Effects of liquid organic mineral complex (MultiMix®) on milk yield, composition and cheesemaking capacity of milk in dairy cows

T. Angelova1*, K. Nedelkov2, D. Yordanova1, V. Karabashev1, J. Krastanov1

1Agricultural Institute, 6000 Stara Zagora, Bulgaria
2Department of Nutrition, dietetics and veterinary expertise of feed, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 26 October 2020; accepted for publication 22 April 2021)

Abstract. The objective of this experiment was to investigate the effects of liquid organic mineral complex (MultiMix®) on the milk yield, composition and cheesemaking capacity of milk in dairy cows. Thirty Holstein cows (8 primiparous and 22 multiparous) were used in a randomized complete block design experiment with 15 cows per treatment. Feeding was ad libitum targeting 5% refusals. Milk yield data and samples for fat, true protein, solids not fat (SNF), lactose content and parameters characterizing the milk’s coagulation properties were collected throughout the experiment. Data suggested that MultiMix® administered through the cows’ drinking water had a positive effect on the milk productivity with a high degree of significance (p<0.001). A positive effect on the indicators characterizing the quality composition of milk has also been observed (p<0.001). Additionally, the cheesemaking capacity of milk was enhanced by supplementing animal water with MultiMix® (p<0.001). Overall, the new liquid organic mineral complex used in the present experiment showed promising results for improvement of milk production and composition in dairy cows but further studies are needed to unveil the physiologic mechanisms underlying these beneficial effects.

Classification and regression tree analysis in modeling the milk yield and conformation traits for Holstein cows in Bulgaria

A.Yordanova1*, S. Gocheva-Ilieva1, H. Kulina1, L. Yordanova2, I. Marinov3

1Department of Applied Mathematics and Modeling, Faculty of Mathematics and Informatics, Plovdiv University Paisii Hilendarski, 24 Tzar Asen, 4000 Plovdiv, Bulgaria
2Department of Mathematics and Informatics, Faculty of Economics, Trakia University, 6000 Stara Zagora, Bulgaria
3Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, Тrakia University, 6000 Stara Zagora, Bulgaria

Abstract. In the field of livestock breeding the investigation of the factors that influence to the highest degree the efficiency (e.g. milk yield) is essential for determining the conditions for the improvement of the overall production results. To extract relevant information from the data the appropriate mathematical methods are very useful. The aim of this work is to demonstrate the capabilities of the method of Classification and regression trees (CART) for statistical data processing including data of ordinal and nominal type. For a sample of 97 observations of cattle from 4 farms in Bulgaria, two decision trees are built for studying dependence of the 305 days milk yield for Holshte in cows with respect to 13 independent variables – 12 conformation traits and farm. The model with 12 independent variables for conformation traits describes 48% of the data and identifies the main factors for quantities of milk – udder width, locomotion, stature and chest width with normalized importance 100%, 48.1%, 41.2% and 39%, respectively. The second model includes the farm where the cattle are reared as 13th independent variable and this expanded model accounts for 70% of the data. Following the obtained rules for both models, predictions for new data could be made before end of lactations.

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Effect of body condition score at calving on body condition during lactation in Holstein and Brown Swiss cows

Zh. Gergovska, T. Angelova, D. Yordanova, Zh. Krastanov, Ch. Miteva
Abstract. The study comprises 37 cows of which 20 Holstein and 17 Brown Swiss cows. The rearing technology in both breeds is free rearing in individual cubicles for rest. Milking is two times in milking parlour. Cows are divided in three technological groups depending on the physiological state, respectively: dry cows, І-st – up to 120-150 th day and ІІ-d lactation period. Feeding is on the basis of whole ration mixture including maize silage, alfalfa haylage, concentrated fodder and vitamin and mineral additives. The body condition of cows has been recorded on a monthly basis by using a 5-score evaluation system, from 0 to 5 points, recorded with accuracy up to 0.5 points. In Brown cows average BCS at calving is 3 points, average BCS during lactation is 1.64 points. In Holstein cows average BCS at calving is 2.8 points and average BCS during lactation is 1.38 points. Heifers from both breeds have a bit lower BCS at calving (3.0 points) than older cows, but they have less loss of body condition during lactation – 1.66 points. With cows at ≥ ІІ-d lactation loss is more intensive as early as the first lactation month and till the lowest BCS they lose a total of 2.04 points. Holstein cows lose at the beginning of lactation more points (an average of 2.14) and reach lower BCS (1.05) compared to Brown Swiss ones in which these values are 1.85 an 1.20 points. BCS drops to the lowest value during lactation in cows from both breeds with poor body condition at calving (2 and 2.5 points). The smoothest are the changes in the body condition of cows that had reached BCS at calving 3.5 and 4 points.

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