Mineral and fatty acid composition of milk from native Jutland and Danish Red 1970 cattle breeds

ABSTRACT

Mineral and fatty acid composition in milk from two minor native dairy breeds in Denmark; Danish Red 1970 (RDM-1970) and Jutland cows were analyzed. Results showed that for most compositional traits breed only played a minor role, whereas management and feeding played a significant role. Biodynamic management and very low milk yield resulted in a very characteristic fatty acid composition and a strongly elevated n-3/n-6 ratio (ratio 0.9 compared to 0.3). For milk minerals, RDM-1970 had significantly higher contents of P, Mg, Mn, whereas milk from Jutland cows had significantly higher K content.     

Trypanosomiasis in different breeds of cattle from Benin.

Blood of different breeds of cattle, namely Lagune from the Atlantic province, Borgou and Borgou x Zebu from the Borgou province, and Somba and Zebu from the Atacora province of Benin, were examined for trypanosome infection. Thick and thin blood smears for trypanosomes, the card agglutination test (CATT), indirect immunofluorescent antibody test (IFAT) and trypanolytic test for antibodies to trypanosomes were used. Trypanosomes were detected in 19.3% (range 9.8-31.4%) of animals by examination of blood smears; antibodies to trypanosomes were found in 89.8% (range 88.4-100%) of samples by IFAT, 50.6% (range 34-87.5%) by CATT and 3.4% (range 1.1-7.1%) by trypanolytic test. Trypanosoma vivax and Trypanosoma congolense were the main species in Benin with a low number of Trypanosoma brucei. Zebu had lower infection rates than trypanotolerant breeds of Benin. The infection rates of various trypanotolerant breeds were not significantly different.     

Quantitative trait loci for milk production and functional traits in two Danish Cattle breeds

Quantitative trait loci (QTL) in Danish Jersey and Danish Red cattle were independently mapped by least squares regression analysis. For Jersey breed, five grandsire families were genotyped for 186 markers on 16 chromosomes (BTAs). Eight traits analysed were milk yield (MY), fat percentage (FP), protein percentage (PP), clinical mastitis (CM), somatic cell score (SCS), maternal stillbirth, maternal calf size (MCS) and maternal calving difficulty. For Red breed, nine grandsire families were genotyped for 166 markers on 18 BTAs. Six traits analysed were MY, FP, PP, CM, SCS and female fertility. Nine and five QTL were detected in Jersey and Red breed, respectively, in across family tests. In Jersey breed, the results indicate QTL for CM and MCS on BTA 3. Additionally, there is an indication of QTL for MCS and FP on BTA 1 and a tentative evidence for a QTL for MY on BTA 26. There is a high risk of detected QTL being false positives. The detected QTL in Jersey breed indicate interesting results from a breeding perspective, but a practical application should await genome-wide association studies.     

Evaluation of serum and milk ELISAs for paratuberculosis in Danish dairy cattle

A milk and a serum ELISA for detection of antibodies against Mycobacterium avium ssp. paratuberculosis (MAP) were evaluated against the complement-fixation test (CFT) and culture of faecal samples from 580 cows collected between August 1996 and December 1996. Milk and serum were obtained concurrently from six dairy herds infected with MAP and from two dairy herds without history of infection with MAP.

A cut-off value of 7 OD% was used in the ELISAs. At this cut-off value, all six culture-positive herds were positive in the serum ELISA but one was negative in the milk ELISA. All six culture-positive herds were positive in the CFT. In the two culture-negative herds, the serum and the milk ELISA deemed all serum samples negative at this cut-off value, whereas four serum samples from one of these herds were positive in the CFT. The highest cut-off value enabling the milk ELISA to record all six culture-positive herds as positive was 4 OD%. The highest cut-off value enabling the serum ELISA to record all six culture-positive herds as positive was 17 OD%. Individual-sample relative sensitivities of the ELISAs ranged from 49 to 64% and relative specificities were 80–96% at the cut-off values of 4, 7 and 17 OD%.     

