Swiss Breeds Research Articles

Serological prevalence of Neospora caninum in healthy and aborted dairy cattle in Mashhad, Iran

A total of 810 dairy cattle were blood sampled and used to evaluate serological screening for Neospora caninum infection in dairy cattle herds in Mashhad (Khorasan province, Iran). In 4 herds, of the 810 cattle, 123 (15.18%) were seropositive by IFA Test (VMRD Inc., Pullman, WA 99163, USA) with titer 1:200 and range of prevalence per herd from 9.92 to 19.60%. Seroprevalence was not significantly different between Holstein breed (14.88%) and Brown Swiss breed (19.60%). Comparison of N. caninum serological status with age groups (≤2 years, 2–4 years, ≥4 years) showed no significant difference. Of the 139 aborted cattle sampled, 19.42% were seropositive for N. caninum.

Results of a producer survey regarding crossbreeding on US dairy farms.

Comprehensive surveys were sent to 528 US dairy producers who are currently practicing crossbreeding in their herds. Fifty usable surveys were returned, and the resulting data included qualitative responses regarding facilities, milk recording plans, milk pricing, crossbreeding goals, breed selection, advantages, disadvantages, and future plans. Quantitative variables included producer scores on a 1 to 5 scale for questions regarding ability to fit into the free stalls and milking parlor, milk volume, component percentages, involuntary culling rate, conception rate, calving difficulty, calf mortality, and prices for breeding stock, cull cows, market steers, and bull calves. The most common first generation crosses involved Jersey and Brown Swiss bulls mated to Holstein cows, and backcrosses to one of these parental breeds were most common in the next generation. Producers who responded to this survey desired, and indicated that they achieved, improvements in fertility, calving ease, longevity, and component percentages through crossbreeding. Respondents indicated that crosses involving the Jersey and Brown Swiss breeds had a clear advantage in longevity relative to purebred Holsteins, and conception rates for crosses of Jersey or Brown Swiss sires on Holstein cows were similar to the (high) conception rates typically achieved in purebred Jersey matings. Respondents also indicated that milk composition was improved in the crossbred cattle, but producers cited some difficulties in marketing crossbred breeding stock and bull calves, and noted that the lack of uniformity within the milking herd created management challenges. Based on results of this survey, it appears that crossbreeding can improve the health, fertility, longevity, and profitability of commercial dairy cattle. However, further research is needed regarding specific heterosis estimates for functional traits in crosses involving each of the major dairy breeds, and improvements are needed in systems for recording the ancestry and breed composition of crossbred animals.

Management factors associated to the duration of postpartum anoestrus interval in Brown Swiss and Pirenaica beef cows

A global analysis of several productive indicators and the postpartum anoestrous interval (PPI) of 549 beef cowswas carried out to determine the management factors related with postpartum ovarian reactivation in extensive mountainfarming systems. Multivariate statistic methods (Multiple Correspondence Analysis and Cluster Analysis) were usedto analyse the data due to the multifactorial nature of the processes involved. PPI was associated to four factors thatexplained 59% of the total inertia of the sample and were defined as follows: «Prepartum feeding level» (19% of theinertia), «Postpartum feeding level-Parity» (16.4%), «Suckling frequency» (13%) and «Calving difficulty» (10.5%).These factors were introduced into a Cluster Analysis that identified five types of cows: «Primiparous cows», «Twicedailysuckling», «Ad libitum suckling-Brown Swiss», «Autumn calving season» and «Spring calving season». Cowbreed was not related to PPI, although the Cluster Analysis associated the suckling-induced prolonged PPI with BrownSwiss animals. In Brown Swiss breed, PPI was longer in the spring than in the autumn due to nutritional differencesrather than to a seasonal effect. Autumn calving was better adapted to dry mountain conditions.

