sampai Desember 2008 di perairan Samudera Hindia. Hasil penelitian menunjukan bahwa ikan todak berparuh pendek memiliki kisaran panjang tubuh 135-175 cmLJFL dan modus pada kisaran 155-165 cmLJFL.Perbandingan jenis kelamin ikan jantan dan betina 1:13,5, berdasarkan atas hasil uji chi-square menunjukan bahwa rasio ikan jantan dan betina pada periode penelitian ini tidak seimbang. Pada bulan September ikan todak berparuh pendek betina didominansi oleh tingkat kematangan gonad IIsebesar 66,7%, bulan Oktober oleh tingkat kematangan gonad V sebesar 46,2%, bulan Nopember oleh tingkat kematangan gonad II sebesar 53,3%, sedangkan pada bulan Desember oleh tingkat kematangan gonad III sebesar 42,9%. Pada bulan Nopember sampai Desember terlihat bahwa tingkat kematangan gonad V mulai berkurang, hal ini menunjukan bahwa pada bulan Nopember sampai Desember diduga banyak ikan todak berparuh pendek betina yang sudah memijah. Shortbill Spearfish (Tetrapturus angustirostris) is one of bycatch of tuna longline. Information about shortbill spearfish on the size composition, sex ratio, and maturity stage is still very limited. The objective this paper is to present the data and information about shortbill spearfish which is a bycatch of tuna longline that operated in the Indian Ocean. Research was conducted during September until December 2008 in Indian Ocean. The results showed that the shortbill spearfish have body length about 135-175 cmLJFL and modes in 155-165 cmLJFL. Sex ratio of the male and female was 1:13.5. Based on chi-square test showed that the ratio of male and female in the period of the study was not balanced. In September, the female stage maturity was dominated by level II of 66.7%, October by level V of 46.2%, November by level II of 53.3%, and December by level III of 42.9%. During November until December showed that the maturity stage of level V was decreased, this shows that in this time the female of shortbill spearfish was spawned.

scholarly journals BEBERAPAASPEKBIOLOGI IKANBELOSO(Sauridamicropectoralis) DI PERAIRANUTARAJAWATENGAH

2017 ◽  
Vol 3 (6) ◽  
pp. 363
Author(s):  
Adrian Damora ◽  
Tri Ernawati
Keyword(s):  
Sex Ratio ◽  
Maturity Stage ◽  
Chi Square ◽  
Central Java ◽  
Weight Growth ◽  
Gonadal Maturity ◽  
Carnivorous Species ◽  
Chi Square Test ◽  
Java Sea ◽  
Stadium I

Indeks kelimpahan stok ikan beloso (Saurida micropectoralis) di Laut Jawa cenderungmengalami penurunan dari tahun ke tahun dan untuk mencegahnya perlu bahan masukan yang bersumber dari hasil penelitian yang dijadikan sebagai dasar pengelolaannya. Penelitian dilakukan untukmengkaji beberapa aspek biologimeliputi hubungan panjangberat, nisbah kelamin, tingkat kematangan gonad, panjang pertama kali tertangkap dan panjang pertama kali matang gonad, serta kebiasaan makan ikan beloso. Penelitian dilakukan pada bulanApril–Agustus 2009 di perairan utara Jawa Tengah. Hasil penelitian menunjukkan bahwa nisbah kelamin ikan jantan dan betina berada dalam keadaan tidak seimbang. Pertumbuhan ikan beloso bersifat allometrik positif, dimana pertambahan berat lebih cepat dibandingkan pertumbuhan panjangnya dan tingkat kematangan gonad (TKG) ikan beloso didominasi oleh stadium I. Panjang pertama kali ikan beloso tertangkap lebih kecil dari panjang pertama kali matang gonadnya (Lc < Lm) sehingga akan mengancam kelestariaannya. Ikan beloso bersifat karnivora, dimana makanan utamanya adalah potongan ikan dasar, cumi, dan teri. Index of stock abundance of Lizardfish (Saurida micropectoralis) in Java Sea tend to decreased from year to year. The decline was expected because of the potential of Lizardfish decreasing but the effort continue to rise. The objective of this study is to assess the biological aspects including length-weight relationship, sex ratio, gonadal maturity stage, length of first capture (Lc) and length of first mature (Lm), and feeding habit of Lizardfish in north waters of Central Java. This study was conducted from April to August 2009 in north waters of Central Java. Results showed that the sex ratio between males and females was 1:0,97. Based on Chi-square test it is showed that sex ratio is not balanced. The growth of Lizardfish indicated positive allometric where the weight growth more faster than its length growth. The gonadalmaturity stage of Lizard fish is dominated by the first stage. The length of first capture of Lizardfish was under the length of first mature (Lc < Lm) so that will threaten its sustainability. Lizardfish was indicated carnivorous species where its main food are part of demersal fishes, squids and anchovies.

