Butterfat Yield Research Articles

Association of Production and Selected Dimensional Conformation Traits in Holstein Friesian Cows.

The objective of this study was to estimate the heritability of dairy production traits and that for dimensional traits and to calculate the correlation between the two heritability values in a Holstein Friesian cow herd bred in Hungary. Data of 15,032 Holstein Friesian cows born in the period 2008-2018 from 666 sires were collected for the study in 6 large dairy herds. Among the conformation traits, stature (ST), chest width (CW), body depth (BD), and rump width (RW), and for production traits, in the first lactation of cows, the 305-day milk yield (MY), milk butterfat yield (FY), and milk protein yield (MY) were evaluated. Heritability estimates of ST, CW, BD, and RW were 0.49, 0.25, 0.31, and 0.30, and those of MY, FY, and PY were 0.40, 0.35, and 0.30, respectively. BD and RW had no phenotypic (b = -0.01) or genetic (b = 0.00-0.01) change. The production traits (MY, FY, PY) increased to a greater extent (b = 2.2-43.3) than the examined conformation traits over time. Consequently, it is indicated that the selection for dairy production did not result in an increase in the studied dimensional traits.

Prediction of dry matter intake and gross feed efficiency using milk production and live weight in first-parity Holstein cows.

Direct measurement of dry matter intake (DMI) presents a major challenge in estimating gross feed efficiency (GFE) in dairy cattle. This challenge can, however, be resolved through the prediction of DMI and GFE from easy-to-measure traits such as milk production (i.e. milk yield, energy-corrected milk (ECM), butterfat, protein, lactose) and live weight (LW). The main objective of this study was, therefore, to investigate the feasibility of predicting dry matter intake and gross feed efficiency for first-parity Holstein cows using milk production traits and LW. Data comprised of 30 daily measurements of DMI and milk production traits, and 25 daily LW records of a group of 100 first-parity Holstein cows, fed a total mixed ration. Gross feed efficiency was calculated as kg ECM divided by kg DMI. The initial step was to estimate correlations of milk production traits and LW with DMI and GFE, to identify the best potential predictors of DMI and GFE. Subsequently, a forward stepwise regression analysis was used to develop models to predict DMI and GFE from LW and milk production traits, followed by within-herd validations. Means for DMI, butterfat yield (BFY) and LW were 21.91 ± 2.77kg/day, 0.95 ± 0.14kg/day and 572 ± 15.58kg/day, respectively. Mean GFE was 1.32 ± 0.22. Dry matter intake had positive correlations with milk yield (MY) (r = 0.32, p < 0.001) and LW (r = 0.76, p < 0.0001) and an antagonistic association with butterfat percent (BFP) (r = - 0.55, p < 0.001). On the other hand, GFE was positively associated with MY (r = 0.36, p < 0.001), BFP (r = 0.53, p < 0.001) and BFY (r = 0.83, p < 0.0001), and negatively correlated with LW (r = - 0.23, p > 0.05). Dry matter intake was predicted reliably by a model comprising of only LW and MY (R2 = 0.79; root mean squared error (RMSE) = 1.05kg/day). A model that included BFY, MY and LW had the highest ability to predict GFE (R2 = 0.98; RMSE = 0.05). Live weight and BFY were the main predictor traits for DMI and GFE, respectively. The best models for predicting DMI and GFE were as follows: DMI (kg/day) = - 54.21 - 0.192 × MY (kg/day) + 0.146 × LW (kg/day) and GFE (kg/day) = 4.120 + 0.024 × MY (kg/day) + 1.000 × BFY (kg/day) - 0.008 × LW (kg/day). Thus, daily DMI (kg/day) and GFE can be reliably predicted from LW and milk production traits using these developed models in first-parity Holstein cows. This presents a big promise to generate large quantities of data of individual cow DMI and GFE, which can be used to implement genetic improvement of feed efficiency.

De-oiled palm kernel cake for stall-fed buffaloes: effect on milk constituents, nutrient digestibility, biochemical parameters, and rumen fermentation.