Genetic diversity among Canadienne, Brown Swiss, Holstein and Jersey cattle based on mitochondrial D-loop sequence variation

Polymorphisms creating 36 unique haplotypes were observed with in breeds at 55 sites in the displacement loop (D-loop) region of the mitochondrial DNA (mtDNA) consisting of 814 bp. The majority (56%) of the differences observed were the result of nucleotide substitution events with 19 transitions, 12 transversions, 11 deletions, 12 insertions and 1 inversion. In all cases, the insertions and deletions were of a single nucleotide. Canadienne cattle were found to have 60% unique haplotypes within the population compared to 89% in Brown Swiss, 90% in Holstein and 100% in Jersey cattle, possibly reflecting the narrow genetic base in the Canadienne breed. The degree of sequence divergence in the D-loop region of mtDNA was based on samples from 20 Canadienne, 9 Brown Swiss, 10 Holstein and 10 Jersey cattle and a phylogenetic analysis showed that these cattle (Bos taurus) were not evolutionarily distinct. All four breeds grouped together when a strict consensus tree was generated. Intra-breed variability proved to be high for the Canadienne, Holstein and Jersey breeds (57–73%) but not the Brown Swiss breed (29%). The Canadienne and Brown Swiss (45%), and Brown Swiss and Holstein (43%) showed the lowest degree of inter-breed variability. The greatest variability among the four breeds was between Canadienne and Jersey (80%) cattle. These findings question the validity of phenotypic assessment of genetic diversity, such as Canadienne cattle being described as “Black Jersey”. Key words: Genetic distance, phylogenetic analysis, D-loop sequence, cattle

β-Lactoglobulin genetic variants in Brown Swiss breed and its association with compositional properties and rennet clotting time of milk

β-Lactoglobulin (β-Lg) polymorphism of Holstein Friesian and Brown Swiss breeds were studied by applying native polyacrylamide gel electrophoresis. In addition, total solids, protein, fat ash, lactose and solid non-fat contents, rennet clotting time and major minerals (potassium, calcium, phosphorus and magnesium) of milk from Brown Swiss breed were examined. Phenotype and allele frequencies of β-Lg in both breeds were estimated and the association of the β-Lg genetic variants with the examined properties of Brown Swiss milk was studied. As a result of the study, β-Lg AA, AB and BB phenotypes were found in both Holstein Friesian and Brown Swiss breeds. The gene frequencies of β-Lg A and B were 0.27 and 0.73 in Holstein Friesian and 0.44 and 0.56 in Brown Swiss breeds, respectively. Therefore, β-Lg B allele gene was found more common in both breeds. In addition, significant differences were observed in β-Lg genotypes between two breeds. Also, significant relationships were found between β-Lg genetic variants and total solids (p<0.05), fat (p<0.01), calcium (p<0.05) and phosphorus (p<0.05), while no relationship was obtained for the other parameters studied in the milk of Brown Swiss breed.

Oestrous synchronization under range conditions in dairy goats treated with different PGF2α doses during the transitional period in Greece

AbstractEfficacy of oestrous synchronization and post-treatment fertility was studied in a herd of 149 dairy goats (Swiss breed no. = 104, indigenous Greek breed no. = 45) kept under an extensive farming system. All does were synchronized during the transitional period (during July prior to the breeding season) using fluorogestone acetate (FGA) impregnated intra-vaginal sponges, equine chorionic gonadotropin (eCG) and different prostaglandin F2a (PGF2α) analogues. Four doses of prostaglandin F2a (group 1: 4·5 mg luprostiol; group 2: 2·25 mg luprostiol; group 3: 0·2 mg cloprostenol; group 4: 0·1 mg cloprostenol) were administered i. m. 48 h prior to the end of progestagen treatment and 400 IU eCG was administered at sponge removal. All does were inseminated with fresh semen (300 ✕ 106 spermatozoa per insemination) 42 to 44 h after sponge removal. There were no significant differences (P &gt; 0·05) in the number of goats showing ovarian activity (blood progesterone concentration ³ 1 ng/ml) prior to oestrous synchronization between PGF2α treatment groups. No significant differences (P &gt; 0·05) were observed for the kidding rates between the treatment groups. Our results indicate that goats with ovarian activity prior to sponge application who received high doses of PGF2α showed lower conception rates than those detected in anoestrus (P 0·05). No differences (P 0·05) were observed in conception rates between groups that received lower doses of PGF2α. July is considered to be a transitional period suitable for oestrous synchronization for both Swiss and indigenous dairy goats. Natural mating during the two subsequent cycles after artificial insemination improved kidding rate, but without any significant difference either between treated groups or between Swiss and indigenous breeds.

Genetic diversity and assignment tests among seven French cattle breeds based on microsatellite DNA analysis.

