Holstein Cross Research Articles

Comparison of time budget of behaviors between penned and ranged young cattle focused on general and oral behaviors

ABSTRACTTo consider cattle welfare, time budget of behaviors of young cattle in pen and pasture conditions were compared. Behavioral observations of 103 steers in seven pens and 1136 steers in six ranges were performed during daylight over 3 days in each rearing condition. The pen condition had Japanese Black × Holstein cross, and the pasture conditions had assorted breeds of Angus, Murray Grey, Shorthorn, Hereford, Santa Gertrudis and their crosses aged 5–15 months. The ranges varied in vegetation from extensive native pasture to intensive improved pasture. The daytime proportion of behaviors and activity patterns were compared between rearing conditions. The proportion of walking was much lower in the pen condition (1.0 ± 0.2%) compared to all pasture conditions (at least 9.4 ± 4.0%; all P < 0.05), but grooming (5.9 ± 1.2%), investigating (2.5 ± 0.2%) and tongue playing (1.1 ± 0.2%) covered the loss. Fluctuation patterns of the proportions of eating (P < 0.001) and resting (P < 0.001) were different between pen and pasture conditions, whereas the pattern of the proportion of walking was not different. The proportion of eating in the pen condition (32.4 ± 0.3%) was not different to that in one on the farm (42.2 ± 12.6%), which had a thick improved pasture. However, the proportion of eating in the pen condition (32.4 ± 0.3%) was lower than that in two farms (58.8 ± 5.0% and 61.6 ± 16.5%) with low pasture availability (both P < 0.05). The proportions of oral behaviors such as self‐grooming (3.9 ± 1.0%), allogrooming (2.0 ± 0.2%), licking objects (1.3 ± 0.4%) and tongue‐playing (1.1 ± 0.2%) compensated for the lack of eating. These results indicate that we can learn a well‐balanced proportion of behaviors for cattle by making comparisons of time budget of behaviors and activity pattern between various rearing conditions. In addition, it is indicated that cattle under pen conditions under a restricted feeding period might compensate for a lower time spent feeding by performing other oral behaviors.

Grazing, social and comfort behaviour of Ankole and crossbred (Ankole × Holstein) heifers on pasture in south western Uganda

The aim of this study was to assess the grazing, social and comfort behaviour of the indigenous purebred Ankole cattle breed and crossbred (Holstein × Ankole) animals under typical management conditions in south western Uganda. Twelve focal animals in each of four groups (two groups per genotype) were observed regarding their grazing, social and comfort behaviour on pasture. No significant differences in grazing behaviour patterns (eating, walking, standing) were found between the genotypes. Resting occurred only very rarely in both genotypes. Walking distances of Ankole and Ankole × Holstein crosses were also similar. There was no difference in the occurrence of agonistic interactions between the two genotypes. However, Ankole cattle engaged in more non-agonistic social interactions than their crossbred counterparts. Individual distances were lower in Ankole heifers and more herd mates were found within a radius of 5 m around the Ankole animals. The most important comfort behaviour pattern in both genotypes was self-licking, which occurred to similar frequency in Ankole and crossbred heifer groups. Crossbred animals scratched themselves and rubbed on objects more often than Ankole heifers. Although Ankole cattle and their Holstein crosses did not differ in grazing, distances walked and agonistic behaviours, the significant differences between the two genotypes in herd cohesion and comfort behaviour may pose challenges on the management of crossbred animals under extensive open grazing conditions as present in south western Uganda. Thus, apart from (re)productive performance traits, behavioural traits of both genotypes may also be taken into account for breeding decisions and management under current production conditions.

Comparison of milk production, mastitis, lameness and days to conception of Brown Swiss, Holstein and Holstein cross Brown Swiss dairy cattle

Mastitis is a complex disease causing inflammation of the udder, which has been estimated to cost the dairy farmer between £40-£117/cow per year (Stott et al., 2002). Economic loss occurs as a result of discarded milk, reduced milk yield and milk quality, increased vet costs and an increase in replacement costs. The objective of this study was to examine the effect of breed on the incidence of mastitis and somatic cell counts and milk production capabilities of Holstein Friesian, Brown Swiss and Brown Swiss crossbred cows.

