Gir Heifers Research Articles

Influence of bovine pestivirus heterogeneity on serological responses to 10 different commercial vaccine formulation

Bovine Pestivirus typically involves one or more organ systems, with clinical manifestations ranging from mild to severe fatal systemic illness that lead to significant reproductive, productive, and economic losses. Vaccines face the challenge of addressing the significant variability of pestiviruses, which affects the interaction between viral antigens and the immune system’s ability to provide protection. This study aimed to evaluate the serological responses against bovine viral diarrhea virus 1 (Pestivirus A) and Pestivirus B induced by 10 commercial vaccines, including one recombinant (vaccine E), two modified live (MLV multivalent, vaccine I, and MLV monovalent, vaccine J), and seven killed vaccines (KLV, vaccines A to H). Additionally, we evaluated the cross-reactivity between Pestivirus A and B from vaccines and HoBi-like pestivirus (Pestivirus H). In Phase 1, guinea pigs were used to screen for non-MLVs. They were divided into nine groups (n=6 each) and received two doses (⅕ of bovine dose) of eight different non-MLV on Days 0 and 21. Serum samples were collected on Days 0 and 30 for serological analyse. In Phase 2, Holstein × Gir heifers (n= 45) were divided into five groups, comprising 6–9 animals. They were vaccinated either once with MLVs or twice with the top non-MLVs screened in Phase 1. Serum samples were harvested on d0 (vaccination day) and d60 (60 days after the first dose) for MLV and non-MLV. Specific antibody titers were assessed virus neutralization (VN) and transformed in log2 for statistical analysis using PROC-MIXED. Significant effects were observed for vaccine groups, time points, and their interactions concerning neutralizing antibodies against Pestivirus A and B in both Guinea pigs and heifers. The Phase 1 study revealed serological responses against Pestivirus A exclusively in non-MLV D (85.33±13.49) and E (72.00±19.26). In the bovine study, the KLD vaccine D (72.00±15.10), recombinant vaccine E (90.66±25.85), and MLV I (170.66±28.22) resulted in an average of neutralizing antibodies against Pestivirus A that exceeded the protective threshold (≥ 60). However,individual analysis of heifers showed a higher frequency of animals presenting titers of Pestivirus A Ab surpassing 32 following vaccination with MLV I and J. None of the vaccine formulations in either study elicited a protective immune response against Pestivirus B or demonstrated cross-reactivity against Pestivirus H.

Comparing the Impact of Jowar Straw and Soybean Straw on Growth Performance in Gir Heifers

Comparing the Impact of Jowar Straw and Soybean Straw on Growth Performance in Gir Heifers

Serological Responses of Guinea Pigs and Heifers to Eight Different BoAHV-1 Vaccine Formulations.

Bovine alphaherpesvirus 1 (BoAHV-1) infection affects the production and reproductive performance of dairy and beef livestock, resulting in considerable economic losses. In addition to biosecurity measures, vaccination programs are effective strategies for controlling and preventing BoAHV-1 infection and transmission. We evaluated the serological immune response against BoAHV-1 induced by eight different formulations of commercial vaccines: three modified live vaccines and five killed vaccines containing BoAHV type 1 or types 1 and 5. In the first experiment, 50 BoAHV-1-seronegative guinea pigs were assigned to eight groups; each individual in the treatment groups received two doses (one-fifth of the bovine dose). The second experiment was conducted using 29 crossbred Holstein × Gir heifers in four groups of six to nine animals each. The serological immune response against BoAHV-1 was measured using virus neutralization and enzyme-linked immunosorbent assays to measure the total IgG against BoAHV. We evaluated the effects of the vaccine, time, and interaction of the vaccine and time on neutralizing antibodies against BoAHV-1. Killed vaccines produced low levels of antibodies against BoAHV-1, whereas modified live vaccines produced high levels of antibodies capable of providing neutralizing titers in the vaccinated animals, with the thermosensitive modified live vaccine showing the highest levels of antibodies.

