Step behaviour and autonomic nervous system activity in multiparous dairy cows during milking in a herringbone milking system

Behavioural and cardiac responses of multiparous dairy cows (n=24) during milking in a 2×4 stall herringbone milking system were evaluated in this study. Heart rate (HR), parasympathetic tone index (high frequency component, HF) of heart rate variability and sympathovagal balance indicator LF/HF ratio (the ratio of the low frequency (LF) and the HF component) were analysed. Measurement periods were established as follows: (1) standing calm (baseline), (2) udder preparation, (3) milking, (4) waiting after milking in the milking stall and (5) in the night (2 h after milking). Step behaviour was recorded and calculated per minute for the three phases of the milking process (udder preparation, milking and waiting after milking). HR was higher during udder preparation and milking compared with baseline (P=0.03, 0.027, respectively). HF was significantly lower than baseline levels during waiting in the milking stall after milking (P=0.009), however, during udder preparation, milking and 2 h after milking did not differ from baseline (P>0.05, in either case). LF/HF during the three phases of the milking process differed neither from baseline levels nor from each other. Steps occurred more often during waiting after milking than during udder preparation (P=0.042) or during milking (23; P=0.017). Our results suggest that the milking procedure itself was not stressful for these animals. After milking (following the removal of the last teat cup and before leaving the milking stall), both decreased parasympathetic tone (lower HF) and increased stepping rate indicated a sensitive period for animals during this phase.     

Genotype by environment interaction for livability of dairy calves from first parity cows

Death of calves around parturition is a matter of concern for dairy farmers. Relatively high stillbirth rates and unfavourable trends have been reported for Holstein heifers in the Netherlands and several other countries. In our study, we investigated herd differences, genetic parameters and genotype by environment interaction for heifer calf livability. A large dataset with data from calvings between 1993 and 2012 of Dutch dairy farms was used. There were considerable differences between herds in livability of calves from heifers, with averages ranging from 74% to 95%. Both herds with relatively high and low averages showed the same negative trend between 1993 and 2012, with largest declines in herds with the lowest averages. We found that heritability and genetic variation of first parity livability were substantially larger in herd environments where the likelihood of stillbirth was high v. environments where stillbirth was at a low level. The genetic correlations between herd environment levels were all very close to unity, indicating that ranking of sires was similar for all environments. However, for herds with a relatively high stillbirth incidence selecting sires with favourable breeding values is expected to be twice as profitable as in herds with a relatively low stillbirth incidence.     

Brief Communication: Lactase persistence and dairy intake in Mapuche and Mestizo populations from southern Chile

Lactase persistence (LP) occurs at a very low frequency in indigenous populations from Latin America, offering an opportunity to understand the relationship between this genetic trait and patterns of dairy consumption. Here, the frequency of LP is analyzed from Mapuche and ‐an adjacent‐ mestizo population inhabiting the Araucanía region. In addition to genotyping for LP, participants were surveyed in relation to general perception and consumption habits of dairy products. Low LP frequency (10%) and very low dairy intake was found among the Mapuche population as compared with Mestizo populations inhabiting Chile. The survey reported that the main reasons for avoidance of dairy were the gastrointestinal symptoms after dairy intake and cultural dietary habits. The interaction between low LP genotype frequency, low dairy intake, and sociocultural determinants is here discussed in the light of their potential health outcomes. Am J Phys Anthropol 155:482–487, 2014. © 2014 Wiley Periodicals, Inc.     

Sperm status and DNA dose play key roles in sperm/ICSI‐mediated gene transfer in caprine

In relation to the growing recent interest in the establishment of sperm‐mediated gene transfer (SMGT) technology as a convenient and effective method for the simple production of transgenic animals, in this study the possibility of using SMGT to produce transgenic caprine embryos was investigated for the first time. Buck sperm were directly incubated with different concentrations (0–500 ng) of pcDNA/his/Lac‐Z plasmid and used for IVF or ICSI. Sperm used for ICSI were categorized into motile or live‐immotile group before being injected into oocytes. In a separate experiment, dead sperm prepared by repeated freezing/thawing were used for DNA‐incubation before ICSI. Sham injection was carried out by intracytoplasmic injection of approximately the same volume of media containing different doses of DNA using an ICSI needle. Transgene expression and transmission were detected by X‐Gal staining and PCR analysis of developed embryos, respectively. A reasonable blastocyst rate was observed in all the groups. Only embryos in the sham group were negative for transgene transmission. Transgene expression was completely dependent on the delivery technique and status of sperm, and was only observed in the live‐immotile and dead ICSI groups. The results of this study showed that the technique (IVF vs. ICSI vs. sham injection), sperm status (motile vs. live‐immotile vs. dead) and to some extent DNA concentration affect embryo development, transgene transmission and expression. Mol. Reprod. Dev. 77:868–875, 2010. © 2010 Wiley‐Liss, Inc.     

