The effect of first-lactation calving season, milk production, and morphology on the survival of Simmental cows.

Longevity in dairy and dual-purpose cattle is a complex trait which depends on many individual and managerial factors. The purpose of the present study was to investigate the survival (SURV) rate of Italian Simmental dual-purpose cows across different parities. Data of this study referred to 2 173 primiparous cows under official milk recording that calved between 2002 and 2020. Only cows linearly classified for type traits, including muscularity (MU) and body condition score (BCS) were kept. Survival analysis was carried out, through the Cox regression model, for different pairwise combinations of classes of milk productivity MU, BCS, and calving season. Herd-year of first calving was also considered in the model. SURV (0 = culled; 1 = survived) at each lactation up to the 6th were the dependent variables, so that, for example, SURV2 equal to 1 was attributed to cows that entered the 2nd lactation. Survival rates were 98, 71, 63, 56, and 53% for 2nd, 3rd, 4th, 5th, and 6th lactation, respectively. Results revealed that SURV2 was not dependent on milk yield, while in subsequent parities, low-producing cows were characterized by higher SURV compared to high-producing ones. Additionally, cows starting the lactation in autumn survived less (47.38%) than those starting in spring (53.49%), suggesting that facing the late gestation phase in summer could increase the culling risk. The present study indicates that SURV in Italian Simmental cows is influenced by various factors in addition to milk productivity. However, it is important to consider that in this study all first-calving cows culled before the linear evaluation - carried out between mid- and late lactation in this breed - were not accounted for. Finding can be transferred to other dual-purpose breeds, where the cows' body conformation and muscle development - i.e. meat-related features - are often considered as important as milk performance by farmers undertaking culling decisions.

Strategies for choosing core animals in the algorithm for proven and young and their impact on the accuracy of single-step genomic predictions in cattle.

Nowadays, in some populations, the number of genotyped animals is too large to obtain the inverse of the genomic relationship matrix. The algorithm for proven and young animals (APY) can be used to overcome this problem. In the present work, different strategies for defining core animals in APY were tested using either simulated or real data. In particular, core definitions based on random choice or on the contribution to the genomic relationship matrix (GCONTR) calculated using Principal Component Analysis were tested. Core sizes able to explain 90, 95, 98, and 99% of the total variance of the genomic relationship matrix (G) were used. Analyzed phenotypes were three simulated traits for 3 000 individuals, and milkability records for 136 406 Italian Simmental cows. The number of genotypes was 4 100 for the simulated dataset, and 11 636 for the Simmental data, respectively. The GCONTR values in Simmental dataset were moderately correlated with the analyzed phenotype, and they showed a decreasing trend according to the year of birth of genotyped animals. The accuracy increased as the size of the core increased in both datasets. The inclusion in the core of animals with largest GCONTR values led to the lowest accuracies (0.50 and 0.71 for the simulated and Simmental datasets, respectively; average across traits and core sizes). On the contrary, the selection of animals with the lowest rank according to their contribution to the G provided slightly higher accuracies, especially in the simulated dataset (0.68 for the simulated dataset, and 0.76 for the Simmental data; average across traits and core sizes). In real data, particularly for larger sizes of core animals, the criteria of choice appear less important, confirming the results of earlier studies. Anyway, the inclusion in the core of animals with the lowest values of GCONTR led to increases in accuracy. These are preliminary results based on a small sample size that need to be confirmed on a larger number of genotypes.

Genetic correlations between fertility traits and milk composition and fatty acids in Holstein-Friesian, Brown Swiss, and Simmental cattle using recursive models.

This study aimed to investigate the genetic and putative causal relationships between fertility traits [i.e., days open (DO) and calving rate (CR)] and milk quality, composition, and fatty acid contents (milk composition traits) in Holstein-Friesian, Brown Swiss, and Simmental cattle, using recursive models within a Bayesian framework. Trivariate animal models were run, each including one fertility trait, one milk composition trait, and, in all models, milk yield. The DO and CR data were merged with the test days closest to the insemination date for milk composition traits. After editing, 16,468 to 23,424 records for Holstein-Friesian, 23,424 to 46,660 for Brown Swiss, and 26,105 to 35,574 for Simmental were available for the analyses. Recursive animal models were applied to investigate the possible causal influences of milk composition traits on fertility and the genetic relationships among these traits. The results suggested a potential cause-and-effect relationship between milk composition traits and fertility traits, with the first trait influencing the latter. We also found greater recursive effects of milk composition traits on DO than on CR, the latter with some putative differences among breeds in terms of sensitivity. For instance, the putative causal effects of somatic cell score on CR (on the observed scale, %) varied from -0.96 to -1.39%, depending on the breed. Concerning fatty acids, we found relevant putative effects of C18:0 on CR, with estimates varying from -7.8 to -9.9%. Protein and casein percentages, and short-chain fatty acid showed larger recursive effects on CR, whereas fat, protein, and casein percentages, C16:0, C18:0, and long-chain fatty acid had larger effects on DO. The results obtained suggested that these milk traits could be considered as effective indicators of the effects of animal metabolic and physiological status on fertility.

