Losses of precision associated with simplified designs of milk recording for dairy ewes

2003 ◽  
Vol 70 (4) ◽  
pp. 441-444 ◽  
Author(s):  
Carlos Gonzalo ◽  
M Houcine Othmane ◽  
J Ángel Fuertes ◽  
L Fernando De La Fuente ◽  
Fermín San Primitivo
Keyword(s):  
Milk Yield ◽  
Production Level ◽  
Dairy Ewes ◽  
Preceding Interval

Simplified designs of milk yield recording based on the yield of a single monthly milking, adjusted or not for interval between milkings and for production level, were simulated and evaluated for 3173 ewe-test-day records belonging to 155 lactations of Churra dairy ewes. Losses of precision associated with simplified methods were evaluated by comparing estimated lactation yields with those observed both in a reference plan, where the two daily milkings were recorded at weekly intervals, and in the official A4 milk recording (monthly records of the two daily milkings). Estimates of lactation yields were less precise when the usual monthly designs were compared with a weekly sampling of both a.m. and p.m. milkings. The losses of precision were high at 9·4–36·2% including the A4 plan. The yield from only the milking period was more predictable than milk yield from the whole lactation (suckling and milking periods) and should consequently be adopted in dairy ewes. All options with one daily milking every month were more accurate when the corresponding plan was based on, or began with, the a.m. milking (loss of precision 14·9–15·8%). There was no evidence of improvement in sampling accuracy by adjusting for the preceding interval between milkings or production level. For practical and economic reasons, the design alternating a.m. and p.m. milkings every month, without adjustment, is suggested for ovine milk recording.

Accuracy of simplified sampling procedures for estimating milk composition in dairy ewes

2006 ◽  
Vol 73 (1) ◽  
pp. 109-114 ◽  
Author(s):  
M Houcine Othmane ◽  
J Angel Fuertes ◽  
Carlos Gonzalo ◽  
L Fernando De La Fuente ◽  
Fermín San Primitivo
Keyword(s):  
Milk Yield ◽  
Total Solid ◽  
Milk Composition ◽  
Dairy Ewes ◽  
Milk Component ◽  
Component Traits ◽  
Preceding Interval ◽  
Fat Yield ◽  
Sampling Procedures

Simplified designs of milk-composition recording, based on information from a single monthly milking, adjusted or not for interval between milkings and for milk yield, were simulated and evaluated for 2553 ewe-test-day records belonging to 155 lactations of Churra dairy ewes. Accuracy of simplified methods was evaluated by comparing estimated trait values (fat, protein, casein and total solid yields) with those observed both in a reference plan, where the two daily milkings were recorded at weekly intervals (A1), and in the official A4 milk recording (monthly records of the two daily milkings). Trait yields per lactation were estimated and adjusted to the only milking period (days in milk 30–120). Estimates of milk component traits were less precise when monthly designs, including the A4 design, were compared with a weekly sampling of both a.m. and p.m. milkings, with fat yield being the most difficult trait to estimate. All options with one daily milking every month were more accurate when the corresponding plan was based on, or began with, the a.m. milking. Adjustment for the preceding interval between milkings or milk yield did not improve sampling accuracy. The design alternating a.m. and p.m. milkings every month, without adjustment, is suggested for recoding milk component traits in dairy ewes.

scholarly journals Mammary Pathogens and Their Relationship to Somatic Cell Count and Milk Yield Losses in Dairy Ewes

2002 ◽  
Vol 85 (6) ◽  
pp. 1460-1467 ◽  
Author(s):  
C. Gonzalo ◽  
A. Ariznabarreta ◽  
J.A. Carriedo ◽  
F. San Primitivo
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Milk Yield ◽  
Somatic Cell Count ◽  
Yield Losses ◽  
Dairy Ewes

scholarly journals Association of lameness with milk yield and lactation curves in Chios dairy ewes