Double diapering facilitates hip maturation in newborns: a prospective randomised control study

2020 ◽  
Author(s):  
Wei C. Lee ◽  
Hsuan K. Kao ◽  
Mei C. Chen ◽  
Wen E Yang ◽  
Shih M. Chu ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Gestational Age ◽  
Birth Rate ◽  
Hip Dysplasia ◽  
Alpha Angle ◽  
First Year ◽  
Type I ◽  
Chi Square ◽  
Chi Square Test ◽  
Control Study

Abstract Background Maintaining the hips in flexion and abduction posture is a common recommendation to facilitate hip maturation in infants. Double diapering helps to maintain a baby’s hips in flexion and abduction posture, but the efficacy of double diapers in hip development has never been verified. We investigated whether double diapering results in greater improvement of the alpha angle in the first months of life. Methods This prospective randomised control study enrolled newborns with Graf type IIa hips. Babies were assigned to the double-diaper or single-diaper group. Parents were instructed on proper hip positioning, except for diapering. Change in the alpha angle from newborn to 1 month after birth, rate of improvement to bilateral Graf type I hips in 1 month, and number of ultrasound examinations and orthopaedic clinic visits in the first year were compared between the two groups. For babies with bilateral IIa hips, we used the averaged data from both hips, and for babies with unilateral IIa hips, we used the data from the IIa hips. Results Seventy newborns with 102 type IIa hips were included from January to December 2017. They were allocated to the double-diaper group (N=33) and single-diaper group (N=37). With a comparable sex ratio, gestational age, and newborn alpha angle, the double-diaper group had a greater increase of alpha angles in 1 month than the single-diaper group (+7.9° vs. +5.2°, t-test, p=0.011). Twenty-eight babies in the double-diaper group (84.8%) and 20 babies in the single-diaper group (54.1%) improved to having bilateral Graf type I hips (chi-square test, p=0.006). Subsequent clinical visits and hip ultrasounds before 1 year were significantly reduced in the double-diaper group. Conclusions Our results support double diapering for enhancing hip maturation in babies with Graf type IIa hips. The amount of improvement may not indicate double diapering as a treatment for hip dysplasia, but its effects in immature hips are noteworthy in reducing further clinical and ultrasound follow-ups.

scholarly journals Sex Ratio And Size At First Maturity Of Blue Swimming Crab (Portunus pelagicus) Salemo Island Pangkep Regency

2016 ◽  
Vol 21 (1) ◽  
pp. 17 ◽  
Author(s):  
Muh. Saleh Nurdin ◽  
Syamsu Alam Ali ◽  
Dewi Yanuarita Satari
Keyword(s):  
Sex Ratio ◽  
Coral Reefs ◽  
Swimming Crab ◽  
High Demand ◽  
Chi Square ◽  
Portunus Pelagicus ◽  
Ratio Size ◽  
Chi Square Test ◽  
First Maturity ◽  
Size At First Maturity

Blue swimming crab (Portunuspelagicus) is aeconomical valuable fisheries importantcommodity  due to the high demand and availability jobs created for the fishermen. Due to their high demand blue swimming crab heavily exploited from Salemo Island. This study aimed at comparing the sex ratio and the size at first maturity of blue swimming crab caught in mangrove ecosystems, coral reefs, and seagrass. Sex ratio was analyzed using chi square test and the size at first maturity was analyzed using the Spearman-Karber formula. The results showed the sex ratio ofmales and femalessmall crab caught in every ecosystem is balanced. The size at first maturity of blue swimming crab caught in mangrove, seagrass and coral reefs, each to the male 81,08 mm, 102,36 mm and 102,87 mm in width and size of female 94,54 mm, 83,35 mm, 98,31 mm width. In a reference to government regulations, the blue male swimming crab caught in the coral reef and seagrass ecosystems have yet to size at first maturity is allowed to be captured. Keywords: blue swimming crab, sex ratio,size at first maturity, Salemo Island

scholarly journals ASPEK BIOLOGI IKAN TEMBANG (Sardinella gibbosa BLEEKER, 1849) DI PERAIRAN PRIGI DAN SEKITARNYA