Selecting oocyte donors based on anti-Müllerian hormone (AMH) concentrations: A critical analysis of using cutoff values as exclusion criterion for an in vitro embryo production program in Gir cattle

The aims of this study were to determine anti-müllerian hormone (AMH) cutoff values for selecting Gir (Bos taurus indicus) oocyte donors and estimate the impact of using AMH concentrations as a selection criterion. In Exp. 1, Gir heifers (n=120) were sampled for AMH analysis and submitted to ovum pick-up and in vitro embryo production (OPU-IVEP). AMH cutoff values were calculated using ROC analysis or, alternatively, by the successive exclusion of heifers with the lowest AMH values. The correlations between AMH and OPU-IVEP outcomes were significant (P<0.001), though low or moderate (r= 0.34–0.52). We estimated an improvement (P<0.05) after the use of AMH cutoff values to select donors of +15.3% for total oocyes, +19.4% for viable COC, and +23.4% for blastocysts. This selection pressure, however, led to the exclusion of 32.8%, 37.9%, and 50.0% of the initial potential donors, respectively. In Exp. 2, we analyzed data from OPU-IVEP sessions of 658 Gir donors with known genomic values for predicted transmitting ability for milk (GPTAm) and age at first calving (GPTAafc). The selection based on the number of oocytes recovered had no effect (P>0.05) on the average GPTAm nor GPTAafc values of the remaining donors. In summary, plasma AMH ≥700 pg/mL is a cutoff value that can be used to select Gir heifers with a greater potential as oocyte donors. Nevertheless, this selection leads to the exclusion of up to 50% of potential donors. Finally, exclusion of poor responders had no effect on mean genomic estimates for milk production or age at first calving in the selected subset of donors.

Comparing Bayesian models for the genetic evaluation of oocytes and embryo counts in Dairy Gir cattle.

Count traits are usually explored in livestock breeding programs, and they usually do not fit into normal distribution, requiring alternatives to adjust the phenotype to estimate accurate genetic parameters and breeding values. Alternatively, distribution such as Poisson can be used to evaluate count traits. This study aimed to compare and discuss the genetic evaluation for oocyte and embryo counts considering Gaussian (untransformed variable - LIN; transformed by logarithm - LOG; transformed by Anscombe - ANS) and Poisson (POI) distributions. The data comprised 11,343 total oocytes(TO), viable oocytes(VO), cleaved embryos(CE), and viable embryo(VE) records of ovum pick-up from 1740 Dairy Gir heifers and cows. The genetic parameters and breeding values were estimated by the MCMCglmm package of the R software. The posterior means of heritability varied from 0.40 (LIN) to 0.49 (POI) for TO, 0.39 (LIN) to 0.49 (POI) for VO, 0.30 (LOG) to 0.41 (POI) for cleaved embryos, and 0.19 (LIN) to 0.32 (POI) for viable embryos. The posterior means of repeatability varied from 0.56 (LIN) to 0.65 (POI) for TO, 0.53 (LOG) to 0.63 (POI) for VO, 0.44 (LOG) to 0.60 (POI) for CE, and 0.36 (LOG) to 0.56 (POI) for VE. Deviance information criterion and mean squared residuals indicated that POI model should be used for the genetic evaluation of embryo and oocyte count traits. Spearman's rank correlation between estimated breeding value (EBV) for embryo and oocyte count traits computed by POI, LOG, and ANS models was high (ranging from 0.77 to 0.99), indicating little reranking among the best animals. The POI model is the most adequate for genetic evaluation, resulting in more reliable EBV of oocyte and embryo count traits for Dairy Gir cattle.

Evaluation of pregnancy per artificial insemination of dairy animals detected in estrus during the synchronization protocol and assigned to conventional or sexed semen

Three experiments were designed to evaluate the effects of conventional and sexed-semen on reproductive performance of dairy females detected in estrus. In Exp. 1, 978 lactating Holstein cows and 116 Holstein heifers were used. Cows or heifers were randomly assigned to receive conventional (CONV) or sexed (SEXD) semen on day 0 of a TAI protocol. The TAI was performed using commercial CONV or SEXD frozen-thawed semen from the same 6 Holstein bulls, and SEXD semen was sexed through fluorescence cytometry. In Exp. 2, 390 lactating Holstein × Gir dairy cows and 344 Holstein × Gir heifers were used. Cows and heifers were randomly assigned to receive CONV or SEXD semen on day 0 with frozen-thawed semen from 5 Holstein × Gir bulls. The SEXD was sorted through the Sexcel™ methodology. In Exp. 3, 789 primiparous lactating Holstein cows were enrolled. Cows were randomly assigned to receive CONV or SEXD semen from 5 Holstein bulls, and the SEXD semen was sexed using the same semen allocation methodology described in Exp. 2. All data were analyzed using SAS. Regardless of the experiment, no treatment × bull interaction was observed for any of the variables analyzed herein (P ≥ 0.20). In Exp. 1, multiparous cows assigned to CONV had a greater P/AI vs. cohorts assigned to SEXD (P < 0.01) and a similar response tended to be observed for secundiparous cows (P = 0.10). No treatment effects were further observed when the effects of semen on day 60 P/AI were stratified by heat stress, milk yield, and CL at the beginning of the protocol. In Exp. 2, no P/AI differences between treatment were detected either on days 32 (P = 0.32) or 60 of pregnancy (P = 0.20). In Exp. 3, cows assigned to SEXD had reduced P/AI on day 32 (P = 0.03) and tended to have a reduced P/AI on day 60 of pregnancy (P = 0.06). No further treatment effects or interactions were observed herein (P ≥ 0.13). Overall P/AI of SEXD semen was 78% of the CONV (P < 0.01), but the variation of these results requires some attention. Moreover, an additional analysis was performed considering the median value of P/AI in bulls assigned to CONV and SEXD, and bulls that had a greater P/AI in CONV also had a greater P/AI in SEXD (P = 0.03). In summary, although not directly comparable, the sexing technologies herein provided similar results in heifers, but not in other categories (primiparous, secundiparous, and multiparous cows). Additionally, the P/AI of a sexed semen is associated to its performance on the conventional semen counterpart. Moreover, in the present experiment, no other parameters were shown to impact fertility of dairy females assigned to conventional or sexed-semen.