Effects of DGAT1 variants on milk production traits in German cattle breeds

Various QTL mapping experiments led to the detection of a QTL in the centromeric region of cattle chromosome 14 that had a major effect on the fat content of milk. Recently, the gene encoding diacylglycerol O-acyltransferase (DGAT1) was proposed to be a positional and functional candidate for this trait. This study investigated the effects of a nonconservative lysine to alanine (K232A) substitution in DGAT1, which very likely represents the causal mutation, on milk production traits. Existing granddaughter designs for Fleckvieh and German Holstein, the two major dairy/dual-purpose breeds in Germany, were used to estimate allele frequencies and gene substitution effects for milk, fat, and protein yield, as well as fat and protein content. A restriction fragment length polymorphism assay was applied to diagnose the K232A substitution in DGAT1. Estimates of the allele frequencies for the lysine-encoding variant were based on maternally inherited alleles in sons and amounted to 0.072 for Fleckvieh and 0.548 for German Holstein. Effects of DGAT1 variants on content traits were pronounced; estimates of the gene substitution effect for the lysine-encoding variant were 0.35 and 0.28% for fat content and 0.10 and 0.06% for protein content in Fleckvieh and German Holstein, respectively. Conversely, negative effects of the lysine variant of -242 to -180 kg for Fleckvieh and -260 to -320 kg for German Holstein were revealed for milk yield from first to third lactation, resulting in enhanced fat yield of 7.5 to 14.8 kg in Fleckvieh and 7.6 to 10.7 kg in German Holstein. For protein yield, however, mainly negative effects of -3.6 to 0.2 kg in Fleckvieh and -4.8 to -5.2 kg in German Holstein were observed. Pearson correlations between residuals of milk yield and content traits were decreased when omitting DGAT1 effects in the analysis, thereby indicating that DGAT1 contributes to negative correlations between these traits. Molecular tests allow for the direct selection among variants; however, the benefits of the alternative alleles depend on economic weights given to the different milk production traits in the breeding goal.     

The fat content of milk from dairy cattle infected with bovine leukosis virus

Two groups of cows infected with the bovine leukosis virus (BLV) were kept on two different diets and the fat content of their milk was assayed. The results were compared with those obtained from two comparable groups of BLV-free cows. The cows in each group were of similar ages, those in the groups on the poorer diet being 1–4 months post partum, while those on the richer diet were 5–7 months post partum. The mean percentage of fat in the milk from uninfected cows on the poorer diet was 2.94 while that from the similar infected cattle was 3.06. Uninfected cows on the richer diet produced milk containing 3.39% fat, while those that were infected produced milk containing 3.30% fat. No statistical differences in milk fat production were observed between the BLV seropositive and seronegative cows.     

Variants of somatotropin in cattle: gene frequencies in major dairy breeds and associated milk production

The amino acid sequence of bovine somatotropin (bST) varies at position 127 where either valine or leucine is found. The frequencies of leucine₁₂₇ and valine₁₂₇ bST gene alleles in cows (n = 302) and sires (n = 70) from major dairy breeds (Holstein, Brown Swiss, Guernsey, Jersey, and Ayrshire) were determined using DNA extracted from whole blood or spermatozoa. A 428 base pair fragment of the bST gene was amplified using polymerase chain reaction (PCR) and variants of the bST gene were detected as polymorphisms by Alu I restriction endonuclease digestion of PCR products. Restriction enzyme DNA fragments for the leucine₁₂₇ variant were 265, 96, 51, and 16 base pair and for the valine₁₂₇ variant were 265, 147, and 16 base pair as a polymorphism of bST was present in the 147 base pair DNA fragment. Frequencies of leucine₁₂₇ and valine₁₂₇ alleles for cows (n=302) were 1.0 and 0 for Brown Swiss, .93 and .07 for Holstein, .92 and .08 for Guernsey, .79 and .21 for Ayrshire, and .56 and .44 for Jersey, respectively. In Holstein sires used for artificial insemination (n=70), the frequency of leucine₁₂₇ and valine₁₂₇ alleles was .96 and .04. Estimates of transmitting ability for milk production tended to be greater for Holstein cows that were homozygous for leucine₁₂₇ bST and Jersey cows that were homozygous for valine₁₂₇ bST whereas Holstein sires with different bST genotypes were similar. In summary, frequencies of alleles for the bST gene were not similar in different dairy breeds and estimates of milk production were correlated with bST gene variant in cows but not sires.     