Genetic variability and relationships among six native French cattle breeds (Abondance, Tarentaise, Villard de Lans, Montbéliarde, Limousin, and Charolais) and one foreign breed (Holstein) were investigated using 23 microsatellite markers. These breeds were also compared with four Swiss breeds genotyped in a previously published study. Interestingly, the French alpine breeds have smaller population sizes but showed higher genetic variability than the larger Holstein breed. Neighbor-joining trees and PCA (principal components analysis) showed that alpine breeds tend to cluster together. Abondance and Tarentaise breeds were closely related, whereas the Holstein was highly differentiated from all breeds analyzed. Two different assignment tests for determining the breed of origin of individuals were compared: "direct" and "exclusion-simulation" approaches. The exclusion-simulation significance test correctly assigns fewer individuals than the direct approach but provides a confidence level (e.g., P < 0.01) for each individual being assigned. Accurate assignment with high statistical confidence is required for animal traceability. Unfortunately, the accuracy of assignment greatly decreases as the threshold level of confidence of assignment increases (e.g., from P < 0.05 to P < 0.001). Assignment accuracy also greatly declines as the level of population differentiation decreases below the level often found between related breeds (e.g., F(ST) < 0.1).

Genetic relationships in Swiss sheep breeds based on microsatellite analysis

Genetic relationships between Swiss sheep breeds were estimated on the basis of microsatellite analysis. In addition to the Swiss breeds wild‐type Mouflon was included in this investigation. Polymerase chain reaction amplifications of 31 ovine, bovine and caprine microsatellites were performed in a total of 307 animals representing eight populations. The average heterozygosity within each population was high in the domestic breeds (0.60–0.71) and lower in Mouflon 0.45. The average coefficient of gene differentiation GST over all loci was 0.17, i.e. a small part of the variability at the 31 microsatellite loci analysed must be ascribed to between‐breed variability. Genetic distances between breeds were obtained, which were used to construct a phylogenetic tree. Microsatellites developed from closely related species of cattle and goat are useful for estimating genetic relationships among sheep breeds.

Genetic diversity in Swiss goat breeds based on microsatellite analysis.

Genetic diversity in eight Swiss goat breeds was estimated using PCR amplification of 20 bovine microsatellites on 20-40 unrelated animals per breed. In addition, the Creole breed from the Caribbean and samples of Ibex and Bezoar goat were included. A total of 352 animals were tested. The bovine microsatellites chosen amplified well in goat. The average heterozygosity within population was higher in domestic goat (0.51-0.58) than in Ibex (0.17) and Bezoar goat (0.19). Twenty-seven per cent of the genetic diversity in the total population could be attributed to differences between the populations. However, with the exclusion of Ibex from the total population, this proportion dropped to 17%. Principal component analysis showed that all Swiss goat breeds are closely related, whereas the Creole breed, Ibex and Bezoar goat are clearly distinct from all eight Swiss breeds.

Genetic diversity in Swiss cattle breeds

Introduction First attempts at establishing the genetic relationships among cattle populations relied on archeological evidence (Epstein 1971; Epstein and Mason 1984) and protein polymorphisms (Baker and Manwell 1980, 1991). Loftus et al. (1994) examined mitochondrial DNA to determine the divergence time between Bos taurus and Bos indicus. Today most studies on genetic diversity are based on microsatellite analysis (Litt and Luty 1989; Tautz 1989; Weber and May 1989). Microsatellites were used in, e.g. man (Bowcock et al. 1994), canids (Roy et al. 1994; Fredholm and Winter&amp;oslash; 1995) and sheep (Buchanan et al. 1994). Recent studies in cattle are also microsatellite based (e.g. Machugh et al. 1994; Ciampolini et al. 1995; Moazami‐Goudarzi et al. 1997) and aim at facilitating the development of management programs for endangered breeds (FAO 1981).Our microsatellite‐based investigation on the genetic diversity between and within Swiss cattle breeds included Original Swiss Brown, purebred Simmental, Holstein, Hérens and Evolènard. Previous studies in Swiss breeds made use of blood group systems (Reuse 1969), serum transferrin and hemoglobin (Krummen 1964), amylase (Buser 1970) and carboanhydrases (K&amp;auml;stli et al. 1980).The Hérens breed is endemic to the canton of Wallis. The Evolènard, which are very few in numbers and restricted to a single valley in the canton of Wallis, are phenotypically very similar to the Hérens with the exception of the coat colour. In the Aosta valley (Italy) which borders the canton of Wallis these two breeds find their counterparts. The phenotype of the Aosta Chestnut fits the Hérens and the Aosta Black Pied fits the Evolènard. The Holstein breed replaced the Fribourg breed which was a colour variant of the purebred Simmental breed (Engeler et al. 1961) and is now extinct. The Original Swiss Brown and the purebred Simmental are endemic to Switzerland.