Palm kernel cake, the main by-product of the palm kernel oil extraction process, is a highly available and low-priced agro-industrial by-product. However, several concerns exist to arriving at a safe inclusion level, especially for buffaloes. Two experiments were conducted to evaluate the effects of feeding de-oiled palm kernel cake (DPKC) to tropical buffaloes. In trial I, four fistulated Murrah buffaloes arranged in a 4 × 4 Latin square design were fed diets containing DPKC inclusions at 0, 15, 30, and 45% levels of compound feed to study their effects on rumen fermentation parameters. Trial II involves feeding twelve lactating buffaloes with DPKC inclusion levels at 0 or 15% of the compound feed to evaluate the effect of DPKC on the nutrient digestibility, serum biochemical constituents, rumen fermentation patterns, and lactation profile. The DPKC diets did not affect rumen pH, TCA-ppt nitrogen, and TVFA proportion; nevertheless, the NH3-N data revealed a decreased trend (P = 0.076). The acetate fraction decreased linearly (P < 0.05) with increased DPKC diets. Replacing the conventional protein sources with DPKC at a 15% level did not influence the nutrient intake and digestibility coefficients. No significant effects were observed for serum biochemical and mineral profiles of the lactating buffaloes fed the DPKC diet. Neither milk yield nor milk constituents (SNF, total solids, density, lactose, protein) were altered with the diets fed, except for milk fat%, which tended to increase (P = 0.092) on feeding DPKC diets. All the lactation parameters varied with time of collection, and diet × time interactions were noticed for fat, density, protein, 6% FCM yield, and butterfat yield. The feed efficiency tended to increase (P = 0.070) in the buffaloes fed DPKC diets. The profit margins were ₹6.07 and ₹1.63 for the DPKC included diets and feed cost per Kg 6% FCMY, respectively. Inconclusion,the inclusion of DPKC in the diet decreases feed cost without affecting the nutrient intakes, digestibility coefficients, serum biochemical and mineral profile, and lactation parameters.

АССОЦИАЦИЯ АЛЛЕЛЕЙ ГРУПП КРОВИ С МОЛОЧНОЙ ПРОДУКТИВНОСТЬЮ САМАРСКОГО ТИПА ЧЕРНО-ПЕСТРОЙ ПОРОДЫ СКОТА

The purpose of the research is the improvement of the population of the Samara type of Black-Motley breed of cattle for signs of milk production by controlling entry into the herd geomarketing desirable complexes. The evaluation of erythrocyte antigens of animals in laboratories of immunogenetic control of authenticity of origin of the animals, OAO «Samara» for 9 genetic systems by using hemolytic tests obdarena the method of the Fortieth. Allelofond analysis was carried out taking into account the classification proposed by N. Popov and G. Eskin. The data of breeding zootechnical accounting were used to study the level of productivity. Statistical data processing is performed using a computer program Microsoft Excel. The level of milk productivity in the studied cows of Samara type in farms ranged from 5899 to 6886 kg, fat content from 3.78 to 4.07 %, protein from 3.08 to 3.22 %. Herds of Samara type are significant different in the yield of milk, butterfat and alcoholocaust. All farms showed significant superiority over Close corporation «Lunacharsky» (agriculture-originator) protein content in milk is 0.05-0.14%. In the stud of the population of Samara was identified markers associated with high milk yield: Close corporation «Lunacharsky» (6045-6220 kg): G2Y2E/1Q/, O2A/2J/1K/O/, «-»; the limited liability company «Plemzavod «Druzhba» (6633-7218 kg): O4Y2A/1I//, «-»,O4Y2A/2, G2Y2E/1Q/, I2, B1O3Y2E/3G/G//, O1G1, O4D/E/3F/2G/O/; SPK (kolkhoz) named Kuibyshev (6131-6881 kg): G2Y2E/1Q/, I2, B1O3Y2E/3G/G//, «-», O4Y2A/1I//, O1G1; PSK named Kirova (5876-6210 kg): B1O3Y2E/3G/G//, E/3F/2G/O/G//, G2Y2E/1Q/, «-»; joint stock company «Plemzavod «Kryazh» (5045-6217 kg): O4Y2A/1I//, E/3F/2G/O/G//, G2Y2E/1Q/, O1G1, «-».