Luteinizing hormone secretion, ovulatory capacity, and oocyte quality in peripubertal Gir heifers.

Induction of puberty in cattle breeds that attain puberty in later stages, such as Gir, allows the earlier beginning of reproductive life and it might increase oocyte quality. Here, the ovulatory capacity of prepuberal Gir heifers was studied and its relationship to follicular growth, luteinizing hormone (LH) secretion and oocyte quality was evaluated. Peripubertal Gir heifers were treated with a progesterone-based protocol and according to ovulatory response were separated into groups: not-ovulated (N-OV) and ovulated (OV). Serial blood samples were taken 24 h after estradiol treatment on day 12 to evaluate LH secretion. Cumulus-oocyte complexes (COCs) were collected using ovum pick-up and assessed for brilliant cresyl blue (BCB) staining rate, IVF-grade oocytes rate, and mean oocyte diameter, in comparison with cow oocytes. Gene expression of developmental competence markers (ZAR1, MATER, and IGF2R) was also analyzed. The largest follicle diameters were similar between N-OV and OV groups on the day of estradiol treatment (d12) and the next day and decreased (P = 0.04) in the N-OV group thereafter. LH pulse secretion was different between groups (N-OV = 3.61 ± 0.34 vs OV = 2.83 ± 0.21 ng/ ml; P = 0.04). COC assessment showed that the number of recovered oocytes, BCB+ rate, IVF-grade oocytes and oocyte size was similar (P > 0.05) among groups, resembling adult cow patterns. ZAR1, MATER and IGF2R gene expression in oocytes were also similar (P > 0.05) in N-OV and OV groups. In conclusion, our results demonstrate a lower LH secretion profile in peripubertal Gir heifers prone to ovulate after induction protocol, and that oocyte quality is not affected on a short-term basis by ovulation itself.

Efficiency of Growth in an Organized Herd of Gir cattle in North Saurashtra Agro-climatic Region of Gujarat

The present study was undertaken to find the efficiency of growth performance in Gir calves born (N=52) and raised at Bull Mother Farm, Kamdhenu University, Amreli. The overall birth weight in Gir calves was 24.66 ± 0.40 kg, male calves being significantly (P, 0.004) heavier (9.88%) at birth than female calves. Irrespective of sex, the Gir calves weighed 66.83 kg at 3 months and 109.25 kg at 6 months of age, whereas yearling body weight was 192.82 kg. At 2 years of age, the Gir heifers attained 263.57 ± 17.29 kg body weight, which was above the optimum/ desired breedable body (240-250 kg). The body weight gains from birth to 3 month and from 3 to 6 month growth phases were almost similar, values being 466.9 ± 12.81 and 468.94 ± 20.15 gm/day, respectively. After attaining 1 year of age, the rate of body weight gain showed a diminishing trend, from 312.37 to 270.61 gm/day, with advancement of age. Relative body weight gain, irrespective of sex, was a maximum of 172.88 ± 6.51 % in the birth to 3 month age group, followed by 63.66 ± 2.66% in the 3 to 6 month age group. The findings indicated that due care of the Gir calves, especially during birth to 3 month age is vital to explore their growth potential, as relative weight gain of calves during this phase is maximum (172.88%) for attaining early breedable body weight and in turn, reducing age at first calving.