The Chehr Abad "Salt men" and the isotopic ecology of humans in ancient Iran

We have carried out isotopic analysis (δ(13)C and δ(15)N) on five salt-preserved bodies from the salt mine at Chehr Abad, Iran, dating from the 4th C. BC through to the 4th C. AD. In an attempt to identify the geographical origins of these people, we have analyzed over a hundred archeological bone samples from various archeological sites in Iran. From the faunal remains, we observe that the entire ecosystem appears to be enriched in (15)N, which we suggest is due to the semi-arid nature of the region. We have also observed a number of cattle remains from one site (Nargas Tepe) which have a significant C(4) component to their diet from the 4th millennium BC. By combining our data with those published by [Bocherens et al.: Environ Archaeol 5 (2000) 1-19; Bocherens et al.: J Arch Sci 33 (2006) 253-264], we suggest that two of the "mummies" may have come from the Tehran/Qazvin Plain region (i.e., relatively local to the salt mine), and a further two appear on isotopic grounds to have come from the northeast of Iran or the Turkmenistan steppes. The fifth (no. 4), the best preserved, appears to have come from further afield. Collectively, these mummies and their contexts augment our knowledge of social mobility and technical innovation in Iran during the Achaemenid period.     

Gene expression patterns in anterior pituitary associated with quantitative measure of oestrous behaviour in dairy cows

Intensive selection for high milk yield in dairy cows has raised production levels substantially but at the cost of reduced fertility, which manifests in different ways including reduced expression of oestrous behaviour. The genomic regulation of oestrous behaviour in bovines remains largely unknown. Here, we aimed to identify and study those genes that were associated with oestrous behaviour among genes expressed in the bovine anterior pituitary either at the start of oestrous cycle or at the mid-cycle (around day 12 of cycle), or regardless of the phase of cycle. Oestrous behaviour was recorded in each of 28 primiparous cows from 30 days in milk onwards till the day of their sacrifice (between 77 and 139 days in milk) and quantified as heat scores. An average heat score value was calculated for each cow from heat scores observed during consecutive oestrous cycles excluding the cycle on the day of sacrifice. A microarray experiment was designed to measure gene expression in the anterior pituitary of these cows, 14 of which were sacrificed at the start of oestrous cycle (day 0) and 14 around day 12 of cycle (day 12). Gene expression was modelled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model on data from day 0 cows alone (analysis 1), day 12 cows alone (analysis 2) and the combined data from day 0 and day 12 cows (analysis 3). Genes whose expression patterns showed significant linear or non-linear relationships with average heat scores were identified in all three analyses (177, 142 and 118 genes, respectively). Gene ontology terms enriched among genes identified in analysis 1 revealed processes associated with expression of oestrous behaviour whereas the terms enriched among genes identified in analysis 2 and 3 were general processes which may facilitate proper expression of oestrous behaviour at the subsequent oestrus. Studying these genes will help to improve our understanding of the genomic regulation of oestrous behaviour, ultimately leading to better management strategies and tools to improve or monitor reproductive performance in bovines.     

Understanding the reproductive performance of a dairy cattle herd by using both analytical and systemic approaches: a case study based on a system experiment

Reproductive performance has recently been a growing concern in cattle dairy systems, but few research methodologies are available to address it as a complex problem in a livestock farming system. The aim of this paper is to propose a methodology that combines both systemic and analytical approaches in order to better understand and improve reproductive performance in a cattle dairy system. The first phase of our methodology consists in a systemic approach to build the terms of the problem. It results in formalising a set of potential risk factors relevant for the particular system under consideration. The second phase is based on an analytical approach that involves both analysing the shapes of the individual lactation curves and carrying out logistic regression procedures to study the links between reproductive performance and the previously identified potential risk factors. It makes it possible to formulate hypotheses about the biotechnical phenomena underpinning reproductive performance. The last phase is another systemic approach that aims at suggesting new practices to improve the situation. It pays particular attention to the consistency of those suggestions with the farmer's general objectives. This methodology was applied to a French system experiment based on an organic low-input grazing system. It finally suggested to slightly modify the dates of the breeding period so as to improve reproductive performance. The formulated hypotheses leading to this suggestion involved both the breed (Holstein or Montbéliarde cows), the parity, the year and the calving date with regard to the turnout date as the identified risk factors of impaired performance. Possible use of such a methodology in any commercial farm encountering a biotechnical problem is discussed.     