二、奶牛的品种特征

1、世界奶牛品种 世界奶牛品种主要有:荷斯坦牛(主要是黑白花牛,也有红白花牛)、娟姗牛(毛色为淡黄色或黄褐色)、更赛牛(毛色为黄褐色或褐黄色,带有白斑,腹下、四肢下部、尾稍多为白色)、爱尔夏牛(毛色为白色与桃红或深红相间,头部额至鼻梁、腹下、四肢下部及尾稍多为白色)。 2、我国奶牛品种     

Genetic differences among native and modern cattle breeds in Lithuania based on milk protein loci polymorphism

The intrabreed and interbreed genetic diversity of Lithuanian cattle breeds - two native, namely Lithuanian Light Grey and Lithuanian White-Backed and two modern, namely Lithuanian Red and Lithuanian Black and White was investigated by determination of genetic markers: 4 milk protein systems, Alpha(s1)-casein, Kappa-casein, Beta-casein and Beta-lactoglobulin, which are comprised of 12 different milk protein types. According to results, the B type of Alpha(s1)-casein was found as predominant in all four studied breeds. The most common A and B types of Kappa-casein were found at high frequency in all investigated cattle breeds. All investigated Lithuanian dairy cattle breeds had high frequency of Beta-lactoglobulin whey protein B types, with the highest frequency in Lithuanian Red breed, and the lowest in Lithuanian Light Grey. After investigation the diversity of alleles and genotypes of milk proteins in Lithuanian dairy cattle breeds was determined that, Lithuanian Red breed was distinguished private C allele and BC genotype of Beta-lactoglobulin and CC genotype of Alpha(s1)-casein. The interbreed genetic diversity was estimated by a principal component analysis (PCA). The first principal component (PC) explains 63.39% and the second principal component (PC) explains 33.67% of the genetics diversity between the breeds. Principal component analysis, suggests the hypothesis that native Lithuanian White Backed and Lithuanian Light Grey breeds still have traits tracing to old native populations.     

Relationship between leptin content, metabolic hormones and fat deposition in three beef cattle breeds

The aim of the study was to determine if cattle breeds differing in their carcass characteristics also differ in the profiles of their leptin and metabolic hormones. Three breeds, Belgian Blue (BB) (n = 12), Limousin (L) (n = 12) and Aberdeen Angus (AA) (n = 12) with varying ability to deposit fat and protein were compared. Blood, muscle and subcutaneous (SC) adipose tissue were sampled. Animal performance, carcass and meat characteristics were determined as well as plasma leptin concentration, leptin gene expression in SC adipose tissue, leptin-receptor gene expression in SC adipose tissue and plasma concentration of insulin, tri-iodothyronin (T3), thyroxin (T4) and cortisol. The BB bulls showed the lowest values of leptin gene expression (P < 0.05). Values of plasma leptin concentration and of leptin-receptor gene expression tended to be lower in BB than in the other breeds. For a similar amount of adipose tissue (after normalisation), BB bulls showed a higher ratio of plasma leptin (P < 0.05), whereas normalised leptin gene and leptin-receptor gene expressions did not significantly differ between breeds. Belgian Blue bulls also differed in their metabolic hormone profile, tending to show lower values of insulin, T3 and T4 than the two other breeds. Cortisol levels were significantly lower (P < 0.05) in BB than in L and AA animals.     

Genetic parameters for nitrogen fractions content in Mexican Brown Swiss cattle milk

Tropical Animal Health and Production - Nitrogen plays an important role in the metabolism of living organisms due to the variety of physiological functions that involve molecules that contain it....     

Breed difference in water content of faeces from five breeds of sheep

Water content of faeces from five breeds was examined (14 weekly observations — eight sheep of each breed). A higher water content was found of faeces from New Zealand Romney Marsh than from their pasture mates of breeds originating from drier areas — Somali, Merino, Karakul; but Nandi originating from a medium to wet area had a similar dry matter content of faeces as the dry area breeds mentioned above. The growth rate in New Zealand Romney Marsh is greater than in the other breeds.