Comparison of factor-analytic and reduced rank models for test-day milk yield in Gyr dairy cattle (Bos indicus)

We analyzed 46,161 monthly test-day records of milk production from 7453 first lactations of crossbred dairy Gyr (Bos indicus) x Holstein cows. The following seven models were compared: standard multivariate model (M10), three reduced rank models fitting the first 2, 3, or 4 genetic principal components, and three models considering a 2-, 3-, or 4-factor structure for the genetic covariance matrix. Full rank residual covariance matrices were considered for all models. The model fitting the first two principal components (PC2) was the best according to the model selection criteria. Similar phenotypic, genetic, and residual variances were obtained with models M10 and PC2. The heritability estimates ranged from 0.14 to 0.21 and from 0.13 to 0.21 for models M10 and PC2, respectively. The genetic correlations obtained with model PC2 were slightly higher than those estimated with model M10. PC2 markedly reduced the number of parameters estimated and the time spent to reach convergence. We concluded that two principal components are sufficient to model the structure of genetic covariances between test-day milk yields. © FUNPEC-RP.

Molecular epidemiology and extended-spectrum β-lactamases production of klebsiella pneumoniae isolated from three dairy herds

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

The application of a surface response methodology in the solar/UV-induced degradation of dairy wastewater using immobilized ZnO as a semiconductor

An Advanced Oxidation Process (AOPs) was carried out in this study with the use of immobilized ZnO and solar/UV as an energy source to degrade dairy wastewater. The semibatch reactor system consisted of metal plate of 800 × 250 mm and a glass tank. The reaction time was of 3 h for 3 L of dairy wastewater. Experiments were performed based on a surface response methodology in order to optimize the photocatalytic process. Degradation was measured in percentage terms by total organic carbon (TOC). The entry variables were ZnO coating thickness and pH, using three levels of each variable. The optimized results showed a TOC degradation of 31.7%. Optimal parameters were metal-plate coating of 100 m of ZnO and pH of 8.0. Since solar/UV is a constant and free energy source in most tropical countries, this process tends to suggest an interesting contribution in dairy wastewater treatment, especially as a pretreatment and the optimal conditions to guarantee a better efficiency of the process. © 2013 Gisella R. Lamas Samanamud et al.

Estrus synchronization and fixed time artificial insemination (FTAI) in dairy buffaloes during seasonal anestrus

The aim of this work was to study estrus synchronization and fixed time artificial insemination (FTAI) in dairy buffaloes during season anestrus. One hundred thirty-nine dairy buffaloes in seasonal anestrus were divided in two groups as G1(n=66) and G2(n=73). The protocols for both the groups were the same until day (D)14:D0 administration of 2.0 mg estradiol benzoate and implantation of progesterone device (P4) for 14 days; D14 removal of P4 plus 150 mg of cloprostenol and 400 IU of equine chorionic gonadotropin. On D16, G1 received 10 mg of buserelin and G2 100 mg deslorelin acetate. On D17, both the groups were submitted to FTAI. Ultrasonographic examinations of ovaries were performed on D0, D14, D16 and D17. Results showed that pregnancy rates in G1 and G2 were 20 and 41% (p<0.05) and the ovulation rates were 16.6 and 37%, respectively (p<0.05). The dominant follicle (DF) diameter on D16 was 7.9 mm in G1 and 8.9 mm in G2 (p>0.05). Thirty-five percent of the animals in G1 and 54.1% in G2 showed a diameter DF greater than 8.0 mm on D16 (p>0.05). Thus, it could be concluded that the protocols synchronized the estrus, leading the concentration of the parturitions in the period of low milk production. Deslorelin was more efficient than buserelin due the higher percentage of DF ovulation and higher pregnancy rates.

Characteristics of the world dairy products market: aspects of interest for Latin America

Includes bibliography

Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

O objetivo deste estudo foi avaliar a eficiência do uso de duas doses de PGF associadas ou não à administração de hCG no início do estro sobre os parâmetros reprodutivos de cabras leiteiras. Um total de 29 cabras receberam duas doses de 30 µg d-cloprostenol pela via latero-vulvar com 10 dias de intervalo (Dia 1 e Dia 10). As cabras foram alocadas para receberem o hCG (250 IU) ou salina i.m. no momento em que o estro foi detectado. Depois da realização da segunda dose de PGF, o estro foi monitorado e exames ultrassonográficos foram realizados duas vezes ao dia. Todas as fêmeas foram inseminadas 16 h após o inicio do estro. Amostras de sangue foram coletadas diariamente para determinação das concentrações plasmáticas de progesterona. O uso do hCG no momento do início do estro não afetou os parâmetros estudados e, portanto, os dados serão apresentados agrupados. A taxa de manifestação de estro foi similar (P > 0,05) na primeira (75,9% - 22/29) ou na segunda dose de PGF (79,3% - 23/29). O intervalo entre a administração de PGF e o início do estro foi maior (P < 0,05) no Dia 1 (75,8±53,9 h) que no Dia 10 (47,7±10,1 h). Duração do estro também diferiu (P < 0,05) 35,4±15,9 (Dia 1) vs 26,8±15, 0 h (Dia 10). A taxa de ovulação foi 79,3% (23/29) após a segunda dose PGF. Não foi encontrada diferença (P>0,05) entre os grupos experimentais quanto aos parâmetros reprodutivos: intervalo entre a aplicação da segunda dose e a ovulação (86,6±11,4h), intervalo do estro a ocorrência da ovulação (39,9±12,3h), diâmetro do maior folículo (7,2±1,4) e número de ovulações (1,8±0,6). No Dia 1, 52,4% (11/21) apresentavam concentrações de progesterona < 1 ng/mL. No Dia 10, 100% dos animais apresentavam concentrações >1ng/mL. O presente estudo permite concluir que o estro pode ser eficientemente sincronizado em cabras leiteiras com duas doses de PGF intervaladas em 10 dias. Novas pesquisas devem se realizadas para avaliar diferentes doses e momentos de utilização do hCG.

