• Title, Summary, Keyword: Lactation

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Phenotypic Relationship between Lactation Persistency and Change in Body Condition Score in First-lactation Holstein Cows

  • Yamazaki, Takeshi;Takeda, Hisato;Nishiura, Akiko;Sasai, Youji;Sugawara, Naoko;Togashi, Kenji
    • Asian-Australasian Journal of Animal Sciences
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    • v.24 no.5
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    • pp.610-615
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    • 2011
  • We examined the correlations between lactation curve shape, including persistency and changes in body condition score (BCS) during early-stage (0 to 30 days in milk (DIM)), nadir-stage (31 to 90 DIM), and late-stage (91 to 240 DIM) lactation in 191 first-lactation cows. Data used were first-parity BCS records, scored twice every month after calving, and daily milk yields. Individual lactation curves were depicted by the Wilmink function. Lactation persistency was defined as the difference in estimated milk yields between 240 DIM and 60 DIM. Changes in BCSs in the early and late stages were defined as linear regression coefficients. There were no significant correlations between traits for lactation curve shape and change in BCS in early-stage lactation. Peak yield and total milk yield were negatively correlated with BCSs in nadir- and late-stage lactation and with BCS change in late-stage lactation, suggesting that cows with high lactation yields had low body reserves and health status in mid- to late lactation and had delayed recovery of body reserves. Lactation persistency was positively correlated with change in BCS in late-stage lactation, suggesting that cows with high lactation persistency tended to be healthy and to recover their body reserves well in late lactation.

Effect of Number of Lactation Records on the Selection Rates in Holstein Dairy Cattle

  • Cho, Kwang-Hyun;Choy, Yun-Ho;Kong, Hong-Sik;Lee, Hak-Kyo;Kim, Sung-Hoon;Park, Kyung-Do
    • Journal of Animal Science and Technology
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    • v.55 no.2
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    • pp.81-85
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    • 2013
  • This experiment was conducted to investigate the effects of lactation records in Holstein dairy cattle on the selection rates using a total of 341,436 test records from 113, 812 heads of cattle from first to third lactation. Heritabilities for milk, fat, and protein yields were highest at first lactation (0.28, 0.24, and 0.27, respectively), and decreased to 0.14, 0.15, and 0.13 at third lactation. For the milk yields, phenotypic correlations between first and second lactation, first and third lactation, and second and third lactation were low (0.49, 0.39, and 0.47, respectively), while genetic correlations among consecutive lactations and between second and third were above 0.8 and 0.9. In Model I, of the 1,138 heads the top 1% were selected based on first lactation records, only 32.4% (396 heads) were re-selected when the second lactation records were included and the 67.6% (769 heads) were newly selected animals. While in Model II, 85.1% (1,138 heads) of the animals which were selected as the top 1% on the basis of first and second lactation records were included. A multiple trait evaluation method using multiple lactation records is more desirable than a single trait evaluation method using first lactation records only.

FACTORS AFFECTING THE LACTATION LENGTH AND MILK YIELD IN NILI-RAVI BUFFALOES

  • Chaudhry, M.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.5 no.2
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    • pp.375-382
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    • 1992
  • The effect of certain factors such as sex of calf, status of buffalo, season of calving, parity and sire on lactation length and total lactation yield was studied in 391 Nili-Ravi buffaloes. The average lactation length was $301.73{\pm}1.87$ (mean $\pm$ SE) days with a range of 181 to 505 days whereas the average lactation yield was $2031.08{\pm}19.16kg$ and ranged from 1023 to 6535 kg for 984 lactations. The differences in the means of lactation length and lactation yield due to the sex of calf were significant (p<0.05). The status of buffaloes had a significant (p<0.05) effect on lactation length but its effect on lactation yield was non-significant. The season of calving had no effect on lactation length but it influenced the lactation yield significantly. The milk yield was highest ($2150.81{\pm}43.52kg$) in buffaloes which calved in spring and lowest ($1959.92{\pm}30.83kg$) in autumn. The effect of parity on both traits under study was significant (p<0.01). The maximum and minimum lactation lengths of $309.82{\pm}3.96$ and $284.16{\pm}7.17$ days were observed in the first and sixth lactations, respectively. The milk yield was maximum ($2150.38{\pm}58.79kg$) in the seventh lactation and minimum (1818.31 60.04 kg) in the sixth lactation. The influence of sire was significant on lactation length (p<0.05) and milk yield (p<0.01).

