Consistency of side choice in the milking parlour by holstein-friesian cows and its relationship with their reactivity and milk yield

Dairy cows often have to choose which of two sides to enter in the milking parlour. Some cows are very consistent in this choicė, and it is common to assume that when these cows are more disturbed are being milked in their non-preferred side. Such disturbance might involve significantly poor welfare. In order to assess this assumption, we decided to study the behaviour and milk yield of dairy cows and their relationships with side preference in the milking parlour. The study was carried out at Cambridge University Farm, in a two-sided tandem milking parlour. The data collection followed the daily management routine. We recorded the side chosen by each cow (left or right) during 40 milking sessions. Data from 70 cows, which were present in at least 25 milking sessions (mode = 36), were included in the statistical analysis. Cows' reactivity (CR) during premilking udder preparation, time spent fitting the milking cluster (FT), milk yield (MY) and duration of milking (DM) were measured. There was evident individual variation in the consistency of side choice. Individual differences (ANOVA, P < 0.001) were also found in CR, FT, MY and DM; although these variables were not significantly affected by the side or the interaction animal × side (ANOVA, P < 0.05). The comparison between left and right side means (paired t-test) of these variables did not show significant differences (P < 0.05). We concluded that there is no evidence that the cows were discomforted or stressed when milked in the non-preferred side of the milking parlour. © 2001 Elsevier Science B.V.

Embryo recovery and pregnancy rates after the delay of ovulation and fixed time insemination in superstimulated beef cows

The aim of this study was to evaluate the effect of delaying ovulation subsequent to superstimulation of follicular growth in beef cows (Bos indicus) on embryo recovery rates and the capacity of embryos to establish pregnancies. Ovulation was delayed by three treatments using either progesterone (CIDR-B®) or a GnRH agonist (deslorelin). Multiparous Nelore cows (n = 24) received three of four superstimulation treatments in an incomplete block design (n = 18 per group). Cows in Groups CTRL, P48 and P60 were treated with a CIDR-B device plus estradiol benzoate (EB, 4 mg, i.m.) on Day-5, while cows in Group D60 were implanted with deslorelin on Day-7. Cows were superstimulated with FSH (Folltropin-V® 200 mg), from Day 0 to 3, using twice daily injections in decreasing amounts. All cows were treated with a luteolytic dose of prostaglandin on Day 2 (08:00 h). CIDR-B devices were removed as follows: Group CTRL, Day 2 (20:00 h); Group P48, Day 4 (08:00 h); Group P60, Day 4 (20:00 h). Cows in Group CTRL were inseminated at 10, 20 and 30 h after first detected estrus. Ovulation was induced for cows in Group P48 (Day 4, 08:00 h) and Groups P60 and D60 (Day 4, 20:00 h) by injection of LH (Lutropin®, 25 mg, i.m.), and these cows were inseminated 10 and 20 h after treatment with LH. Embryos were recovered on Days 11 or 12, graded and transferred to synchronized recipients. Pregnancies were determined by ultrasonography around Day 100. Data were analyzed by mixed procedure, Kruskal-Wallis and Chi-square tests. The number of ova/embryos, transferable embryos (mean ± S.E.M.) and pregnancy rates (%) were as follows, respectively: Group CTRL (10.8 ± 1.8, 6.1 ± 1.3, 51.5), P48 (12.6 ± 1.9, 7.1 ± 1.0, 52.3), P60 (10.5 ± 1.6, 5.7 ± 1.3, 40.0) and D60 (10.3 ± 1.7, 5.0 ± 1.2, 50.0). There were no significant differences among the groups (P > 0.05). It was concluded that fixed time AI in association with induced ovulation did not influence embryo recovery. Furthermore, pregnancy rates in embryos recovered from cows with delayed ovulation were similar to those in embryos obtained from cows treated with a conventional superstimulation protocol. © 2002 Elsevier B.V. All rights reserved.