Comparative Study on the Productive and Reproductive Performance of Different Dairy Genotypes Reared in Bangladesh Agricultural University Dairy Farm

The study was conducted at Bangladesh Agricultural University Dairy Farm for a period of six months. A total of 164 dairy cows belongs to different breeds, such as Jersey cross, Sahiwal cross, Sindhi cross, Holstein cross and Red Chittagong cows were selected and their information regarding milk production and other reproductive parameters were collected from farm records for a period of last five years (1993-1997). The number of animals of each of the genotypic classes were 48 for Jersey cross, 46 for Sahiwal cross, 35 for Sindhi cross, 20 for Holstein cross and 15 for Red-Chittagong. Significant difference was found within the milk yield (p 0.05). Highest milk yield (3.20 lit/day), highest birth weight of calves (15.2 kg) and lowest calving interval (414 days) were observed for Holstein cross. The lowest milk yield (2.46 lit/day) and lowest birth weight of calves were found in Red-Chittagong cows. Production performance of Holstein crossbred were superior to other dairy crossbreds. Jersey crossbred ranked second and performances of other genotypes were nearly similar.

Caracterización de canales de ganado bovino en los valles centrales de Oaxaca

Bovines slaughtered at the Central Oaxaca Valleys in Mexico show high diversity due to their source and production systems. The objective of the present study was to grade slaughtered cattle in this region. A total of 1,375 carcasses were valuated by breed, age, origin, production system, dorsal fat depth, marbling, conformation and weight. Ninety five percent of the carcasses evaluated came from tropicalre as and 75 % of them were reared under grazing conditions. Slaughtered animals were predominantly Zebu x Brown Swiss (37 %) and Zebu x Holstein (16 %) crosses, three to four years old. Bulls from the humid tropics showed the higher carcass weight (309.4 kg P<0.05). Zebu, Zebu x Creole and Zebu x Brown Swiss bulls showed the higher carcass weights (325.8, 301.6 and 297.8 kg, respectively). Bullocks and bulls from the humid tropics showed the higher rate of carcasses with good conformation (P<0.05) as well as those from feed lots and grazing plus supplement (85.2 and 78.8 %, respectively). Breed has strong influence on growth and carcass composition, however, after genetics, the production system, feeding and maturity are determinants of yield and carcass quality.

296LIPIDIC CONTENT IN JERSEY BLASTOCYSTS COMPARED WITH HOLSTEIN AND IVP EMBRYOS

The objective of this study was to compare the ultrastructure of bovine embryos from different breeds and origin in terms of lipid contents. Jersey and Holstein embryos produced in vivo were obtained from superovulated donors by non-surgical method 7 days after AI. Embryos produced in vitro (Holstein cross breed) were obtained from cumulus-oocytes complexes (COC) aspirated from slaughterhouse ovaries. The COC were matured and fertilized in vitro. The zygotes were cultivated in vitro for 7 days in SOFaa media. Embryos produced in vivo (Holstein n=5; Jersey n=5) and in vitro (n=5) classified as blastocyts grade II were fixed in Karnovsky solution immediately after embryo recovery or embryo culture and prepared for microscopic electronic evaluation. Ultrastructure of inner cell mass and trophoblast cells was analyzed. Morphometry on electron microscopy was performed using a point-count method in random samples of electron micrographs of each embryo category. The data were analyzed by chi square test. The volume density occupied by number of lipid droplets was greater in Jersey and in vitro-produced embryos compared with Holstein embryos (24.3%±11.7; 28.4%±19.6 and 9%±6.68, respectively, P&amp;lt;0,05).

A study of relative horn fly, Haematobia irritans (Diptera: Muscidae), abundance on Holstein steers and steers of two Holstein crosses.

A study was performed to determine if the number of horn fly (Haematobia irritans) adults differ significantly on Holstein (black and white coat color), Holstein x Holstein Friesian (black and white coat color) and Holstein x Jersey (black coat color) steers, 10-12 months old at the onset of the study. All steers were run together on lucerne paddocks and the number of flies counted at 30-day intervals from September 2000 to August 2001. No significant differences (P > 0.05, test of Kruskal-Wallis) were found in fly numbers, even in the period April-May 2001 when the infestation reached its peak. We were unable to demonstrate that coat color influenced horn fly abundance in the present study. It appears that none of the biotypes evaluated had any advantage for natural control of H. irritans.

