• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.471-476
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• 1995

The relationship between udder maximum capacity (36-h accumulated milk yield) and the response of dairy cows (average producers) to thrice-daily milking was studied in 25 Friesian and 15 Jersey cows using the technique of half-udder study. Maximum half-udder capacity (acual yield) as well as whole udder capacity (estimated by udder measurements) was not altered significantly after 12-day thrice-daily milking period compared with a similar twice-daily period, although there was a positive response to increased milking frequency on secretion rate during this period. No effect of breed, season of the year or stage of lactation was observed on the above relationship. Hours-worth of capacity was higher with increased milking frequency, with Jersey than Friesian. These results suggest that udder capacity is not a limiting factor in increased milk production.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.1-5
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• 2008

To analyze genetic effects on milk production traits, 164 unrelated Italian Jersey cows reared in 15 farms located in Southern Italy were characterized at the growth hormone locus. Using a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism protocol all three possible genotypes for the Leucine/Valine polymorphism were identified even if in the considered population the number of homozygous animals (Leucine/Leucine = 36; Valine/Valine = 28) was smaller than Leucine/Valine (n = 100) cows; the Hardy-Weinberg equilibrium was verified. Statistical analysis showed that daily milk yield in the Leucine/Leucine genotype was higher (p<0.01) than in Leucine/Valine (22.76 kg vs. 16.96 kg ); cows with Leucine/Valine genotype differed significantly from Leucine/Leucine and Valine/Valine genotypes particularly in fat (4.95% vs. 4.13% and 4.82%, respectively) and protein content (4.00% vs. 3.47% and 3.79%, respectively). No significant effect on lactation length was observed.

• Journal of Animal Science and Technology
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• v.65 no.2
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• pp.324-335
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• 2023

Korea, located in East Asia in the northern hemisphere, is experiencing severe climate changes. Specifically, the heat stress caused by global warming is negatively affecting the dairy sector, including milk production and reproductive performance, as the major dairy cattle Holstein-Friesian is particularly susceptible to heat stress. Here, we collected artificial insemination and pregnancy data of the Holstein and the Jersey cows from a dairy farm from 2014 to 2021 and analyzed the association between the conception rate and the temperature-humidity index, calculated using the data from the closest official weather station. As the temperature-humidity index threshold increased, the conception rate gradually decreased. However, this decrease was steeper in the Holstein breed than in the Jersey one at a temperature-humidity index threshold of 75. To evaluate the effects of heat stress on the oocyte quality, we examined the nuclear and cytoplasmic maturation of Holstein (n = 158, obtained from six animals) and Jersey oocytes (n = 123, obtained from six animals), obtained by ovum pick-up. There were no differences in the nuclear maturation between the different conditions (heat stress: 40.5℃, non- heat stress: 37.5℃) or breeds, although the Holstein oocytes seemed to have a lower metaphase II development (p = 0.0521) after in vitro maturation under heat stress conditions. However, we found that the Holstein metaphase II oocytes exposed to heat stress presented more reactive oxygen species and a peripheral distribution of the mitochondria, compared to those of the Jersey cattle. Here, we show that weather information from local meteorological stations can be used to calculate the temperature-humidity index threshold at which heat stress influences the conception rate, and that the Jersey cows are more tolerant to heat stress in terms of their conception rate at a temperature-humidity index over 75. The lower fertility of the Holstein cows is likely attributed to impaired cytoplasmic maturation induced by heat stress. Thus, the Jersey cows can be a good breed for the sustainability of dairy farms for addressing climate changes in South Korea, as they are more resistant to hyperthermia.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.382-383
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• 2001

The experiment was undertaken to study the effect of subclinical mastitis on the biochemical parameters of milk in crossbred (Sahiwal $\times$ Jersey) cows. Subclincial mastitis was judged using California Mastitis Test and graded on a scale of 0 to 2. Twenty six milk samples of each grade were subjected to somatic cell count. Separated milk whey was analysed for total protein, immunoglobulin and trace mineral content. Results indicate linear increases in somatic cell count, total protein and immunoglobulin concentrations in milk with increase in grade of subclinical mastitis. However, copper, zinc, manganese and iron concentration in milk was not affected by grade of mastitis.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.4
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• pp.321-323
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• 1995

Observations were recorded regarding various fertility parameters on 26 Jersey donor cows following superovulation under tropical conditions. These cows, in their mid-luteal phase were treated with 2,500-3,000 i.u. PMSG or 28-40 mg FSH followed by $500{\mu}g$ $PGF_{2{\alpha}}$ injection 48-60 hours later, to induce oestrus. The cows were bred artificially twelve hours following standing oestrus. Embryo collection was carried out 7 days after oestrus. $PGF_{2{\alpha}}$ was injected to each donor cow after embryo recovery to regress the corpora lutea. Fertility data($PGF_{2{\alpha}}$-Oestrus interval, services per conception, days between embryo collection and successful service and any pathololgical condition) were recorded. $PGF_{2{\alpha}}$-Oestrus interval and correlation (r) between number of corpora lutea and $PGF_{2{\alpha}}$-Oestrus interval were $30.9{\pm}6.3$ and 0.17, respectively. Of 26 treated donors, 19 conceived within a period of $91.7{\pm}18.8$ days after embryo recovery. Average services per conception were $2.3{\pm}0.3$. Only two cows developed metritis which conceived after treatment with antibiotics. These observations indicated no profound adverse effect of superovulation on subsequent reproduction of donor cows, except some effect on services per conception, under tropical conditions.