Acute reduction in serum progesterone concentrations after feed intake in dairy cows

This study tested the hypothesis that high feed consumption will acutely decrease circulating progesterone concentrations. In the first experiment, a Latin Square design was used to test whether feeding pattern would alter circulating progesterone in pregnant lactating Holstein cows (n = 12). Feed was removed for 12 h before the experiment and cows were then either fed 100% of the total mixed ration (TMR), 50% of TMR every 12 h, 25% of TMR every 6 h, or left unfed for an additional 12 h. Blood samples were taken every hour for 24 h. Provision of 100 or 50% of TMR decreased circulating progesterone by 1 h after feeding and progesterone remained depressed until 8-9 h after feeding. Feeding 25% of TMR did not reduce circulating progesterone concentrations. Experiment 2 used a crossover design to measure the effect of acute feeding on circulating progesterone and LH concentrations during delivery of a constant amount of exogenous progesterone (Eazi-Breed CIDRs) in lactating Holstein cows (n = 8) and nonpregnant dry Holstein cows (n = 6). Blood samples were taken every 15 min for 8 h. There was no change in serum progesterone during the 8 h treatment period in unfed cows; however, feeding decreased (P < 0.05) circulating progesterone between 2 and 6 h after feeding. In lactating cows, feeding increased mean LH (P < 0.05). There were more LH pulses (P = 0.01) in lactating than nonlactating cows. Thus, acute feeding reduced circulating progesterone in pregnant lactating cows apparently due to an increase in progesterone metabolism. Interestingly, feeding multiple smaller meals eliminated the acute effect of feeding on circulating progesterone. © 2003 Published by Elsevier B.V.

Grazing time and milk production of crossbred cows in a rotational area of Elephant grass and Tanzania grass

This study was carried out in January of two consecutive years. The objective was to evaluate the grazing time, the grazing rate and the milk production of crossbred cows, managed in two rotational grazing areas, one with elephant grass (Pennisetum purpureum Schum. cv. Guaçu) and another one with Tanzania grass (Panicum maximum Jacq. cv. Tanzania), both with natural shade in the rest area. The experiment was divided in two phases, the first with 12 cows that remained day and night in the paddock and were milked twice a day. In the second phase 15 cows were observed and remained 10.43 hours in the paddock during the day, and were kept in a corral during the night. Each cow was observed every 15 minutes. Grass specie had no effect on milk production in the two phases of the experiment. The grazing time was 564 and 474 minutes and the grazing rate was 28.7 and 24.4 minutes/hour for the Elephant grass and Tanzania grass, respectively, in first phase. In the second phase,the grazing time was 461 and 426 minutes and the grazing rate was 42.7 and 39.4 minutes/hour for the Elephant grass and Tanzania grass, respectively. Correlations were observed (P<0.01) between grazing rate and the minimum temperature (-0.68), the maximum temperature (-0.76), the relative humidity (0.44) and the THI (-0.76).

Distribution of antibodies against Neospora caninum, BVDV and BHV-1 among cows in brazilian dairy herds with reproductive disorders.

Neospora caninum, bovine viral diarrhea virus (BVDV) and bovine herpes virus 1 (BHV-1) are worldwide spread pathogens associated with reproductive problems in cattle. The present work aimed to observe the infection pattern of these three pathogens in two dairy herds with distinct reproductive managements from Triângulo Mineiro, Minas Gerais State, Brazil. The herds were not vaccinated against either N. caninum, BVDV or BHV-1. Blood samples were collected and analyzed for presence of specific antibodies, and N. caninum IgG avidity was measured in N. caninum positive samples. In herd 1, 34 out of 174 sampled cows (20%) had antibodies to N. caninum and the seropositivity of BVDV and BHV-1 were 62% and 86%, respectively. Of 69 sampled cows in herd 2. 7 (10%) had antibodies to N. caninum, and 49% and 39% were seropositive to BVDV and BHV-1, respectively. The IgG avidity profiles indicated that N. caninum had been present in both herds for some years and that herd 1 had an ongoing horizontal spread of the parasite. The results indicate that the studied reproductive pathogens were present in the herds and partly may have contributed to their reproductive problems.