Breeding objectives for Holstein cattle in South Africa

Well-defined breeding objectives form the basis of sound genetic improvement programmes. Breeding objectives for Holstein cattle in South Africa were developed in the current study. Economic values were calculated for those economically relevant traits that had adequate bio-economic data, namely milk volume, fat yield, protein yield, liveweight, longevity, calving interval and somatic cell score (SCS). A bio-economic herd model for pasture-based and concentrate-fed systems in South Africa was used to calculate economic values by determining changes in profit arising from an independent unit increase in each trait. Alternative payment systems were used from four major milk buyers in South Africa. Relative economic values, standardized to the value of protein yield, were used to compare the relative importance of traits. Protein yield and longevity consistently had positive economic values and the converse was true for liveweight and calving interval. Economic value for volume was positive or negative, depending on whether the payment system rewarded or ignored volume. Sensitivity analysis showed that economic values were reasonably robust against fluctuations in the cost of feed and price of beef; with the exception of fat yield, whose value became negative when feed price exceeded ZAR 3.50. Generally, protein yield was the most important trait, although volume, longevity and SCS were more important in some situations. Calving interval was the least important trait, its value ranging from 4% to 22% of protein yield, although the model may have underestimated its value. Further work should focus on facilitating the wide adoption of these breeding objectives by industry.Keywords: Butterfat yield, economic value, liveweight, longevity, milk yield, protein yield, relative economic value, somatic cell score

Genetic parameters for production traits and somatic cell score of the SA Dairy Swiss population

The SA Dairy Swiss population could not previously be incorporated into the National Dairy Genetic Evaluation System, owing to inadequate population numbers and data structures. However, in recent years participation in Milk Recording has improved sufficiently to allow for genetic evaluation of the population. The aim of the study was therefore to estimate genetic parameters for the SA Dairy Swiss for production traits and somatic cell score in order to estimate breeding values routinely from the National Dairy Genetic Evaluation System. After editing procedures, a dataset of 25 621 test-day records for milk, butterfat and protein yields and a dataset of 10 438 test-day records for somatic cell count were obtained for further analysis. (Co)variance components for milk (kg), butterfat and protein yields (kg), as well as for somatic cell score, were estimated using a fixed regression multi-lactation animal model, based on test-day records of the first three lactations. Records from the various lactations were included as repeated measures. A multi-trait evaluation was performed for the production traits, while a single trait evaluation was done for somatic cell score, using the software package VCE4. Heritability estimates were 0.19 for milk, 0.16 for butterfat, and 0.16 for protein yields. The heritability estimate for somatic cell score was lower, at 0.07. The genetic correlations between the production traits were lowest for milk and butterfat (0.83), and were similar for milk and protein (0.94) and butterfat and protein yields (0.94). These values compare favourably with those of the other South African dairy breeds, based on the same model. The (co)variances were then implemented for estimation of breeding values for the SA Dairy Swiss population. Genetic trends were favourable for milk production traits with milk yield, butterfat and protein yields increasing by 25.13 kg/year, 0.96 kg/year and 0.79 kg/year, respectively; while the trend for somatic cell score was unfavourable, increasing by 0.86 units/year, since 1983. The SA Dairy Swiss could therefore be incorporated into the National Dairy Genetic Evaluation System of South Africa, using these covariance components and model.

A Proposed Selection Index for Jersey Cattle in Zimbabwe

A multitrait selection index (I T) for Zimbabwean Jersey cattle was constructed. The breeding objective was defined in terms of production and functionality traits. The production component of the index included milk yield (M), butterfat yield (F), protein yield (P), butterfat percent (F%), and protein percent (P%), while the functional component included the somatic cell count (SCC). The index was termed as I T = 0.0004M + 0.0109F + 0.0313P + 1.0004F% + 2.4491P% − 0.1905SCC. The accuracy of the index was 91.1%, and the correlation between this index and the aggregate breeding objective was 0.954. A selection index is more important in the selection of sires and cows. This leads to the greatest genetic progress and hence productivity in the dairy sector. Therefore, the application of the selection index developed is necessary if the dairy cattle industry is to maximise the exploitation of genetics and to improve its relative competitive position.

