Abstract: The objective of this study was to determine the effects of environmental stressors on the performance of lactating dairy cows and discuss some future trends. There exists a relationship between the meteorological data and milk yield prediction accuracy in pasture-based dairy systems. New precision technologies are available and are being developed to improve the sustainability of the dairy industry. Some of these technologies focus on welfare of individual animals on dairy farms. These technologies allow the automatic identification of animal behaviour and health events, greatly increasing overall herd health and yield while reducing animal health inspection demands and long-term animal healthcare costs. The data set consisted of records from 489 dairy cows at two dairy farms and temperature measured from the nearest meteorological weather station in 2018. The effects of temperature on milk production and behaviour of animals were analyzed. The statistical results indicate different effects of temperature on milk yield and behaviour. The “comfort zone” for animals is in the range 10 °C to 20 °C. Dairy cows out of this zone had to decrease or increase their metabolic heat production, and it affected their milk production and behaviour.
Abstract: κ-casein is one of milk proteins which are very important for milk processing. Genotypes of κ-casein affect milk yield, fat, and protein content. The main factors which affect local Latvian dairy breed milk yield and composition are analyzed in research. Data were collected from 88 Latvian brown and 82 Latvian blue cows in 2015. AA genotype was 0.557 in Latvian brown and 0.232 in Latvian blue breed. BB genotype was 0.034 in Latvian brown and 0.207 in Latvian blue breed. Highest milk yield was observed in Latvian brown (5131.2 ± 172.01 kg), significantly high fat content and fat yield also was in Latvian brown (p < 0.05). Significant differences between κ-casein genotypes were not found in Latvian brown, but highest milk yield (5057 ± 130.23 kg), protein content (3.42 ± 0.03%), and protein yield (171.9 ± 4.34 kg) were with AB genotype. Significantly high fat content was observed in Latvian blue breed with BB genotype (4.29 ± 0.17%) compared with AA genotypes (3.42 ± 0.19). Similar tendency was found in protein content – 3.27 ± 0.16% with BB genotype and 2.59 ± 0.16% with AA genotype (p < 0.05). Milk yield increases by increasing parity. We did not obtain major tendency of changes of milk fat and protein content according parity.
Abstract: The age of first calving (AFC) is one of the most important factors that have a significant impact on cow productivity in different lactations and its whole life. A belated AFC leads to reduced reproductive performance and it is one of the main reasons for reduced longevity. Cows that calved in time period from 2001-2007 and in this time finished at least four lactations were included in the database. Data were obtained from 68841 crossbred Holstein Black and White (HM), crossbred Latvian Brown (LB), and Latvian Brown genetic resources (LBGR) cows. Cows were distributed in four groups depending on age at first calving. The longest lifespan was conducted for LBGR cows, but they were also characterized with lowest lifetime milk yield and life day milk yield. HM breed cows had the shortest lifespan, but in the lifespan of 2862.2 days was obtained in average 37916.4 kg milk accordingly 13.2 kg milk in one life day. HM breed cows were also characterized with longer calving intervals (CI) in first four lactations, but LBGR cows had the shortest CI in the study group. Age at first calving significantly affected the length of CI in different lactations (p30 months old in the fourth lactation had the longest CI in all study groups (421.4 days). The LBGR cows were characterized with the shortest CI, but there was slight increase in second and third lactation. Age at first calving had a significant impact on cows’ age in each calving time. In the analysis, cow group was conducted that cows with age at first calving 30 months (932.6 days) at the time of fifth calving were 2560.9 days (7.3 years) old.
Abstract: The objective of this study was to evaluate the
effects of calving season on the production and economic efficiency
of dairy farms in Egypt. Our study was performed at dairy
production farms in the Alexandria, Behera, and Kafr El-Sheikh
provinces of Egypt from summer 2010 to winter 2013. The
randomly selected dairy farms had herds consisting of Baladi,
Holstein-Friesian, or cross-bred (Baladi × Holstein-Friesian) cows.