Genomic information allows for more accurate breeding values for milkability in dual-purpose Italian Simmental cattle.

Milkability is a trait related to the milking efficiency of an animal, and it is a component of the herd profitability. Due to its economic importance, milkability is currently included in the selection index of the Italian Simmental cattle breed with a weight of 7.5%. This lowly heritable trait is measured on a subjective scale from 1 to 3 (1 = slow, 3 = fast), and genetic evaluations are performed by pedigree-based BLUP. Genomic information is now available for some animals in the Italian Simmental population, and its inclusion in the genetic evaluation system could increase accuracy of breeding values and genetic progress for milkability. The aim of this study was to test the feasibility and advantages of having a genomic evaluation for this trait in the Italian Simmental population. Phenotypes were available for 131,308 cows. A total of 9,526 animals had genotypes for 42,152 loci; among the genotyped animals, 2,455 were cows with phenotypes, and the other were their relatives. The youngest cows with both phenotypes and genotypes (n = 900) were identified as selection candidates. Variance components and heritability were estimated using pedigree information, whereas genetic and genomic evaluations were carried out using BLUP and single-step genomic BLUP (ssGBLUP), respectively. In addition, a weighted ssGBLUP was assessed using genomic regions from a genome-wide association study. Evaluation models were validated using theoretical and realized accuracies. The estimated heritability for milkability was 0.12 ± 0.01. The mean theoretical accuracies for selection candidates were 0.43 ± 0.08 (BLUP) and 0.53 ± 0.06 (ssGBLUP). The mean realized accuracies based on linear regression statistics were 0.29 (BLUP) and 0.40 (ssGBLUP). No genomic regions were significantly associated with milkability, thus no improvements in accuracy were observed when using weighted ssGBLUP. Results indicated that genomic information could improve the accuracy of breeding values and increase genetic progress for milkability in Italian Simmental.

Comparison between direct and indirect methods for exploiting Fourier transform spectral information in estimation of breeding values for fine composition and technological properties of milk.

The aim of this study was to compare the common method of exploiting infrared spectral data in animal breeding; that is, estimating the breeding values for the traits predicted by infrared spectroscopy, and an alternative approach based on the direct use of spectral information (direct prediction, DP) to predict the estimated breeding values (EBV). Traits were pH, milk coagulation properties, contents of the main casein and whey protein fractions, cheese yield measured by micro-cheese making, lactoferrin, Ca, and fat composition. For the DP method, the number of spectral variables was reduced by principal components analysis to 8 latent traits that explained 99% of the original spectral variation. Restricted maximum likelihood was used to estimate variance components of the latent traits. (Co)variance components of the original spectral traits were obtained by back-transformation and EBV of all derived milk traits were then predicted as traits correlated with the genetic information of the spectra. The rank correlation between the EBV obtained for the infrared-predicted traits and those obtained from the DP method was variable across traits. Rank correlations ranged from 0.07 (for the content of saturated fatty acids expressed as g/100 g of fat) to 0.96 (for dry matter cheese yield, %) and, for most traits, was <0.5. This result can be explained by the nature of the principal components analysis: it does not take into account the covariance between the spectral variables and the reference traits but produces latent traits that maximize the spectral variance explained. Thus, the direct approach is more likely to be effective for traits more related to the main sources of spectral variation (i.e., protein and fat). More research is required to study spectral genetic variation and to determine the best way to choose spectral regions and the type and number of considered latent traits for potential applications.

Short communication: Mid-infrared spectroscopy prediction of fine milk composition and technological properties in Italian Simmental.

The objective of this study was to evaluate the ability of mid-infrared predictions of fine milk composition and technological traits to serve as a tool for large-scale phenotyping of the Italian Simmental population. Calibration equations accurately predicted the fatty acid profile of the milk, but we obtained moderate or poor accuracy for detailed protein composition, coagulation properties, curd yield and composition, lactoferrin, and concentration of major minerals. To evaluate the role of infrared predictions as indicator traits of fine milk composition in indirect selective breeding programs, the genetic parameters of the traits predicted using mid-infrared spectra need to be estimated.