Development of intramuscular fat in Wagyu beef cattle depends on adipogenic or antiadipogenic substances present in serum

AbstractIn blood, there are many kinds of adipogenic or antiadipogenic factors such as hormones and vitamins. In this study, adipogenic activity in sera of fattened beef cattle was evaluated using cultured mouse 3T3-L1 preadipocytes. After the preadipocytes were grown to reach confluence, serum of fattened beef cattle was added into the culture medium (10%, vol/vol)for 3 days, and thereafter cellular sn-glycerol-3-phosphate dehydrogenase (GPDH) activity was determined as an index ofadipocyte differentiation. Sera were collected from 19 beef cattle (Wagyu and Wagyu × Holstein cross cattle) from three different farms at slaughter. Cellular GPDH activity was significantly different among the farms, and was affected by sex difference (i.e. sera from fattened heifers induced higher GPDH activity than those from steers). There was a positive correlation between GPDH activity and beef marbling performance (T = 0·62,P&lt; 0·02), suggesting that serum factor(s) play a role in development of intramuscular fat deposition. Adipogenic activity was negatively correlated with serum retinol concentration (r = −0·73,P&lt; 0·001). Neither serum cholesterol, triacylglycerol nor non-esterified fatty acid was related to adipogenic activity.Furthermore, serum retinol concentration was negatively correlated with beef marbling performance. These data imply that retinol level in blood during the fattening period may influence intramuscular fat deposition of beef cattle through its antiadipogenic action on preadipocytes present in muscle tissues.

Genetic and Environmental Influences on Semen Traits in A.I. Bulls

Contents: Repeatability and heritability coefficients were estimated for ejaculate volume, mass movement, individual motility, sperm concentration, first and second post‐freezing control of motility, number of doses frozen, total number of spermatozoa and total number of motile spermatozoa per ejaculate in the first ten ejaculates of 175 Swiss Holstein and 673 Simmental young bulls (200 pure Simmental, 473 Simmental x Red Holstein crosses). Data were analysed using the univariate individual animal model with effects of interval between consecutive collections, age of bull at collection, season of collection, breed group of Simmental bulls according to percentage of Red Holstein genes, bull (within breed group) and permanent environment. Crossbred bulls had a better performance in all traits. Repeatability coefficients ranged from 0.28 to 0.46. They indicate that the prediction of semen quality in young bulls of the Swiss Holstein and the Simmental breed is possible to some extent. Heritabilities in Swiss Holstein bulls were generally very low and did usually not exceed 0.10, but standard errors of these estimates were high. Relatively high heritabilities (0.18–0.30) were found for Simmental bulls, Differences in heritabilities between these two breed groups were probably a consequence of the low number of Swiss Holstein bulls.

Importance of interindividual differences in quantitative descriptive psychophysics

Bulls (n = 115) of four slaughter ages (9, 12, 15 or 18 months) and of 15 genotypes were studied. In this analysis, each bullock was assigned to one of four breed groups—British and British crosses, Brahman and Brahman crosses. Jersey and Jersey crosses or Holstein and Holstein crosses. Slaughter age had an (P < 0·01) effect on marbling score, longissimus muscle area, fat thickness and yield grade while breed group had an (P < 0·01) effect on marbling score and quality grade. In general, British and British cross bullocks produced carcasses with the thickest subcutaneous fat, the highest marbling score and the highest USDA quality grade while Jersey and Jersey cross bullocks yielded carcasses with the lowest weight, smallest longissimus muscle area and the lowest USDA quality grade of the four breed-type groups. Increases in chronological age (from 9 to 18 months) were generally associated with a decrease in USDA maturity score, and increases in marbling score, USDA quality grade, longissimus muscle area, subcutaneous fat thickness and USDA yield grade. Shear force values decreased as bulls matured from 9 to 18 months of age. The meat from Brahman-type bulls had higher shear force values (P < 0·01) than that from bulls of the other breed groups. Steaks from British-type carcasses received the highest numerical ratings for sustained juiciness and flavor while steaks from the Brahman-type carcasses were assigned the lowest numerical ratings for juiciness. Breed-type had a greater effect on tenderness of bull beef than did chronological age.