The data were collected from production records and responses to a
structured questionnaire. The average total return differed
significantly (P < 0.05) between the different cattle breeds and
calving seasons. The average total return was highest for the
Holstein- Friesian cows that calved in the winter (29106.42
EGP/cow/year), and it was lowest for Baladi cows that calved in the
summer (12489.79 EGP/cow/year). Differences in total returns
between the cows that calved in the winter or summer or between
the foreign and native breeds, as well as variations in calf prices,
might have contributed to the differences in milk yield. The average
net profit per cow differed significantly (P < 0.05) between the cattle
breeds and calving seasons. The average net profit values for the
Baladi cows that calved in the winter or summer were 2413 and
2994.96 EGP/cow/year, respectively, and those for the Holstein-
Friesian cows were 10744.17 and 7860.56 EGP/cow/year,
respectively, whereas those for the cross-bred cows were 10174.86
and 7571.33 EGP/cow/year, respectively. The variations in net profit
might have resulted from variation in the availability or price of feed
materials, milk prices, or sales volumes. Our results show that the
breed and calving season of dairy cows significantly affected the
economic efficiency of dairy farms in Egypt. The cows that calved
in the winter produced more milk than those that calved in the
summer, which may have been the result of seasonal influences,
such as temperature, humidity, management practices, and the type
of feed or green fodder available.
Abstract: The objective of this study was to determine effect of
dietary essential oil (EO) compounds, which contained
cinnamaldehyde, eugenol, peppermint, coriander, cumin, lemongrass,
and an organic carrier on feed intake, milk composition, and rumen
fermentation of dairy cows during heat exposure. Thirty-two Holstein
cows (days in milk= 60 ± 5) were assigned to one of two treatment
groups: a Control and EO fed. The experiment lasted 28 days. Dry
matter intake (DMI) was measured daily while and milk production
was measured weekly. Our result showed that DMI and milk yield
was decreased (P < 0.01) in control cows relative to EO cows.
Furthermore, supplementation with EO was associated with a
decrease in the molar proportion of propionate (P < 0.05) and
increase (P < 0.05) in acetate to propionate ratio. In conclusion, EO
supplementations in diets can be useful nutritional modification to
alleviate for the decrease DMI and milk production during heat
exposure in lactating dairy cows.
Abstract: Domestic goats (Capra hircus) are extremely diverse
species and principal animal genetic resource of the developing
world. These facilitate a persistent supply of meat, milk, fibre, and
skin and are considered as important revenue generators in small
pastoral environments. This study aimed to fingerprint β-LG gene at
PCR-RFLP level in native Saudi goat breeds (Ardi, Habsi and Harri)
in an attempt to have a preliminary image of β-LG genotypic patterns
in Saudi breeds as compared to other foreign breeds such as Indian
and Egyptian. Also, the Phylogenetic analysis was done to investigate
evolutionary trends and similarities among the caprine β-LG gene
with that of the other domestic specie, viz. cow, buffalo and sheep.
Blood samples were collected from 300 animals (100 for each breed)
and genomic DNA was extracted. A fragment of the β-LG gene
(427bp) was amplified using specific primers. Subsequent digestion
with Sac II restriction endonuclease revealed two alleles (A and B)
and three different banding patterns or genotypes i.e. AA, AB and
BB. The statistical analysis showed a general trend that β-LG AA
genotype had higher milk yield than β-LG AB and β-LG BB
genotypes. Nucleotide sequencing of the selected β-LG fragments
was done and submitted to GenBank NCBI (Accession No.
KJ544248, KJ588275, KJ588276, KJ783455, KJ783456 and
KJ874959). Phylogenetic analysis on the basis of nucleotide
sequences of native Saudi goats indicated evolutional similarity with
the GenBank reference sequences of goat, Bubalus bubalis and Bos
taurus. However, the origin of sheep which is the most closely
related from the evolutionary point of view, was located some
distance away.