Variability of butterfat content in cacao (Theobroma cacao L.): combination and correlation with other seed-derived traits at the International Cocoa Genebank, Trinidad

Cocoa butterfat and cocoa powder are key economic products from the seeds of the cacao tree (Theobroma cacao L.). In this study, 323 accessions (comprised mainly of Upper Amazon Forasteros and Refractarios) from the International Cocoa Genebank, Trinidad were characterized for one biochemical and five morphological seed-derived traits. The data were analysed using non-parametric statistics including correlation analysis to identify promising parental candidates for future cacao breeding programmes. The Upper Amazon Forastero group had the greatest proportion of accessions with high butterfat content in cotyledons, whereas Refractario and Trinitario groups tended to contain more accessions with high butterfat content per fruit. The correlation of butterfat content of cotyledons with the dry mass of cotyledons was inconsistent in significance and direction. However, consistent significant positive correlations between butterfat content per fruit, cotyledon size and dry mass of cotyledons were found. The results suggested that butterfat content is a likely trait for independent selection but that selection for increased cotyledon size could lead to the selection of genotypes for high butterfat yield. Several promising accessions exhibited favourable levels of multiple traits and MATINA 1/7, CRU 51, AM 2/91 [POU], CRU 133, EET 58 [ECU] and POUND 18/A [POU] could be recommended as good choices for parental stock in breeding programmes for improving cacao butterfat content.

Genetic correlations between female fertility and production traits in South African Holstein cattle

Female fertility is increasingly gaining importance in national dairy cattle breeding objectives worldwide. In South Africa, there is no routine prediction of breeding values for reproductive performance in dairy cattle and selection is mainly focused on production traits. The objective of this study was to estimate genetic parameters among female fertility traits (age at first calving and calving interval) and first, second and third lactation production traits in South African Holstein cattle to determine the effect that selection on production per se may have on female fertility. Performance records on 40 437 South African Holstein cows in 766 herds were used. (Co)variance estimates were obtained by multitrait analysis, using the REML procedure. Heritability estimates were moderate for age at first calving (0.24 ± 0.02) and low for calving interval (0.03 ± 0.01). Genetic correlations between age at first calving and yield traits were low to moderately negative, ranging from -0.17 ± 0.07 with second lactation butterfat percentage to -0.50 ± 0.05 with first lactation butterfat yield. Calving interval had moderate to highly positive genetic correlations with yield traits, ranging from 0.37 ± 0.10 with second lactation milk yield to 0.69 ± 0.06 with first lactation milk yield. Correlations between female fertility and butterfat and protein percentages across all lactations, were close to zero. The observed antagonistic relationship between calving interval and production traits highlights the need to include calving interval in breeding objectives for South African Holstein cattle. Keywords: Age at first calving; calving interval; milk yield South African Journal of Animal Science Vol. 37 (3) 2007: pp.180-188

Test-day models for South African dairy cattle for participation in international evaluations

Variance components and breeding values of production traits and somatic cell score of South African Guernsey, Ayrshire, Holstein and Jersey breeds have been estimated using a multi-lactation repeatability test-day model, including tests of the first three lactations as repeated measures and fitting the permanent environmental effect across lactations. Multitrait evaluations were done for the production traits (milk, butterfat and protein) and single trait evaluations for somatic cell score. Heritability estimates were comparable with yield and somatic cell score estimates obtained by test-day models from other countries (17-24% for milk yield; 10-13% for butterfat yield; 14-19% for protein yield and 6-8% for somatic cell score). Proofs of qualifying sires were sent to the International Bull Evaluation Service (INTERBULL) for participation in the March 2005 test runs. Genetic correlations between South Africa and other participating countries, estimated by INTERBULL, compared well with those amongst the other participating countries. Trend validation tests were successful using this methodology for all traits and breeds except for somatic cell score of the Guernsey breed, due to insufficient data for this trait. South Africa can now participate in routine INTERBULL evaluations to obtain Multiple Across Country Evaluation (MACE) breeding values, using this methodology.

