Factors affecting milk quality and quantity

A presentation made for Livestock Farm Practices Assignment while doing my Bachelor's in Veterinary Science and Animal Husbandry

1. Factors affecting milk quality and quantity Prem Agarwal 2019-V-66 Prem Agarwal 2019-V-66

2. Introduction Milk Production 187.75 Million tonnes in 2019 ( 6.5% more than last year) Variation in Composition and Yield of Milk is a regular phenomenon in any milking animals. Prem Agarwal 2019-V-66

3. Factors Affecting Milk Quantity & Quality Species Breed Age Stage of lactation Estrus Dry period Pregnancy Seasonal differenc e Maintanance conditions Nutritional Factors Feed and water supply Milking intervals Milking frequency Diseases Feed Disease Geographical location Stress Microbiological count Other management factors… Prem Agarwal 2019-V-66

4. Species Prem Agarwal 2019-V-66

5. Breed Highest Producing Indigenous Cow Highest Producing Buffalo Breed Cow Breed with Highest Fat % Cow Breed with Lowest Fat % Prem Agarwal 2019-V-66 The concentrations (%) of the three major milk constituents are genetically controlled to a considerable extent. Heritiabilities of fat, protein, and lactose contents average 0.58,0.49, and 0.5 , respectively, while that of milk yield average 0.27 . Gir (Longest lactation), Sahiwal (Best Milch Breed) Murrah (2200 L/lactation) Jersey (7%), Sahiwal (5%) Holstein Friesian (3.2%)

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8. Age & Lactation Number (Parity) The amount of milk increases with age due to two reasons An increase in body weight, which results in a larger digestive system and a larger mammary gland for the secretion of milk. Recurring pregnancies and lactation can result in increases of 30 % in milk production. Milk production increases with lactation number and is maximized in the fourth or the fifth lactation . Prem Agarwal 2019-V-66

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10. Pregnancy Pregnancy has an inhibitory effect on milk yield. The inhibitory effect of pregnancy is not likely due to fetal requirement. It is believed that the increase in estrogen and progesterone levels as pregnancy progresses, inhibits milk secretion. Prem Agarwal 2019-V-66

11. Stage of Lactation Prem Agarwal 2019-V-66

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14. Dry Period Dairy cows are dried-off for 2 months prior to the next calving. Rest period is necessary to maximize milk production in subsequent lactation. Milk yield is usually reduced when the dry period is less than 40-60 days ( 25-40% less milk ). Dry period longer than 60 days in length does not result in any significant increase in milk production Long dry periods decrease the average annual production of the cow by extending the calving interval beyond the normal 13-14 month interval Also causing a decrease in the lifetime production of the dairy cattle. Part of the dry period effect is related to body condition of the cow at calving. Cows in good body condition at calving produce higher milk yield during the following lactation than in cows in thin body condition at calving. Prem Agarwal 2019-V-66

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17. Seasonal Differences Calving at Winter, Spring or Autumn is preferable not in Summer as it decreases milk production. Calving schedule should be adjusted keeping this in mind Prem Agarwal 2019-V-66

18. In general, milk fat and solid-not-fat percentages are highest in winter and lowest in summer. Milk fat and protein percentages are lower by 0.2-0.4% in summer than winter. Prem Agarwal 2019-V-66

19. Temperature & H umidity No effect on milk production in Comfort Zone . Milk production declines when environmental temperature exceeds 27 °C . The reduction in milk yield is largely due to drop in feed intake . High temperature affect high producing cows more than low producers and it is particularly harmful during the peak of lactation.

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21. Stress Prem Agarwal 2019-V-66 Signs of Stress in Cattle Respiratory Issues - Sickness Standing While Other Cows Are Lying Down Frequent Urination Rapid Heart Rate – Adrenaline induced stress Trembling – Fear or Weather Stress Seeking out Shade – Heat Stress Open- Mouthed Breathing- Heat Stress Slobbering - Hypersalivation Lack of Coordination – Heat Stress Restlessness Splashing Water – Heat Stress Huddling Together – Cold Stress

22. Prem Agarwal 2019-V-66 STRESS LH GH Cortisol Oxytocin CA Prolactin Reproductive Problems Reduced Growth Immuno - supression Milk ejection Problems Lactation Problems Calving Problems CA