Abstract: The main goal of this paper was evaluate the effect of
diets containing different levels of probiotic on performance and milk
composition of lactating cows.
Eight Holstein cows were distributed in two 4x4 Latin square. The
diets were based on corn silage, concentrate and the treatment (0, 3, 6
or 9 grams of probiotic/animal/day). It was evaluated the dry matter
intake of nutrients, milk yield and composition.
The use of probiotics did not affect the nutrient intake (p>0.05)
neither the daily milk production or corrected to 4% fat (p>0.05).
However, it was observed that there was a significant fall in milk
composition with higher levels of probiotics supplementation.
These results emphasize the need of further studies with different
experimental designs or improve the number of Latin square with
longer periods of adaptation.
Abstract: The influence of copper and zinc supplements on milk
production performances and health indicators was tested in a 20-
week feeding trial, with 40 Holstein-Friesian lactating cows, devided
in four groups (copper, zinc, copper-zinc and control). Correlations of
the Cu and Zn plasma values with some animal performance criteria
of health (body condition score and somatic cell counts) and
production (milk yield, peak milk yield, fat and crude protein
content) were done. During the 140 days of the experiment, the two
added minerals caused a statistically significant increase (p < 0.05) of
their plasma values after the peak of the cows’ lactations. It was also
observed that subjects that have received copper and zinc
supplements had the lowest number of somatic cell counts in milk.
The Pearson correlation test showed a positive corellation (p = 0.007,
r = + 0.851) between the plasma Zn and the milk production. The
improvement of the nutritional status improved the milk production
performances of the cows as well as their health performances.
Abstract: The objective of this study was to investigate the effects of dietary supplementation with raw or heat-treated sunflower oil seed with two levels of 7.5% or 15% on unsaturated fatty acids in milk fat and performances of high-yielding lactating cows. Twenty early lactating Holstein cows were used in a complete randomized design. Treatments included: 1) CON, control (without sunflower oil seed). 2) LS-UT, 7.5% raw sunflower oil seed. 3) LS-HT, 7.5% heat-treated sunflower oil seed. 4) HS-UT, 15% raw sunflower oil seed. 5) HS-HT, 15% heat-treated sunflower oil seed. Experimental period lasted for 4 wk, with first 2 wk used for adaptation to the diets. Supplementation with 7.5% raw sunflower seed (LS-UT) tended to decrease milk yield, with 28.37 kg/d compared with the control (34.75 kg/d). Milk fat percentage was increased with the HS-UT treatment that obtained 3.71% compared with CON that was 3.39% and without significant different. Milk protein percent was decreased high level sunflower oil seed treatments (15%) with 3.18% whereas CON treatment is caused 3.40% protein. The cows fed added low sunflower heat-treated (LS-HT) produced milk with the highest content of total unsaturated fatty acid with 32.59 g/100g of milk fat compared with the HS-UT with 23.59 g/100g of milk fat. Content of C18 unsaturated fatty acids in milk fat increased from 21.68 g/100g of fat in the HS-UT to 22.50, 23.98, 27.39 and 30.30 g/100g of fat from the cow fed HS-HT, CON, LS-UT and LS-HT treatments, respectively. C18:2 isomers of fatty acid in milk were greater by LSHT supplementation with significant effect (P < 0.05). Total of C18 unsaturated fatty acids content was significantly higher in milk of animal fed added low heat-treated sunflower (7.5%) than those fed with high sunflower. In all, results of this study showed that diet cow's supplementation with sunflower oil seed tended to reduce milk production of lactating cows but can improve C18 UFA (Unsaturated Fatty Acid) content in milk fat. 7.5% level of sunflower oil seed that heated seemed to be the optimal source to increase UFA production.