Nutrient intake, productive performance and body measurements of dairy heifers fed with different sources of protein

This study evaluated the effect of different protein sources (soybean meal, cottonseed meal, peanut meal and sunflower meal) on dry matter and nutrient intake, productive performance and body measurements of dairy heifers, Holstein x Zebu, recreated in confinement. The experiment consisted in a randomized complete block design made up by 6 replications and 4 treatments. The mean values of ingestion of ether extract (EEI, kg day-1) were statistically different (p < 0.05). The neutral detergent fiber intake (NDFI, %BW) also presented differences (p < 0.05), with higher values in the diet containing sunflower meal (1.01% BW) in relation to the diet with soybean meal (0.84% BW). The average daily weight gain using the diet with soybean meal was superior (0.95 kg day-1) to the diet with sunflower meal (0.82 kg day-1), and considering the final body weight, the diet with soybean meal was superior to the other treatments (p < 0.05). The heart girth presented greater association with body weight (0.93). The soybean meal promoted the best productive performance of crossbred Holstein x Zebu heifers fed diets based on sugarcane. However, cottonseed meal, peanut meal and sunflower meal can be possible alternatives to soybean meal.

Sources of omega-6 fatty acids do not alter the rumen degradation and transit of fibre from dairy cow diets

The objective of this study was to evaluate the behaviour of fibre in the digestive tract on the basis of the passage kinetics of forage and concentrate particles in cows fed different omega-6 fatty-acid sources. The scientific hypothesis of this study was that omega-6 fatty acids do not interfere with the digestion of fibre in the diets of dairy cows. Five primiparous lactating Holstein cows were used in the experiment. The experimental diets were: control (C), ground soyabean (GS), cottonseed (CS), soyabean oil (SO), calcium salts of fatty acids (CSFA). The global mean estimates for the parameters of passage rate (gamma) were 0.038 and 0.055 h(-1) for forage and concentrate, respectively. The only significant effect with respect to the passage rate was a high negative correlation between the concentrate passage rate and dry matter intake. There was less undegradable neutral detergent fibre (NDF) in treatments without added lipid. Dietary supplementation with lipid sources does not alter the kinetic parameters of roughage and concentrate particle passage or in vitro NDF degradation. Sources of omega-6 fatty acids do not alter the rumen degradation and transit of fibre.

Inducing ovulation early postpartum influences uterine health and fertility in dairy cows

The objective of the current study was to evaluate the effect of GnRH early postpartum on induction of ovulation, uterine health, and fertility in dairy cows. Holstein cows without a corpus luteum (CL) at 17 +/- 3 DIM were assigned randomly to receive i.m. GnRH (n = 245) at 17 +/- 3 and 20 +/- 3 DIM or remain as controls (n = 245). Ovaries were scanned by ultrasonography twice weekly totaling 4 examinations. Ovulation was characterized by the appearance of a CL >= 20 mm at any ultrasound or CL <20 mm in 2 consecutive examinations. Clinical and cytological endometritis were diagnosed at 35 DIM. Compared with control, GnRH increased ovulation up to 3.5 d after the last treatment (78.7 vs. 45.0%) and did not affect the prevalence of clinical endometritis (23.9 vs. 18.6%) or cytological endometritis (30.9 vs. 32.8%). Prevalence of clinical endometritis increased in cows that had calving problems (32.6 vs. 15.9%) and metritis (40.6 vs. 15.8%). Metritis increased prevalence of cytological endometritis (50.7 vs. 23.5%). Treatment with GnRH did not affect pregnancy per artificial insemination at 32 (37.6 vs. 38.6%) or 74 d after artificial insemination (35.0 vs. 31.5%), but reduced pregnancy loss (6.8 vs. 18.1%). No overall effect of GnRH treatment on hazard of pregnancy was observed; however, an interaction between GnRH treatment and ovulation showed that GnRH-treated cows that ovulated had increased hazard of pregnancy by 300 DIM compared with GnRH-treated and control cows that did not ovulate (hazard ratio = 2.0 and 1.3, respectively), but similar to control cows that ovulated (hazard ratio = 1.1). Gonadotropin-releasing hormone early postpartiim induced ovulation without affecting uterine health, but failed to improve pregnancy per artificial insemination or time to pregnancy, although it reduced pregnancy loss.