Non-linear modelling to describe lactation curve in Gir crossbred cows

  • Bangar, Yogesh C.;Verma, Med Ram
    • Journal of Animal Science and Technology
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    • v.59 no.2
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    • pp.3.1-3.7
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    • 2017
  • Background: The modelling of lactation curve provides guidelines in formulating farm managerial practices in dairy cows. The aim of the present study was to determine the suitable non-linear model which most accurately fitted to lactation curves of five lactations in 134 Gir crossbred cows reared in Research-CumDevelopment Project (RCDP) on Cattle farm, MPKV (Maharashtra). Four models viz. gamma-type function, quadratic model, mixed log function and Wilmink model were fitted to each lactation separately and then compared on the basis of goodness of fit measures viz. adjusted $R^2$, root mean square error (RMSE), Akaike's Informaion Criteria (AIC) and Bayesian Information Criteria (BIC). Results: In general, highest milk yield was observed in fourth lactation whereas it was lowest in first lactation. Among the models investigated, mixed log function and gamma-type function provided best fit of the lactation curve of first and remaining lactations, respectively. Quadratic model gave least fit to lactation curve in almost all lactations. Peak yield was observed as highest and lowest in fourth and first lactation, respectively. Further, first lactation showed highest persistency but relatively higher time to achieve peak yield than other lactations. Conclusion: Lactation curve modelling using gamma-type function may be helpful to setting the management strategies at farm level, however, modelling must be optimized regularly before implementing them to enhance productivity in Gir crossbred cows.

Comparison of Lactation Problems, Knowledge, and Adaptation on Breastfeeding between Users and Non-Users of Lactation Clinic (모유수유클리닉 이용군과 비이용군의 모유수유 문제, 지식 및 적응 비교)

  • Yun, Myoung Hee;Shin, Hye Sook
    • Journal of East-West Nursing Research
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    • v.20 no.2
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    • pp.112-120
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    • 2014
  • Purpose: The purpose of this study was to compare the differences in characteristics, lactation problems, knowledge, and adaptation of breastfeeding between users and non-users of a lactation clinic. Methods: The descriptive study design was utilized using self-report questionnaires. 446 breastfeeding mothers participated in this study. Data were collected from lactation clinics, postpartum care centers, mother's culture centers, public health centers, pediatrics and obstetrics & gynaecology outpatient clinics in Seoul, Gyeonggi province, and Chungcheongnam province from August 20 to September 30, 2011. The questionnaires to measure lactation problems, knowledge and adaptation of breastfeeding were used. Data were analyzed using SPSS ver. 18.0 for Windows. Results: There was statistically significant differences in the breast feeding problems(t=5.71, p<.001) and breastfeeding knowledge(t=2.87, p=.004) between users and non-users of a lactation clinic. Conclusion: The results of this study may provide a foundation to develop nursing intervention for mothers in breastfeeding, and an evidence to expand the role of nurses as breastfeeding specialists.

Lactation Persistency as a Component Trait of the Selection Index and Increase in Reliability by Using Single Nucleotide Polymorphism in Net Merit Defined as the First Five Lactation Milk Yields and Herd Life

  • Togashi, K.;Hagiya, K.;Osawa, T.;Nakanishi, T.;Yamazaki, T.;Nagamine, Y.;Lin, C.Y.;Matsumoto, S.;Aihara, M.;Hayasaka, K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.8
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    • pp.1073-1082
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    • 2012
  • We first sought to clarify the effects of discounted rate, survival rate, and lactation persistency as a component trait of the selection index on net merit, defined as the first five lactation milks and herd life (HL) weighted by 1 and 0.389 (currently used in Japan), respectively, in units of genetic standard deviation. Survival rate increased the relative economic importance of later lactation traits and the first five lactation milk yields during the first 120 months from the start of the breeding scheme. In contrast, reliabilities of the estimated breeding value (EBV) in later lactation traits are lower than those of earlier lactation traits. We then sought to clarify the effects of applying single nucleotide polymorphism (SNP) on net merit to improve the reliability of EBV of later lactation traits to maximize their increased economic importance due to increase in survival rate. Net merit, selection accuracy, and HL increased by adding lactation persistency to the selection index whose component traits were only milk yields. Lactation persistency of the second and (especially) third parities contributed to increasing HL while maintaining the first five lactation milk yields compared with the selection index whose only component traits were milk yields. A selection index comprising the first three lactation milk yields and persistency accounted for 99.4% of net merit derived from a selection index whose components were identical to those for net merit. We consider that the selection index comprising the first three lactation milk yields and persistency is a practical method for increasing lifetime milk yield in the absence of data regarding HL. Applying SNP to the second- and third-lactation traits and HL increased net merit and HL by maximizing the increased economic importance of later lactation traits, reducing the effect of first-lactation milk yield on HL (genetic correlation ($r_G$) = -0.006), and by augmenting the effects of the second- and third-lactation milk yields on HL ($r_G$ = 0.118 and 0.257, respectively).

Effects of Controlled Compensatory Growth on Mammary Gland Development and Lactation in Rats

  • Moon, Yang S.;Park, Chung S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.9
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    • pp.1364-1370
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    • 2002
  • The objective of this study was to examine the effect of compensatory growth nutritional regimen on mammary gland growth and lactation. One hundred twenty-two Sprague Dawley female rats (35 days of age) were randomly assigned to either a control or a stair-step compensatory nutrition (SSCN) feeding regimen or an alternating 2-2-3-3-week schedule beginning with 40% energy restriction for 2 weeks followed by re-alimentation (control diet) for 2 weeks. Pup weight gain and milk yield were improved 8% and 8 to 15%, respectively, by the SSCN regimen. The gene expression of $\beta$-casein was 2.3-fold greater in the SSCN group than in the control group during early lactation, but they were greater at all stages of the second lactation. The gene expression of insulin-like growth factor-I was 40% lower in the SSCN group than in the control group during early lactation of the second lactation, but during late lactation it was 80% greater than in the control group. The concentration of serum corticosterone tended to be higher in the SSCN group during the late stage of the first lactation. These results suggest that the stair-step compensatory nutrition regimen improves lactation performance and persistency by modulation of cell differentiation and apoptotic cell death.