In vitro fertilization of goat oocytes during the non-breeding season

A total of 12 does, from mixed Swiss breeds (11 Alpine and 1 Saanen), comprising donors ( n = 6) and recipients ( n = 6), were used in two experiments during the non-breeding season (January to June 1997) at the Agricultural Research Station of Fort Valley State University, Georgia, USA. Immature cumulus-oocyte complexes (COC) were collected either by laparotomy (surgery, Experiment 2) or aspirated from ovaries obtained from ovariectomized does (Experiment 1). The oocytes were recovered from 2 to 6 mm diameter follicles and matured in vitro for 24 h in TCM-199 medium supplemented with 10% fetal bovine serum (FBS), 100 μg LH/ml, 0.5 μg FSH/ml and 1 μg estradiol 17β/ml at 38.5°C in humid 5% CO 2 in air. Expanded COC, obtained from 24 h maturation, were fertilized as described by Parrish et al. (Parrish, J.J., Susko-Parrish, J.L., Leibfried-Rutledge, M.L., Critser, E.S., Eyestone, W.H., First, N.L., 1986. Theriogenology 25, 591–600). Methods of oocyte retrieval (laparotomy vs. ovariectomy) did not affect maturation and fertilization rates. Although the cleavage rate was significantly higher for oocytes obtained by ovariectomy (100%) compared to those retrieved after laparotomy (79%; P < 0.05), there was no significant difference in the percentage of eight-cell (80% vs. 65%; P > 0.05) and morula/blastocyst-stage embryos (90% vs. 65%; P = 0.05) after ovariectomy and laparotomy, respectively. A total of 21 morula/blastocyst-stage embryos were transferred to six recipients. No pregnancy was detected either by progesterone assay or ultrasonography. Results from this study indicate that oocytes from Swiss Alpine and Saanen breeds born and raised under the climate conditions prevailing in Georgia, USA (32°5'N latitude and 83°8'W longitude) can be successfully matured and fertilized in vitro, during the non-breeding season, and that embryo production through in vitro fertilization technology may be an alternative approach to circumvent seasonal anestrus in temperate climates.

Technology to Produce Ragusano Cheese: A Survey

A survey was carried out to characterize the composition of milk on 70 farms in the Hyblean region in the Province of Ragusa in Sicily, the processing methods used on the 20 of those farms producing the highest quality Ragusano cheese, and the average composition of the cheese at 4 to 6 mo of age. The milk used for cheese making is predominantly from the Modicana and Brown Swiss breeds, but some farms used Holstein cows. Characterization of the traditional Ragusano cheese manufacturing process (including times, temperatures, and pH) is needed. A flow chart of the average cheese-making conditions necessary for production of Ragusano cheese, has been created as an example of the first step that must be taken to document and preserve traditional cheese varieties that are part of the history and culture in various regions of the world. Ragusano is an aged pasta filata cheese. The process of Ragusano cheese making has some characteristics of cultured Mozzarella and some characteristics of Provolone manufacture. However, differences in the manufacturing and aging processes among the three cheeses produce different flavors and texture. The critical steps in the cheese-making process were identified, and recommendations were provided to cheese makers for practical approaches to improve the consistency of cheese quality. The results from the present study form the basis of future research designed to characterize cheese composition, chemical changes during aging, microbiology, yield, and flavor chemistry of Ragusano cheese.

Comparative susceptibility of Pyrenean and Brown Swiss calves to gastrointestinal nematodes in subclinical naturally acquired infections

The susceptibility of two common breeds of cattle in the Pyrenees, Brown Swiss and Pyrenean breed, to parasitism by gastrointestinal nematodes was studied. Twenty-two female calves (13 Brown Swiss and 9 Pyrenean), 3 months old with a mean weight of 112.8 ± 18.33 and 103.3 ± 17.11 kg respectively at the start of the study, were used. The calves began their first grazing season grazing with 200 cattle following the traditional grazing system for mountainous areas: Stabling during winter (December–April), grazing on harvesting meadows at an elevation of 900 m in the spring (May–June) and autumn (October–November), and grazing areas between 1200–2100 m during the summer (July–September). Faeces, blood samples and calves growth rate were taken at 2-week intervals throughout the grazing season. Faecal egg counts of gastrointestinal nematodes, level of serum pepsinogen, total serum protein and blood parameters were measured. The worm egg counts and Cooperia sp. counts were significantly smaller in the calves of Pyrenean breed than in Brown Swiss throughout the experiment. Numbers of eggs of the other genera of parasites found were smaller in the calves of Pyrenean breed than in calves of Brown Swiss breed, but no statistical differences were found. Blood was compared during two periods: the prepatent and patent periods. During the first period, no differences were found between the breeds for any parameter studied. However, during the patent period, Pyrenean animals had significantly greater numbers of erythrocytes, haemoglobin values and packed cell volume (PCV) values, and smaller numbers of eosinophils than animals of the Brown Swiss breed.