Heterosis retention for birth and weaning characters of calves in the third generation of a five-breed diallel2

Data were 876 birth records and 727 weaning records of straightbred and F3 crossbred calves produced in the third generation of a five-breed diallel. Among straightbreds at birth, Holstein calves were heaviest and widest at the shoulders and hips. Jersey calves were lightest and narrowest at the hips, and Brahman calves were narrowest at the shoulders. Holstein crosses tended to be larger at birth than crosses among other breeds. Among straightbreds at weaning, Holstein calves were heaviest and tallest, and Hereford calves were lightest and shortest. Angus calves had the highest survival to weaning rate, and Holstein calves had the lowest survival rate. Among crossbred calves, Holstein crosses tended to be larger at weaning. Estimates of average heterosis retained for birth characters were not significant. Significant breed mean heterosis retention was observed for birth weight, shoulder width, and hip width of Hereford calves and for shoulder width and hip width of Holstein calves. Estimates of average heterosis retained for weaning weight and height were 6.1 kg (P less than .01) and 1.02 cm (P less than .05), respectively. In general, estimates of specific and average heterosis retained for survival to weaning were nonsignificant. Significant breed mean heterosis was observed for weaning weight and height of Brahman, Hereford, and Holstein calves and for survival to weaning of Hereford, Holstein, and Jersey calves.

Net Margins from Different Fractions of Holstein Genes in Venezuelan Herds Based on Performance Estimates by Producers and Advisors

The objective was to estimate the profitability of different fractions of Holstein genes from subjective predictions of milk yield, calving interval, calf mortality, and length of productive herd life by Venezuelan producers and others for an upgrading program from a Zebu breed to Holstein. Data were from surveys of 157 farms in 1987 to 1988 to obtain input use; variable costs for feed, labor, health and reproduction; product prices; and market values by animal category. Predictions of performance in multiple traits were from a complementary survey of the same producers and others (16 consultants and 10 Venezuelan professors; 9 US germplasm exporters, and 17 US professors). Profit was approximated by lifetime net margin (gross income from milk plus male and female offspring plus salvage value minus variable costs) per cow for each breed group and discounted to the date of first calving.Survey respondents predicted that the 75% Holstein breed group was most profitable and that milk yield and calving interval were the most important traits economically. For net margin equal to 75% Holstein, 100% Holstein cows would have to increase milk yield by 23% or reduce calving intervals by 17%, and 50% Holstein cows would have to increase milk yield by 18% or reduce calving intervals by 12% to obtain profits equal to 75% Holstein. Most literature reports show differences in milk yield of less than 10% between 50 and 75% Holstein groups. Thus, 50 to 75% Holstein crosses are likely the most profitable ones when multiple traits were considered for Venezuelan conditions.

Breed effects on crossbred cow-calf performance.

Effects of seven breeds of cow's sire and 12 breeds of cow's maternal grandsire on preweaning performance of crossbred cows and their calves were examined in data from two experiments conducted at the Roman L. Hruska U.S. Mean Animal Research Center. Data included 1,836 records over three to five parities for 516 cows by 143 sires and by 307 maternal grandsires. The statistical model fitted effects of calf sex, parity, cow birth-breeding year or cow-calf birth year, the breed effects and their interactions. Deviations of breed of sire or equivalent grandsire effects on each trait from the mean for Hereford x Angus cows ranged from -1.6 to 5.5 kg (P less than .001) for calf birth weights, -15 to 1% (P less than .001) for calving difficulty, nonsignificant for preweaning calf mortality and -2 to 27 kg (P less than .001) for calf weaning weight. Deviations were nonsignificant for conception rate and calves weaned per cow exposed to breeding, but -2 to 40 kg (P less than .001) for calf weight weaned per cow exposed for breeding, -7 to 78 kg (P less than .001) for cow weight and -20 to 2% (P less than .001) for body condition score. The advantages of Holstein and Brahman cross over Hereford x Angus cows of 23 and 13% in weight of calf weaned/cow-breeding exposure must be compared with the expected greater feed requirements from 7 or 8% heavier cows and at least 50% higher milk production, which emphasizes the need to include input measures and costs in breed evaluation schemes.

Production characters of straightbred, F1 and F2 cows: birth and weaning characters of terminal-cross calves.