121 Anti-Müllerian hormone cutoff values for the selection of oocyte donors in the Gir (Bos indicus) breed

Anti-Müllerian hormone (AMH) has a well-known association with antral follicle count (AFC) and the number of oocytes recovered by OPU in cattle. However, to be used as a criterion to select candidate donors for ART, AMH reference values must be established for each breed. The aim of this study was to estimate AMH cutoff values for selecting oocyte donors in Gir (Bos indicus) cattle. A blood sample was collected at a random day of oestrous cycle from Gir heifers (n=120) at 23.3±0.5 months of age, and the plasma was stored for further AMH analysis by ELISA, using a commercial kit (AL114, AnshLabs) in a private laboratory (LEAC, Sao Paulo, Brazil). Data from 506 ovum pickup-invitro embryo production (OPU-IVEP) sessions (4.2±0.2 per donor) performed in these heifers from 2017 to 2019, starting 120 days after blood sampling, were then analysed. Donors were ranked in quartiles according to the number of total oocytes recovered, viable oocytes recovered, and embryos produced. Those classified in the first quartile for each endpoint were considered poor responders. The AMH values were then analysed using the receiver operating characteristic (ROC) curve, and cutoff values for each endpoint were estimated based on best values for sensitivity and specificity. A second analysis was performed to check which cutoff value would result in a significant increase in average for each endpoint. The OPU-IVEP data were ranked according to corresponding AMH values (smaller to greater), and the average of the selected group of donors was compared with the original group by ANOVA, using the PROC GLM of SAS (SAS Institute Inc.), after successive exclusion of donors with lower AMH concentrations. Results are shown as mean±s.e.m. On average, heifers presented AMH concentrations of 932.9±48.4pgmL−1 (ranging from 112.7 to 2044.8pgmL−1) and produced 32.3±1.5 total oocytes, 25.9±1.4 viable oocytes, and 5.3±0.4 embryos per OPU-IVEP session. The heifers ranked in the third and last quartiles yielded more total oocytes, viable oocytes, and blastocysts than those ranked in the first quartile (P&amp;lt;0.05). Based on the total number of oocytes recovered (59.2±3.1), heifers of the last quartile had an estimated AFC &amp;gt;60. The area under the ROC curve (AUC) for total oocytes, viable oocytes, and embryos produced were 0.77 (P&amp;lt;0.0001), 0.75 (P&amp;lt;0.0001), and 0.72 (P=0.0003), and the estimated cutoffs for AMH concentration were 761.4, 622.5, and 681.5pgmL−1, respectively. After successive exclusions of donors with lower AMH values, averages were greater (P&amp;lt;0.05) at a cutoff value of 632.4pgmL−1 for total oocytes (36.9±1.6 vs. 32.3±1.5; +15.3%), 672.3pgmL−1 for viable oocytes (30.3±1.4 vs. 25.9±1.4; +19.4%), and 776.8pgmL−1 for embryos produced (6.6±0.3 vs. 5.3±0.4; +23.4%). However, the use of these cutoff values to increase the averages would result in the exclusion of 32.8, 37.9, and 50.0% of the potential donors for each endpoint, respectively. In summary, these results demonstrated that an AMH concentration of approximately 700pgmL−1 can be used to select donors with higher oocyte yield and thus to increase IVEP outcomes in Gir heifers. This research was supported by Fazendas do Basa, Fapemig CVZ APQ 03430-17.

Differential expression of LHCGR and its isoforms is associated to the variability in superovulation responses of Gir cattle

The aim of this study was to evaluate the pattern of expression of LHCGR isoforms in Gir heifers characterized as good (10.3 ± 1.2 ova/embryos per flush, n = 5) or poor responders (1.1 ± 0.3 ova/embryos per flush, n = 5) to superovulation protocols. In both groups, an adapted ultrasound-guided follicular aspiration system was used to collect granulosa cells from 8 mm follicles formed either during a synchronized, non-stimulated follicular wave (no stimulation control, NS) or on the fourth day of a superovulation protocol (SOV) induced with 200 IU of pFSH. The recovered follicular fluid was centrifuged and granulosa cells were washed with NaCl 0.9% and kept in RNAlater®. RNA extraction was performed using a commercial RNeasy Micro Kit and eluted samples were quantified and reverse transcribed using the commercial Superscript III kit. cDNA samples were amplified by real-time PCR using a primer to target LH/hCG receptor gene - not selective for LHCGR isoforms (total LHCGR) - and four sets of isoforms selective primers (S1, S10, S10 + 11, and S11). Analyses were performed using the REST software and expression levels are shown as mean ± SEM. Under physiological conditions (NS), poor responders had a higher expression of total LHCGR (4.9 ± 1.7 fold-change, P < 0.01) as well as isoforms S10, S11 and S10 + 11, compared to good responders. In both phenotypes, superovulation down-regulated total LHCGR expression (−0.5 ± 0.2 and −0.9 ± 0.0 for good and poor responders, respectively; P < 0.05). However, in poor responders the exogenous FSH treatment up-regulated the S10 (2.4 ± 2.0; P < 0.05), S10 + 11 (3.8 ± 3.2; P < 0.01), and S1 isoforms (1.8 ± 1.3; P < 0.05), compared to good responders We conclude that down-regulation of total LHCGR, associated to up-regulation of their inactive isoforms, may have compromised follicle development and thus contributed to the low efficiency of superovulation in heifers with a poor responder phenotype.