Registro de la utilización de nutrición parenteral en el Hospital de Pediatría Juan P. Garrahan / Registry of the use of parenteral nutrition at the Pediatric Hospital Juan P. Garrahan

La nutrición parenteral (NPT) en pediatría es un recurso que permite mantener el sostén clínico de aquellos pacientes que por la complejidad de la patología que presentan no pueden utilizar la vía enteral. El objetivos es analizar el registro de utilización de NPT en el Hospital de Pediatría Juan P. Garrahan. Estudio retrospectivo descriptivo. Se analizaron 95 solicitudes de NPT durante el período julio-agosto 2011. Se accedió a las historias clínicas, donde se constataron las variables principales: edad (meses), sexo, área de internación, patología asociada a su uso, duración promedio (días), tipo de NPT (Standard o personalizada) y evidencia de complicaciones. Se definió colestasis a valores de Bilirrubina directa mayor a 2 mg%. Sobre un total 114 indicaciones médicas de NPT, se accedió a 95 historias clínicas. Perfil de uso: Neonatología 34,5%, Cuidados Intensivos 35,7% y Cuidados Intermedios y moderados 29,8%. La media de edad 39 meses (0-192). Las patologías más frecuentes son quirúrgicas 52,6%, hematológicas y oncológicas 28,4%. La duración total de la indicación fue en promedio 16,5 días (0-187). Las soluciones personalizadas (a la carta) 83%. Las soluciones con lípidos sumaron un total de 73 (76%). Como complicaciones se observaron 13 casos de colestasis (13,68%) los cuales se asociaron a soluciones con lípidos. La mayoría de los pacientes que requirieron uso de NPT presentaron patologías que requerían cuidados críticos neonatales o pediátricos. Las soluciones personalizadas o "a la carta" fueron las más utilizadas. El tiempo de administración fue muy variable, la presencia de colestasis se relacionó con los usos más prolongados; superior a los 71 días promedio (AU)

In pediatrics, total parenteral nutrition (TPN) is a resource that allows to clinically support those patients who, due to the severity of their disease, do not tolerate the enteral route. The aim of this study was to analyze the registry of TPN use at the Pediatric Hospital Dr. Juan P. Garrahan. A retrospective descriptive study was conducted. Ninety-five requests for TPN made in July and August 2011 were analyzed. Clinical charts of the patients were assessed recording the main variables: Age (months), sex, area the child was admitted to, pathology associated with TPN use, duration of TPN (days), type of TPN (standard or personalized), and evidence of complications. Cholestasis was defined as direct bilirubin greater than 2 mg%. For a total of 114 medical indications for PN, access to 95 clinical charts was obtained. User's profile: Neonatology 34.5%, intensive care 35.7%, intermediate and moderate care 29.8%. Mean age of the patients was 39 months (0-192). The most common pathologies were surgical in 52.6% and hematological and oncological in 28.4%. Mean duration of TPN was 16.5 days (0-187). Personalized formulations ("a la carte") were used in 83%. Overall, 73 (76%) formulations with lipids were used. Complications observed were 13 cases of cholestasis (13.68%) that were associated with the use of lipid formulations. Most patients that needed TPN had pathologies requiring neonatal or pediatric critical care. Personalized or "a la carte" formulations were most often used. The duration of TPN administration was variable. Cholestasis was related with longer TPN use, with a mean of 71 days (AU)

Bovine colostrum: changes in lipid constituents in the first 5 days after parturition.

Despite the great interest paid to protein components in colostrum, fat also plays an important role in the supply of essential nutrients to provide energy, increase metabolism, and protect the newborn calf against microbial infections. This work aimed to elucidate levels of different fat components in colostrum, in particular fatty acid (FA), triglyceride (TG), cholesterol, and phospholipid contents. Colostrum samples from primiparous and multiparous (3-5 lactations) Holstein dams, fed the same ration indoors, were collected on the first 5d after parturition, analyzed, and compared with milk samples from the same cows collected at 5mo of lactation. Fat content during the first 5d of milking did not vary. However, the proportion of short-chain saturated FA increased and that of long-chain FA decreased. The concentration of n-3 FA was higher on the first day of calving than on the other days, with clear differences in the number and type of n-3 FA. Conjugated linoleic isomers and trans FA slowly increased from d 1 to 5, reaching a maximum at 5mo of lactation. Changes in the distribution profile of TG were observed as lactation progressed, with a shift from a prevalence of high-carbon-number TG (C48-50) on d 1 to a bimodal distribution (maxima at C38 and C50) on d 5, characteristic of mid-lactation milk. Cholesterol content was high in the first hours after calving and rapidly decreased within 48h. Colostrum sampled on d 1 also had a high content of phospholipids. Phosphatidylethanolamine and sphingomyelin were, respectively, lower and higher in the first 5d than in mid-lactation milk. The influence of lactation number on colostrum fat composition was also considered and significant results were obtained for all FA groups (except for polyunsaturated and n-6 FA) and TG content.