2019 ◽  
Vol 11 (3) ◽  
pp. 151
Author(s):  
Prawira A. R. P. Tampubolon ◽  
Maya Agustina ◽  
Zulkarnaen Fahmi
Keyword(s):  
Sex Ratio ◽  
Logistic Function ◽  
Purse Seine ◽  
Chi Square ◽  
Gonadal Maturity ◽  
Fish Samples ◽  
Sardinella Gibbosa ◽  
Chi Square Test ◽  
Relationship Of ◽  
The Relationship

Ikan tembang (Sardinella gibbosa Bleeker, 1849) adalah salah satu jenis ikan pelagis kecil, bernilai ekonomis penting serta banyak tertangkap di perairan Prigi dan sekitarnya. Informasi terkait ikan ini masih sangat terbatas di perairan Prigi. Penelitian ini bertujuan untuk mengungkap beberapa aspek biologi ikan tembang hasil tangkapan pukat cincin di perairan Prigi dan sekitarnya. Penelitian berlangsung selama lima bulan, dari Mei hingga September 2019. Ikan tembang yang dijadikan contoh merupakan hasil tangkapan pukat cincin yang didaratkan di PPN Prigi. Contoh ikan yang diukur panjang dan ditimbang bobotnya berjumlah 705 ekor. Tiga ratus diantaranya kemudian dibedah untuk diamati jenis kelamin dan tingkat kematangan gonadnya secara visual. Analisis data dilakukan menggunakan regresi power yang diuji menggunakan uji-t untuk hubungan panjang bobot, uji khi kuadrat untuk menentukan keseimbangan nisbah kelamin, dan fungsi logistik untuk menentukan ukuran pertama kali ikan matang gonad. Panjang cagak ikan yang dianalisis berkisar antara 91-183 mm dengan ikan terbanyak pada selang kelas 110-119 mm. Pola pertumbuhan ikan tembang adalah allometrik negatif dengan nisbah kelamin yang seimbang. Ukuran pertama kali matang gonad ikan tembang di perairan Prigi dan sekitarnya adalah 128 mm. Sebagian besar ikan tembang yang tertangkap pada alat tangkap pukat cincin adalah ikan tembang yang masih belum dewasa.Goldstripe sardinella (Sardinella gibbosaBleeker, 1849) is a kind of small pelagic fish, economically important and caught a lot in Prigi and adjacent waters. The information regarding this fish was still very limited in Prigi waters. This study aimed to reveal several aspects of the biology of goldstripe sardinella caught by purse seine in Prigi and adjacent waters. The research was held for five months, from May to September 2019. Fish samples were from purse seiners that landed the caught at PPN Prigi. There were 705 fish measured and weighed. Three hundred of them were dissected to be observed the sex and gonadal maturity visually. Data analysis was performed using power regression which was tested using t-test for the relationship of weight length, chi-square test to determine the balance of sex ratio, and logistic function to determine the first length of maturity. The length of the fish was ranged from 91-183 mmFL and mostly was at 110-119 mmFL length class. The growth pattern of the goldstripe sardinella was allometric negative with a balanced sex ratio. The first length of maturity for goldstripe sardinella in Prigi and adjacent waters was 128 mm. Most of the fish which were caught by purse seine were still immature.