Records of 2,449 births and 2,120 weanings of terminal-cross calves were used to characterize maternal productivity of first- and second-generation cows from a diallel of Angus, Brahman, Hereford, Holstein and Jersey when mated to third-breed sires. Third- and later-parity cows were randomly assigned after each parturition to Charolais and Red Poll bulls in multiple-sire pastures. Calves were weaned at approximately 7 mo of age; males were not castrated. A mixed model was assumed for data analysis. Effects included in the model were breed-type of dam, cow within breed-type of dam (random), breed of sire of calf, season of record, year of record, age of dam group, sex of calf and age of calf (covariate). Age of dam groups were 4- and 5-yr-olds, 6- and 7-yr-olds, 8-, 9- and 10-yr-olds, and those greater than 10 yr of age. Dependent variables were calf weight, shoulder width and hip width at birth, weaning weight, weaning height and survival to weaning. Holstein and Holstein crosses tended to produce the largest calves at birth and weaning. Among straightbred dams, the smallest calves were born to Brahman, whereas Hereford weaned the smallest calves. Brahman-Jersey dams produced the smallest calves at birth among crossbreds; Angus-Hereford cows weaned the smallest calves. Average maternal heterosis estimates for birth weight were small and non-significant. Calves of F1 crossbred dams were 17.4 kg heavier (P less than .01) and 1.70 cm taller (P less than .01) at weaning than calves of first-generation straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronological age and breed-type effects on carcass characteristics and palatability of bull beef

Bulls (n = 115) of four slaughter ages (9, 12, 15 or 18 months) and of 15 genotypes were studied. In this analysis, each bullock was assigned to one of four breed groups—British and British crosses, Brahman and Brahman crosses. Jersey and Jersey crosses or Holstein and Holstein crosses. Slaughter age had an (P < 0·01) effect on marbling score, longissimus muscle area, fat thickness and yield grade while breed group had an (P < 0·01) effect on marbling score and quality grade. In general, British and British cross bullocks produced carcasses with the thickest subcutaneous fat, the highest marbling score and the highest USDA quality grade while Jersey and Jersey cross bullocks yielded carcasses with the lowest weight, smallest longissimus muscle area and the lowest USDA quality grade of the four breed-type groups. Increases in chronological age (from 9 to 18 months) were generally associated with a decrease in USDA maturity score, and increases in marbling score, USDA quality grade, longissimus muscle area, subcutaneous fat thickness and USDA yield grade. Shear force values decreased as bulls matured from 9 to 18 months of age. The meat from Brahman-type bulls had higher shear force values (P < 0·01) than that from bulls of the other breed groups. Steaks from British-type carcasses received the highest numerical ratings for sustained juiciness and flavor while steaks from the Brahman-type carcasses were assigned the lowest numerical ratings for juiciness. Breed-type had a greater effect on tenderness of bull beef than did chronological age.

Sire breed effects in matings with Angus cows: I. Fertility, calf survival and performance to 18 months.

Over six calf crops, 524 exposures of Angus cows to three sire breeds resulted in 432 weaned calves for an 82.4% calf crop. Least-squares means for weaning rate by sire breed were 81.8, 80.5 and 83.9% for Angus, Charolais and Holsteins, respectively. Sire breed effect was not significant for calving rate, calf mortality or overall weaning rate, but was significant for all growth traits from birth to 18 mo. Angus-sired calves were smallest at birth, grew at a slower rate and were lightest in weight at all ages. Charolais-sired calves were heaviest at all weigh periods and Holstein-sired calves were intermediate. Holstein-sired calves scored significantly lower for both grade and condition than did Angus- and Charolais-sired calves. Charolais-sired calves had the highest grade. Calving rate tended to be influenced by the effect of cow (P less than .10) and sire breed X year (P less than .001). Calving rate was highest for 3-yr-old and for 6- to 10-yr-old cows and was also 1.5 percentage units higher for crossbred matings. Cow productivity (kg of calf weaned/cow exposed) is a combined measure of fertility, calf survival and weaning weight. Although sire breed did not significantly affect cow productivity (P less than .20), actual values favored cows producing crossbred calves by 14 and 9 kg for Charolais and Holstein crosses, respectively. Likewise, weight differences at 18 mo favored these crosses by 50 and 32 kg for heifers and 72 and 62 kg for steers. Among the two crossbred types, Charolais X Angus heifers were 28 kg heavier (P less than .05) than Holstein X Angus heifers at 18 mo but the 10 kg difference in steers was not significant. The fact that the large sire breeds produced calves with heavier weaning weights without demonstrating significant increases in overall productivity points out the importance of high weaning rates.

Performance of Bos taurus X zebu crossbreds under village conditions.