2015 ◽  
Vol 82 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Athanasios I Gelasakis ◽  
Georgios Arsenos ◽  
Georgios E Valergakis ◽  
Georgios Banos
Keyword(s):  
Linear Model ◽  
Milk Yield ◽  
General Linear Model ◽  
General Linear ◽  
Sheep Population ◽  
Dairy Ewes ◽  
Daily Milk Yield ◽  
A Prospective Study ◽  
On Farm ◽  
Selection Of

The objective of the study was twofold: (i) to quantify the differences in daily milk yield (DMY) and total milk yield (TMY) between lame and non-lame dairy ewes and (ii) to determine the shape of lactation curves around the lameness incident. The overall study was a prospective study of lameness for the surveyed sheep population, with a nested study including the selection of matching controls for each lame ewe separately. Two intensively reared flocks of purebred Chios ewes and a total of 283 ewes were used. Data, including gait assessment and DMY records, were collected on a weekly basis during on-farm visits across the milking period. A general linear model was developed for the calculation of lactation curves of lame and non-lame ewes, whereas one-way ANOVA was used for the comparisons between lame ewes and their controls. Lameness incidence was 12·4 and 16·8% on Farms A and B, respectively. Average DMY in lame ewes was significantly lower (213·8 g, P < 0·001) compared with the rest of the flock, where DMY averaged 1·340 g. The highest DMY reduction in lame ewes was observed during the week 16 of the milking period (P < 0·001), whereas the reduction of DMY, for lame ewes, remained significant at P < 0·001 level from week 8 to week 28 of milking. Comparisons between lame and controls revealed that at the week of lameness diagnosis a significant DMY reduction (P ≤ 0·001) was observed in lame ewes (about 32·5%), which was maximised 1 week later (35·8%, P ≤ 0·001) and continued for several weeks after recovery, resulting in 19·3% lower TMY for lame ewes for the first 210 d of the milking period (P < 0·01). Moreover, at flock level, TMY for non-lame and lame ewes, as calculated by the general linear model, was 318·9 and 268·0 kg, respectively. The results of this study demonstrate evidence of significant financial losses in dairy sheep due to lameness which, however, need to be accurately estimated in further, more detailed, analyses.

scholarly journals Connection of somatic cell count and milk yield as well as composition in dairy ewes

2010 ◽  
Vol 53 (1) ◽  
pp. 95-100
Author(s):  
J. Olechnowicz ◽  
Z. Sobek ◽  
J. M. Jaśkowski ◽  
P. Antosik ◽  
D. Bukowska
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Milk Yield ◽  
Somatic Cell Count ◽  
Threshold Value ◽  
Milk Composition ◽  
Milk Samples ◽  
Dairy Ewes ◽  
Cell Counts ◽  
Daily Milk

Abstract. The aim of this study was to determine the effect of somatic cell count (SCC) on milk yield and composition using a threshold value of 250 ∙103 cells/ml in dairy ewes of line 05. A total of 1 512 milk samples from udder halves were collected throughout milking periods at monthly intervals. In the present study milk composition (from halves of the udder) and daily milk yield (from udders) was examined in terms of SCC in ewe milk in three groups: from both halves of the udder below 250 ∙103 cells/ml, from one halves of the udder below 250 ∙103 cells/ml and from second half udder above 250 ∙103 cells/ml and from both halves of the udder above 250 ∙103 cells/ml. Milk yield from udders, somatic cell count in milk samples from udder halves and milk composition depended on the level of SCC recorded for halves of the udder. Somatic cell counts in milk from one or both halves of udders exceeding 250 ∙103 cells/ ml resulted in a statistically significant (P<0.01) decrease in daily milk production of ewes, by approx. 15.89 and 30.22 %, respectively. The analysis of variance showed also a significant effect of parity and stage of lactation of ewes on somatic cell count (log SCC) and milk composition from udder halves below 250 ∙103 cells/ml.

scholarly journals Associations of periparturient β-hydroxybutyric acid and non-esterified fatty acids blood serum concentrations with milk yield, milk composition and milk somatic cells count of intensively managed Chios dairy ewes

