Adaptations in Body Muscle and Fat in Transition Dairy Cattle Fed Differing Amounts of Protein and Methionine Hydroxy Analog

Abstract

The objectives were to determine effects of prepartum protein intake and dietary amino acid balance on production, adaptations in body fat and protein, amino acid concentrations, and, indirectly, body protein breakdown in early lactation. Multiparous Holstein cows (n = 42) were fed diets containing 11 or 14% crude protein with or without 20 g/d of methionine hydroxy analog for 21 d prepartum and then fed a common diet of 17% crude protein for 120 d postpartum, with or without 50 g/d of methionine hydroxy analog. Dry matter intake postpartum averaged 25.4 kg and milk production 41.6 kg. Cows fed the 14% CP diet ate 0.7 kg more dry matter and gave 1.7 kg more milk than those fed the 11% diet postpartum, but this difference was not significant. Cows fed methionine hydroxy analog prepartum lost less body protein from -14 to 60 d in milk. From d 60 to 120, body fat increased 8.5 and 11.5 kg for low and high protein groups and body protein increased 0.5 and 1.0 kg. Serum concentrations of branched chain amino acids fell 17% in the first few weeks postpartum, lysine fell 15%, histidine fell 16%, methionine increased 20%, and cysteine increased 30%. The ratio of serum 3-methylhistidine to creatinine was determined to indicate muscle protein degradation. An increase in this ratio at 7 d postpartum indicated increased body protein breakdown, there was no effect of prepartum ration. Increased protein intake prepartum may allow more feed intake and milk production postpartum, and supplementing a methionine analog on a ration already balanced in methionine by contemporary models may spare body protein.

Heritabilities and Genetic Correlations of Body Condition Score and Muscularity with Productive Traits and their Trend Functions in Italian Simmental Cattle

“…Therefore, in addition to the negative energy balance, cows are in a negative nitrogen balance in early lactation (Plaizer et al, 2000). Phillips et al (2003) have suggested that the breakdown of muscle protein to provide amino acids for production of milk protein is a mechanism of the normal metabolic adaptation to the high nutrient demand typical of the early lactation. Moreover there can be a redistribution of protein away from carcass toward tissues that support lactation, i.e., gastro intestinal tract and mammary gland (Andrew et al, 1994).…”

Periparturient Dönem Sütçü Sığırlarda Metionin ve Lizinin Metabolik Profil Üzerine Etkileri

“…TG is used for making milk fat by mammary gland during lactation period 4 ; therefore, TG serum concentration is lower in lactation than dry period 23 . On the other hand, At their recent study, Phillips et al 25 demonstrate that inclusion of methionine into diets of cows drops off their serum TG at postpartum 1 st week. By contrast, the studies using methionine during early lactation period report no change in serum TG levels 26,27 .…”

“…Likewise, methionine supplementation during periparturient period in cows is reported not to affect normal concentration of NEFA 25 . In the present study, we observed statistically significant changes in serum NEFA concentrations according to all sampling days in all groups (Table 4).…”

“…It reports that while methionine supplementation during prepartum period does not alter NEFA concentration 25 , its inclusion to diets during postpartum period either reduces NEFA level 21 , or does not affect its level 9 . Likewise, methionine supplementation during periparturient period in cows is reported not to affect normal concentration of NEFA 25 .…”

“…Acute increase in NEFA levels during calving is reported to be associated with the initiation of TG infiltration 25,33 . A positive correlation between negative energy balance and NEFA concentration is demonstrated 33 .…”