23. Feed and Water Supply Inadequate feed nutrients probably limit the secretion of milk Galactopoisis is closely related to an adequate feed intake by the lactating animal. The most dramatic effect is brought about by shortage of water as the cow has no means of storing water. Withholding access to water, or insufficient supply of water for few hours will result in a rapid drop in milk yield.. Prem Agarwal 2019-V-66

24. Effect of Nutrition on Composition Out of all milk components, milk fat is the most influenced by dietary manipulations. Most of changes in milk composition due to dietary manipulation are related to changes in ruminal acetate : propionate ratio . Several nutritional factors can influence milk composition. These include Plane of nutrition - Underfeeding ↓ Lactose % & ↑ Fat %, Energy : Protein Ratio should be maintained Forage : Concentrate ratio - ↑Conc. → ↓Fat % Forage quality (e.g. particle size) Level and type of dietary fat – PUFA → ↓Fat % ( Biohydrogenation in Rumen) Veg Oil → ↑Fat % Prem Agarwal 2019-V-66

25. Milking Interval Cows are usually milked at equal intervals ( 12-h interval for 2 x milking ). Cows milked at unequal intervals produce less milk than those milked at equal intervals. The reduction in milk yield is more in high producing cows than in low producing ones. The pressure measured in the teat cistern increases in three phases. An initial rapid increase in the pressure- residual milk The second- newly synthesized milk The third phase is marked by an accelerated pressure increase and probably represent overfilling of alveoli, ducts and gland cisterns. Prem Agarwal 2019-V-66

26. Prem Agarwal 2019-V-66 Milking time for most cows is 5-6 minutes per cow. Milking should be done rapidly and completely – by Full hand method then Stripping Incomplete milking permanently reduce milk yield for the entire lactation. Residual milk decreases milk secretion due to feedback inhibition and physical disruption.

27. Change in Milk Composition during Milking Milk fat % increases continuously during the milking process. First drawn milk may contain only 1-2% fat, whereas, at the end of milking, fat % may be 5-10%. This is because of the tendency of the fat globules to cluster and be trapped in the alveoli. Thus after incomplete milking, milk fat content will be lower than normal. Residual milk (milk remains in the udder after milking) may contain up to 20% fat. Prem Agarwal 2019-V-66

28. Milking Frequency Cows are usually milked twice daily. Milking a twice a day yields at least 40% more milk than once a day. The increase is usually highest for first lactation cow and declines as the cow gets older. Reasons for increased milk production as frequency of milking increases are 1) Less intramammary pressure generated with frequent milking, 2) Increased stimulation of hormone activity favorable of milk production 3) Less negative feedback on the secretory cells due to the accumulation of milk components. Increasing milking frequency to 3 x day increases milk yield byup to 20% (range 5-20%). There are several problems associated with 3 x per day milking. May increase the incidence of mastitis Existing problems will be aggravated in poorly managed herds More management cost Prem Agarwal 2019-V-66

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30. Disease The main disease that affect milk yield of dairy cows is mastitis . It impairs the ability of secretory tissue synthesize milk components and destroys the secretory tissues and consequently lowering milk yield. A decrease in production persists after the disappearance of the clinical signs of mastitis due to a destruction in the secretory tissues . In severe mastitis, the casein content may be below the normal limit of 78% of total protein and the chloride content may rise above the normal maximum level of 0.12%. FMD, Tuberculosis, Brucellosis, Blue Tongue, and Vesicular Stomatitis  Prem Agarwal 2019-V-66

31. Factors Affecting Microbiological quality of Milk Endogenous sources , (the cow itself) Exogenous sources , such as environment (soil, water, manure or human contact) collection and processing equipment human milk handlers on the farm and in the factory. Prem Agarwal 2019-V-66

32. Somatic Cell Count Prem Agarwal 2019-V-66 One of the quality parameter of raw milk. High somatic cell counts (SCC) present in milk are the main indicators of mammary gland infection , caused by specific and non specific micro-organisms. An elevated SCC in milk has a negative influence on the quality of raw milk, low production and shelf life . Undesirable organoleptic characteristics and poor yogurt fermentation is also seen.

33. Conclusion – The Way Forward Prem Agarwal 2019-V-66