2019 ◽  
Vol 69 (4) ◽  
pp. 1195 ◽  
Author(s):  
I. Karagiannis ◽  
C. Brozos ◽  
E. Kiossis ◽  
C. Boscos ◽  
G. Fthenakis ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Milk Yield ◽  
Milk Composition ◽  
Hydroxybutyric Acid ◽  
Dairy Ewes ◽  
Blood Biochemical ◽  
Cell Counts ◽  
Esterified Fatty Acids ◽  
Intensively Managed ◽  
Intensive System

This Research Paper addresses the hypothesis whether in dairy ewes: periparturient β-hydroxybutyric acid (BHBA) and non-esterified fatty acids (NEFA) concentrations are associated with milk yield, composition and udder halves with increased somatic cell counts (SCC ≥ 0.5 × 106 cells/mL). A total of 186 Chios ewes reared under intensive system were used for this research. Serum BHBA and NEFA concentrations were measured before lambing (-30d,  -15d), and BHBA concentrations after lambing (+7d, +15d, +30d, +45d). Milk samples were collected at 15, 30 and 45days in milk (DIM). Total milk yield (MY) of the first 30, 60 and 90 DIM and total fortnightly milk yield (FMY) produced from 15 to 59 DIM were recorded. Positive associations between BHBA at +7d and MY of the first 30, 60 and 90 DIM were revealed (P < 0.001). For every increased unit of BHBA at +15d, +30d and +45d, FMY was decreased (DIM: 15 – 29 and 30 – 44) (P = 0.001 and P = 0.015, respectively) or increased (DIM: 45 – 59) (P < 0.001). BHBA before lambing (-30d, -15d) affected the number of halves presented SCC ≥ 0.5 × 106 cells/mL at 15 and 30 DIM (P = 0.011, P = 0.014, P = 0.009, P = 0.096, respectively). Finally, for every increased unit of BHBA during lactation (+15d, +30d, +45d) a decrease in the concentration of milk in proteins, solids not fat and lactose was noted (P < 0.001). This work demonstrates the associations of periparturient blood biochemical parameters (BHBA, NEFA) with milk yield and specific milk production characteristics.

Application of the Wood model to analyse lactation curves of organic dairy sheep farming

2014 ◽  
Vol 54 (10) ◽  
pp. 1609 ◽  
Author(s):  
Juan Carlos Ángeles Hernández ◽  
Octavio Castelán Ortega ◽  
Benito Albarrán Portillo ◽  
Hugo H. Montaldo ◽  
Manuel González Ronquillo
Keyword(s):  
Milk Yield ◽  
Goodness Of Fit ◽  
Evaluation Criteria ◽  
Coefficient Of Determination ◽  
Dairy Sheep ◽  
Organic System ◽  
Dairy Ewes ◽  
Lactation Curve ◽  
Total Milk ◽  
Wood Model

The aim of the present study was to evaluate the performance of the Wood model to describe the characteristics of lactation curves of dairy ewes under organic management in Mexico. In total, 4861 weekly test-day milk yield records from 194 lactations of crossbred dairy ewes were analysed to assess the performance of an empirical model to fit their lactation curve. We used the mathematical model proposed by Wood. The evaluation criteria were the correlation coefficient (r) between the values of total milk yield observed and estimated, the coefficient of determination (R2), and the mean square prediction error (MSPE). In addition, the peak yield (PYest) and time at peak yield (PTest) were calculated. The Wood model showed adequate goodness of fit (r = 0.95, R2 = 0.92 and MSPE = 0.024). The Wood model detected that 52.06% of lactation curves had a continuously decreasing shape (atypical curve), probably as a consequence of the characteristic management of the organic system, mainly due to the genotype used and the nutritional management. Residuals were greater for atypical curves than for typical ones, indicating differences in the ability of the Wood model to fit the two types of shapes. In typical curves, the Wood model showed adequate estimates of total milk yield and time at peak yield. The peak yield was underestimated both in typical and atypical curves. The Wood model in atypical curves underestimated the time at peak yield and milk yields in late lactation. The Wood model showed a reasonable fit of lactation curve in dairy sheep in organic systems but presented deficiencies of fit in atypical curves; therefore, estimates should be interpreted carefully.

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