Subclinical mastitis caused by staphylococcus aureus: Analysis cost benefit of antibiotic therapy in lactating cows

The cost benefit analysis of treatment of bovine subclinical mastitis caused by S. aureus was evaluated. Two hundred and seventy udder quarters with subclinical mastitis and healthy were selected in four groups, in conformity to lactational stage and with the treatment or not. Group 1 included treated animals 10 to 60 days in milk; group 2 included treated animals 61 days in milk until two months before the end of lactation; group 3 included animals not treated 10 to 60 days in milk; group 4 included animals not treated from 61 days in milk until two months before the end of lactation. Treatment with gentamicin (150 mg) was accomplished by intramammary doses, once a day, after sensitivity tests. The mammary quarters were evaluated after 30 days again. The costs with the treatment were calculated considering a S. aureus prevalence of 5%, expenses with antibiotic, loss in milk, tests of sensitivity and workload. There was loss of income of 2% and 14% in the groups 1 and 2, respectively, when compared with the incomes before treatment. In such case, the treatment of bovine subclinical mastitis by S. aureus in the lactation was economically not practicable.

Profitability measures of dairy cows

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

LH surge in Nelore cows (Bos indicus), after induced estrus or after ovarian superestimulation

Considering that there is limited information about the preovulatory LH surge in Zebu cattle (Bos indicus), the purpose of the present work was to assess the LH surge in Nelore cows during the estrous cycle and after ovarian superestimulation of ovarian follicular development with FSH. This information is particularly important to improve superovulatory protocols associated with fixed-time artificial insemination. Nelore cows (n = 12) had their estrus synchronized with an intravaginal device containing progesterone (CIDR-B ®) associated with estradiol benzoate administration (EB, 2.5 mg, i.m., Day 0). Eight days later all animals were treated with PGF2α (Day 8) in the morning (8:00 h) and at night, when CIDR devices were removed (20:00 h). Starting 38 h after the first PGF2α injection, blood sampling and ovarian ultrasonography took place every 4 h, during 37 consecutive hours. Frequent handling may have resulted in a stress-induced suppression of LH secretion resulting in only 3 of 12 cows having ovulations at 46.7 ± 4.9 and 72.3 ± 3.8 h, respectively, after removal of CIDR-B. Thirty days later, the same animals received the described hormonal treatment associated with FSH (Folltropin ®, total dose = 200 mg) administered twice a day, during 4 consecutive days, starting on Day 5. Thirty-six hours after the first injection of PGF2α, to minimize stress, only seven blood samples were collected at 4 h interval each, and ultrasonography was performed every 12 h until ovulation. In 11 of 12 cows (92%) the LH surge and ovulation were observed 34.6 ± 1.6 and 59.5 ± 1.9 h, respectively, after removal of progesterone source. The maximum values for LH in those animals were 19.0 ± 2.6 ng/ml (mean ± S.E.M.). It is concluded that, in Nelore cows submitted to a ovarian superstimulation protocol, the LH surge occurs approximately 35 h after removal of intravaginal device containing progesterone, and approximately 12 h before the LH surge observed after an induced estrus without ovarian superstimulation. © 2008 Elsevier B.V. All rights reserved.

Comportamento sócio-sexual e de manutenção de touros nelore durante a estação de monta

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Neither plasma progesterone concentrations nor exogenous eCG affects rates of ovulation or pregnancy in fixed-time artificial insemination (FTAI) protocols for puberal Nellore heifers