Antigènes leucocytaires caprins (ALC), chez les chèvres Créole sensibles ou résistantes à la cowdriose

A genetic predisposition to the manifestation of disease symptoms has been demonstrated for heartwater in certain goat lines. In order to clarify a possible involvement of the major histocompatibility complex (MHC) in the pathogenesis of heartwater, over 100 Creole goats have been typed serologically for their CLA class I antigens coded by the caprine MHC. The MHC is a genetic system that influences different immunological processes, i.e. the individual immune response. With our alloantisera we were able to detect 13 different CLA alleles also present in the Swiss breeds, two non-MHC antigens, a new cluster defined by the splitting of two antigens and several specific reaction patterns of single reagents. The allele frequencies of the detected CLA antigens differed for the resistant and susceptible groups examined. Whether the differences represent regional sire effects or indicate pathogen-induced selection pressure remains to be clarified. Additional testing of resistant/susceptible goats originating from common environment as well as of specially crossbred (resistant x susceptible) animals are underway.

Hormonal changes during lactation in cows of three different breeds

Changes of somatotropin (bST), insulin-like growth factor I (IGF-I), insulin (INS) and free fatty acids (NEFA), and milk yield were measured ante partum and during an entire lactation period in groups of dual-purpose cows of the German Fleckvieh (FV) and German Brown Swiss (BS) breeds and of German Black and White (BW) dairy type cows. In total, 26 cows were studied located on two farms. Blood was collected weekly (8 weeks ante partum (ap) until 40 weeks post partum (pp)) and more frequently (10 h, 30 min intervals) at 6 and 2 weeks ap and Weeks 2, 4, 8, 12, 20 and 30 pp. Episodic secretion pattern was recorded only for bST. bST, NEFA and milk showed a clear increase after parturition in all three breeds. NEFA started to rise 2 weeks ante partum. In contrast, INS and IGF-I fell immediately post partum to significantly lower concentrations. As lactation progressed, all of the investigated plasma parameters returned to values seen in pregnancy. The three groups studied of FV, BS and BW cows exhibited significantly different values for bST, INS, IGF-I and milk yield during the first 8 weeks of lactation. NEFA concentrations were significantly higher in BW vs. FV and BS cows. The relation between bST and milk yield was positive and significant in BS cows ( r = 0.58). The elevation of bST pp is due to an increase of episodic secretion pattern (baseline, peak frequency, peak amplitudes and rise of suprabasal peak secretion).

Maternal heterosis and grandmaternal effects in beef cattle: postweaning growth and carcass traits.

Crossbred steer and heifer progeny from 5-, 6- and 7-yr-old dams produced in a four-breed diallel crossing experiment involving the Brown Swiss, Red Poll, Hereford and Angus maternal grandsires and maternal granddams were evaluated for postweaning growth and carcass traits to estimate breed mean maternal heterosis, maternal heterosis for specific breed cross females, average maternal heterosis for all crosses, breed grandmaternal effects and net breed effects in crosses. All progeny evaluated were born in 1979 and 1980 and were sired by 7/8 or 15/16 Simmental bulls. Average maternal heterosis was significant for 200-d weight in heifers but not in steers and was not significant for final weight (444-d) in either heifers or steers. The effects of maternal heterosis on postweaning growth were not important. Differences among breeds in mean maternal heterosis values were small for growth-related traits. Breeds did not differ (P greater than .05) in grandmaternal effects for growth-related traits; Brown Swiss tended to be highest, Red Poll lowest, with Hereford and Angus intermediate. Differences in net breed effects in crosses favored Brown Swiss over the three other breeds and were generally significant for growth traits. Average maternal heterosis, though generally positive, was not significant for carcass traits on either an age-constant or weight-constant basis. Differences among breeds were small in grandmaternal effects, specific heterosis and net effects in crosses for carcass traits associated with both weight or composition; generally the Brown Swiss breed was favored on carcass traits associated with weight in the age-constant analysis and generally had a higher lean-to-fat ratio than the three other breeds in both the age-constant and weight-constant analyses.