Cocoa byproduct in diets for dairy heifers

ABSTRACT This study was conducted to evaluate the effect of substituting Tifton 85 hay (Cynodon sp. cv. Tifton 85) with levels of cocoa (Theobroma cacao) byproduct (0, 8, 16, and 24%, diet dry matter basis) in the diet of 16 Holstein × Gir heifers with an average body weight of 363.0±27.7 kg on their nutrient intake, digestibility, and protein balance. The experimental period was 17 days, and the sample collection period was five days. There was no effect of cocoa [...]

Effect of Doublesynch and Estradoublesynch protocols on estrus induction, conception rate, plasma progesterone, protein, and cholesterol profile in anestrus Gir heifers.

AimThis study aimed to evaluate the efficacy of Doublesynch and Estradoublesynch protocols on estrus induction, conception rates, plasma progesterone, protein, and cholesterol profile in anestrus Gir heifers.Materials and MethodsIn this study, 50 pubertal anestrus Gir heifers were selected from the field and farm conditions. The heifers were dewormed (injection ivermectin, 100 mg, s/c) and supplemented with minerals and vitamins (injection organic phosphorus 800 mg and injection Vitamin AD3E and Biotin 10 ml i/m) and multi-mineral bolus at 1 bolus daily for 7 days. The heifers were randomly divided into three groups: Doublesynch (n=20), Estradoublesynch (n=20), and control (n=10). The animals were monitored for estrus response, estrus interval, behavioral signs, and conception rates after induced/first, second, and third cycle post-treatment. Blood samples were obtained on day 0, day 9, day 12, and on day 12 post-artificial insemination (AI) for determination of plasma progesterone, protein, and cholesterol profile.ResultsThe estrus response rate between Doublesynch and Estradoublesynch protocols was similar between treated heifers (85% and 95%). The interval from the second prostaglandin F2α (PGF2α) injection to estrus induction did not differ between the groups (63.87±4.19 vs. 58.27±3.83 h). The conception rates following induced estrus (20% vs. 30%), at the second cycle (23.07% vs. 16.66%), at the third cycle (22.22% vs. 30.00%), and the overall conception rate (45% and 55%) within 27.89±5.75 and 26.45±5.48 days were the same across the treatment groups. The mean plasma progesterone concentrations were significantly (p<0.01) higher on day 9 (second PGF2α injection) and day 12 post-AI compared to day 0 (first PGF2α injection) and the day of fixed-timed artificial insemination. The concentrations were also significantly (p<0.05) higher in conceived than non-conceived heifers on day 9 of treatment and day 12 post-AI in both the protocols. The mean plasma cholesterol concentrations were significantly higher during peak follicular and luteal phases compared to the initial anestrus phase in both the protocols. The values were also higher in non-conceived than conceived animals in both the protocols. The plasma protein profile was not influenced by the sampling days or conceived and non-conceived status.ConclusionThe results showed that both Doublesynch and Estradoublesynch protocols resulted in similar estrus induction and conception rates with modulation of plasma progesterone and cholesterol profile in anestrus Gir heifers.

347 COULD THE DIFFERENTIAL EXPRESSION OF LUTEINIZING HORMONE RECEPTOR ISOFORMS EXPLAIN THE VARIABILITY IN SUPEROVULATORY RESPONSES IN CATTLE?