Testday models for production traits in dairy cattle

Methodology has been developed to implement testday models in the national genetic evaluation of dairy breeds for production traits in South Africa. Positive definite covariance matrices have been estimated, using multitrait, multi-lactation, fixed regression testday BLUP animal models, including testday records of the first three lactations as repeated measures for the Holstein and Jersey breeds. Heritability estimates were 0.40 + 0.007 for milk yield, 0.25 + 0.006 for butterfat yield and 0.37 + 0.006 for protein yield for the Holstein breed and 0.39 + 0.004 for milk yield, 0.21 + 0.002 for butterfat yield and 0.34 + 0.002 for protein yield for the Jersey breed. These estimates are well in the range of estimates reported by countries participating in INTERBULL evaluations. South African Journal of Animal Science Supp 2 2004: 35-37

Smallholder dairy systems in the Kenya highlands: breed preferences and breeding practices

A stratified random sample, cross-sectional survey of 1755 households in the Kenya highlands was conducted between June 1996 and April 1998 to evaluate the rationale underlying smallholders’ breeding decisions. Additional data were collected in a follow-up survey of 50 households sub-sampled from the main survey sample. Cattle-keeping households were 987, of which 62% kept Friesian (FR) and Ayrshire (AY), 22% kept East African Zebu, Boran and Sahiwal (ZB) cattle and 16% kept Guernsey and Jersey (GJ) breeds. Farmers keeping ZB and GJ ranked producing milk for family consumption the most important reason for keeping cattle, whereas those keeping FR and AY ranked producing milk for cash income most highly. Farmers’ relative preference for GJ, AY and FR for high milk yield over hardiness was respectively 3.46, 7.58 and 17.63 times more when compared with preference for ZB. Additional attributes rated highly in the Bos taurus breeds were high butterfat yields, heavier bodyweight, unselective feeding behaviour in zero-grazing systems, hardiness and disease resistance in semi-zero- and free-grazing systems and high market value. Breeding practices tended to favour the use of dairy breeds of larger body size, particularly Friesian, which is inconsistent with technical recommendations that favour the use of the smaller dairy cattle breeds. These findings suggest that multiple objectives, including the need for more milk, adaptability to local feed conditions and diseases, and the provision of non-market production such as manure, insurance and financing roles of cattle, underlie smallholders’ breeding decisions in the Kenya highlands.

The effect of flavophospholipol (Flavomycin ®) on milk production and milk urea nitrogen concentrations of grazing dairy cows

Milk production and milk composition responses to supplementation of Holstein-Friesian cows grazing kikuyu pasture in summer and a combination of annual ryegrass and maize silage in winter with 64 mg/d flavophospholipol were determined. There was no difference in the average milk yield over the first 100 days of lactation between the control group (19.8 kg/day) and the Flavomycin supplemented group (20.5 kg/day). Milk production over the full lactation of 300 days was also not influenced by Flavomycin addition (control: 5 525 kg; treatment: 5 627 kg). There was no difference between the control and treatment group in average butterfat percentage (3.55% vs. 3.62%), butterfat yield over 300 days (195.3 kg vs. 201.2 kg), average protein percentage (3.12% vs. 3.14%) or protein yield over 300 days (170.2 kg vs. 178.5 kg). Flavomycin addition only reduced the milk urea nitrogen (MUN) concentrations during the third week of April (treatment: 16.0 ± 0.8 mg MUN/dl; control: 18.6 ± 0.4 mg MUN/dl) and the second week of September (treatment: 16.0 ± 1.2 mg MUN/dl; control: 19.6 ± 0.9 mg MUN/dl). Cows grazing nitrogen-fertilized pastures displayed great variation in weekly and monthly milk urea nitrogen concentrations which frequently exceed 18 mg MUN/dl. (South African Journal of Animal Science, 2001, 31(2): 101-106)

Lactation performance of purebred Arsi cows and Friesian × Arsi crosses under pre-partum and post-partum supplementary feeding regimes