Risk factors for anaplasmosis in dairy cows during the peripartum

Anaplasma marginale is endemic in tropical and subtropical areas around the world. Some studies have suggested that cows during peripartum may present a transient immunosuppression state and development of clinical signs of anaplasmosis. The aim of this study was to investigate the relationship between some risk factors and the seroprevalence of A. marginale in dairy cows during peripartum in Rio de Janeiro, Brazil. The risk factors analyzed in association with the prevalence of antibodies against A. marginale in dairy cows were calving season, reproductive experience, breed standard, tick infestations, stocking density, and milk yield. The antibodies against A. marginale were tested in indirect enzyme-linked immunosorbent assays. A primary screening using a 2 x k contingency table of the exposed variables with the outcomes was performed. All variables for which p < 0.20 were included in a fixed effects log regression. The risk factors investigated to anaplasmosis were calving (OR 2.61, IC 1.08-7.63), breed standard (OR 3.83, IC 0.08-0.28), reproductive experience (OR 33.7, IC 2.14-5.16), milk yield (OR 3.9, IC 2.24-7.03), Rhipicephalus microplus infestations (OR 10.3, IC 0.05-0.17), and stocking density (OR 22.3, IC 0.05-0.17). Low titers of antibodies against A. marginale during peripartum had been characterized as a period previous to development of clinical anaplasmosis. Thus, studies on anaplasmosis should consider each farm as an epidemiological unit, where environmental and immunological factors may influence the endemic status of the pathogen.

Effects of supplementation of calcium salts of polyunsaturated fatty acids on serum concentrations of progesterone and insulin of pregnant dairy cows

Forty-five non-lactating, pregnant Holstein animals (18 heifers and 27 multiparous cows; BW = 561 +/- 114 kg; BCS = 2.9 +/- 0.3; days pregnant = 110 +/- 56 d) were stratified by initial BW and BCS, and randomly assigned to receive daily (as-fed basis) 0.50 kg of ground corn plus 0.22 kg of kaolin (CON), calcium salts of saturated fatty acids (SFA) or polyunsaturated fatty acids (PF) for 14 d. Blood samples were collected on days 0, 7 and 14, immediately prior to (0 h) and 3, 6, 9 and 12 h after feeding, to determine the serum concentrations of P 4 and insulin. No treatment effects were detected for serum concentrations of P 4 (5.52, 6.13 and 5.63 +/- 0.41 ng/mL for CON, SFA and PF, respectively). No treatment effects were detected for serum concentrations of insulin (11.5, 10.5 and 10.1 +/- 1.43 mu IU/mL for CON, SFA and PF, respectively). Heifers had greater serum concentrations of P 4 than multiparous cows (6.35 vs. 5.16 +/- 0.42 ng/mL), but lower serum concentrations of insulin (7.0 vs. 14.4 +/- 1.49 mu IU/mL). Feeding 0.22 kg of calcium salts of polyunsaturated fatty acids is not sufficient to increase the serum concentrations of P 4 and insulin of non-lactating, pregnant dairy cows.

Relationships between growth of the preovulatory follicle and gestation success in lactating dairy cows

This report summarizes three studies conducted with lactating dairy cows aiming to increase pregnancy rates to fixed time artificial insemination (TAI) protocols. Experiment 1 was designed to determine if changing the timing of PGF2 alpha treatment during an E2/P4-based program would affect fertility to TAI or fixed-time embryo transfer (TET). In experiment 2, pregnancy rates to AI were compared following synchronized ovulation using two protocols that have been developed to reduce the period between follicular wave emergence and TAI. The Ovsynch-type protocol utilizes GnRH to synchronize the follicular wave by inducing ovulation of a dominant follicle at the beginning of the protocol, and to synchronize ovulation at the end of the protocol allowing TAI. In contrast, E2/P4-based protocols utilize E2 products in the presence of P4 to induce atresia of antral follicles and synchronize emergence of a new follicular wave. At the end of E2/P4-based protocol another E2 treatment in the absence of P4 is used to induce LH release and synchronize ovulation and allow TAI. Experiment 3 was designed to determine whether increasing the length time interval with reduced circulating P4 (proestrus) would increase fertility in a TAI program that utilized E2 and P4 to synchronize ovulation of cycling, lactating dairy cows. The overall conclusions are that circulating concentrations of progesterone and estradiol prior to and circulating concentrations of progesterone following ovulation can affect fertility in cattle. In addition, small increases in P4 concentrations near the time of AI, due to lack of complete CL regression, result in reductions in fertility. Earlier treatment with PGF2 alpha should allow greater time for CL regression, an increase in estradiol and subsequent reductions in circulating P4 that could be critical for fertility. Optimization of follicle size in TAI programs is clearly an intricate balance between oocyte quality, adequate circulating E2 near AI, and adequate circulating P4 after AI.