Embryo production in vivo is highly variable among donors. The Gir breed (Bos indicus) is well known to show a low embryo production after superovulation (2.5 to 3.5 viable embryos per flush), and a high variance in superovulatory responses, which makes this breed an interesting model to study this trait. The aim of this study was to evaluate the expression pattern of LHR isoforms in Gir heifers previously characterised as good (10.3 ± 1.2 embryos/flush, N = 5) or poor (1.1 ± 0.3 embryos/flush, N = 5) responders to superovulation protocols. In both groups, an adapted ultrasound-guided follicular aspiration system (Arashiro et al. 2012 Reprod. Fertil. Dev. 24, 175) was used to collect granulosa cells (GC) from 8-mm follicles growing in either a synchronized but not stimulated follicular wave (FW) or in the fourth day of superovulation (SOV), induced with 200 UI of FSHp (Pluset, Serono). The recovered follicular fluid was centrifuged and the cells were washed with NaCl 0.9% saline and kept in RNA Later (Ambion, Austin, TX, USA). Total RNA extraction was performed using the commercial RNeasy Micro Kit (Qiagen, Valencia, CA, USA). The RNA samples were quantified and reverse transcribed using the commercial Superscript III kit (Invitrogen, Carlsbad, CA, USA). Complementary DNA samples were amplified through real-time PCR, using a LH receptor primer – not selective for LHR isoforms (total LHR) – and 4 sets of isoform selective primers (S1, S10, S10+11, and S11). All samples were previously tested for theca cell contamination through detection of CYP17A1 gene, and those showing contamination were excluded. The β-actin gene was used as endogenous control. Analyses were performed using the REST software and the expression values are shown as mean ± s.e.m. For comparisons between good and poor responders, the first was set as 1.00. For comparisons between FW and SOV, FW was set as 1.00. In the good responder group, there was no difference (P &gt; 0.05) in total LHR expression among GC samples from FW and SOV. However, the S10+11 isoform was down-regulated (0.4 ± 0.1; P &lt; 0.01) after SOV. In the poor responders group, total LHR expression was down-regulated (0.2 ± 0.1; P &lt; 0.01) after SOV, but there was no difference in the expression of isoforms (P &gt; 0.05). Contrasting the response groups (good and poor), total LHR (15.1 ± 7.6; P &lt; 0.001), and the isoforms S10 (5.7 ± 2.7; P &lt; 0.01), S10+11 (1.9 ± 0.6; P &lt; 0.01), and S11 (5.1 ± 2.5; P &lt; 0.01) were up-regulated in FW of poor responders, but there was no difference (P &gt; 0.05) in any LHR form during SOV. We concluded that 1) LHR expression is different between heifers characterised as good or poor responders to superovulation; 2) superovulation modulates the LHR expression and reduces the original differences observed in unstimulated cycles; 3) diminished expression of total LHR, but not in the isoforms, in poor responders heifers could suggest a reduction in the expression of full-length LHR, with possible consequences to ovulatory capability after superovulation.Financial support was provided by CNPq Project 477701 and Fapemig PPM 0067/11.

Despalha da cana-de-açúcar e desempenho de novilhas e vacas leiteiras

Dois experimentos avaliaram a resposta em ganho de peso de novilhas e a produção de leite de vacas à remoção de folhas apicais e laterais da cana-de-açúcar. Em ambos, os animais foram alimentados individualmente em confinamento total. No Experimento 1, 32 novilhas Girolando (295±45kg de peso vivo) foram blocadas em pares e alocadas a um tratamento por 42 dias, após um período de padronização de 14 dias. Os tratamentos foram: cana integral ou despalhada. O peso vivo e o consumo foram mensurados ao longo do tempo. Os teores de ingredientes e nutrientes na matéria seca (MS) das dietas foram 77,1% de cana, 19,2% de farelo de soja, 1% de ureia, 14,1% de proteína bruta (PB) e 38,8% de fibra em detergente neutro (FDN) na cana despalhada, e 78,6%, 17,9%, 0,9%, 13,7% e 45,3% na cana integral, respectivamente. O ganho diário de peso foi 1,395kg na cana despalhada e 1,125kg na integral (P=0,05). Não houve efeito de tratamento sobre o consumo de MS (P=0,78). A despalha aumentou a taxa de ingestão de alimento (P=0,04) e o consumo diário de matéria orgânica não FDN digestível (P=0,03). No Experimento 2, 14 vacas Holandesas (256±124 dias em lactação) foram blocadas em pares e alocadas a uma sequência dos dois tratamentos em delineamento de reversão simples, com períodos de 21 dias e mensuração da resposta na terceira semana. A dieta com cana despalhada teve 18,4% de cana na MS, 37,6% de silagem de milho, 44% de concentrado baseado em milho, polpa cítrica e farelo de soja, 17,3% de PB e 32,9% de FDN, enquanto a dieta com cana integral teve 18,2%, 37,7%, 44,1%, 16,6% e 34,7%, respectivamente. A despalha tendeu a aumentar a digestibilidade da MS (P=0,06) e o consumo diário de matéria orgânica digestível (P=0,10), sem afetar a produção de leite (18,4kg, P=0,65). A despalha da cana aumentou o ganho de peso de novilhas consumindo alta proporção de cana na dieta, mas essa prática não induziu resposta positiva no desempenho de vacas em final de lactação consumindo 18% de cana na dieta.