Data on first lactation performance of 751 Holstein X zebu and Jersey X zebu crossbred heifers of various grades were collected under rural field conditions in Maharashtra. The heifers were the progeny of seven Danish Holstein (Sortbroget Dansk Malkekvoeg) sires, 33 homebred Holstein sires, six Danish Jersey sires and 35 homebred Jersey sires. The least-squares analysis showed that the location and genetic group within the two classes of crossbreds significantly affected the milk yield. In pooled data the 7/8 Holstein crossbreds produced by homebred sires were significantly superior to other genetic groups of either Holstein or Jersey inheritance. The milk yield increased with increasing level of homebred Holstein inheritance and with Jersey inheritance. Danish Holstein sires were the best to produce the halfbred Holstein crosses. The differences in the genetic groups accounted for 20% of the phenotypic variance in 305-day milk yield and for 2% of the variance of the lactation length in the crossbred population. It is inferred that the optimum level of exotic breed inheritance in Maharashtra would be above 50% and that the genetic group of the dams needs to be considered when evaluating the performance of a sire's progeny.

Comparison of Three Mating Systems: II. Weights and Body Measurements of Heifers

Body dimensions and weights of female progeny from three systems of mating were studied from birth to first calving. Heifers produced by outcrossing to Holstein sires in artificial insemination were largest up to first calving, at which time the average of heifers produced by crossbreeding (Ayrshire, Brown Swiss, and Holstein sires) exceeded the outcrosses in weight and body length from withers to pins. Heifers produced by mild inbreeding within a separate line were consistently smaller than outcrosses and crossbreds. Brown Swiss x Holstein heifers were largest of the six crosses; Ayrshire X Holstein crosses were smallest. Brown Swiss X Holstein crosses were also larger than both purebred Holstein groups. Heifers born in November and born of fourth parity dams were generally larger than heifers born in other seasons or of other parity dams, either in weight or in aspects of body dimension.

Production of Milk and Milk Constituents by Brown Swiss, Holsteins, and Their Crossbreds1,2

Least squares procedures were used to evaluate yields by crossbred and back-cross Brown Swiss and Holstein in relation to purebred contemporaries many of which were paternal or maternal half-sisters. Foundation females were taken at random from groups of females in the University herd. Bulls, 16 Brown Swiss and 13 Holstein selected at random from bulls in 13 artificial insemination studs, sired the crossbreds and purebreds. From foundation cows, were 34 Holsteins, 26 Brown Swiss, and 13 each of the Holstein x Swiss (breed of bull first, breed of cow last.) and Swiss x Holstein crosses that completed first lactations. First-generation purebreds were bred for purebreds and crossbreds, and crossbreds were bred for backcrosses. Both first-generation crossbred groups had fewer days open than purebreds. Numbers in second-generation groups with lactation records varied from 9 to 13. Crossbreds in each generation averaged higher than the purebreds for yields of milk, milk fat, 4% fat-corrected milk, solids-not-fat, and protein. Interaction (sire-dam) constants were not significant; neither was heterosis for production traits. For days open these estimates ranged from 14 to 31%.

Factors affecting body weight at birth and at 90 days of age in pure-bred and cross-bred cattle in a tropical environment

SUMMARYLive weights of 8764 calves born in seven herds in Cuba during the years 1966–8 were measured at birth and at approximately 3 months of age. Over 2600 were pure bred: Zebu (2002), Santa Gertrudis (435) and Charolais (212); the remainder were crossbred Holstein x Zebu (4955) and Brown Swiss x Zebu (1160).Year, season of birth, herd and sex were associated with variation in mean birth weight in all breeds and crosses except Charolais in which no seasonal effect was apparent and in Brown Swiss x Zebu cross-breeds in which herd and sex effects were absent.At 90 days there was a general tendency for calves born in late spring and summer to be heavier than those bom at other times. By this age, herd variation had subsided among Brown Swiss x Zebu cross-breds, and variation due to sex had ceased to be important among Charolais calves.Estimates of heritability of birth weight ranged from 0·09 in Holstein crosses to 0·62 in Brown Swiss crosses, and of weight at 90 days from 0·05 in Brown Swiss crosses to 0·44 in the Charolais breed. Phenotypic correlations between birth and 90 days weights were of the order of + 0·25 while genetic correlations were positive for pure breeds and negative for cross-breeds.