Effects of varying proportions of concentrates on ruminal-reducing power and bacterial community structure in dry dairy cows fed hay-based diets

The objectives of this study were to evaluate the influence of diet composition on ruminal parameters, more particularly redox potential (Eh). Four Holstein dry dairy cows, fitted with ruminal cannulas, were allocated in a 4 × 4 Latin square design. They were given four experimental hay-based diets D0, D25, D42 and D56 consisting of 0%, 25%, 42% and 56% of ground wheat and barley concentrate mixture, respectively. They were fed at a daily feeding rate of 8.0 kg DM per cow during a 24-day experimental period (a 21-day diet adaptation, three consecutive days of measurement and sampling). The physicochemical parameters, such as pH and Eh, were measured and Clark's exponent (rH) was calculated from 1 h before feeding to 8 h after feeding at 1-h interval. Samples of ruminal fluid were taken at 0, 1, 2, 4, 6 and 8 h after feeding for the determination of volatile fatty acid (VFA) and ammonia N (NH3-N) concentrations. Ruminal bacterial populations were also studied by means of capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) technique to focus on the structure of the ruminal microbiota and the diversity index was calculated. Mean ruminal Eh and rH were not modified by the concentrate-to-forage ratio and averaged - 210 mV and 6.30, respectively, across diets. The pH decreased slightly by 0.10 pH unit between treatments D0 and D56 with an average of 6.58. Nevertheless, the time during which physicochemical parameters remained at nadir value after feeding varied with diets: 2 and 7 h for D0 and 6 and 5 h for D56, respectively for pH and Eh. Moreover, fermentative parameters were altered by treatments: total VFA and NH3-N were greater in D56 (72.2 mM and 17.5 mg/100 ml) compared with D0 (65.2 mM and 14.2 mg/100 ml). However, neither the structure of bacterial populations of the rumen nor the diversity index (Shannon) was altered by treatments.     

Identifying native animals in crossbred populations: the case of the Sardinian goat population

The aim of this work was to develop a strategy for using a genetic analysis for identifying native animals in regions where local breeds have been crossed with improved breeds and then compare that strategy to the overall morphology and breeding histories of the herds for identifying these animals. The experiment included the Sardinian goat population, which is a crossbred of native animals with the Maltese breed. Whole herds were assigned to Maltese (five herds; 49 animals), crossbred (18 herds; 117 animals) or Sardinian (12 herds; 164 animals) groups. For the genetic analysis, genotypes of 22 microsatellites were determined on 330 animals, and basic measurements of genetic diversity were calculated. Genetic variability in the microsatellites was different in the three groups. High positive F _IS showed that inbreeding existed in the subpopulations. The index of genetic differentiation, Nei's standard genetic distance and Reynolds' genetic distance were calculated and found to be significantly different between the three groups. The Sardinian and Maltese groups were the most distant whereas the crossbred group was closer to the Sardinian group. The proportion of the genome derived from two ancestral populations (native Sardinian and Maltese) was assessed using the structure software. Animals were assigned to three clusters on the basis of native Sardinian thresholds. A good correspondence between the empirical (morphology and breeding histories) and the objective genetic analysis was found. Both approaches indicate the presence of three different subpopulations in the Sardinian goat population.     

Conjugated linoleic acid conversion by dairy bacteria cultured in MRS broth and buffalo milk

AIMS: To evaluate strains of Lactobacilli, Bifidobacteria and Streptococci for their ability to produce conjugated linoleic acid (CLA) from free linoleic acid (LA). METHODS AND RESULTS: Eight dairy bacteria tolerant to LA were grown in MRS broth containing LA (200 microg ml(-1)) and CLA was assessed. Seven bacteria were able to form CLA after 24 h of incubation, varying percentage conversion between 17% and 36%. Lactobacillus casei, Lactobacillus rhamnosus, Bifidobacterium bifidum and Streptococcus thermophilus showed the highest LA conversion and were inoculated into buffalo milk supplemented with different concentration of LA. The production of CLA at 200 microg ml(-1) of LA was two- or threefold in milk than MRS broth. All evaluated strains were able to produce CLA from high LA levels (1000 microg ml(-1)). CONCLUSIONS: The most tolerant strain to LA was Lact. casei. Lacttobacillus rhamnosus produced the maximum level of CLA at high LA concentrations (800 microg ml(-1)). The selected bacteria may be considered as adjunct cultures to be included on dairy fermented products manufacture. Low concentration of LA must be added to the medium to enhance CLA formation. SIGNIFICANCE AND IMPACT OF THE STUDY: The production of CLA by strains using milks from regional farms as medium offer a possible mechanism to enhance this beneficial compound in dairy products and those the possibility to develop functional foods.