Desempenho produtivo de novilhas leiteiras suplementadas na época da seca em pastagens diferidas, sob duas taxas de lotação

The objective was to evaluate the characteristics of productive performance of crossbred Holstein x Gir heifers grazing on Brachiaria brizantha differed (Hochst. A. Rich.) Stapf. cv. Marandu managed in a rotational stocking, during the dry season of the year. The treatments evaluated were stocking rate of 1.0 UA / ha and 6.0 g / kg body weight (BW) / day and stocking rate of 2.0 UA / ha and 12.0 g / kg BW / day-energy protein supplement. The heifers had a average age of 17.46 ± 3.74 months and BW averaging 304.83 ± 33.7 kg and were distributed to a randomized block. The animals were weighed and measured for height at the withers (HW), heart girth (HG), rump length (RL) and body condition score (BCS). The BW average batch was used for the calculations to adjust the amount of supplement offered. It was found that the performance of heifers that were subjected to stocking with 2 UA/ha and 12.0 g / kg BW had higher average daily gain (0.579 kg / animal) in comparison to those undergoing stocking with 1 UA/ha and 6.0 g / kg BW (0.361 kg / animal). With respect to the development of animal body, it was found that the initial HG, initial and final HW, the initial RL and BCS did not differ between combinations of stocking rates and levels of supplementation. The heifers showed better productive performance in situations differed pastures, with 2 UA/ha and 12.0g/kg BW/day the protein-energetic supplement.

172 P450 AROMATASE GENE EXPRESSION, ESTRADIOL PRODUCTION, AND DOMINANT FOLLICLE DEVIATION IN BOS TAURUS AND BOS INDICUS DAIRY HEIFERS

It is well documented that the size of the dominant follicle at deviation is smaller in Bos indicus compared with in Bos taurus breeds. The physiological mechanisms underlying this difference, however, are unknown. The aim of the present study was to evaluate the dynamic of oestradiol production during follicle development close to the expected moment of deviation in Bos taurus and Bos indicus dairy heifers. Intrafollicular concentration of oestradiol (E2) and P450 aromatase gene expression in granulosa cells (GC) were evaluated in Gir (n = 10) and Holstein (n = 10) heifers. Follicular waves were synchronized with an intravaginal progesterone device (1 g, Sincrogest, Ourofino Agropecuária, São Paulo, Brazil) and benzoate oestradiol (2 mg im, Sincrodiol, Ourofino Agropecuária). Ultrasonography evaluations (MyLab30 Vet Gold, Esaote, Genova, Italy, with a 7.5-MHz transducer) were performed every 24 h to detect the emergence of the new follicular waves. The largest follicle of each wave was individually aspirated by ovum pickup before, at the expected diameter, or after deviation in both Gir (4.6 ± 0.2, 6.3 ± 0.2, and 8.5 ± 0.6 mm, respectively) and Holstein heifers (6.0 ± 0.5, 8.6 ± 0.4, and 10.2 ± 0.2 mm, respectively), as previously described (Arashiro et al. 2012 Reprod. Fertil. Dev. 24, 175). Follicular fluid (FF) samples were centrifuged and the supernatant stored at –20°C until E2 and progesterone (P4) determination by RIA. The pellet of GCs was washed twice with PBS, kept in RNAlater, and frozen at –20°C until RNA extraction and reverse transcription. Relative transcript quantification was performed by real-time PCR. The β-actin gene was used as control. Samples of FF with E2:P4 ratio &lt;1 or presenting contamination by theca cells (detected by the expression of 17α-hydroxylase) were not used for statistical analyses. Concentration of E2 in FF was evaluated between breeds and among follicle size classes by ANOVA and differences among means compared by Student t-test or Tukey’s test, respectively. Within breeds, relative gene expression was accessed by pair-wise fixed reallocation randomization test (software REST®). Results are shown as mean ± SEM. In both breeds, concentration of E2 in FF progressively increased with follicular diameter (P &lt; 0.05). Intrafollicular concentration of E2 (ng mL–1) was greater (P &lt; 0.05) in Holstein than in Gir before (58.5 ± 11.7 v. 8.8 ± 2.0), at expected (226.0 ± 49.9 v. 78.9 ± 21.0), and after follicle deviation (579.1 ± 45.0 v. 185.0 ± 34.9). Interestingly, however, follicles with similar diameters (~6 or 8 mm) showed similar (P &gt; 0.05) E2 concentrations between Holstein and Gir. Moreover, in both breeds, the relative expression of P450 aromatase gene in GC first increased (3.9 ± 2.4 and 67.5 ± 52.8 for Holstein and Gir, respectively; P &lt; 0.05) at the same stage of follicular development (8 mm). The present results suggest that the smaller size of follicles at deviation in Bos indicus is not related to an earlier increase in intrafollicular E2 production. CNPq, CAPES, and Fapemig (CVZ APQ 02863/09).