AbstractA study was conducted at the Asella Station in the Arsi Region of Ethiopia to investigate the dairy performance of indigenous purebred Arsi and Friesian × Arsi crosses under different pre-partum and post-partum supplementary feeding regimes. A total of’343 first-lactation animals were involved in the experiment. Lactation performance was not significantly affected by pre-partum supplementation. Post-partum supplementary feeding significantly affected total lactation milk and butterfat yields of the crosses but not the purebred Arsi. Arsi crosses produced more milk (1873 (s.e. 65·1) v. 258 (s.e. 31·7) kg) and butterfat (92 (s.e. 4·0) v. 25 (s.e. 2·8) kg) than purebred Arsi. The crosses stayed in lactation longer (474 (s.e. 13·0) v. 179 (s.e. 15·4) days) than the latter. Purebred Arsi manifested much more variation in total lactation milk yield (CV: 1·27 v. 0·37), lactation length (0·91 v. 0·30) and butterfat yield (0·71 v. 0·42) than Arsi crosses. F1 crosses produced slightly more milk (+266 kg) and butterfat (+19·3 kg) but had shorter (-30 days) lactations than the backerosses.

An evaluation of a dried yeast culture on milk yield and composition in dairy cows fed grass and maize silage

There is considerable interest in the effect of dietary supplementation with probiotics or yeast cultures on dairy cow performance. Yeast cultures such as Diamond V ‘XP’ are produced by growing selected yeast strains on a semi-solid medium under stressed conditions, which are then dried. They are now used by a majority of the high yielding herds in North America (McCullough, 1995) and have been shown to have a significant effect on butterfat and protein yield with grass silage fed UK dairy cows (Rowlinson et al., 1995). The objective of this work was to evaluate the effect of feeding a yeast culture to a medium-high yielding (8,100 kg) herd of dairy cows fed a diet based on grass and maize silage.

Genetic and environmental trends in a large commercial Jersey herd in the Central Rift Valley, Kenya.

Records from a large commercial Jersey herd covering the period 1980 to 1993 were used to estimate genetic and environmental trends in production traits, fertility traits and age at first calving. The farm is located in the upper midland agroecological zone of the Central Rift Valley in Kenya. The estimated annual genetic trends were 0.8 kg (milk yield), 0.003% (butterfat per cent), 0.09 kg (butter fat yield), 0 d (calving interval), -0.001 (number of services per conception), 0.22% (conception rate) and -0.5 d (age at first calving). All the traits studied showed an environmental trend in the desired direction: 14.6 kg (milk yield), 0.029% (butterfat per cent), 1.31 kg (butterfat yield), -2.52 d (calving interval), -0.62 (number of services per conception), 0.89% (conception rate), and -17 d (age at first calving). Despite great genetic variation in the production traits, the genetic trend in all traits was very small reflecting ineffective selection, whereas the results for the environmental trends indicate a substantial improvement in the management.

Effects of ensilage of grass on performance and nutrient utilization by dairy cattle 1. Food intake and milk production

AbstractTwelve lactatiug dairy cows were offered either fresh grass (G) or grass silage prepared from the same pasture which had undergone either an extensive (E) or restricted (R) fermentation, in a three-period change-over design experiment. Ensilage resulted in a reduction in forage pH and water-soluble carbohydrate concentration and an increase in ammonia-nitrogen concentration. The ensiling techniques used ensured that both silages were well preserved with pH values for E and R of 3.81 and 4.08 respectively, while the respective lactic acid concentrations were 124.6 and 27.0 g/kg dry matter respectively. Whilst there were no significant differences in dry-matter intake between treatments, when corrected for losses of volatile compounds, animals offered silage with a restricted fermentation consumed their food at a higher rate of intake (P &lt; 0.001) than did animals on the other treatments. It was also found that while there was no significant difference in milk yield between animals offered fresh or ensiled forage, both butterfat and protein concentration and yields of butterfat were significantly higher (P &lt; 0.01 or greater) with grass and restricted fermented silage than with extensively fermented silage. Ensiling of herbage had no significant effect on apparent digestibility. It is concluded that ensiling of herbage per se had little effect on overall animal performance but pattern of silage fermentation resulted in alterations in milk composition.

Influence of weather conditions on milk production and rectal temperature of Holsteins fed two levels of concentrate.