Abstract: Twenty - nine Holstein cows were used to evaluate the effects of different dry period (DP) lengths on milk yield and composition, some blood metabolites, and complete blood count (CBC). Cows were assigned to one of 2 treatments: 1) 60-d dry period, 2) 35-d DP. Milk yield, from calving to 60 days, was not different for cows on the treatments (p =0.130). Cows in the 35-d DP produced more milk protein and SNF compare with cows in treatment 1 (p ≤ 0.05). Serum glucose, non-esterified fatty acids (NEFA), beta hydroxyl butyrate acid (BHBA), blood urea nitrogen (BUN), urea, and glutamic oxaloacetic transaminase (GOT) were all similar among the treatments. Body condition score (BCS), body weight (BW), complete blood count (CBC) and health problems were similar between the treatments. The results of this study demonstrated we can reduce the dry period length to 35 days with no problems.
Abstract: Ten lactating multiparous Holstein cows were used in
a cross-over design with two dietary treatments and 28-d periods
(with 14 d as an adaptation) to study the effect of restaurant fat on
milk production and composition. Each cow was offered 14.7 kg
DM /d of the basal concentrate diet based on barley and corn (crude
protein = 17.7%, neutral detergent fiber = 23.5%, and acid detergent
fiber = 5.8% of dry matter) with free access to alfalfa. Dietary
treatments were arranged as supplying each cow with 0 (CONTROL)
or 150 g/day (RF) of restaurant fat. Supplemental RF did not
significantly (P > 0.25) affect milk yield, composition, and
composition yields, except for milk fat contents. Milk fat contents
were depressed (P < 0.05) with supplemental RF. Our results indicate
that RF could depress milk fat without affecting milk yield and that
the depression in milk fat in response to RF precedes the depression
in milk yield.
Abstract: The experiment was then conducted to investigate the
effect of cassava peel addition in the concentrate on the performance
of lactating dairy cows. Twenty four Holstein Friesian crossbred
(>87.5% Holstein Friesian) lactating dairy cows in mid lactation;
averaging 12.2+2.1 kg of milk, 119+45 days in milk, 44.1+6.2
months old and 449+33 kg live weight, were stratified for milk yield,
days in milk, age, stage of lactation and body weight, and then
randomly allocated to three treatment groups. The first, second and
third groups were fed concentrates containing the respective cassava
peel, 0, 20 and 40%. All cows were fed ad libitum corn silage and
freely access to clean water. Dry matter intake, 4%FCM, milk
composition and body weight change were affected (P
Abstract: Twelve lactating Etawah Crossedbred goats were used
in this study. Goat feed consisted of Cally andra callothyrsus,
Pennisetum purpureum, wheat bran and dried fermented cassava
peel. The cassava peels were fermented with a traditional culture
called “ragi tape" (mixed culture of Saccharomyces cerevisae,
Aspergillus sp, Candida, Hasnula and Acetobacter). The goats were
divided into 2 groups (Control and Treated) of six does. The
experimental diet of the Control group consisted of 70% of roughage
(fresh Callyandra callothyrsus and Pennisetum purpureum 60:40)
and 30% of wheat bran on dry matter (DM) base. In the Treated
group 30% of wheat bran was replaced with dried fermented cassava
peels. Data were statistically analyzed using analysis of variance
followed SPSS program. The concentration of HCN in fermented
cassava peel decreased to non toxic level. Nutrient composition of
dried fermented cassava peel consisted of 85.75% dry matter;
5.80% crude protein and 82.51% total digestible nutrien (TDN).
Substitution of 30% of wheat bran with dried fermented cassava peel
in the diet had no effect on dry matter and organic matter intake but
significantly (P< 0.05) decreased crude protein and TDN
consumption as well as milk yields and milk composition. The study
recommended to reduced the level of substitution to less than 30% of
concentrates in the diet in order to avoid low nutrient intake and milk
production of goats.