Effects of beta-kappa-casein (CSN2-CSN3) haplotypes, beta-lactoglobulin (BLG) genotypes, and detailed protein composition on coagulation properties of individual milk of Simmental cows.

The aim of this study was to investigate the effects of CSN2-CSN3 (beta-kappa-casein) haplotypes, BLG (beta-lactoglobulin) genotypes, content of milk protein fractions, and protein composition on coagulation properties of milk (MCP). Rennet coagulation time (RCT) and curd firmness (a(30)) were measured using a computerized renneting meter, and the contents of major milk protein fractions were quantified by reversed-phase HPLC in individual milk samples of 2,167 Simmental cows. Cow genotypes at CSN2, CSN3, and BLG were ascertained by reversed-phase HPLC, and CSN2-CSN3 haplotype probabilities were estimated for each cow. Phenotypes for MCP were regressed on CSN2-CSN3 haplotype probabilities using linear models that also included the effects of herd-test-day, parity, days in milk, pH, somatic cell score, renneting meter sensor, sire of the cow, BLG genotype, and content of major protein fractions or, alternatively, protein composition. When the statistical model did not account for protein fraction contents or protein composition, haplotypes carrying CSN3 B were associated with shorter RCT and greater a(30) compared with those carrying CSN3 A. Haplotypes carrying CSN2 B had the effect of decreasing RCT and increasing a(30) relative to haplotype A(2)A. When effects of protein fractions content or protein composition were added to the model, no difference across haplotypes due to CSN3 and CSN2 alleles was observed for MCP, with the exception of the effect of CSN2 B on RCT, which remained markedly favorable. Hence, the effect of CSN3 B on MCP is related to a variation in protein composition caused by the allele-specific expression of kappa-casein, rather than to a direct role of the protein variant on the coagulation process. In addition, the favorable effect exerted by CSN2 B on a(30) was caused by the increased beta-casein content in milk. Conversely, CSN2 B is likely to exert a direct genetic effect on RCT, which does not depend upon variation of beta-casein content associated with CSN2 B. Increased RCT was observed for milk yielded by BLG BB cows, even when models accounted for protein composition. Rennet clotting time was favorably affected by kappa-casein content and percentage of kappa-casein to total casein, whereas a(30) increased when contents and percentages of beta-CN and kappa-CN increased. Changes of milk protein composition and allele frequency at casein and whey protein genes affect variation of MCP.

Milk quality and automatic milking: fat globule size, natural creaming, and lipolysis.

Thirty-eight Italian Friesian first-lactation cows were allocated to 2 groups to evaluate the effect of 1) an automatic milking system (AMS) vs. milking in a milking parlor (MP) on milk fat characteristics; and 2) milking interval (< or =480, 481 to 600, 601 to 720, and >720 min) on the same variables. Milk fat was analyzed for content (% vol/vol), natural creaming (% of fat), and free fatty acids (FFA, mEq/100 g of fat). Distribution of milk fat globule size was evaluated to calculate average fat globule diameter (d(1)), volume-surface average diameter (d(32)), specific globule surface area, and mean interglobular distance. Milk yield was recorded to calculate hourly milk and milk fat yield. Milking system had no effect on milk yield, milk fat content, and hourly milk fat yield. Milk from AMS had less natural creaming and more FFA content than milk from MP. Fat globule size, globular surface area, and interglobular distance were not affected by milking system per se. Afternoon MP milkings had more fat content and hourly milk fat yield than AMS milkings when milking interval was >480 min. Milk fat FFA content was greater in AMS milkings when milking interval was < or =480 min than in milkings from MP and from AMS when milking interval was >600 min. Milking interval did not affect fat globule size, expressed as d32. Results from this experiment indicate a limited effect of AMS per se on milk fat quality; a more important factor seems to be the increase in milking frequency, generally associated with AMS.