288 KINETICS OF FERTILIZATION, DEVELOPMENT, AND SEX RATIO OF IN VITRO-PRODUCED BOVINE EMBRYOS OBTAINED WITH FOUR DIFFERENT BULLS

2007 ◽  
Vol 19 (1) ◽  
pp. 259 ◽  
Author(s):  
M. Alomar ◽  
H. Tasiaux ◽  
S. Remacle ◽  
F. George ◽  
D. Paul ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Bovine Embryos ◽  
In Vitro Production ◽  
Chi Square ◽  
Cell Stage ◽  
Chi Square Test ◽  
Kinetics Of

The between-bulls variation in in vitro fertility and the shift of sex ratio toward male embryos are two problems affecting the in vitro production (IVP) of bovine embryos. Our objective was to evaluate the possible correlation between the kinetics of fertilization, embryo development, and the sex ratio of the resulting embryos. In a first experiment, and using frozen-thawed semen of 4 different AI bulls, the kinetics of pronucleus (PN) formation was evaluated at 8, 12, and 18 h post-in vitro insemination (hpi) after fixation and staining with Hoechst 33342. Fertilized oocytes were classified in 3 PN stages: PN1: showing the first signs of sperm head decondensation; PN2: with two pronuclei of different sizes, the two being far from each other; and PN3: showing two symmetric pronuclei of equal size, close to each other. Differences between bulls were observed at each time point, but were greater at 12 hpi than at 8 or 18 hpi. At 8 hpi and 12 hpi, bull C showed a significantly faster PN formation by comparison with the 3 other bulls (chi-square test: P &lt; 0.05), whereas at 18 hpi, the proportion at each of the PN stages was similar to that of bulls A and D, with bull B showing delayed PN development. In a second experiment, a standard IVP procedure was conducted with the 4 bulls to determine cleavage and blastocyst rates. The timing of first cleavage was measured using time-lapse cinematography. Compared with those of bull B, the embryos generated with bull C led to significantly higher Day 7 blastocyst yields (31.3 � 9.5% vs. 21.9 � 6.7%; ANOVA: P &lt; 0.05). Moreover, the embryos from bull C reaching the blastocyst stage cleaved faster (first cleavage at 23.1 � 2.1 hpi vs. 25.4 � 2.7 hpi for bull B; ANOVA: P &lt; 0.05). In a third experiment, 65 to 76 Day 8 blastocysts were sexed per bull. Embryo sexing was performed by PCR using the co-amplification of a Y-specific bovine SRY sequence and an autosomal btRep-137 sequence. Only blastocysts obtained with bull C showed a shift in sex ratio toward male embryos (76.0% male embryos vs. 53.8% for bull B; chi-square test: P &lt; 0.05), whatever the size of the blastocyst. The shift in sex ratio was already present at the 2-cell stage (64.2% male embryos; n = 53; chi-square test: P &lt; 0.05). In conclusion, for 2 out of 4 bulls, a correlation was observed between the kinetics of PN formation, the timing of first cleavage, and the sex ratio of the resulting embryos.

155 Fertility of sexed semen in Holstein heifers and cows

2020 ◽  
Vol 32 (2) ◽  
pp. 204
Author(s):  
M. Yamaguchi ◽  
M. Takayama ◽  
T. Nishisouzu ◽  
H. López ◽  
O. Dochi
Keyword(s):  
Sex Ratio ◽  
Dairy Cattle ◽  
Female Offspring ◽  
The Novel ◽  
Chi Square ◽  
Frozen Semen ◽  
Conception Rates ◽  
Sexed Semen ◽  
Parity Number ◽  
Chi Square Test