• 축산식품과학과 산업
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• v.6 no.1
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• pp.5-11
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• 2017

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.230-238
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• 2021

This study attempted to determine the characteristic features of postpartum dairy cows during their return to estrus. Moreover, it investigated the effects of abnormal ovarian cycles (AOC) on subsequent reproductive performance and the relationship between normal ovarian cycles (NOC) and the blood urea nitrogen (BUN) level postpartum. Incidentally, 56.3% of the Holstein cows and 66.7% of the Jersey cows had NOC, whereas the 43.7% and 33.3% of the Holstein and Jersey, respectively, had AOC. Within 100 days of calving, the cows with AOC had significantly lower rates of artificial insemination (AI) submission as well as pregnancy and a significantly longer interval to first AI, as compared to that in the cows with NOC. Additionally, the cows with NOC had a significantly higher first AI conception rate than that in the cows with AOC. In this study, of the 32 Holstein cows, 8 resumed their ovarian cycle within 20 days of calving, 10 resumed the cycle with 21-40 days of calving, 8 within 41-60 days of calving, while the remaining 6 did not resume their ovarian cycles until 60 days postpartum. Furthermore, the likelihood ratios of incidence of NOC are 0.93, 1.94, and 0.38, respectively, in the groups with BUN levels < 15, 15-19.9, and ≥ 20 mg/dl. In conclusion, AOC postpartum adversely affects reproductive performance such as AI submission rate, pregnancy rate, interval to first AI and first AI conception rate; moreover, an increase or decrease in the BUN levels beyond 15-19.9 mg/dL leads to the AOC postpartum.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1371-1377
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• 2002

During a 5-yr period, 1994-1998, pre-weaning and weaning data were collected on 591 calves produced by mating either straightbred Jersey, straightbred Limousin or $F_1$ (Limousin${\times}$Jersey) bulls to mature purebred Jersey or Limousin cows. Traits recorded included birth and weaning weight, height, length, girth, fat depth and a measure of muscle (ratio of stifle to hip width expressed as a percentage). All traits were analyzed assuming a model with sire and dam random effects that included effects of year and date of birth, sex, breed and year${\times}$sex interaction. Main effects were generally significant with few exceptions. Direct genetic effects were large for weight, height, girth and muscle with a breed trend from purebred Jersey (small) to purebred Limousin (large). At weaning, the maternal effect of the Jersey dam was positive for weight (10.9${\pm}$4.9 kg), girth (3.7${\pm}$1.0 cm) and muscle (6.0${\pm}$0.9%). Heterosis was highly significant and positive only for fat depth (1.5${\pm}$0.2 mm) with the $F_1$ progeny being the fattest, followed by the backcrosses, then purebred Jersey and purebred Limousin. Also, significant (p<0.001) but negative heterosis was observed for weight, girth and muscle. The change in ranking for fat depth relative to other traits is a reflection of the large heterotic effects relative to direct effects on fat depth. Epistatic effects were not significant on any trait at birth or weaning. This study has indicated the possibility of exploiting the positive heterotic and maternal effects for fat depth and muscularity to meet specific meat quality and quantity demand by consumers.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.3
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• pp.253-259
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• 1997

Holstein Friesian and Jersey crossbreds are being widely introduced in the state of Gujarat in India. This paper evaluates feeding practices at farm level and examines whether the crossbreds fit into the existing mixed farm systems. Over a period of four years milk-offtake and feeds offered were recorded for 1331 cows at fortnightly intervals. The breed and the amount of concentrates fed contributed most to the variation in milk offtake. The introduction of crossbred cattle has a major impact on smallholder mixed farming systems. Crossbreds produced, on average, 1.8 times more milk than Desi, Gir, and Kankrej cows. They were fed 1.4 times more concentrates, and about 1.2 times more green and dry feeds than local cows. The major limiting constraint is the quality of the roughages offered. Farmers with crossbreds try to adjust their feeding of concentrates according to the needs of their cows. On tribal farms, local cows produced less milk than on non-tribal farms, whereas crossbreds produced the same amount of milk on both tribal and non-tribal farms. Crossbreds fit into the farming systems of both tribal and non-tribal farmers. The differences in agro-climatic characteristics between different areas in Gujarat were not reflected in differences in milk offtakes.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.685-693
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• 1996

A total of 3,610 Ayrshire and 1,711 Jersey cows were phenotyped for the genetic variants of ${\alpha}_{s1}$-casein, ${\beta}$-casein, $\chi$-casein, ${\beta}$-lactoglobulin and ${\alpha}$-lactalbumin. Least squares analyses showed possible associations between milk protein phenotypes and lactational production traits. Depending on lactation number, ${\beta}$-casein phenotypes in Ayrshires were associated with milk production ($A^2A^2$ > $A^1A^2$ > $A^1A^1$), and with milk protein content. In the third lactation, Ayrshire cows with ${\beta}$-casein $A^1A^1$ produced milk with 3.43% fat compared to 3.37% fat for ${\beta}$-casein $A^2A^2$. In Ayrshire, $\chi$-casein phenotypes affected the protein content during the three lactations (BB > AB > AA) and ${\beta}$-lactoglobulin phenotypes significantly influenced the milk fat during the first lactation (4.06% for AA and 3.97% for BB). In Jerseys, protein content of milk was influenced by phenotypes of ${\alpha}_{s1}$-casein(3.98% for CC v/s 3.86% for BB in the first lactation). In the third lactation, $\chi$-casein AA of Jersey milk contained 5.35% fat compared to 4.82% for phenotype BB. The effects of ${\beta}$-lactoglobulin phenotypes on protein content were apparent in Jerseys during the second lactation with the A variant being superior to the B (4.00% for AA v/s 3.87% for BB).