Milk Production, Blood Metabolites and Circulatory Levels of Hormones in Crossbred Goats

  • Singh, Mahendra;Ludri, R.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.7
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    • pp.963-967
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    • 2002
  • Eighteen crossbred goats were selected from the Institute's goat herd to determine the changes in hormones, blood metabolites and yield and composition of milk during lactation. The blood and milk samples were collected from each goat in a heparinized vacutainer tubes at fortnightly interval for a period of 150 days. In milk samples, fat, protein and lactose contents were estimated while in blood plasma hormones viz., prolactin, GH, cortisol, insulin, $T_4$ and $T_3$ were measured using radioimmunoassay methods. The plasma concentration of prolactin, GH and cortisol were high during early lactation when the goats acquired peak milk yield. During remainder of lactation their concentration varied. The high NEFA concentration during early lactation indicated mobilization of body reserves as the body weights also decrease during early lactation. However, with the advancement of lactation, the body weights of the goats and the concentration of NEFA declined which indicated utilization of NEFA for energy yielding purposes in addition to fatty acid synthesis. The ambient temperatures did not influence plasma concentration of prolactin, GH, insulin, $T_3$ and $T_4$ during the lactation cycle. The fat content of milk varied significantly (p<0.01) but protein and lactose content of milk remains unchanged during different stages of lactation. Growth hormone was positively correlated with insulin (p<0.05) during lactation while prolactin had a positive correlation with lactose and plasma NEFA (p<0.01) and negative correlation with $T_3$ (p<0.05).

Genome Wide Association Studies Using Multiple-lactation Breeding Value in Holsteins

  • Cho, Kwang-Hyun;Oh, Jae-Don;Kim, Hee-Bal;Park, Kyung-Do;Lee, Joon-Ho
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.3
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    • pp.328-333
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    • 2015
  • A genome wide association study was conducted using estimated breeding value (EBV) for milk production traits from 1st to 4th lactation. Significant single nucleotide polymorphism (SNP) markers were selected for each trait and the differences were compared by lactation. DNA samples were taken from 456 animals with EBV which are Holstein proven bulls whose semen is being sold or the daughters of old proven bulls whose semen is no longer being sold in Korea. High density genome wide SNP genotype was investigated and the significance of markers associated with traits was tested using the breeding value estimated by a multiple lactation model as a dependent variant. As the result of significance comparisons by lactations, several differences were found between the first lactation and subsequent lactations (from second to 4th lactation). A similar trend was noted in mean deviation and correlation of the estimated effects by lactation. Since there was a difference in the genes associated with EBV for each trait between first and subsequent lactations, a multi-lactation model in which lactation is considered as a different trait is genetically useful. Also, significant markers in all lactations and common markers for different traits were detected, which can be used as markers for quantitative trait loci exploration and marker assisted selection in milk production traits.

Compensatory nutrition-Mediated Lactation Potential and Milk Protein Gene Expression in Rats (보상성장에 의한 에너지 섭취량 조절이 흰쥐의 유생산능력과 유단백질 유전자 발현에 미치는 영향)

  • 김상훈
    • Journal of Nutrition and Health
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    • v.33 no.7
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    • pp.697-702
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    • 2000
  • The objective of this study was to determine the extent to which the compensatory nutrition regimen modulates lactation performance and milk protein gene expression in the first and second lactation cycles. Female rats(28 days of age) were assigned to 1)control ad libitum ; 2) stari-step compensatory nutrition(SSCN) regimen an alternating 3-2-3-4-week schedule beginning with an energy restriction diet(40% restriction) for 3 weeks followed by the control diet(ad libitum) for 2 weeks and then alternating another 3-4 week feeding regimen. The SSCN rats were received an overall 20% energy restriction(average from all stair-step periods) compared with the conventionally fed control group. Rats were bred during the first week of the second realimentation. All pups were weaned on day 21 of lactation. About 1 week after weaning all dams were mated for the second pregnancy. Mammary tissues were obtained from pregnant and lactating rats during the first and second lactation cycles. During these lactation cycles the SSCN group had a 11% increase in average lactation performance over that of control. The SSCN group had significantly increased levels of milk protein gene($\alpha$- and $\beta$-casein) expression in mammary tissues during the first lactation cycle compared with those of the control group. During the second lactation period the levels of milk protein gene expression in lactating mammary tissues of the SSCN group were also higher than those of the control group. These results suggest that the effects of compensatory growth imposed at an early age extend to the second lactation cycle with regard to increased lactation performance and milk protein gene expression.

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