Compared with conventional semen, use of sexed semen decreases the conception rate (CR); therefore, it is important to address the factors that lead to sperm damage. Recently, a novel sexed semen technology was developed for improving dairy cattle fertility (Betthauser et al. 2016 J. Dairy Sci. 99 (E-Suppl. 1), 534). However, there are few reports about the fertility of this novel sexed semen in dairy cattle in Japan. The objective of this study was to compare the CR of traditional sorting semen (S1: flow cytometry/cell sorting) and the novel sexed semen (S2: SexcelTM, ABS Global Inc.) in Holstein heifers and cows in Japan. The CR for the first insemination was obtained from 391 Holstein cows and 148 heifers (10.7-17.8 months old) from 14 dairy farms in Hokkaido from June 2017 to April 2019. Semen used for AI was collected from six bulls and packaged into 0.25-mL straws and frozen. Cows inseminated with conventional frozen semen (S3: unsexed semen in 0.5-mL straws) were used as controls. Calving data were collected from 123 cows and 69 heifers that had calved between January 2018 and May 2019. The diagnosis of pregnancy was confirmed using ultrasonography between 30 and 45 days after insemination. The CR and sex ratio were analysed using chi-square test. The average parity number was 1.9±1.1, and average days open was 84.9±20.4 days. The average interval between calving and the first service was 86.2±20.3 days. The average milk yield (at 305 days) was 12 195±1595 kg. All of the animals were inseminated after the onset of standing heat or removal of the tail chalk of natural heats and oestrus and ovulation synchronisation programmes on the farm. Conception rates of heifers of the first service of S1 (n=54) and S2 (n=94) were 68.5 and 70.2%, respectively. Conception rates of cows of the first service of S1 (n=32), S2 (n=173), and S3 (n=186) were 56.3, 57.8, and 53.8%, respectively. There were no significant differences in CR between these groups (P&gt;0.4). The proportion of female calves produced using S1 (n=61) and S2 (n=57) was 91.8 and 93.0%, respectively, which was significantly more (P&lt;0.01) compared with the 50.0% produced using S3 (n=74). There were no significant differences between S1 and S2 (P&gt;0.8) in terms of the proportion of calves produced. The results of this study demonstrated that the traditional sorting and novel sexed semen (S1 and S2, respectively) did not differ in terms of the first-service CR and produced considerably more female calves than when the conventional semen (S3) was used. Furthermore, these findings indicate that the use of this novel sexed semen could achieve a sex ratio close to 90% female offspring.

scholarly journals A preliminary study on the size structure and sex ratio of orange-spotted grouper (Epinephelus coioides Hamilton, 1822) harvested from Kwandang Bay, Sulawesi Sea, Indonesia

2021 ◽  
Vol 6 (2) ◽  
pp. 34-38
Author(s):  
Dewi Shinta Achmad ◽  
Muh Saleh Nurdin ◽  
Indri Afriani Yasin ◽  
Merita Ayu Indrianti ◽  
Meity M Mokoginta ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Size Structure ◽  
Economic Value ◽  
Total Sample ◽  
Epinephelus Coioides ◽  
Chi Square ◽  
Gonad Differentiation ◽  
Protogynous Hermaphrodite ◽  
Female Phase ◽  
One Year

Orange-spotted grouper is one of the coral reef fish has the economic value and exploited by local fisherman. Information about the size structure and sex ratio are urgent to formulate a policy for sustainability. This research aims to analyze the size structure and sex ratio of the orange-spotted grouper in Kwandang Bay. The research was conducted from December 2016 to November 2017. Sampling is carried out twice a month for one year. The total sample of orange-spotted grouper used for the analysis of the sex ratio was 149 individuals. Sample of orange-spotted grouper collected from fish landed and middlemen (grouper traders) at the Kwandang Fishing Port. Data analysis applying chi-square. The results show that males bigger than females. The sex ratio of orange-spotted grouper is 87.25 % female, 7.38 % male, and 5.37 % hermaphrodites. Orange-spotted grouper dominated by females and undergoes a gonad differentiation to male (protogynous hermaphrodite). It is concluded that The size of the male orange-spotted grouper is larger than that of the female grouper. The caught orange-spotted grouper is dominated by the female phase and undergoes a differentiation of the gonad from female to male (protogynous hermaphrodite)

scholarly journals Some aspects of the reproductive biology and sex-ratio of Cirrhina reba (Hamilton) (Cyprinidae : Cypriniformes)

2012 ◽  
Vol 30 ◽  
pp. 21-24
Author(s):  
Sarmin Akther ◽  
Shirin Akther
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Standard Length ◽  
Total Weight ◽  
Chi Square ◽  
Male And Female ◽  
Total Length ◽  
Chi Square Test ◽  
Somatic Index

Some aspects of the reproductive biology viz. sex-ratio gonadal length index (G.L.I.), gonado somatic index (G.S.I.) and sex-ratio of Cirrhina reba were studied during September 2004 to July 2005. In present study the highest values of GLI (33.76) and GSI (0.63) were in the month of July. Total length (TL) and gonadal length (GL), total weight (TW) and gonadal weight ( GW ), standard length (SL) and gonadal length ( GL ) and gonadal weight relationships were found to be positive; and the relationships were: GL = -3.873 + 0.219 TL (r = 0.992), GW = 0.01511+0.000815 TL (r = 0.979), GL = -2.6030+0.253 SL (r = 0.990), GL = 0.01997+0.000938 SL (r= 0.976), GW = 13.2952+0.6064 TW (r = 0.958), GW = 0.0772+0.00233 TW (r = 0.979). The sex- ratio of C. reba were 1:1.62 for male and female respectively. The Chi-square test showed significant differences of sex-ratio among months and totals.DOI: http://dx.doi.org/10.3329/ujzru.v30i0.10739Univ. j. zool. Rajshahi Univ. Vol. 30, 2011 pp. 21-24