Additive and heterosis effects on preweaning traits, maternal ability and reproduction from crossing of the Angus and brown Swiss breeds in Florida.

Angus (A), Brown Swiss (S) and A X S reciprocal F1 (AS) dams were mated to A, S and AS (also reciprocal F1) sires resulting in nine breed groups of progeny with varying proportions of Angus and Brown Swiss breeding. Breed group of dam and of sire significantly influenced birth weight, preweaning daily gain, weaning weight, 205-d weight, condition score and frame size. The means for birth weight and weaning weight were 33 and 213 kg, respectively. Brown Swiss bulls sired calves with the heaviest birth and weaning weights. Calves produced by S dams likewise were heavier at birth and weaning. Pregnancy rates were influenced significantly by year, age and breed of dam and averaged 79, 95 and 92% for S, AS and A cows, respectively. Survival rate averaged 97% and was not influenced significantly by any of the effects examined. Because survival rates were similar for all breed groups, the results for weaning rate paralleled those for pregnancy rate. Genetic influences on preweaning growth traits and survival rate were partitioned into additive breed differences (B) and heterosis (H) effects for direct (d) and maternal (m) components. Pregnancy and weaning rates were examined using similar analyses except that genotype of service sire of dam replaced that of the offspring for the direct additive breed and direct heterosis components. The Bd values indicated that the Angus breed was inferior (P less than .01) to the Brown Swiss breed for all preweaning growth traits except for condition score, in which the Angus breed surpassed (P less than .01) the Brown Swiss. The Bm values also showed an advantage for the Brown Swiss breed for all preweaning growth traits. The additive maternal effect (the genotype of the females exposed), Bm, was important for pregnancy rate and weaning rate (P less than .001 and P less than .05) but not for survival rate (P greater than .10). The direct additive breed effect was not important for any reproductive trait. Direct heterosis did not affect any of the preweaning or reproduction traits; however, maternal heterosis (Hm) significantly affected all traits except birth weight, frame score and survival rate. The Hm estimates were 12.0 and 8.4 kg for weaning weight and 205-d weight, respectively. The Hm estimates for pregnancy rate, survival rate and weaning rate were 10, 2 and 13%, respectively.

Variances of Prediction Errors for Differences of Estimated Genetic Values of Cows in the Same and in Different Herds

A modification of the evaluation method for cows in the northeast United States allowed simultaneous evaluation of cows in pairs of herds and computation of variances of prediction errors of differences of genetic potential between pairs of cows within and across herds. These variances were examined for 20 pairs of herds in Holstein, Jersey, and Brown Swiss breeds. Current evaluations of cows are nearly as accurate for comparing cows from different herds as they are for comparing cows from the same herd.

Daughters’ Maternal Grandsires in Sire Evaluation

First lactation records of 808,796 artificially sired cows in the Northeast United States were used to compare sire evaluations with and without maternal grandsires in the model. Maternal grandsires were identified on 55.7% of the records. Including maternal grandsire increased percent filled subclasses in absorbed best linear unbiased prediction equations by 43% (Guernseys) to 95% (Holsteins). Rank correlations between sire evaluations for the two models ranged from .91 (Ayrshires) to .97 (Holsteins). Product moment correlations ranged from .92 to .98. Holstein sires changed an average of 52kg of milk. Negative assortative mating (good sires and poor maternal grandsires) was observed in the Guernsey and Brown Swiss breeds. Positive assortative mating (good sires and good maternal grandsires) occurred in the Ayrshires, Holsteins, and Jerseys. Including maternal grandsires of cows in the model is a step toward utilizing more genetic relationships in a practical sire evaluation system.

Oxytocin determination by RIA in cows around parturition

Oxytocin was determined by means of a specific radioimmunoassay in blood plasma of cows around parturition. Blood samples were collected from the jugular vein via an indwelling canula from 7 cows of the local Brown Swiss breed. During late pregnancy, oxytocin levels were below the sensitivity of the assay (< 3 pg/ml) but increased during the period when the calf was expelled (range 62–194 pg/ml), then decreased to lower measurable levels and increased again for a short period at the time of expulsion of the placenta. Afterwards oxytocin levels were again below the detectable range.