The objective was to evaluate the effects of plasma progesterone (P4) concentrations and exogenous eCG on ovulation and pregnancy rates of pubertal Nellore heifers in fixed-time artificial insemination (FTAI) protocols. In Experiment 1 (Exp. 1), on Day 0 (7 d after ovulation), heifers (n = 15) were given 2 mg of estradiol benzoate (EB) im and randomly allocated to receive: an intravaginal progesterone-releasing device containing 0.558 g of P4 (group 0.5G, n = 4); an intravaginal device containing 1 g of P4 (group 1G, n = 4); 0.558 g of P4 and PGF2α (PGF; 150 μg d-cloprostenol, group 0.5G/PGF, n = 4); or 1 g of P4 and PGF (group 1G/PGF, n = 3). On Day 8, PGF was given to all heifers and intravaginal devices removed; 24 h later (Day 9), all heifers were given 1 mg EB im. In Exp. 2, pubertal Nellore heifers (n = 292) were treated as in Exp. 1, with FTAI on Day 10 (30 to 36 h after EB). In Exp. 3, pubertal heifers (n = 459) received the treatments described for groups 0.5G/PGF and 1G/PGF and were also given 300 IU of eCG im (groups 0.5G/PGF/eCG and 1G/PGF/eCG) at device removal (Day 8). In Exp. 1, plasma P4 concentrations were significantly higher in heifers that received 1.0 vs 0.588 g P4, and were significantly lower in heifers that received PGF on Day 0. In Exp. 2 and 3, there were no significant differences among groups in rates of ovulation (65-77%) or pregnancy (Exp. 2: 26-33%; Exp. 3: 39-43%). In Exp. 3, diameter of the dominant ovarian follicle on Day 9 was larger in heifers given 0.558 g vs 1.0 g P4 (10.3 ± 0.2 vs 9.3 ± 0.2 mm; P < 0.01). In conclusion, lesser amounts of P4 in the intravaginal device or PGF on Day 0 decreased plasma P4 from Days 1 to 8 and increased diameter of the dominant follicle on Day 9. However, neither of these nor 300 IU of eCG on Day 8 significantly increased rates of ovulation or pregnancy. © 2011.

Implementation of DNA markers to produce genomically - Enhanced EPDs in nellore cattle

Background: The sequencing and publication of the cattle genome and the identification of single nucleotide polymorphism (SNP) molecular markers have provided new tools for animal genetic evaluation and genomic-enhanced selection. These new tools aim to increase the accuracy and scope of selection while decreasing generation interval. The objective of this study was to evaluate the enhancement of accuracy caused by the use of genomic information (Clarifide® - Pfizer) on genetic evaluation of Brazilian Nellore cattle. Review: The application of genome-wide association studies (GWAS) is recognized as one of the most practical approaches to modern genetic improvement. Genomic selection is perhaps most suited to the improvement of traits with low heritability in zebu cattle. The primary interest in livestock genomics has been to estimate the effects of all the markers on the chip, conduct cross-validation to determine accuracy, and apply the resulting information in GWAS either alone [9] or in combination with bull test and pedigree-based genetic evaluation data. The cost of SNP50K genotyping however limits the commercial application of GWAS based on all the SNPs on the chip. However, reasonable predictability and accuracy can be achieved in GWAS by using an assay that contains an optimally selected predictive subset of markers, as opposed to all the SNPs on the chip. The best way to integrate genomic information into genetic improvement programs is to have it included in traditional genetic evaluations. This approach combines traditional expected progeny differences based on phenotype and pedigree with the genomic breeding values based on the markers. Including the different sources of information into a multiple trait genetic evaluation model, for within breed dairy cattle selection, is working with excellent results. However, given the wide genetic diversity of zebu breeds, the high-density panel used for genomic selection in dairy cattle (Ilumina Bovine SNP50 array) appears insufficient for across-breed genomic predictions and selection in beef cattle. Today there is only one breed-specific targeted SNP panel and genomic predictions developed using animals across the entire population of the Nellore breed (www.pfizersaudeanimal.com), which enables genomically - enhanced selection. Genomic profiles are a way to enhance our current selection tools to achieve more accurate predictions for younger animals. Material and Methods: We analyzed the age at first calving (AFC), accumulated productivity (ACP), stayability (STAY) and heifer pregnancy at 30 months (HP30) in Nellore cattle fitting two different animal models; 1) a traditional single trait model, and 2) a two-trait model where the genomic breeding value or molecular value prediction (MVP) was included as a correlated trait. All mixed model analyses were performed using the statistical software ASREML 3.0. Results: Genetic correlation estimates between AFC, ACP, STAY, HP30 and respective MVPs ranged from 0.29 to 0.46. Results also showed an increase of 56%, 36%, 62% and 19% in estimated accuracy of AFC, ACP, STAY and HP30 when MVP information was included in the animal model. Conclusion: Depending upon the trait, integration of MVP information into genetic evaluation resulted in increased accuracy of 19% to 62% as compared to accuracy from traditional genetic evaluation. GE-EPD will be an effective tool to enable faster genetic improvement through more dependable selection of young animals.