296 FREQUENT RECTAL PALPATIONS FOLLOWING SUPEROVULATORY TREATMENT AFFECT SEX RATIO OF EMBRYOS RECOVERED FROM HOLSTEIN HEIFERS

2008 ◽  
Vol 20 (1) ◽  
pp. 228
Author(s):  
A. Ideta ◽  
K. Hayama ◽  
M. Urakawa ◽  
Y. Aoyagi
Keyword(s):  
Sex Ratio ◽  
Animal Health ◽  
Transrectal Ultrasonography ◽  
Control Group ◽  
Chi Square ◽  
Female Ratio ◽  
Significant Difference ◽  
Chi Square Test ◽  
Rectal Palpation ◽  
And Control

Skewing the sex ratio of offspring towards males or females is very important for the livestock industry. Many factors, such as maternal stress, have been suggested to affect the sex ratio (Pratt NC et al. 1989 J. Reprod. Fertil. 87, 763–769). In a recent study (Ideta A et al. 2007 J. Reprod. Dev. doi:10.1262/JRD.19035), the proportion of female embryos recovered from superovulated heifers in which ovulation patterns were observed by repeated transrectal ultrasonography tended to be higher than the expected ratio of 50:50 (66.7%, 26/39). To investigate this phenomenon, we repeated the experiment using a larger number of Holstein heifers. The superovulatory treatment began in the midluteal phase of the estrous cycle (days 8 to 10) and consisted of eight decreasing doses of FSH i.m. (total of 28 Armour units, Antrin R-10, Kawasaki-Mitaka, Kanagawa, Japan) for 4 days with treatment twice daily. Doses of 5 mL and 3 mL of a PGF2α analogue (Veterinary Pronalgon F Injection containing 5 mg mL–1 Dinoprost, Pfizer Animal Health, Tokyo, Japan) were administered i.m. to the animals along with the seventh and eighth FSH treatment, respectively. The heifers were divided into two groups. One group, the rectal palpation (RP) group (n = 9), received transrectal ultrasonography with rectal palpation at 4-h intervals from 36 to 76 h after the first PGF2α treatment. The other group, the Control group (n = 8) received no treatment. The heifers were artificially inseminated at 56 and 72 h after the first PGF2α treatment using frozen–thawed semen from one bull. Seven-day embryos were recovered nonsurgically. Grade 1 to 3 embryos (IETS classification) were selected for this study. Male and female embryos were separated using the loop-mediated isothermal amplification procedure (Hirayama H et al. 2004 Theriogenology 62, 887–896). Data were analyzed using ANOVA and chi-square test. The mean number of recovered ova and embryos was 15.7 � 3.8 (RP) and 14.4 � 2.2 (Control). There was no significant difference in the percentages of unfertilized ova (RP; 14.9 %, 21/141 and Control; 11.3% 13/115, P > 0.05), grade 1 embryos (RP; 51.1%, 72/141 and Control; 54.8%, 63/115, P > 0.05) and grade 1 to 3 embryos (RP; 65.2%, 92/141 and Control; 69.6%, 80/115, P > 0.05) between the two groups. The proportion of female grade 1 embryos in the RP group (66.7%, 48/72) was significantly higher than the expected ratio of 50:50 (P < 0.01). The female ratio of grade 1 embryos in the Control group was 50.8% (32/63). Furthermore, the proportion of female grade 1 to 3 embryos in the RP groups (66.3%, 61/92) was significantly higher than the expected ratio of 50:50 (P < 0.005). The female ratio of grade 1 to 3 embryos in the Control group was 51.3% (41/80). Results indicate that frequent ultrasound examinations and rectal palpations following superovulatory treatment may skew the sex ratio of embryos towards females in Holstein heifers.

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