Metabolism and ruminal parameters of Holstein × Gir heifers fed sugarcane and increasing levels of crude protein

The objective of this study was to evaluate the effect of increasing levels of crude protein (CP) in the diet (13, 15, 19 and 22 g/100 g of dry matter, DM) on the metabolism and ruminal parameters of crossbred heifers fed forage sugarcane. Four crossbred Holstein × Gir heifers of average initial weight of 200 kg and average age of 14 months were used. The experimental design was in a 4 × 4 latin square. The intake values of DM, organic matter (OM), neutral detergent fiber (NDF) and non-fibrous carbohydrates (NFC) were not affected by the protein contents of the diet. The apparent and ruminal digestibility of DM and OM were affected by the protein content of the diet. Greater total apparent digestibility coefficient of CP (0.749) was observed for the content of 22 g CP/100 g DM, whereas the ruminal digestibility of CP was not affected by treatments. The efficiency of microbial protein synthesis was not different between the CP contents of the diet. There was increasing linear effect of the CP content in the diet on the plasma concentration of urea. The rumen pH of the heifers was similar between treatments, with an average of 6.3. The concentration of rumen ammonia nitrogen was affected by the protein content of the diet, with the highest averages at 22 and 19 CP/100 g DM (27.5 and 31.6 mg/dL); an average of 21.1 mg/dL in the diet with 15 g CP/100 g DM; and the lowest average observed in the diet containing 13 g CP/100 g DM, 14.0 mg/dL. It is recommended to use 13 g CP/100 g DM in the diet for crossbred Holstein × Gir heifers in the post-weaning phase consuming diets based on sugarcane, because this level promotes increase in the digestibility of the diet and lower concentrations of plasma urea nitrogen and ammonia nitrogen, showing better animal metabolism, in addition to a possible decrease in the cost of the diet.

Intake and digestibility in cattle fed low-quality tropical forage and supplemented with nitrogenous compounds

The effects of supplementation with nitrogenous compounds on intake, digestibility, and microbial protein synthesis in cattle fed low-quality tropical forage were assessed. Five rumen fistulated crossbred Holstein x Gir heifers were used, with initial average live weight of 180 +/- 21 kg. Signal grass (Brachiaria decumbens) hay (48.6 g kg(-1) of crude protein (CP), on a dry matter (DM) basis) was used as roughage. Five treatments were defined according to nitrogen supplementation level (0, 20, 40, 60, and 80 g of CP kg(-1) above the CP level of the hay). A mixture of urea, ammonium sulfate, and albumin at the ratios of 4.5:0.5:1.0, respectively, was used as nitrogen source. The experiment consisted of five experimental periods, according to a 5 x 5 Latin square design. The average CP contents in the diets were 51.9, 71.1, 86.0, 116.7, and 130.2 g kg(-1), on a DM basis. A quadratic effect was detected (P < 0.10) of the CP levels in the diets on DM and neutral detergent fiber intake (kg/day), with maximum response at the levels of 102.4 and 100.5 g CP kg(-1) DM, respectively. The average daily concentration of rumen ammonia nitrogen showed increasing linear pattern (P < 0.01) as function of CP levels in the diet, with estimated value of 9.64 mg dL(-1) equivalent to the maximum DM intake. Microbial nitrogen flow in the intestine was linearly and positively related (P < 0.01) with the CP levels in the diet.

Surface Evaporation from the Normal Body Surface and with Sweat Glands Inactivated in Indian Cattle

The contribution of the sweat glands to skin surface evaporation under high temperature conditions was studied using areas on the rump of six Hariana and on the shoulders of six Gir heifers. The sweat glands were inactivated by three cataphoretic administrations of 10% formaldehyde. Evaporation rates were measured for five-minute periods by capsule technique from the two symmetrically opposite body locations after exposing the animals in a controlled room at 40.5C for four to six hours. These were compared with rates recorded under similar conditions 15 days after one of the test sites on each animal had been treated with the formaldehyde. The formaldehyde suppressed the sweat gland activity 84% in Harianas and 79% in the Gir. Breed differences were not important, but the between-animal variances for rate from both treated and untreated areas were significant. The results corroborate the assumption that the major portion of the substance available for evaporation from the skin surface of cattle under thermal stress comes from the sweat glands.