Rumen microbial diversity under influence of a polyclonal antibody preparation against lactate-producing and proteolytic bacteria in cows fed different energy sources

Nine ruminally cannulated cows fed different energy sources were used to evaluate an avianderived polyclonal antibody preparation against specific ruminal bacteria and monensin on microbial community diversity. The experimental design was three Latin squares 3 x 3 distinguished by the main energy source in the diet [dry-ground corn grain, high moisture corn silage or citrus pulp]. Inside each Latin square, animals received one of the feed additives per period [control, monensin or polyclonal antibody preparation]. Each period lasted 21 days where 20 were used for treatments adaptation and the last one for sampling collection. Microbial diversity was evaluated by protozoa counts and denaturing gradient gel electrophoresis. Polyclonal antibodies plus citrus pulp (CiPu) addition in the diet resulted in an increase of relative counting of Isotricha protozoa that indicates a possible effect on this ruminal ciliate population. In general lines, in the present experiment, it was not possible to assign that there was a pattern in the structures of amplification of Bacteria and Archaea communities of the ruminal content. Oral passive immunization is a technology that arises as an effective alternative for feed additive production. Further research is still necessary to better understand its mechanisms of action.

Lipid and selenium sources on fatty acid composition of intramuscular fat and muscle selenium concentration of Nellore steers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic correlations between mature cow weight and productive and reproductive traits in Nellore cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Progesterone-based strategies to induce ovulation in prepubertal Nellore heifers

Four experiments were conducted to evaluate hormonal strategies to induce ovulation in Nellore heifers. In experiment 1, heifers (N = 1039) received a controlled internal drug release (CIDR) of fourth use (CIDR-4) on Day -12 or no CIDR (CIDR-0). The CIDR was removed on Day 0 in the CIDR-4 treatment, and estrus detection and AI were performed from Days 1 to 7. On Day 8, heifers not detected in estrus were evaluated for CL presence and received the same treatment again, followed by estrus detection and AI from Days 21 to 27. All heifers in experiments 2 (N = 896), 3 (N = 839), and 4 (N = 948) received the CIDR-4 treatment on Day -12. In experiment 2, heifers were randomly assigned to a control group (no additional treatment) or to receive equine chorionic gonadotropin (eCG; 200 IU eCG im) on Day 0. In experiment 3, heifers received the same treatments as in experiment 2, or a treatment that included eCG and estradiol cypionate (ECP) (eCG+ECP; 200 IU im eCG plus 0.5 mg ECP im) on Day 0. In experiment 4, heifers received the treatments described in experiment 3 or only ECP (0.5 mg) on Day 0. In experiments 2 and 3, estrus detection and AI was performed from Days 1 to 7 and on Day 8, heifers not detected in estrus were evaluated for CL presence. In experiment 4, heifers were evaluated for presence of a CL between Days 10 and 14. In experiment 1 heifers treated with CIDR-4 had greater estrus detection, ovulation induction, and pregnancy rates than in the CIDR-0 group. In experiment 2, heifers treated with eCG had greater estrus detection, ovulation induction, and pregnancy rates in 7 days than heifers in the control group. In experiment 3, heifers treated with eCG+ECP had greater estrus detection, ovulation induction, and pregnancy rates than the control and eCG treatments. In experiment 4, ovulation induction was greater for heifers treated with eCG and eCG+ECP relative to control, but did not differ from the ECP treatment. In conclusion, the use of a CIDR of fourth use for 12 days and the addition of eCG and/or ECP at CIDR removal efficiently induced ovulation and increased pregnancy rates in prepubertal Nellore heifers. © 2013 Elsevier Inc.