Abstract: Data on 657 lactation from 163 Maltese goat,
collected over a 5-year period were analyzed by a mixed model to
estimate the variance components for heritability. The considered
lactation traits were: milk yield (MY) and lactation length (LL). Year,
parity and type of birth (single or twin) were significant sources of
variation for lactation length; on the other hand milk yield was
significantly influenced only by the year. The average MY was
352.34 kg and the average LL was 230 days. Estimates of heritability
were 0.21 and 0.15 for MY and LL respectively. These values
suggest there is low correlation between genotype and phenotype so
it may be difficult to evaluate animals directly on phenotype. So, the
genetic improvement of this breed may be quite slow without the
support of progeny test aimed to select Maltese breeders.
Abstract: The objective was to determine the single gene and
interaction effect of composite genotype of beta-kappa casein and
DGAT1 gene on milk yield (MY) and milk composition, content of
milk fat (%FAT), milk protein (%PRO), solid not fat (%SNF), and
total solid (%TS) in crossbred Holstein cows. Two hundred and
thirty- one cows were genotyped with PCR-RFLP for DGAT1 and
composite genotype data of beta-kappa casein from previous work
were used. Two model, (1), and (2), was used to estimate single gene
effect, and interaction effect on the traits, respectively. The
significance of interaction effects on all traits were detected. Most
traits have consistent pattern of significant when model (1), and (2)
were compared, except the effect of composite genotype of betakappa
casein on %FAT, and the effect of DGAT1 on MY, which the
significant difference was detected in only model (1).The results
suggested that when the optimum of all traits was necessary,
interaction effect should be concerned.
Abstract: A study was conducted to determine the effect of
feeding glycerol on dairy cows performance. Twenty four Holstein
Friesian crossbred (>87.5% Holstein Friesian) lactating dairy cows in
early lactation; averaging 13+2.4 kg of milk, 64+45 days in milk,
55+16 months old and 325+26 kg live weight, were stratified for
milk yield, days in milk, age, stage of lactation and body weight, and
then randomly allocated to three treatment groups. All cows were fed
approximate 8 kg of concentrate together with ad libitum corn silage
and freely access to clean water. Nil or 150 and 300g of glycerol
were supplemented to the cows according to treatment groups. All
cows consumed similar concentrate, corn silage and total DM and
NELP. There were no significant differences in DM intake, CP intake,
NELP intake, milk and milk composition yields. All cows had similar
fat, protein, lactose, solid not fat and total solid percentage. All cows
gain similar live weight. The present study indicated that,
supplementation of glycerol did not enhance milk yield, milk
composition and live weight change.
Abstract: The paper makes part from a complex research project
on Romanian Grey Steppe, a unique breed in terms of biological and
cultural-historical importance, on the verge of extinction and which
has been included in a preservation programme of genetic resources
from Romania. The study of genetic polymorphism of protean
fractions, especially kappa-casein, and the genotype relations of
these lactoproteins with some quantitative and qualitative features of
milk yield represents a current theme and a novelty for this breed. In
the estimation of the genetic parameters we used R.E.M.L.
(Restricted Maximum Likelihood) method.
The main lactoprotein from milk, kappa - casein (K-cz),
characterized in the specialized literature as a feature having a high
degree of hereditary transmission, behaves as such in the nucleus under
study, a value also confirmed by the heritability coefficient (h2 = 0.57
%). We must mention the medium values for milk and fat quantity
(h2=0.26, 0.29 %) and the fat and protein percentage from milk
having a high hereditary influence h2 = 0.71 - 0.63 %.
Correlations between kappa-casein and the milk quantity are
negative and strong. Between kappa-casein and other qualitative
features of milk (fat content 0.58-0.67 % and protein content 0.77-
0.87%), there are positive and very strong correlations. At the same
time, between kappa-casein and β casein (β-cz), β lactoglobulin (β-
lg) respectively, correlations are positive having high values (0.37 –
0.45 %), indicating the same causes and determining factors for the
two groups of features.