Twelve lactating Holstein cows in 2nd lactation were allocated randomly, six each, to two feeding treatments: high concentrate (1 kg dairy concentrate to 2 kg milk produced) and low concentrate (1 kg dairy concentrate to 4 kg milk produced) from 7 to 106 days postcalving. Forage and water were provided ad libitum. Milk and butter fat yields and rectal temperatures were examined in relation to 9 weather variables (minimum, maximum and mean temperatures, relative humidity, temperature-humidity index (THI), radiation, wind velocity and mean temperature of the previous day). Averages for milk yield, fat yield and rectal temperature were respectively 20.4 kg, 0.7 kg and 38.9 degrees C for the high concentrate treatment and 18.4 kg, 0.6 kg and 38.6 degrees C for the low concentrate treatment. Whether conditions accounted for 5.6%, 0.8% and 10.8% of the day to day variation in milk yield, fat yield and rectal temperature, respectively, for the high concentrate group and 29.4%, 9.7% and 0.6%, respectively, for the low concentrate group. Only measures of ambient temperature, especially mean temperature, were closely associated with these traits.

Feed intake, milk yield and milk composition by replacing unprotected fat by Ca-soaps for dairy cows

The effect of substituting traditional animal fat with saponified animal fat was investigated in experiments in 2 commercial herds: (1) a Danish Black and White herd (18 cows in mid-lactation per treatment) given a complete ration ad libitum; (2) a Jersey herd (15 cows in mid-lactation per treatment) given fixed amounts of concentrates containing the fat and given silage ad libitum. In both experiments, the daily allowance of saponified animal fat was lower than the corresponding level of traditional animal fat because of a lower fat content in the saponified product than expected. The degree of saponification was estimated at ∼ 70%. In Experiment 1, where the level of experimental fat amounted to 759 and 882 g, respectively, per cow daily, feed intake and milk yield tended to increase and the yield of butter fat was increased significantly (100 g per cow daily) when using saponified animal fat. Furthermore, the content of linoleic acid in the milk was increased. In Experiment 2, the level of experimental fat was ∼ 500 and 600 g, respectively, per cow daily, while the basic ration contained ∼ 300 g. No significant effect on yield of milk and butter fat or the content of linoleic acid in the milk was found. It is concluded that the use of saponified animal fat is a means by which the positive effect on milk production of supplementing fat can be prolonged to higher levels of fat in the ration than can be reached with traditional animal fat.

Use of plasma hormone and metabolite levels to predict breeding value of young bulls for butterfat production

ABSTRACTThe purpose of the experiment was to investigate the possibility of using concentrations of hormones and metabolites in plasma of potential breeding bulls early in life as indirect selection criteria for butterfat production. Sixteen Red Danish bull calves were included in the experiment, 10 were offspring of parents selected for high butterfat production for two or three generations, and six were from parents selected for low butterfat yield. The average estimated relative breeding values of the calves in the two groups were 111 and 91.At 3·5 and 7 months of age blood samples were collected every 6 h during 2 days of ad libitum feeding, 5 days of fasting and 2 days of refeeding. The samples were analysed for glucose, urea, free fatty acids, insulin and thyroxine. At 3·5 months plasma concentrations of free fatty acids were significantly correlated with breeding value under all feeding conditions examined. The increase in plasma glucose during refeeding at both ages was positively related to breeding value. Plasma insulin during the 1st day of fasting was positively correlated with genetic merit at 3·5 months of age and negatively correlated at 7 months. Plasma thyroxine was negatively correlated with breeding value at both ages, but the correlation was only significant at 7 months. Multiple regression analyses showed that a large part of the variation in breeding value for butterfat production could be described by plasma levels of hormones and metabolites when more than one variable was included in the model. With six variables in the model 0·67 and 0·73 of the variation could be accounted for at 3·5 and 7 months of age respectively.The results of the experiment have to be considered with caution because only one sire was used per group, the parents were preselected, and the number of animals was small. The results, however, do indicate that plasma levels of hormones and metabolites in the early life of potential breeding bulls, measured after suitable physiological challenges, may be useful as selection criteria for butterfat production of their offspring.